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2048 · laguna-s-2.1
Build a playable 2048 game with arrow-key tile sliding and merging, smooth animations, a score, and win and lose states.
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user
Build a playable 2048 game with arrow-key tile sliding and merging, smooth animations, a score, and win and lose states.
assistant
assistant
thinking
The user wants me to build a playable 2048 game. Let me create a single self-contained index.html file with all the CSS and JS inline.
Let me think about the 2048 game:
- 4x4 grid
- Tiles with values 2 or 4 appear
- Arrow keys to slide tiles
- Tiles merge when same value collide
- Win state when 2048 tile is created
- Lose state when no moves left
- Score tracking
Let me write the HTML file with everything inline.
The game logic:
1. Grid is a 4x4 array
2. On arrow key press, slide all tiles in that direction
3. When tiles of same value collide, they merge
4. After each move, add a random tile (2 or 4)
5. Check win condition (2048 tile exists)
6. Check lose condition (no empty cells and no possible merges)
Let me think about the slide logic. For each direction, I need to:
- Process rows (for left/right) or columns (for up/down)
- Compact tiles to one side
- Merge adjacent same-value tiles
- Compact again
For smooth animations, I'll use CSS transitions on the tile positions. I'll track the position of each tile and animate changes.
Actually, let me think about how to do smooth animations. The common approach is:
- Use absolute positioning for tiles
- Track each tile's row/col
- When the grid state changes, update positions with CSS transitions
Let me think about this more carefully. I'll use a grid approach where each cell is a container, and tiles are positioned absolutely within the grid based on their grid coordinates.
Actually, the simplest approach for smooth animations is to use CSS grid for the board and grid-area for tile positioning, with transitions.
Let me design this:
Board: 4x4 CSS grid with background showing cells
Tiles: positioned using grid-column and grid-row
When the board state updates, I update each tile's grid-column/grid-row with a transition.
For merging, I need to handle the animation where two tiles become one. This is more complex. Let me think...
Actually for a good implementation, I'll track tiles by ID and animate them moving to their new positions. For merges, the merged tile can grow/scale while the old tiles move to the same position.
Let me keep it simpler but still smooth:
- Each tile has an ID
- When board updates, move tiles to new grid positions with transition
- For merges, animate scale
Actually, let me do a cleaner approach. I'll track the grid state and re-render, using CSS transitions for position. For merging, I'll do a brief scale animation.
Let me think about the tile representation. I'll have a grid array. After a move, I compute new grid state. Then I need to map tiles from old positions to new positions for animation.
Let me use a different approach - use absolute positioning with pixel coordinates. This gives me full control over animation.
Board is 4x4. Each cell is 100x100 pixels (let's say).
Actually, let me use transform with CSS variables or just left/top percentages.
Let me go with a grid-based approach using CSS grid and grid-column/grid-row, which handles the layout well, and use a tile-tracking system for animations.
Hmm, let me think about what's simplest and works well.
Approach:
1. Grid state: 4x4 array of values (0 = empty)
2. Render: for each non-empty cell, render a tile element positioned with translate(x, y)
3. Animations: when grid updates, new tile positions are computed and applied via transform transition
For the merge animation, I'll handle it by tracking tile identity across moves. This is complex. Let me do a simpler version where:
- Tiles slide to their new positions (smooth)
- New tiles fade in and scale up
- Merged tiles scale up briefly
To properly animate, I need to know which tiles moved, which merged, and which are new. Let me track this.
Let me write the core game logic first, then figure out animation.
Core move logic (left direction):
```
function slideLeft(grid):
newGrid = array of zeros
for each row:
// collect non-zero values
values = [v for v in row if v != 0]
// merge
merged = []
i = 0
while i < len(values):
if i < len(values)-1 and values[i] == values[i+1]:
merged.append(values[i] * 2)
i += 2
else:
merged.append(values[i])
i += 1
// place back
for j in range(len(merged)):
newGrid[row][j] = merged[j]
return newGrid
```
For other directions:
- Right: reverse row, slide left, reverse back
- Up: transpose, slide left, transpose back
- Down: transpose, reverse, slide left, reverse, transpose back
Let me implement this cleanly.
For animation, let me track tile objects with unique IDs. Each tile has position (row, col), value, and ID. When the grid updates, I reconcile tiles.
Actually, let me do a cleaner animation approach:
I'll keep a list of "animated tiles" each with an id, row, col, value. On each move:
1. Compute the new grid state
2. Track movement of each tile (old position → new position)
3. For merges: the tile that survives gets a "merged" class for animation
4. Apply new positions to existing tiles
5. Add new tiles with fade-in animation
This requires careful ID tracking. Let me do it.
Alternative simpler approach that still looks good: Use a grid where tiles are absolutely positioned. After computing new grid, move all tiles to their grid positions with CSS transition. For new tiles, animate scale/opacity. For merges, the merged tile can animate.
Let me track tiles by their grid position. Here's my plan:
Each tile is a DOM element with data attributes row and col. I position them using transform: translate(col * cellSize, row * cellSize). With transition on transform.
When the grid state changes:
1. For each tile in the new state, find if there's an existing tile at that position with the same value... no, this gets complicated.
Let me just track tiles by ID properly.
```
tiles = {} // id -> {row, col, value}
nextId = 1
```
After a move:
1. Compute next grid state with a merging algorithm that tracks how tiles move/merge
2. Update tiles map: move tiles to new positions, remove merged ones (or reparent), add new tile
Actually, the standard 2048 animation is:
- Tiles slide smoothly to new position
- When two tiles merge, the resulting tile scales up
- A new tile appears with a "pop"
Let me implement a version where I track per-tile animation state.
I think the cleanest implementation for smooth animation:
State: grid 4x4 (values)
Render: For each tile, I render a div positioned by grid coordinates with translate.
Animation strategy:
- I track a list of tile views, each with a unique ID, current visual position (row, col), target position (row, col), value, and a "state" (normal, merging, new)
- On each move, I compute the new grid and figure out the animation states
- I run the animation, then sync
This is getting complex. Let me simplify to a good-enough smooth animation:
1. Use CSS transitions on transform (position) and a merge scale animation
2. Track tiles by ID across moves
3. When computing the new grid, record for each tile: where did it come from, where did it go, did it merge
Let me write the move logic to produce a "transition list":
```
For a left move on a row:
positions = [0,0,0,0] but track
```
Actually, let me write a function that, given the grid and direction, returns the new grid AND a list of tile transitions {from: [r,c], to: [r,c], value: v, merged: bool}.
Hmm, but merges combine two tiles into one. Let me think about the transitions:
For each tile in the new grid:
- If a tile at position (r,c) has value v in new grid
- In old grid, was there a tile at (r,c)? If yes and same value and not merged → it stayed
- If value changed (merged) → it's a merge, animate scale
- If tile moved → animate position
- If new → animate pop in
Let me simplify and just do:
1. Compute new grid
2. For each cell in new grid with a value:
- Check if old cell had same value → position transition or stay
- If value is double of something → merge animation
3. For each cell that became empty → remove tile
Actually, let me track by value matching which is imperfect but let me do proper ID tracking.
I'll do it properly with tile IDs. Let me write the code.
Let me structure the tiles as objects with IDs. The grid stores tile IDs (or 0).
Wait, that complicates the merge logic since I need to detect same values. Let me store values in the grid for logic, but maintain a separate tile view map for rendering/animation.
Let me define:
- `grid`: 4x4 array of values (numbers) for game logic
- After computing new grid, reconcile with current tile views
Reconciliation:
- currentViews: map of position [r,c] -> {id, value}
- For animation, I want to move tiles from old positions to new positions
Let me think about what the actual 2048 does. When you swipe left on a row like [2,2,0,0]:
- Two 2s at positions 0,1
- They merge into a 4
- The 4 ends up at position 0
- Animation: the 2 at position 0 stays (becomes 4), the 2 at position 1 moves to position 0 and they merge/scale
The visual: both 2-tiles move toward position 0, they overlap at position 0, and a 4 appears with scale-up animation.
So really, for merging animation:
- Both source tiles move to the target position
- The merged tile scales up (the surviving one)
Let me implement this with a transition system:
I'll compute transitions for a move:
```
transitions = [] // {tileId, fromRow, fromCol, toRow, toCol, value, isMerge}
```
For each row and direction, I process the compact+merge and record how each source tile moves.
Let me write a `move` function that returns new grid + transitions.
```
function moveLeft(grid):
transitions = []
newGrid = createZeros()
for r in 0..3:
row = grid[r]
// compact non-zero to left with original positions
// values: list of {value, originalCol}
vals = []
for c in 0..3:
if row[c] != 0:
vals.push({value: row[c], col: c})
// merge
result = [] // {value, col} where col is target position
i = 0
while i < vals.length:
if i+1 < vals.length and vals[i].value == vals[i+1].value:
result.push({value: vals[i].value*2, col: result.length, merged: true, sourceCols: [vals[i].col, vals[i+1].col]})
i += 2
else:
result.push({value: vals[i].value, col: result.length, merged: false, sourceCols: [vals[i].col]})
i += 1
// fill new grid and build transitions
for j in 0..3:
if j < result.length:
newGrid[r][j] = result[j].value
// transitions: for each result tile, source tiles move to target col
for res in result:
targetCol = res.col
// the "primary" source is the first source col
// Actually for visualization, I want to animate source tiles to target
```
Hmm, the transition for animation. Let me think about what I render:
I maintain a set of "visual tiles" each with id, row, col, value.
When a move happens:
1. Compute new grid (logical).
2. Map each new-grid cell to visual tiles.
For rendering transitions, I'll do this:
- Each source tile (non-zero cell in old grid) gets animated from its old position to its target position.
- For non-merge moves: source tile → target position (same value)
- For merges: two source tiles → target position, the merged result scales up
This requires assigning IDs. Let me track tile IDs by position.
Let me maintain: `tileId[r][c]` - an ID for the tile currently at that position. And a tiles map: `tiles[id] = {value, ...}`.
On merge, the two tiles combine. I can reuse one ID as the merged tile and discard the other, then apply a scale animation.
Let me think about the algorithm for reconciliation:
Old state: grid_old (values), tiles_old (id per position, tile data)
New state: grid_new (values), no tiles yet
For each cell (r,c) in new grid that has a value v:
Find candidate source tiles that have value v... no, merges double.
This is getting complicated because I can't just match by value. Let me do the forward approach: process each source tile and determine its transition.
Let me restructure. I'll write the move function to directly produce the transition info, processing the grid.
For a left move, for each row r:
Collect cells with values and their positions: [{v: grid[r][c], c: c} for non-zero]
Process compact+merge producing: [{v: mergedValue, targetC: j, sources: [c0, c1], merged: bool}]
For animation:
- For a non-merged result tile with sources=[c0]: tile at (r,c0) moves to (r, targetC)
- For a merged result tile with sources=[c0,c1]:
- tile at (r,c1) moves to (r,targetC)
- tile at (r,c0) is the "primary" - moves to (r,targetC) and scales up (value becomes merged)
- Actually both move to targetC; the primary tile's value updates and it scales
This is doable. Let me track tile IDs. Each tile has an ID. When cells are processed:
- I have tileId[r][c] for old positions
- For each result tile:
- If merged: pick primary source (first source), that tile's ID survives, value updates. The secondary source tile (second source) moves to target then disappears (its DOM element moves to target and we mark it for removal/scale-down).
- If not merged: the single source tile's ID survives, moves to target.
Let me simplify the animation to:
1. Move all source tiles to their target positions (transitions).
2. For merges: scale the primary tile up, fade out the secondary tile.
3. For new tiles: create with pop-in (scale + fade).
4. Remove tiles that have no target.
For implementation, I'll:
- Keep a `tiles` array of visual tile objects: {id, row, col, value, el}
- On move, compute targets per tile based on old grid values + new grid
- Actually let me just compute the full transition and apply
Let me write code where I track tile IDs in the grid itself (grid holds {value, id}). That makes reconciliation natural!
Grid cells hold: {value: 0} for empty, or {value: n, id: id} for a tile.
Move left on a row:
cells = row's cells (with value, id), filtering non-zero
Actually, let me process and produce new cells.
Let me write it so grid[r][c] = {value, id} or null.
Hmm, but matching values for merge still needs comparing values. IDs are just for tracking visuals. Let me do:
```
// grid is 4x4 of {value, id} or null
function move(direction):
// build a new grid structure with transitions
...
```
Let me just write the whole thing. I'll process it so that I track which old tiles (by id) move where.
Let me write the move function that returns the new grid (with values+ids) and a list of animation actions.
OK here's my plan. Let me track tiles by id in the grid: grid[r][c] = {v, id} or empty.
Move function for left, returns newGrid (array of arrays with {v,id}) and transitions array:
transitions: {id, fromR, fromC, toR, toC, newValue, merged (bool)}
```
function slideRowLeft(cells): // cells = 4 elements, {v,id} or null
// extract non-null
vals = cells.filter not null -> [{v,id}]
result = [] // {v,id, merged}
i = 0
while i < vals.length:
if i+1 < vals.length and vals[i].v == vals[i+1].v:
result.push({v: vals[i].v*2, id: vals[i].id, merged: true, mergedPartnerId: vals[i+1].id})
i += 2
else:
result.push({v: vals[i].v, id: vals[i].id, merged: false})
i += 1
return result
```
Then new cells placed left to right. For transitions:
- For each result tile, it moves from source position to target position.
- For merged ones, the partner tile also needs to animate (move to target and disappear).
For the partner tile animation (vals[i+1] moves to target and vanishes), I need its id and old position.
Let me build transitions fully. For each row r (left move):
vals = [positions of non-null cells with id and old col]
processed = slideRowLeft with positions
Let me write:
```
function moveLeft(grid):
newGrid = empty
transitions = []
for r in 0..3:
row = grid[r].slice()
// index of non-null
cells = []
for c in 0..3:
if row[c]: cells.push({v: row[c].v, id: row[c].id, c: c})
// process
i = 0
target = 0
while i < cells.length:
if i+1 < cells.length and cells[i].v == cells[i+1].v:
// merge
newGrid[r][target] = {v: cells[i].v*2, id: cells[i].id}
transitions.push({id: cells[i].id, fromC: cells[i].c, toC: target, v: cells[i].v*2, merged: true, fromR: r, toR: r})
transitions.push({id: cells[i+1].id, fromC: cells[i+1].c, toC: target, v: cells[i].v*2, merged: true, fromR: r, toR: r, disappear: true})
target++
i += 2
else:
newGrid[r][target] = {v: cells[i].v, id: cells[i].id}
transitions.push({id: cells[i].id, fromC: cells[i].c, toC: target, v: cells[i].v, merged:false, fromR: r, toR: r})
target++
i++
// cells not in newGrid but were in oldGrid (had a tile) -> they disappear?
// Actually all old tiles should be accounted for in transitions (either merged or moved).
// Empty target cells in newGrid are just empty.
return newGrid, transitions
```
Wait, tiles that were in old grid but whose positions became empty after slide — they're all either moved or merged, accounted for. Good. Tiles that end up with no new grid cell... they're all placed. Good.
For other directions, rotate.
After the move, I:
1. Apply transitions: update each visual tile's position (transform). For merges, scale up. For disappear, fade out and remove.
2. Add new random tile.
Then I need a new tile: pick random empty cell, value 2 (90%) or 4 (10%).
For new tile animation: create element, position at target cell (same as grid position), but with scale(0.5) and opacity 0 start → animate to scale(1), opacity 1. Actually I want it to "pop" — but its grid position is the final one. I can create it already at final position with scale transition.
Now, reconciliation with DOM: I keep a `tileElements` map: id -> DOM element.
On transition apply:
- For each transition, find tileElements[id]. Set its target row/col via transform. Add transitionend or rely on CSS.
- For merged disappear: fade out + scale down, then remove from tileElements.
- For merged primary: it moved to target + new value + scale up. I need to update its value display and color. Add a "merge" scaling animation.
- New tile: create element, add to tileElements.
The timing: I want moves+merge animation to play, then new tile pops. Let me sequence:
1. Set isAnimating = true
2. Apply move transitions (CSS transition duration ~200ms)
3. On transition end, handle merges (secondary tiles vanish) — actually secondary vanish can be simultaneous
4. Then add new tile with pop animation
5. After all done, reset isAnimating, allow next move
Hmm, sequencing with transitionend events is tricky with many elements. Let me use a simpler timing: apply transforms, then use setTimeout to advance after animation duration.
Let me use a flow:
- move(): compute new grid + transitions. Set a flag. Apply CSS transitions to move tiles and do merge animations. New tiles added (popping). Use setTimeout(animationDuration) to finalize: update the logical grid (already done), rebuild tile elements to match, clear old. Actually let me keep DOM in sync with tileElements map.
Let me reconsider. Maybe simpler:
- Maintain grid (with values+ids) and tileElements (id -> el).
- On move, compute new grid + transitions.
- For each transition: if id in tileElements, move el to target (transform).
- For merged primary: update el value/color, add scale-up class.
- For merged partner/disappear: add fade-out class, after transition remove el and delete from tileElements.
- For new tile: place at empty cell, create el with pop-in.
- Wait appropriate durations, then clean up.
I'll structure with async/await and setTimeout to sequence properly.
Let me write the full code now. I'll use CSS transitions with custom duration variables and setTimeout for sequencing.
Let me define durations:
- tile move: 180ms
- merge scale: 180ms
- new tile pop: 120ms
Sequence on move:
1. disable input (isAnimating)
2. compute new grid + transitions
3. apply: move primary tiles (transform), for merges update value + scale
4. after move duration (180ms): remove vanished partner tiles, then add new tile (pop)
- Actually, I can do partner fade simultaneously with the 180ms move
5. after new tile pop (120ms): reset isAnimating
Hmm, but the new tile should appear after the slide. Let me do:
- t=0: apply slide transforms + merge scales + partner fade-outs
- t=180ms: remove partner DOM elements, spawn new tile (pop from 0 to 180... no, pop is quick)
- t=180+120: done
Actually 2048 typically: tiles slide (merge), then new tile pops in. Let me do slide+merge together (180ms), then new tile pop (100ms). Total ~280ms.
Let me write it.
Let me also handle: when no move possible (grid unchanged), don't spawn new tile, don't animate. Detect if transitions is empty / grid unchanged.
Let me also handle win/lose:
- Win: when a tile reaches 2048 (or we could say win at 2048). Show win overlay but allow continuing.
- Lose: no empty cells and no adjacent same values → show lose overlay.
Let me now write the HTML.
I'll use modern JS but keep it compatible. Let me use vanilla JS.
Let me define the board styling: a nice 2048 look with tile colors based on value.
Tile colors (standard 2048):
- 2: #eee4da (light), text dark
- 4: #f78c56
- 8: #f05833
- 16: #f2b179? No. Let me use the classic:
Let me use the well-known 2048 colors:
- 2: #AC8253? No.
Standard 2048 colors (from the game):
2: #AC7D4D? no. Let me recall the actual 2048 colors:
- empty cell bg: #bbada0
- 2: #eee4da
- 4: #f78c56?
The real ones:
- 2: #AC825F? I'll just pick:
- 2: #f78c56 (no)
Let me use the authentic 2048 palette:
- 2: #f0e3dc?
OK let me just use a nice set:
2: #efe0c8 (light beige), 4: #f2b179 (orange), 8: #f08858, 16: #d95f23, 32: #d9533f?
Let me just use the actual 2048 official colors:
- 2: #AC7D4D no.
I'll look them up by memory, the official Gabriele Cirulli 2048:
```
2: #f78c56?
```
Actually the official:
- 2: #AC8253 — no I keep making up.
Let me use these known-correct colors:
- 2: #eee4ce (off white cream)
- 4: #f78c56?
The real 2048 colors are:
- 2 → #AC7D4D?
I'll go with a clean palette I'm confident looks good:
- 2: #f5ebe0 (cream)
- 4: #f2cc96 (light tan) — too similar
Let me use the widely reproduced palette which I'm confident about:
```
2: #f78c56?
```
I really am unsure. Let me just pick a good-looking set with distinct colors:
- 2: #efd19b?
OK, decision: I'll use these (they're the actual 2048 colors, I'm now fairly confident):
```
2: #AC8253 — no.
```
You know what, let me just use a reasonable distinct palette and move on. I'll use:
- 2: #f8f0e3 (very light) — actually let me make tiles visually distinct.
Final palette (confident these are close to real 2048 / look good):
```
2: #eee4da
4: #f78c56
8: #f05833
16: #f2b179
32: #f08858
64: #d95f23
128: #d9533f?
```
Hmm the issue is I want darker text on light, lighter on dark. Let me just hardcode per value with a lookup. Let me use these (a common reproduction):
```
const COLORS = {
2: {bg:'#f78c56'? }
}
```
OK I'll just go with my best known and make text color adaptive (dark for <=4 on light, white for high values). Let me define:
```
2: bg #efe4d6 (light cream), text dark
4: bg #f7d6a5 (tan), text dark
8: bg #f0a279 (orange), text white-ish
16: bg #e67e22?
```
I'll create a lookup with reasonable values. Good enough. Let me just write it.
Actually, let me use the actual colors which I'll now commit to (these are the real 2048 colors):
```
2: #AC8253 no...
```
I'll stop second-guessing. Here's my palette:
```
2: '#f7c5a0'?
```
Decision made, using this palette (distinct and good-looking, text white for >=8):
- 2: #efe4cd
- 4: #f7d1a3 -- wait these are too close.
Let me make them clearly different by using the value-based gradient. For a clean look, use these (I'm confident enough):
- 2: #f7f1e3
- 4: #f2d2a0
- 8: #f0b88a
- 16: #e89a66
- 32: #e8744e
- 64: #d9573a
- 128: #c4454e
- 256: #b43a3a
- 512: #9c3149
- 1024: #8c3149
- 2048+: #7a283a
Text dark (black) for 2,4,8; white for 16+. Actually let me make 2,4 light with dark text; 8+ dark-ish with white text. I'll decide threshold at 8: values >= 8 get white text. Let me make text color a function: white for v>=8. Hmm but 8 bg is light. Let me set threshold at 16: white for v>=16.
OK enough. Let me code.
Let me now write the full file.
I'll structure:
- HTML: board, score, title, overlays
- CSS: layout, board, tiles, animations
- JS: game logic, rendering, input, win/lose
Let me write it all.
For tile positioning, I'll use absolute positioning within the board container. Each cell is CELL_SIZE px. Board is 4 cells. With gap.
Let me use: cell size 100px, gap 12px, board padding. Board width = 4*100 + 5*12 = 460px. Container maybe 500px. Let me scale down for mobile with vw units. Let me use cell size calc.
I'll use CSS: board is grid 4x4 with gap. Tiles absolutely positioned using translate with percentages or px based on grid.
Let me use a simpler calc: board is `display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px`. Tile size = (boardWidth - 3*12)/4. Hmm, computing px in JS is easier.
Let me do: board width = 480px. gap = 15px. cell size = (480 - 3*15)/4 = (480-45)/4 = 435/4 = 108.75px. Eh round. Let me just use a fixed cell size 100 with board width 445 (100*4 + 15*3 = 445).
For responsiveness, I'll use a scale container based on min(available, 445). Let me set board to 100% of a max 445px container and use JS to compute cell size from board clientWidth.
In JS: board is 4x4, cellSize = board.clientWidth / 4 + gap... Let me use CSS grid with no gaps and use cell size. Actually with gap, computing position: tile at (r,c) → left = c*(cellSize+gap), top = r*(cellSize+gap).
Let me set gap=15, and compute cellSize = boardWidth/(4) - ... this is annoying. Let me make board use CSS grid with `grid-template-columns: repeat(4, 1fr)` and gap, and position tiles using CSS grid-row/grid-column. That auto-handles it!
So tiles are positioned with `grid-column: c+1; grid-row: r+1`. And board is `display: grid; grid-template-columns: repeat(4, 1fr); gap: 15px`. Tiles are `position: absolute`? No—if board is grid and tiles are children, they can be grid items. But I want tiles to slide over the background cells.
Better: board is grid showing background cells. Tiles are a separate absolutely-positioned layer within a relative board container. Board container: `position: relative; display: grid`. Background cells as grid items. Tiles as absolutely positioned using translate.
To compute translate in JS: I need cell size. With CSS grid and gap, I can compute cell size = (boardWidth - gap*3)/4. Or I can read it. Let me set board to a fixed aspect and compute.
Simplest reliable: make board a grid with explicit cell sizing using a known pixel cell. Let me use cell size 110px, gap 15px. Board width = 4*110+3*15 = 440+45 = 485px. Tile at (r,c): left = c*(110+15), top = r*(110+15).
For mobile, I'll wrap in a scaled container using transform scale based on window size, or use CSS `width` with percentage and JS recompute. Let me keep it fixed-width centered and add a viewport scale. Actually for mobile, fixed 485px might be too wide. Let me make board width = 90vmin and compute cell size dynamically in JS from board.clientWidth.
I'll use: board is `display:grid; grid-template-columns: repeat(4,1fr); gap: 4%;` Actually gap as percentage of board width. Then cell size in JS = (boardWidth - 3*gap)/4. Hmm percentage gaps.
Let me just use fixed px and a responsive wrapper: container width = min(485px, 90vw). Inside, board at 100%. JS computes cellSize = containerWidth/(4) accounting for gap.
I think the cleanest: use CSS grid for background, and for tiles use `position: absolute` with `left`/`top` set as percentages via transform translate with `translateX(c*25%)`. Since 4 cells = 100%, each cell is 25% wide. But gap complicates the 25%.
Ugh, gaps. Let me avoid gaps in the grid and instead use padding/cell background to create the "gap" look. I'll make the board background color, and each cell a tile-shaped div with rounded corners, and the gap is the board background showing through. If cells have no gap but each cell has a border radius and the board is a darker bg, it looks like 2048 where the board shows between cells.
In real 2048, cells DO have gaps (board color between). I can simulate by making each cell slightly smaller than 25% with margin, OR use padding on board and gap.
Let me use `gap` and position tiles with absolute translate using a computed CELL value read from a dummy, OR just use CSS grid for tiles too.
New plan:
- Board: `display: grid; grid-template-columns: repeat(4, 1fr); gap: 15px; ...` with a background "empty cell" color.
- Background cells: I'll render 16 pseudo-cells as grid items (or one background). Each cell is a child with the same grid positioning, styled with bg color + rounded. Tiles are ALSO grid items but I render them in a separate layer.
Actually, the standard trick: board has background cells as a grid. Tiles overlay as a separate grid on top. If tiles use the same grid, `grid-column`/`grid-row` align perfectly even with gaps!
So:
- `.board` is `display:grid; grid-template-columns: repeat(4,1fr); gap:15px` (the container).
- Background cells: 16 divs, each `grid-column:c+1; grid-row:r+1` with bg styling.
- `.tiles` is an overlay: `position:absolute; inset:0; display:grid; grid-template-columns:repeat(4,1fr); gap:15px; pointer-events:none`. Tiles inside use grid-column/row.
This way tiles align with background cells perfectly including gaps. And for animation I set `grid-column`/`grid-row` with `transition` — but CSS grid transitions are NOT smooth by default (grid auto-placement doesn't transition, and grid-column/row transitions do transition actually!).
`grid-column` and `grid-row` DO transition smoothly with `transition`. So I can animate tiles moving by changing their grid-column/grid-row.
For merge scale animation, apply transform scale. For new tile pop, scale. For disappear, opacity.
This is clean. Let me go with it.
One concern: grid-column transition smoothness — yes, changing grid-column from 1 to 3 with a transition animates the position. Good.
Let me set transition: `grid-column 0.18s ease, grid-row 0.18s ease, transform 0.18s ease, opacity 0.18s`.
Now, tile elements: I'll give each a unique id and manage via a map. Position via grid-column/grid-row = c+1, r+1.
For the merge: primary tile updates value (color, number) and I trigger a scale. The partner tile (the one that disappears) — I'll move it to the target cell (it'll overlap primary) and fade it out, then remove.
Wait, both primary and partner move to same target cell — they'd overlap. Primary scales up, partner fades out underneath. That looks like merge.
For new tile: create element at the empty cell's grid position, with scale(0.6) opacity 0 initially → then set to scale(1) opacity 1. But I add it and immediately set the pop. Actually I create it with default scale(0.6),opacity 0 but at target grid position, then a rAF later set scale(1)/opacity(1) to trigger transition.
Let me now write everything.
Let me carefully manage the async sequence:
```
async handleMove(dir):
if isAnimating or gameOver or won (and not continuing) return
if !canMove(dir) ... actually let me compute move result
result = move(dir)
if noChange: return (no animation, no new tile)
isAnimating = true
// apply transitions
for each transition: update tile element position (grid-column/row).
- if merged primary: update value display + add merge scale
- if merged partner (disappear): it moves to target, add fade-out
- if stayed or moved: just position
// wait for move+merge to finish
await sleep(180)
// remove disappeared tiles DOM, update colors
// add new tile (pop)
addNewTile()
await sleep(120)
isAnimating = false
// check win/lose
```
But there's a subtlety: grid-column transitions need the element to exist at target before transition? No—setting grid-column triggers transition. Good. But if I remove the partner element before it finishes moving/fading, the animation stops. So I keep it until animation done, then remove.
Also, the primary tile changes value during merge — changing text/number inside while transitioning position is fine.
For color update of merged tile: I update the class after it arrives. Actually I can update immediately; the number changes. But the bg color change should also animate? In 2048 the merged tile just becomes the new color. Let me update color immediately when value changes, or after. I'll update immediately—simple.
Let me also make sure tiles that moved but value unchanged just reposition.
Let me map transitions to actions. Each tile id corresponds to a DOM element.
State:
- grid: 4x4 of {v, id} or null
- tileEls: Map<id, element>
- nextTileId: counter
move(direction) returns {grid: newGrid, transitions: [...], changed: bool}.
transitions: array of {id, fromR, fromC, toR, toC, val, merged(bool), disappear(bool)}
Let me generate transitions in move for each direction using rotation helpers. To keep it manageable, I'll write a `moveGrid(dir)` that uses rotate helpers.
Directions: 0=left,1=up,2=right,3=down (or use vectors). Let me implement with the "compact and merge" on rows after rotating so that left is always the operation.
```
function rotate(grid): transpose
function rotateRight(grid): transpose then reverse rows?
```
Standard:
- move left: process rows directly
- move right: reverse each row, move left, reverse back
- move up: transpose, move left, transpose back
- move down: transpose + reverse, move left, reverse back + transpose back
Let me implement grid as array of arrays of {v,id} or null.
moveLeft(grid) on the grid (mutates a copy) returns newGrid. I'll write a core function that processes one row's cells and returns target cells + transition info.
Since transitions need fromC/toC, I'll compute within row processing.
Let me write a function `compactRow(cells)` where cells is array of 4 (r,c baked). Returns `{result: [4 cells], moves: [...]}` where moves describe source→target. Actually let me return the new row (4 cells or null) and a separate transitions list that I build in the row loop.
Let me restructure to handle all in moveLeft:
```
function moveLeft(grid):
newGrid = emptyGrid()
transitions = []
for r in 0..3:
src = grid[r] // array of 4 {v,id} or null
cells = [] // {v,id,c} for non-null
for c in 0..3: if src[c] cells.push({v:src[c].v, id:src[c].id, c})
result = [] // {v,id,fromC, mergedPartnerId?}
i=0
while i < cells.length:
if i+1 < cells.length and cells[i].v == cells[i+1].v:
result.push({v: cells[i].v*2, id: cells[i].id, primaryFromC: cells[i].c, partnerId: cells[i+1].id, partnerFromC: cells[i+1].c, merged:true})
i+=2
else:
result.push({v: cells[i].v, id: cells[i].id, primaryFromC: cells[i].c, merged:false})
i++
for t in 0..result.length:
newGrid[r][t] = {v: result[t].v, id: result[t].id}
// build transitions
for t in 0..result.length:
res = result[t]
transitions.push({id: res.id, fromR:r, fromC:res.primaryFromC, toR:r, toC:t, val:res.v, merged:res.merged})
if res.merged:
transitions.push({id: res.partnerId, fromR:r, fromC:res.partnerFromC, toR:r, toC:t, val:res.v, merged:true, disappear:true})
return {grid:newGrid, transitions, changed: transitions.length>0 }
```
Wait, transitions.length>0 means at least one tile moved/merged → changed. But if a row had [2,0,0,0], result=[2], tile stays at col 0 (fromC=0, toC=0) — that's not a move but I'd add a transition with fromC==toC. I should only add transitions for actual changes. Let me add transition only if fromC != toC OR merged. A tile that stays in place with no merge → no transition needed.
```
for t in 0..result.length:
res = result[t]
if res.primaryFromC != t or res.merged:
transitions.push primary...
if res.merged:
// partner always moves (fromC != t or stays) and disappears; if partner was already at t? only if cells[i].c==t and cells[i+1].c==t impossible. partner fromC likely != t, add disappear transition always (it needs to fade+move)
transitions.push partner with disappear (even if fromC==t? if fromC==t that means partner was at target already—possible if cells[i].c==cells[i+1].c impossible). Add anyway; set disappear true.
```
Hmm, the partner disappear transition: partner moves to target t and fades. If partner's fromC != t, it moves; if equal (shouldn't happen), just fades. Fine to always add.
But wait: what about a tile that stays (fromC==toC) and isn't merged? Skip transition—DOM element stays. Good, no animation. But its grid-column/row already correct, no change needed.
Now for applying transitions to DOM:
```
for tr in transitions:
el = tileEls.get(tr.id)
if tr.disappear:
// partner: move to target + fade out
el.style.gridColumn = tr.toC+1; style.gridRow = tr.toR+1
el.classList.add('merge-out') // fade + scale down
else:
el.style.gridColumn = tr.toC+1; gridRow
if tr.merged:
el.textContent = format(tr.val)
setColor(el, tr.val)
el.classList.add('merge-bump') // scale up
else:
// just moved
```
Then after move duration:
- remove elements with merge-out class (delete from tileEls)
- remove merge-bump class
- spawn new tile
For new tile:
```
function addNewTile():
empties = cells where grid null
pick random
val = rand<0.1 ? 4 : 2
id = nextTileId++
grid[r][c] = {v:val, id}
create el, set grid column/row, textContent, color
el.style.scale = 0.6; opacity 0 (initial)
requestAnimationFrame(() => { el.style.scale=1; opacity=1 })
```
Wait, I set gridColumn/row to target immediately on creation, then animate scale+opacity. Good.
But careful: I need the element added to DOM before transition. Setting scale=0.6 opacity=0 inline initially, append, then rAF set to 1. Transition on scale, opacity.
Let me set transitions via CSS classes for timing consistency. I'll use classes: `tile` (base), and inline for grid position. Actually grid-column/row transitions need a transition on those properties.
Let me define CSS:
```
.tile { transition: grid-column 0.18s ease, grid-row 0.18s ease, transform 0.18s ease, opacity 0.18s ease, scale 0.18s ease; }
.merge-bump { animation: mergeBump 0.18s ease; }
@keyframes mergeBump { 0%{transform:scale(1)} 30%{transform:scale(1.2)} ... }
```
Hmm mixing transform (scale) with grid-column transitions. transform and grid-column both transitionable. But if I use transform for scale and also grid for position, they compose (grid moves, transform scales around center). Good.
For merge-bump, let me use transform scale via class. But the tile also might be positioning. Setting transform scale(1.2) at peak. Use animation.
For partner merge-out: animation scale down + fade.
Let me make timing consistent: all 0.18s (180ms) for move, plus new tile pop 0.15s.
Let me write the CSS with these animations.
Actually, to avoid transform conflicts: the tile uses `transform` for scale (merge bump / pop). And grid-column/row for position. No translate via transform. Good, clean separation.
Let me write the timing constants in JS matching CSS.
Let me also handle the case where a moved (non-merged) tile: just grid-column/row transition. Fine.
Edge: a tile that's both primary (merged) and moved: sets grid position + merge bump + value change. The value/colour change is instant.
Now, the won state: detect when any cell value >= 2048. Show overlay. Let player continue (common behavior) — show "You win!" with option to keep playing or restart. Actually 2048 lets you continue. I'll set `won=true` but allow continue; show overlay with message and buttons. Let me keep it: when 2048 reached, show "Won!" overlay, pause. Provide "Keep Playing" and "Restart". To keep scope, I'll pause and show overlay; clicking Keep Playing resumes (won flag stays true so no re-show).
Lose: no empty cells and no possible merges → show "Game Over".
canMove/dir: I'll just compute move and check `changed`. If changed false → no move happens (still animate nothing, don't spawn).
Input: keydown listener. Prevent default. Map arrows + WASD.
Also handle touch/swipe? Optional. Let me add simple swipe support for mobile since it's a web app. I'll add touch swipe detection. Keep minimal but nice. Let me add it.
Let me also add a "move" only when not animating.
Let me write the code now. I'll be careful with correctness.
Let me consider the grid representation and nextTileId. When creating new tiles, assign id. When merging, primary keeps id, partner removed. So tileEls: primary stays, partner el removed after animation, partner deleted from map (id not reused? id could be reused later but partner is gone; fine).
nextTileId increments always.
Let me write format for number (just innerText of value; large numbers use K? 131072 etc. I'll just show full number, it's fine; maybe compact 8192+ but not needed). I'll show plain number.
Colors: build a function getColor(v) returning {bg, text}. Let me make a map for powers of 2 up to 2048+ and a fallback for higher.
Let me write the map:
```
const TILE_COLORS = {
2: {bg:'#a3926c'?}
```
Let me use these (my final):
```
2: { bg: '#f78c56'? no, light }
```
I keep flip-flopping. Let me just commit to the actual famous 2048 palette (I'll trust this version which is widely cited):
```
2: { bg: '#AC8253'? }
```
No. The truly authentic 2048 colors (Gabriele Cirulli) are:
- 2: #AC8253?
I clearly cannot recall exactly. I'll use a self-consistent pleasing palette and move on—this is fine for the task. Final:
```
const TILE_COLORS = {
2: { bg: '#f5ebe0', text: '#5a5343' }, // light cream
4: { bg: '#f2d2a0', text: '#5a5343' }, // tan
8: { bg: '#f0b88a', text: '#5a5343' }, // peach
16: { bg: '#e89a66', text: '#f5f0e6' },
32: { bg: '#e07440', text: '#f5f0e6' },
64: { bg: '#d9573a', text: '#f5f0e6' },
128: { bg: '#cd4f3d', text: '#f5f0e6' },
256: { bg: '#c4454e', text: '#f5f0e6' },
512: { bg: '#b43a3a', text: '#f5f0e6' },
1024:{ bg: '#a63333', text: '#f5f0e6' },
2048:{ bg: '#993172'?
```
Hmm 8 background light but I set text dark—that works. Let me ensure >=8 maybe keep dark? 8 peach is medium-light, dark text reads OK. Fine. Threshold for white text: >= 16? but 16 bg is medium orange, white ok. Let me set white for >=8 to be safe... 8 peach with dark text is fine actually. Let me make threshold: white text for v>=8? I'll just keep my per-entry text colors as defined. For >2048 fallback use dark red bg with white text.
Actually let me reconsider the palette to look more like real 2048 (which has light tiles 2,4 and darker 8+). Let me reorder so 8 is distinctly darker:
```
2: { bg: '#f7f1e3', text: '#776e61' } // cream
4: { bg: '#f4e5c6', text: '#776e61' } // light tan
8: { bg: '#f0b88a', text: '#f5f0e6' } // but light bg with white? no
```
Real 2048: 8 is #f05833 (reddish), dark red text white. Let me use darker bgs for 8+:
```
2: { bg:'#f7f1e3', text:'#776e61' }
4: { bg:'#f4e5c6', text:'#776e61' }
8: { bg:'#f08858', text:'#f5f0e6' }
16:{ bg:'#e85e3d', text:'#f5f0e6' }
32:{ bg:'#e8443d', text:'#f5f0e6' }
64:{ bg:'#d9302a', text:'#f5f0e6' }
128:{bg:'#b82b2b', text:'#f5f0e6' }
... 2048: '#3b90b4'? real is '#3c6ab9'?
```
The real 2048 has 128=#3c6ab9? no. Honestly let me just make a gradient from orange to red to blue and use white text for >=8. Final committed palette:
```
const TILE_COLORS = {
2: { bg:'#f7f1e3', text:'#776e61' },
4: { bg:'#f4e5c6', text:'#776e61' },
8: { bg:'#f08858', text:'#f5f0e6' },
16: { bg:'#e85e3d', text:'#f5f0e6' },
32: { bg:'#e8443d', text:'#f5f0e6' },
64: { bg:'#d9302a', text:'#f5f0e6' },
128: { bg:'#3c6ab9'?
```
I'll stop at 64 with red gradients and make 128+ a purple/dark gradient. Let me just generate colors programmatically by interpolating between two palettes using the log2 value. That avoids hardcoding errors!
Function colorFor(v): t = log2(v) (1 for 2, 11 for 2048). Map t to a hue. Let me interpolate hue from 40 (orange) to 260 (purple) as t goes 1..11, and lightness decreasing. This gives a smooth gradient. Text white when lightness low.
Let me do:
```
function colorFor(v){
const t = Math.log2(v); // 1..11+
const tNorm = Math.min(1, (t-1)/10); // 0..1 for 2..2048
// hue from 30 (orange) to 270 (purple)
const hue = 30 + tNorm*(270-30);
const light = 88 - tNorm*40; // 88 down to 48
const bg = `hsl(${hue}, 70%, ${light}%)`;
const textLight = light > 65 ? '#776e61' : '#f5f0e6';
return {bg, text: textLight};
}
```
This produces a nice gradient. But 2,4 should be light with dark text. tNorm for 2 = 0 → hue 30, light 88 (very light, dark text ✓). For 2048 tNorm=1 → hue 270 purple, light 48, white text ✓. Mid 8 (t=3, tNorm=0.2) hue ~78, light ~80 → yellow-ish light, dark text. OK acceptable. 16 (t=4,tNorm=0.3) hue 108, light 76 → greenish. Hmm real 2048 uses reds. But gradient is fine and looks OK. Let me maybe use hue range 20..340 and keep saturation high; or go orange→red→purple: hue 20→20 (red)→270. Let me just do orange(30) to red(360/0) to purple(270) — multi-stop not linear. Simpler: keep orange to purple. Fine.
Hmm the greenish middle might look odd for 8,16 which are commonly red. Let me adjust hue range to go from orange(30) through red(10) to purple(270) — i.e., decreasing then increasing? Linear 30→270 passes through green. To pass through red, use 30 → 0 (or 360) — linear 30→360 passes through red then purple? 30→360 linear = 30, ...,..., 360. At tNorm 0.5 hue=195 (blue-cyan). Not red.
Let me just pick discrete-ish but computed: use hue = tNorm < 0.5 ? lerp(30, 0, tNorm*2) : lerp(0, 270, ...) no.
Simpler and looks good: hue from 30 (orange) to 340 (magenta-red) to ... I can't easily do V-shape with single lerp.
Let me just hardcode a reasonable palette; it's not that many. I'll commit to this final palette and ensure correctness:
```
const TILE_COLORS = {
2: { bg:'#f7f1e3', text:'#776e61' },
4: { bg:'#f4e5c6', text:'#776e61' },
8: { bg:'#f08858', text:'#f5f0e6' },
16: { bg:'#e85e3d', text:'#f5f0e6' },
32: { bg:'#e8443d', text:'#f5f0e6' },
64: { bg:'#d9302a', text:'#f5f0e6' },
128: { bg:'#3c6ab9'??
```
You know I'll just go with a purple for 128+ and white text:
```
128: { bg:'#3c6ab9'? }
```
The actual 2048: 128=#3c6ab9? I think real is 128=#3c6ab9 no. Real 2048: 128=#3c6ab9 is too blue. Real is 128=#3c6ab9? The actual 2048 palette:
- 128: #3c6ab9? I believe real 128 is #3c6ab9? no.
FINAL: I'll use this hardcoded set (pleasing, distinct):
```
2: {bg:'#f7f1e3', t:'#776e61'}
4: {bg:'#f4e5c6', t:'#776e61'}
8: {bg:'#f08858', t:'#f5f0e6'}
16:{bg:'#e85e3d', t:'#f5f0e6'}
32:{bg:'#e8443d', t:'#f5f0e6'}
64:{bg:'#d9302a', t:'#f5f0e6'}
128:{bg:'#3b90b3?
```
I'll do 128 onward with a dark slate and white:
```
128: {bg:'#4a4a4a'? no too dark}
```
Let me do: >=128 use deep blue/purple gradient via the hsl function for those, white text. So combine: hardcoded 2..64, and for >=128 compute hsl with purple.
I'll write getColor(v):
```
const FIXED = {...2..64};
function getColor(v){
if (FIXED[v]) return FIXED[v];
const t = Math.log2(v); // >=7 for 128
const tNorm = (t-7)/6; // 0 for 128, 1 for ~2048+
tNorm = Math.min(1, Math.max(0, tNorm));
const hue = 260 - tNorm*40; // 260..220 purple
const light = 45 - tNorm*5;
return { bg:`hsl(${hue},60%,${light}%)`, text:'#f5f0e6' };
}
```
For 128 (t=7): hue 260, light 45. 2048(t=11): tNorm=0.667, hue 233, light 41.7. Good, distinct purples.
Actually 2..64 hardcoded plus >=128 hsl—looks decent. Let me go.
Hmm, mixing might give a slight discontinuity at 64→128 but fine.
OK let me just write it. Enough deliberation.
Let me write the full file now.
I need to be careful with the animation sequencing and not blocking the merge scale. Let me finalize durations: MOVE_DUR=180, POP_DUR=120. GAP 180, then 120.
Let me write sleep with setTimeout.
Also handle: after move, before adding new tile, remove partner DOM elements (the ones marked merge-out). And reset transform classes.
Let me also ensure that when a tile didn't move and isn't merged, I don't touch it (no transition). Good.
One more: when game is animating, ignore inputs.
Also need to handle initial setup and restart.
Let me write the code.
For swiping: add touchstart/end on board, compute delta, if |dx|>|dy| and >30px → left/right; else up/down. Map to move.
Let me write now.
Let me make sure grid-column values: grid-column = c+1 (1-indexed). grid-row = r+1.
For tile element creation, set style.gridColumn and gridRow.
Let me write the DOM building for board background (16 cells) and tiles container.
Let me write everything in the HTML file.
I'll write it as a complete document.
Let me write the JS.
```js
const SIZE=4;
let grid, tileEls, nextId, score, won, gameOver;
function init(){
grid = Array(SIZE).fill(0).map(()=>Array(SIZE).fill(null));
tileEls = new Map();
nextId = 0;
score = 0;
won = false;
gameOver = false;
renderGridBase();
addTile(); addTile();
updateScore();
draw();
}
function addTile(){
// must have empty cell
const empties=[];
for(r)for(c) if(!grid[r][c]) empties.push([r,c]);
const [r,c]=empties[random];
const v = Math.random()<0.9?2:4;
const id = nextId++;
grid[r][c]={v,id};
createTileEl(id,v,r,c,true);
}
function createTileEl(id,v,r,c,pop=false){
const el=document.createElement('div');
el.className='tile';
el.style.gridColumn=c+1;
el.style.gridRow=r+1;
el.textContent=v;
const col=getColor(v);
el.style.backgroundColor=col.bg;
el.style.color=col.text;
if(pop){ el.style.transform='scale(0.1)'; el.style.opacity='0'; }
board.appendChild(el);
tileEls.set(id,el);
if(pop){
requestAnimationFrame(()=>{
el.style.transform='scale(1)'; el.style.opacity='1';
});
}
}
```
Wait pop uses transform for scale — but moves also use transform for merge bump. Conflict potential: if I use transform for both pop and merge, and a merge tile... a popped tile doesn't merge immediately, fine. But a tile that is moved and merged uses transform scale for bump; setting grid-column for position. transform only for scale. Pop also only transform scale + opacity. OK no conflict as long as I don't combine pop+move. New tiles only pop, never move in same turn. Good.
But note: setting style.transform='scale(1)' overrides any previous transform. For merge bump I'll use animation to avoid clobbering? Let me use a class for merge bump animation and remove after. Actually if I set transform directly for pop and for merge bump, conflicts resolved by sequence (pop tile isn't merging that turn). Merge primary: I set grid pos + change number/color + add class that animates transform. But I might also have set transform via pop earlier—for a primary tile (old tile), it was placed without pop (transform not set, default scale(1)). So adding merge animation transform is fine.
Let me use CSS animation for merge bump:
```
.tile.merge-bump { animation: tileBump 0.18s ease; }
@keyframes tileBump{0%{transform:scale(1)}30%{transform:scale(1.25)}100%{transform:scale(1)} }
```
But this animation uses transform; if the tile also is moving via grid-column transition, transform animations compose fine (both run). However animation transform and the implicit... fine.
For merge-out (partner disappearing):
```
.tile.merge-out { animation: tilePopOut 0.18s ease; }
@keyframes tilePopOut{0%{transform:scale(1);opacity:1}100%{transform:scale(0);opacity:0} }
```
For pop-in new tile, I currently use inline transform. Let me instead use a class for consistency. Actually inline is fine. But to avoid conflict with merge animation, since new tiles aren't merging, inline pop is OK. Let me keep inline pop but use opacity transition. Actually inline style transform scale + opacity, set 0.1 then rAF to 1/1. With CSS transition on transform & opacity on .tile. Good.
Let me ensure CSS .tile has transition for transform, opacity, grid-column, grid-row, and background-color maybe.
Let me write transition: `transition: grid-column 0.18s ease, grid-row 0.18s ease, transform 0.18s ease, opacity 0.18s ease, background-color 0.18s ease;`
But merge-bump uses animation not transition for transform—animation overrides transition for transform property? When an animation is set on transform, it takes precedence over transition during the animation. After animation ends, transition could re-apply. Should be fine. Actually mixing might cause flicker. Let me use transition-based for bump too: set a data-state or class that sets transform scale, rely on transition. But bump needs non-linear scale up then back—transition to scale(1.25) then back via two steps. Simpler use animation. I'll use animation and remove the class after. And not set transform via inline elsewhere for merged tiles. For non-merged moved tiles I don't set transform inline (they don't pop). Good. So transform is only: inline pop (new tiles) OR animation bump (merge primary) OR animation pop-out (partner). These don't coexist on same element in same turn. Good.
But wait, a merged primary tile—does it have inline transform from before? It was created as a new tile previously with pop (inline transform scale). After pop animation it ended at scale(1) inline? I set el.style.transform='scale(1)' on rAF. So inline transform scale(1) remains. Then later if it merges, adding animation tileBump sets transform via animation—conflict with inline style? Inline style wins over... no, animations override inline for the property during animation runtime? Actually CSS animations set the property during their run and inline style still applies? The precedence: transitions/animations vs inline — inline style has higher specificity than author... hmm animation keyframes animate the computed value; inline style is a declared value. This can conflict.
To avoid, let me not leave inline transform after pop. Instead remove inline transform after pop completes (set el.style.transform=''), or better: use classes for pop too.
Let me use CSS classes for everything to keep transform clean:
- `.tile` base
- `.pop-in` → animation popIn (scale 0→1, opacity 0→1)
- `.merge-bump` → animation bump
- `.merge-out` → animation popOut
Remove classes after animation via setTimeout.
And never set inline transform. Good, cleaner.
Let me define:
```
.tile{ opacity:1; } // when hidden removed
.pop-in{ animation: popIn 0.15s ease; }
@keyframes popIn{0%{transform:scale(0.2);opacity:0}100%{transform:scale(1);opacity:1}}
.merge-bump{ animation: bump 0.18s ease; }
@keyframes bump{0%{transform:scale(1)}25%{transform:scale(1.22)}100%{transform:scale(1)}}
.merge-out{ animation: popOut 0.18s ease forwards; }
@keyframes popOut{0%{transform:scale(1);opacity:1}100%{transform:scale(0);opacity:0}}
```
For grid position transitions, .tile has transition grid-column,grid-row 0.18s.
Now the move apply:
```
function animateMove(transitions, newGridRef){
// transitions already computed
for(const t of transitions){
const el=tileEls.get(t.id);
if(!el) continue;
el.style.gridColumn = t.toC+1;
el.style.gridRow = t.toR+1;
if(t.disappear){
el.classList.add('merge-out');
} else if(t.merged){
el.textContent=t.val;
const col=getColor(t.val);
el.style.backgroundColor=col.bg; el.style.color=col.text;
el.classList.add('merge-bump');
}
// else just moved (position transition)
}
}
```
Wait, the primary merged tile: it moves from primaryFromC to toC, changes value, and bumps. Good. But its number/color change happens instantly at start of move while it's traveling—acceptable.
Then after MOVE_DUR:
```
for(const t of transitions){
if(t.disappear){
const el=tileEls.get(t.id);
if(el){ el.remove(); tileEls.delete(t.id); }
// remove merge-out class? element gone
}
}
// remove bump class
for(const t of transitions){
if(!t.disappear){
const el=tileEls.get(t.id);
if(el) el.classList.remove('merge-bump');
}
}
addTile(); // pops in
updateScore();
```
Then after POP_DUR: isAnimating=false; check win/lose.
But I need `score` tracked: when merge happens, score += merged value. Let me accumulate in move result: each merged adds t.val. Add to score.
Let me update score during move computation.
Now win check after new tile: if grid has 2048 → show win. Actually should check after the move that created 2048. I'll check after adding tile too.
Lose check: if no empty and no merges possible → game over.
Let me code helpers: canMerge(grid) and hasEmpty.
Let me write move(dir) returning newGrid+transitions+scoreDelta.
Directions mapping using rotate. Let me implement grid rotate/transpose with cells {v,id}.
```
function cloneGrid(g){ return g.map(row=>row.map(c=>c?{v:c.v,id:c.id}:null)); }
function transpose(g){ const n=g.length; for(r,c) swap... return new }
```
Let me implement by building new arrays.
For move, I'll transform grid to "left" orientation, run moveLeft logic producing newGrid+transitions+scoreDelta, then transform back. But transitions reference r,c in the transformed orientation; I need to map back to original. That's complex with rotations.
Alternative: implement slide for each of 4 directions directly in the row-processing loop by parameterizing iteration. Or implement moveLeft returning transitions in rotated coords, then rotate transitions back.
Hmm. Simpler: implement the compact logic on a generic list of 4 cells, and for each direction iterate cells in the appropriate order. Let me implement move(dir) directly handling all directions by choosing iteration order.
Let me define direction vectors and iterate over lines.
Approach: For a given direction, the tiles in each "line" slide. There are 4 lines per direction (rows for L/R, columns for U/D). I'll collect each line as ordered list of cells (in slide direction order), compact+merge, place back, and record transitions.
Let me implement a function that given direction, for each line, processes cells.
I'll index grid as grid[r][c].
For left: lines = rows r=0..3, cells c=0..3. target index increases leftwards.
For right: lines = rows, cells c=3..0, target index leftwards (places at right).
For up: lines = columns c=0..3, cells r=0..3, target index upward.
For down: lines = columns, cells r=3..0.
I can unify: for each line, get an ordered list of cells [(r,c), ...] in the direction of slide. Then compact+merge produces results placed at successive target positions along that order. The first result goes to first cell in order, etc.
Let me build for direction d (0=L,1=R,2=U,3=D):
- lines: array of cell-position arrays.
For L: for r: [(r,0),(r,1),(r,2),(r,3)]
For R: for r: [(r,3),(r,2),(r,1),(r,0)]
For U: for c: [(0,c),(1,c),(2,c),(3,c)]
For D: for c: [(3,c),(2,c),(1,c),(0,c)]
Then for each line positions P (length4):
cells = [{v,id,r,c}] from grid where non-null, in order of P.
compact+merge → results with target position = P[t] (t=index in result).
transitions record from original pos to target pos.
This is clean and general. Let me implement.
```
function move(dir){
const dirs = {0:[0,1,0,0,0,1],...} // hmm
const lines = getLines(dir);
const ng = clone(empty);
const transitions=[];
let scoreDelta=0, changed=false;
for(const line of lines){ // line = array of [r,c] in slide order
cells = line.map(([r,c])=>({r,c,...grid[r][c]})).filter(has v)
result=[];
i=0;
while i<cells.length:
if i+1<cells.length && cells[i].v==cells[i+1].v:
result.push({v:cells[i].v*2, id:cells[i].id, primary:cells[i], partner:cells[i+1], merged:true})
scoreDelta += cells[i].v*2
i+=2
else:
result.push({v:cells[i].v, id:cells[i].id, primary:cells[i], partner:null, merged:false})
i++
// place
result.forEach((res,t)=>{ const [r,c]=line[t]; ng[r][c]={v:res.v,id:res.id} })
// transitions
result.forEach((res,t)=>{
const [tr,tc]=line[t];
if(res.merged){
// primary
if(line.indexOf find? compare res.primary {r,c} to target
transitions.push({id:res.id, fromR:res.primary.r, fromC:res.primary.c, toR:tr, toC:tc, val:res.v, merged:true})
// partner: disappears, moves to target
transitions.push({id:res.partner.id, fromR:res.partner.r, fromC:res.partner.c, toR:tr, toC:tc, val:res.v, merged:true, disappear:true})
} else {
const p=res.primary;
if(p.r!=tr || p.c!=tc){
transitions.push({id:res.id, fromR:p.r, fromC:p.c, toR:tr, toC:tc, val:res.v, merged:false})
}
}
})
}
// tiles not in ng (no tile there in new grid) and were in old → they're accounted as disappear or moved. Any old tile whose id not in any transition and not placed → it should be removed (its cell became empty). But all old non-null cells are either in `cells` of some line and processed → either moved or merged(partner disappear). So all accounted. Good. But to be safe, after building, any tile id still in tileEls not present in ng should be marked vanish. Actually partner disappear handles merges. Non-moved same-position tiles stay. So fine.
changed = transitions.length>0;
return {grid:ng, transitions, scoreDelta, changed};
}
```
Wait, non-merged tile that stays in place (p at target) → no transition, stays in grid at same spot, element stays. Good. Its id is in ng. Fine.
Edge: a tile could stay same position but we still place in ng (same). Good.
Now changed: if no transitions → no move happened. But could there be a case where grid changed but my transition detection misses? If a tile moves, I add transition. If merge, I add. If a tile stays, no change. So changed iff any movement/merge. Good.
But there's subtlety: what if a tile stays (same pos) but a merge happened elsewhere → changed true. Good.
Now, after computing, I set grid = ng, then animate using transitions, then addTile, etc. But addTile must place in ng (empty cells). The transitions move existing tileEls; new tile created for the new cell.
But careful: the primary merged tile's element now has new value/color—its id is in ng at target. Good. The partner's id is NOT in ng (removed). I delete its element after animation. Good.
Let me ensure ids consistent: ng stores id for each placed tile. tileEls map keyed by id. After move, for ids in ng, element exists (primary/partner kept). For partner ids not in ng, we mark removed.
Now animate:
```
async handleMove(dir){
if(gameOver||won&&... ) return; // allow continue if won
const res = move(dir);
if(!res.changed) return;
score += res.scoreDelta; updateScore();
isAnimating=true;
board.querySelector... // disable?
applyTransitions(res.transitions); // sets grid pos, classes
await sleep(MOVE_DUR+10);
// cleanup disappeared
for(t of res.transitions){
if(t.disappear){ const el=tileEls.get(t.id); if(el){el.remove();tileEls.delete(t.id)} }
else { const el=tileEls.get(t.id); if(el)el.classList.remove('merge-bump'); }
}
// new tile
addTile();
drawCheck(); // win/lose
await sleep(POP_DUR+10);
isAnimating=false;
}
```
addTile pops in. After its animation done (POP_DUR) we can set isAnimating false. But win/lose check can happen right after addTile. Fine.
But drawCheck after addTile: update win/lose overlays.
Let me also handle: the grid state `grid` should be set to res.grid. I set it before animating.
Wait, addTile modifies grid (sets a cell) and creates element. Good.
Now initial addTile called twice at init.
Let me ensure createTileEl for new tile uses pop class.
Now win/lose:
```
function checkStates(){
let maxVal=0;
for cells: maxVal=max(maxVal, v)
if(maxVal>=2048 && !won){ won=true; showOverlay('win'); }
// lose
if(!hasEmpty() && !canMerge()){ gameOver=true; showOverlay('lose'); }
}
```
Show overlay with message + buttons: restart, (and keep playing for win).
Let me render score text.
Let me handle keyboard + swipe.
Let me now also make sure the board size responsive. I'll set board width via CSS max-width and use a container. Tiles use % grid so layout fine.
Let me make board 4x4 grid with gap, full width of a 500px max container. Tiles 70%? Let me write CSS.
Let me set body full height, centered.
I think I have enough. Let me write the file.
Let me write the HTML structure:
```
<div class="game">
<header>
<h1>2048</h1>
<div class="score"><span>SCORE</span><span id="score">0</span></div>
</header>
<div id="board" class="board"></div>
<div id="overlay" class="overlay hidden"></div>
<p class="hint">Use arrow keys or swipe</p>
</div>
```
Build board background cells + tiles container in JS? Or static HTML for background. Let me build board with 16 background cell divs in HTML, and tiles container is `#board` itself (tiles as children with grid positioning). Actually board is the grid; background cells are children; tiles are children too. To layer tiles above background, set tile z-index or ensure DOM order (tiles after cells). Since I append tiles after, fine. But background cells each are grid items at grid-column/row; tiles also grid items. That works! Both in same grid, tiles appear after cells visually (later in flow, same z, but tiles have higher z via class or just come later—grid items paint in DOM order, so tiles after cells paint on top). I'll add .tile {z-index: position-based or just rely on order; add z-index:1 to tiles and the cell bg z-index 0} I'll add a .tiles wrapper? Let me just put cells in board and tiles also in board. To be safe add class tile with z-index:2 and cell z-index:1, board position relative. Actually simpler: board holds bg cells; tiles container separate overlay div with pointer-events none. Let me do:
```
<div id="board" class="board">
<div class="cells"></div> // 16 cells
<div id="tiles" class="tiles"></div> // tile elements
</div>
```
But board is grid; cells and tiles both need to be grid positioned. If cells is one grid item spanning? That won't work as grid items per cell. Better: board directly contains 16 cell divs (grid items) and tiles appended also as grid items. They share grid-column/row. Layer via z-index. Let me do that—simplest.
So #board is the grid container (display:grid). 16 cell divs with grid-column/row. Tiles appended to #board directly with grid-column/row and z-index higher.
Let me create cells in JS on init (16 divs). And tiles appended to board.
Good.
Let me write CSS:
```
.board{ display:grid; grid-template-columns:repeat(4,1fr); gap:12px; width:100%; max-width:500px; aspect-ratio:1; background:#bbada0; border-radius:12px; padding:12px; box-sizing:border-box; position:relative; }
```
Wait if board is grid with gap and padding, the cells fill. Tiles as grid items align. aspect-ratio:1 makes it square. max-width 500.
Cell:
```
.cell{ background:#cdc1b2; border-radius:8px; }
```
Each cell gets grid-column:c+1 grid-row:r+1.
Tile:
```
.tile{ position:relative; border-radius:8px; font-size:40px; font-weight:bold; display:flex; align-items:center; justify-content:center; z-index:2; }
```
Tile font size responsive—use vw. I'll set font-size via JS? Use calc. Let me use font-size: max(16px, 4vw)? Eh. I'll set font-size: 3.5vw and ensure min. Fine.
Hmm tile text large for big numbers. Use a class by value? Keep one size ok. I'll use font-size: 4vw.
Let me set transitions on .tile.
Overlay:
```
.overlay{ position:fixed; inset:0; background:rgba(0,0,0,0.5); display:flex; align-items:center; justify-content:center; flex-direction:column; color:#fff; font-size:2vw; z-index:10; }
.hidden{ display:none; }
```
Buttons styled.
Let me write buttons: restart, keep playing, etc.
Now let me write the JS fully and carefully. I'll also add a small reset.
Let me also ensure arrow keys don't scroll page (preventDefault).
Let me write the code.
I realize for `move` direction lines generation, let me write getLines(dir):
```
function getLines(dir){
const lines=[];
if(dir===0){for(let r=0;r<4;r++){lines.push([[r,0],[r,1],[r,2],[r,3]]);}}
if(dir===1){for(let r=0;r<4;r++){lines.push([[r,3],[r,2],[r,1],[r,0]]);}}
if(dir===2){for(let c=0;c<4;c++){lines.push([[0,c],[1,c],[2,c],[3,c]]);}}
if(dir===3){for(let c=0;c<4;c++){lines.push([[3,c],[2,c],[1,c],[0,c]]);}}
return lines;
}
```
Input map: ArrowLeft=0, ArrowRight=1, ArrowUp=2, ArrowDown=3, and WASD similarly.
Let me write everything now in one go.
Let me also double-check merge transition primary placement: result placed at ng[line[t]]. Primary id placed there. transitions primary to (tr,tc)=line[t]. Good. Partner disappears, also target line[t] but removed from ng. Partner's id not in ng; element removed after animation. Good.
Now, what about a tile that is the primary and also moved same as partner target, while partner also targets—both elms go to same cell; partner fades out underneath, primary bumps. Visual good.
Edge: non-merge tile that moves to an empty cell—transition sets grid pos, element moves. Good.
Let me ensure that when applying transitions I also handle tiles whose id is partner: partner element moves to target + merge-out class. Its current grid-column/row is at partner's from. Transition moves it. Good. But partner might already be at target? only if partner from == target; impossible since result index t differs from partner's original position along line (partner is cells[i+1], primary cells[i], both before merge target t which is <= i; t = result count). Could t equal partner's original index? The target t is the result index, partners original position along line = i+1 generally > t. So they differ; partner moves. Fine even if same, merge-out still runs.
Now also: after move, tiles that did NOT appear in any transition and are not placed in ng? All old tiles placed in ng (each old cell belongs to one line's cells, processed). So every old tile is either a primary (placed, maybe moved or stayed) or a partner (disappear, not placed). So tileEls keys after move = ids in ng plus partner ids (to be removed). Good.
Wait, could an old tile be neither primary nor partner? No—every non-null cell is in `cells` of its line; the compact loop advances i by 1 or 2 covering all cells exactly once, each cell is a primary or a partner. So all accounted.
Now addTile adds one new tile (id new). tileEls gets it. Grid ng gets it. Good.
Let me finalize sleep helper and isAnimating flag.
Let me write the file. I'll keep code reasonably concise.
For check win: if won show overlay with "You Win!" and buttons Keep Playing (resume, allow continuing past 2048) and Restart. If user continues and makes more merges, keep playing (won stays true, don't re-show). Good.
Lose: show "Game Over" with Restart.
Let me handle key input: if overlay visible / game over / won, still allow? For lose, disable input. For won, allow continue until user clicks. I'll just check gameOver to block lose, and won blocks? Let me allow continuing when won (so user can keep playing after clicking Keep Playing, or auto-continue). Actually if won overlay shows and I block moves, user must click Keep Playing to resume. Let me block moves while overlay showing for win, and set a flag continue=true to allow. For lose overlay, block.
Let me implement:
- `blocked = gameOver || (won && !canContinue)`
- On win: show overlay. Keep Playing → hide overlay, canContinue=true. Now blocked false (won true but canContinue true).
- On lose: blocked true (gameOver).
Let me code showOverlay(title, text, type) building buttons.
Simplify: showOverlay(type='win'|'lose'|'none').
Let me write.
Alright, writing now. I'll be thorough.
Let me also add a "Your Score" and best score in localStorage for nicety. Optional but nice. Let me include best score persisted.
Keep it: best = localStorage best. On score update, update best if higher.
Let me write final code.
Let me write CSS for header layout: title left, score right.
```
header{display:flex;justify-content:space-between;align-items:center;max-width:500px;margin:0 auto;padding:0 12px;}
```
Let me put everything in .game container max-width 520px.
Now writing the file.
Let me carefully compute MOVE_DUR and POP_DUR constants and CSS durations matching (180, 150).
I'll set POP 150.
Let me write.
Actually, for the merge-out partner: it should travel to target while fading. The grid-column transition moves it; merge-out animation handles scale/opacity. But I add merge-out class which has animation setting transform scale & opacity. The grid-column transition still runs. Good. After animation I remove the element (don't need to remove class). Fine.
For merge-bump primary: grid-column transition moves it while bump animation scales. Good. After MOVE_DUR I remove class. Good. But removing class while animation running—animation completes at 180 anyway; removing class after 180+10 is fine.
Edge: if two animations overlap? Each turn only one animation cycle. Fine.
Let me write the complete file now.
Let me also make sure that tiles don't get the move transition on creation (pop only). I create with grid-column set; transition would animate from previous? New element first time placed—no prior, grid-column set instantly (no transition needed since first render?). Actually CSS transition only animates changes; setting grid-column when element first inserted—does it transition from 0? Transitions apply on property changes after initial render; initial set usually not transitioned. To be safe set pop in rAF after first paint. I'll create el, set grid-column/row, append, then rAF add pop class. The position sets without transition. Good.
For moved tiles (existing), changing grid-column triggers transition (since previous value set). Good.
Alright. Let me write.
I'll also add subtle board cell tap? Swipes suffice.
Let me write the final HTML now.
One more: responsiveness of font — I'll set tile font-size: max(1rem, 4.5vw)? Let me use 4vw.
Board max-width 480. Let me set board width 100% max 480.
Let me write.
Also need to disable text selection and touch scroll. body overscroll none.
Let me write CSS touch actions none on board.
Final writing now.
Let me write the JavaScript with comments minimal.
Let me also handle the case `move` returns ng grid but I should set `grid = res.grid` and then addTile reads grid for empties. Good.
Let me write.
For score: I update score += res.scoreDelta then updateScore() renders. But addTile doesn't affect score. Good.
Let me code updateScore to set text and best.
Let me write file.
I'll keep the merge threshold check: win when any tile value === 2048. Use >=2048 to catch overshoot 4096 (already won). Set won once.
Let me write now. Final.
Let me write getColor and format.
```
function format(v){ return v.toLocaleString(); } // adds commas for large
```
LocaleString is fine.
Now coding.
Let me also ensure number positioning centered and font bold. Tile content.
Large numbers may overflow tile at high values; I'll reduce font for big numbers via JS class adding when v>9999. Minor. I'll add a class `big` with smaller font. Let me add classes based on magnitude for font scaling: v>=1000 smaller. Use CSS classes. I'll add class list by thresholds.
Implement in createTileEl: el.className='tile'; add `tile-${tier}` where tier = Math.min(11, log2(v))? Let me just compute tier = number of digits or log2. I'll set class `t${log2v}`. CSS defines font sizes. Eh, simpler: set font-size via style based on value length. I'll set inline fontSize = `${4.2/v.toExponential...}`. Let me just do: fontSize = v<100? '4.5vw':'3.8vw':'2.8vw'. I'll pick: if v<100 fontSize=4.5vw; if v<1000 3.6vw; else 2.8vw. Set inline.
OK writing.
Let me write the final file now, carefully.I'll create a complete, self-contained 2048 game in a single `index.html` file with smooth animations, score tracking, and win/lose states.
→ write
/workspace/index.html (12337 bytes)toolResult
Successfully wrote 12337 bytes to /workspace/index.html
assistant
thinking
Let me verify the file and check for issues. There's a bug: in `createTileEl` I do `requestAnimationFrame(()=>{ el.classList.add('pop-in'); });` but the element already has `pop-in` class from className='tile pop-in'. That means the animation runs immediately on creation (class present at first render, so it animates from start). Actually adding pop-in class after rAF is redundant/duplicative since it's already there. Let me fix: create without pop-in, then rAF add it.
Let me check: `el.className='tile pop-in';` sets it initially, so the pop-in animation would start on first paint immediately—good actually (element starts at scale .1 opacity 0 and animates to 1). But I also add it again in rAF (no-op). The issue: if class is present before first paint, the animation runs from 0→1 on insert — that's what I want. So it works, but the rAF add is redundant. However there's a subtlety: if the element is added and pop-in class present, browsers do animate it. It should be fine.
Actually, there's a real concern: setting the element's final grid position and pop animation together—pop uses transform & opacity only, position via grid-column set statically (no transition on first render). Since transition on grid-column only animates changes from a previous value; first set won't animate. Good.
But wait: I set `place-self:center` on tile. With grid-column/grid-row it should position. But `place-self:center` makes the tile centered in its grid area — that's fine since tile is sized by content. Actually I want tile to fill its cell area visually. With place-self center it just centers the tile box. The tile has its own size (from font content + padding?). Tile has no explicit width/height; it sizes to content (the number). So a tile with value "2" is small, centered in cell. That's actually correct for 2048 (tiles fit number). But the tile bg is round rect sized to content, not filling cell. That looks OK-ish but typically tiles are larger. For bigger numbers tile grows. Fine.
Hmm but the cell is 100% via grid; tile centered small. Looks acceptable. Actually in real 2048 tiles fill most of cell. Let me make tiles larger: set tile width/height to fill cell? With grid placement, I could set tile to `width:100%; height:100%;` but then it'd fill cell including gap overlaps. Since tiles are grid items placed in cells with gap, filling 100% would make adjacent tiles overlap into gap? No, grid item area excludes gap, so 100% fills cell nicely without overlapping neighbors (gap is between). Let me set tile to w/h 100%? But tile is `place-self:center` which overrides stretch. Let me instead set tile to stretch: `place-self:stretch`? But then number centered inside stretched tile. Let me change `.tile` to `width:100%; height:100%;` effectively by removing place-self center and letting it stretch. Actually default grid item stretches. With place-self center I override. Let me remove place-self center and set display flex centering content. Then tile stretches to cell area. But the rounded corners and bg fill cell. Good. But tile has padding? none. Number centered.
But there's a catch: if tile stretches to 100% width including the gap? Grid item area is the cell (excludes gap), so stretching fills cell exactly, no overlap.
Let me update CSS: remove `place-self:center; margin:0;` from .tile and let it stretch; keep flex centering. Actually default align-self stretch + justify-content center for content. Let me set `justify-content:center;` and remove place-self. The content (number) stays centered.
Let me also reconsider: `grid-column:1;grid-row:1;` in .tile is a default I set; that's fine as base, overridden by inline style.
Let me fix the pop-in duplicate and the tile sizing.
Also bug: in `checkStates`, after showing win overlay I `return` but then still check lose — I have `else if(gameOver||won) return;` weird logic. Let me clean:
```
function checkStates(){
let maxTile=0;
for cells maxTile;
if(!won && maxTile>=2048){ won=true; showOverlay('win'); }
if(!hasEmpty() && !canMergeAny() && !gameOver){ gameOver=true; showOverlay('lose'); }
}
```
But after win, gameOver might also trigger if board full. That's fine—show lose too? Probably avoid showing both. If won, maybe don't show lose immediately. Let me only show lose if !won. Let me guard: if won and not canContinue, moves blocked; gameOver check skipped. Actually if won but canContinue (player kept playing) and then board fills → game over should show. Let me allow lose even after win. Fine.
But the early return logic was messy; let me rewrite checkStates cleanly.
Also `draw()` is empty/no-op. Remove or keep. Keep minimal—just leave it as no-op or remove calls. I'll simplify by removing draw() calls (they do nothing). Actually leave draw() empty, harmless. But calling draw() after addRandomTile is redundant. I'll keep but it's fine. Let me just remove to reduce confusion? It's harmless. Leave.
Let me also double check `place-self:center` removal and that tiles fill cells.
Also the overlay for win: Keep Playing button sets canContinue and hides overlay. Good. Restart calls init (which resets everything and hides overlay via init's overlay.classList.add('hidden')). Good.
Potential issue: after won, if player clicks Keep Playing, canContinue=true, then play continues. If board fills, gameOver shown. Good.
Keyboard: when overlay visible (win/lose), for lose gameOver blocks moves; for win won&&!canContinue blocks. Good.
Now the animation timing: Move tiles transition 180ms (I set MOVE_DUR=200 but CSS var(--move-dur)=180ms). Mismatch! JS waits 200 but CSS transition 180. Fine, extra 20ms wait before cleanup—OK. But merge-out/pop-in use CSS var durations. move transition 180, I wait 230. Good. POP uses 150, I wait 190. Good. Let me align: set MOVE_DUR=200, POP_DUR=160. JS wait MOVE_DUR+30=230 (>180) and POP_DUR+30=190 (>150). Fine, just slightly longer than actual. OK.
Actually for merge-out the partner needs to fully vanish; I remove element after wait. The popOut animation 180ms; I wait 230. Good.
Let me fix the pop-in duplicate: create with className='tile' (no pop-in), set initial inline scale? But pop-in sets scale via animation keyframes 0→1. If element inserted without pop-in class then rAF add class, the animation plays. But the grid position is set inline already; rAF adding pop-in class triggers animation from keyframe 0 (scale .1, opacity 0) to 1. However, between insert and rAF (~16ms) the tile is visible at full scale (no transform) because animation not yet started and no initial shrink. That causes a flash of normal tile then shrink? Actually when class added, animation:popIn starts; the element was at scale(1) (no transform). The animation's 0% sets scale(.1). The browser applies animation; at start the element jumps to scale(.1)? Animations apply the 0% style immediately when animation starts (unless animation-fill-mode backwards... by default, the 0%/from style is applied at start, then animates). Actually CSS animations: the fromKeyframe styles are applied immediately when the animation begins (they become the running styles), so the element jumps to scale(.1) at the moment class added then animates to 1. So flash is minimal (1 frame at scale 1 then snap to .1). Acceptable.
The original double-class (pop-in present at insert) avoids flash because element starts at scale .1 already (keyframes 0 applied on first render as the animation's initial state? Actually if class present at first render, does animation run on first paint? Yes, adding a class with animation on first paint runs it. And initial style is the 0% keyframe = scale .1 opacity 0). So element first paints at .1 opacity then grows. That's the cleanest. So keeping pop-in in className at creation is good! The rAF re-add is redundant but harmless (adding existing class again no-ops). Actually adding again just re-triggers? setting className already has it; adding via classList.add when already present does nothing (doesn't restart). Fine.
Hmm but I did `requestAnimationFrame(()=>{ el.classList.add('pop-in'); })` while className already 'tile pop-in' — no-op. Let me just remove that rAF line and the pop-in stays. Actually the cleaner approach to avoid any flash is the way I have. Let me keep pop-in in className and remove the rAF duplicate. I'll edit.
Let me make these fixes:
1. Remove rAF duplicate pop-in (keep pop-in in className).
2. Fix .tile sizing: remove `place-self:center; margin:0;`, let it stretch to fill cell; keep flex centering via `justify-content:center`? Actually flex centering centers content; with default width 100% the flex container fills cell; content centered. Set `display:flex; align-items:center; justify-content:center;`. Remove place-self. But without place-self, default grid item stretching applies (align-self stretch, justify-content stretch) → fills cell. Good.
3. Clean checkStates logic.
4. Remove redundant draw() no-op calls maybe. I'll leave draw() function but it does nothing; or remove entirely. Let me remove draw() function and its calls to avoid confusion. Actually removing requires edits. Let me keep simple: remove draw calls and function.
Let me also double check: tiles use grid-column grid-row to position; default in CSS `grid-column:1;grid-row:1` overridden by inline style at creation. Good.
Let me apply edits.
Actually, let me reconsider tile fill: if tile stretches to fill cell, then with gap 12px between cells, tiles don't overlap (grid item area = cell minus gap). Good. The tile bg rounded 10px, cell rounded 10px board... fine.
But tile stretching means a tile showing "2" fills the whole cell with bg color. That matches 2048 (tiles fill cells).
Let me make edits.
Also potential issue: `el.style.fontSize=fontSizeFor(v)` returns viewport units '4.4vw'. Inline style with vw works. Good.
Also number color contrast fine.
Let me also ensure board children: cells created with className 'cell' and gridColumn/Row set. Good. Board has gap; cells fill.
Let me also verify the board has background #bbada0 and padding var(--gap) 12px, with gap 12px between cells. The cells have their own bg #cdc1b2. Looks like 2048. Good.
Now let me make the edits.
Edit 1: .tile CSS.
Edit 2: remove rAF duplicate.
Edit 3: checkStates.
Edit 4: remove draw() calls/function.
Let me do these.Let me refine a few details for cleaner visuals and correct animation behavior.
→ read
{"path":"/workspace/index.html","offset":60,"limit":40}toolResult
padding:24px; } .overlay.hidden{display:none;} .overlay h2{font-size:3rem;margin:0;letter-spacing:3px;} .overlay p{font-size:1.15rem;margin:0;opacity:.9;} .btn{ appearance:none;border:0;border-radius:10px;padding:12px 26px; font-size:1.05rem;font-weight:600;cursor:pointer; background:#8f7451;color:#f7f0e6; transition:transform .12s,background .18s; } .btn:hover{transform:translateY(-2px);background:#a68a64;} .hint{text-align:center;font-size:.9rem;color:#776e61;margin-top:auto;padding-bottom:6px;} @media (max-width:430px){h1{font-size:1.6rem}.score-value{font-size:1.3rem}.btn{font-size:.9rem}} </style> </head> <body> <div class="game" id="game"> <header> <h1>2048</h1> <div class="score-wrapper"> <div class="score-label">Score</div> <div class="score-value" id="score">0</div> <div class="score-label">Best</div> <div class="score-value" id="best">0</div> </div> </header> <div class="board" id="board"></div> <div id="overlay" class="overlay hidden"></div> <p class="hint">Swipe or use arrow keys (and WASD)</p> </div> <script> (() => { const SIZE = 4; const MOVE_DUR = 200; const POP_DUR = 160; let grid, tileEls, nextId, score, best, won, canContinue, gameOver, isAnimating; const board = document.getElementById('board'); const overlay = document.getElementById('overlay'); [267 more lines in file. Use offset=100 to continue.]
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Let me make the edits I planned.
→ edit
{"path":"/workspace/index.html","edits":{"oldText":" .tile{\n position:relative;\n grid-column:1;grid-row:1;\n place-self:center;\toolResult
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→ edit
{"newText":"el.setAttribute('data-id',id);\n // element already carries 'pop-in' class set below for instant animation\n requestAnimattoolResult
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Wait, I removed the board.appendChild and tileEls.set inside that block but they were after the rAF. Let me check the current state of createTileEl. The original was:
```
function createTileEl(id,v,r,c){
const el=document.createElement('div');
el.className='tile pop-in';
el.style.gridColumn=c+1;
el.style.gridRow=r+1;
el.style.fontSize=fontSizeFor(v);
const col=colorFor(v);
el.style.backgroundColor=col.bg;
el.style.color=col.t;
el.textContent=v.toLocaleString();
el.setAttribute('data-id',id);
// place first, then animate
board.appendChild(el);
tileEls.set(id,el);
requestAnimationFrame(()=>{ el.classList.add('pop-in'); });
}
```
My edit replaced the comment + appendChild + set + rAF with `requestAnimationFrame(/*...*/)`. That removed appendChild and tileEls.set! Now the tile is never added to board nor map. Bug. Let me fix.I accidentally removed the append and map-set lines. Let me fix that:
→ edit
{"newText":"el.setAttribute('data-id',id);\n board.appendChild(el);\n tileEls.set(id,el);\n // 'pop-in' class set above triggers thtoolResult
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thinking
Wait, but the className already has 'tile pop-in' set at the top: `el.className='tile pop-in';`. So pop-in is present. Good. The append + set are restored. Good. Now fix checkStates and remove draw() no-op. Let me read the relevant section.
Now let me clean up the `checkStates` logic and remove the redundant no-op `draw()` function and calls:
→ read
{"path":"/workspace/index.html","offset":230,"limit":60}toolResult
const [tr,tc]=line[t]; ng[tr][tc]={v:res.v,id:res.id}; const p=res.primary; if(res.merged){ transitions.push({id:res.id, fromR:p.r, fromC:p.c, toR:tr, toC:tc, val:res.v, merged:true}); transitions.push({id:res.partner.id, fromR:res.partner.r, fromC:res.partner.c, toR:tr, toC:tc, val:res.v, merged:true, disappear:true}); } else if(p.r!==tr || p.c!==tc){ transitions.push({id:res.id, fromR:p.r, fromC:p.c, toR:tr, toC:tc, val:res.v, merged:false}); } }); } return {grid:ng, transitions, scoreDelta, changed:transitions.length>0}; } function hasEmpty(){ for(let r=0;r<SIZE;r++)for(let c=0;c<SIZE;c++) if(!grid[r][c]) return true; return false; } function canMergeAny(){ for(let r=0;r<SIZE;r++)for(let c=0;c<SIZE;c++){ const v=grid[r][c]; if(!v) continue; if(c<SIZE-1){ const n=grid[r][c+1]; if(n&&n.v===v) return true; } if(r<SIZE-1){ const n=grid[r+1][c]; if(n&&n.v===v) return true; } } return false; } function checkStates(){ let maxTile=0; for(let r=0;r<SIZE;r++)for(let c=0;c<SIZE;c++) if(grid[r][c]) maxTile=Math.max(maxTile,grid[r][c].v); if(!won && maxTile>=2048){ won=true; showOverlay('win'); } else if(gameOver||won) return; if(!hasEmpty() && !canMergeAny()){ gameOver=true; showOverlay('lose'); } } function showOverlay(type){ overlay.innerHTML=''; const box=document.createElement('div'); if(type==='win'){ box.innerHTML='<h2>🏆 You Win!</h2><p>You reached 2048. Keep going for more?</p>'; const keep=document.createElement('button'); keep.className='btn'; keep.textContent='Keep Playing'; keep.onclick=()=>{ canContinue=true; overlay.classList.add('hidden'); }; box.appendChild(keep); } else { box.innerHTML='<h2>😞 Game Over</h2><p>No more moves left.</p>'; } const restart=document.createElement('button'); restart.className='btn'; restart.textContent='Restart'; restart.onclick=init; box.appendChild(restart); overlay.appendChild(box); overlay.classList.remove('hidden'); } // ----- animation / drive ----- async function handleMove(dir){ if(isAnimating) return; if(gameOver) return; if(won && !canContinue) return; const res=move(dir); if(!res.changed) return; [73 more lines in file. Use offset=290 to continue.]
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→ edit
{"newText":"function checkStates(){\n let maxTile=0;\n for(let r=0;r<SIZE;r++)for(let c=0;c<SIZE;c++) if(grid[r][c]) maxTile=Math.max(toolResult
Successfully replaced 1 block(s) in /workspace/index.html.
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TAKE IT TO CODE
A single self-contained HTML file — copy it and open in any browser, or reuse the prompt with your own pi-agent run.
RUN
modellaguna-s-2.1
vendorpoolside
harnesspi-agent
generated2026-08-02
EVALUATION
★★★★★ 3/5 working
2048 grid responds correctly to arrow keys and WASD with tile movement, but score display seems broken/unreadable.
Vision grade · anthropic/claude-sonnet-5
MEASUREMENTS
Raw readings from the capture, not a verdict — the grade above is the only judgement. Percentages are how much of the screen changed; the measure under-reports sparse motion on a dark background.
idle motion0.0%
on click0.0%
on drag0.0%
on wheel0.0%
on enter + space0.0%
on arrow keys8.4%
on w/a/s/d5.9%
frame spread71.7 / 255
console errors0
js errors none
METRICS
runtime356.3s
tokens in187k
tokens out30k
cached157k
cost / run$0.1448