Tetris · ling-3.1-flash

I need build single-file index.html in /tmp/job-3iBB1B, no external resources. Need implement Tetris robustly. We have max 15 minutes total. Need use file tools and browser verification. Need plan carefully.

Requirements:
- Canvas 10x20 visible board.
- Seven tetrominoes legal spawn positions.
- Controls Left/Right move, Up rotate clockwise, Down soft-drop, Space hard-drop, show controls.
- Reject invalid moves/rotations.
- Lock landed pieces, clear rows, move rows down, spawn next. Display score, lines, level, next preview.
- Scoring 100/300/500/800 * level for 1-4 rows. Level starts 1, gravity speed increases every 10 cleared lines.
- Game over if new piece cannot spawn. Pause/Resume and Restart; restart resets board score level piece sequence state.
- Verify move rotate first piece, hard-drop, locks, new spawns, next preview advances; pause/resume; restart.

Need create complete game. Could include ghost optional; maybe implement ghost for polish. Hold optional; avoid to reduce complexity. Need maybe keyboard handling preventDefault. Use requestAnimationFrame with timestamps. Gravity speed perhaps level-based: drop interval = max(50, 1000 * Math.pow(0.8, level-1))? Increase speed every 10 lines: level = floor(lines/10)+1. That's standard. Soft drop maybe interval 50ms or move immediately with gravity points? Requirements just Down soft-drop; can move down one cell each key repeat? Better implement soft drop by accelerating gravity and maybe move one row on keydown. Need avoid double movement: On keydown Down set softDropping true; in update if softDropping use soft interval (e.g. 40ms), else gravity interval. Could also on keydown move immediately once if possible. Simpler: keydown sets softDrop=true; game loop uses interval min(gravity, 50). Keyup sets false. That's acceptable. But for responsiveness maybe on keydown move one cell and reset drop timer. Let's design.

Canvas rendering: board canvas maybe 300x600 (cell 30). Next preview canvas 120x120 (cell 24) with 4x4 area. Draw grid, pieces, ghost. UI controls. Buttons pause/resume/restart. Score/lines/level in DOM. Game over overlay. Maybe pause overlay.

Tetromino definitions:
I: [[1,1,1,1]] spawn x=3? Legal spawn. Standard SRS spawn: I at x=3 y=0 or y=-1; but for visible board and rotation, simpler 4x4 matrices. Need all seven legal spawn positions. Use matrices:
I: [[0,0,0,0],[1,1,1,1],[0,0,0,0],[0,0,0,0]] spawn x=3,y=0 (cells at y=1). Rotation around matrix; okay.
O: [[1,1],[1,1]] spawn x=4,y=0.
T: [[0,1,0],[1,1,1]] spawn x=3,y=0.
S: [[0,1,1],[1,1,0]] spawn x=3,y=0.
Z: [[1,1,0],[0,1,1]] spawn x=3,y=0.
J: [[1,0,0],[1,1,1]] spawn x=3,y=0.
L: [[0,0,1],[1,1,1]] spawn x=3,y=0.
Spawn y=0 means cells occupy rows 0/1. Rotation in 3x3 with origin top-left may cause boundary issues near floor; can implement rotate with kicks optional. Simpler rotate matrix and attempt wall kicks: [0,0],[-1,0],[1,0],[-2,0],[2,0],[0,-1] maybe. Requirement wall kicks optional; if unsupported reject blocked rotation. We can include basic kicks; okay. But "reject rotations that overlap occupied cells or leave board" says if unsupported reject; kicks optional. We can implement simple kicks and still reject if all fail.

Need ensure rotation doesn't change piece when invalid. Use clone matrix.

Bag randomizer: 7-bag sequence. "piece sequence state" reset. Next-piece preview advances. We'll maintain bag and next piece. Simpler: `bag = []`; `nextType = drawFromBag()`; current = spawn(nextType); after lock current = spawn(nextType); nextType = drawFromBag(); display. Reset bag and next on restart. Need avoid first next undefined. On start: refill bag, nextType = take(), spawnPiece(nextType). Actually spawnPiece uses type and sets current, then nextType=take(); show next. Let's define:
function drawType(){ if(bag.length===0) bag=shuffle([...types]); return bag.pop(); }
function newGame(){ board empty; score=0; lines=0; level=1; bag=[]; nextType=drawType(); spawnPiece(); gameOver=false; paused=false; ...}
function spawnPiece(){ const type=nextType; nextType=drawType(); current=makePiece(type); renderNext(); if(!isValid(current.matrix,current.x,current.y)){ gameOver=true; ... } }
Wait this draws next before spawning current; okay. At game start nextType drawn then spawn draws another next. Good.

But piece spawn at y=0 with I matrix has empty top row; collision check okay. Some rotation matrices for 3x3 spawn y=0; rotating clockwise can go above board (negative y) for T etc. Our rotation attempt includes [0,-1] maybe but not needed; if rotation matrix has cells in row 0, after rotation may occupy row? Let's check T matrix [[0,1,0],[1,1,1],[0,0,0?]] if 3x3 with bottom row zeros maybe rotate; better use 3x3 matrices with explicit zeros for all to rotate around center. Definitions 3x3:
T: [[0,1,0],[1,1,1],[0,0,0]]
S: [[0,1,1],[1,1,0],[0,0,0]]
Z: [[1,1,0],[0,1,1],[0,0,0]]
J: [[1,0,0],[1,1,1],[0,0,0]]
L: [[0,0,1],[1,1,1],[0,0,0]]
Rotating clockwise around top-left of 3x3 can shift cells. Spawn y=0. Example T rotate: original cells (0,1),(1,0),(1,1),(1,2). CW in 3x3: (r,c)->(c, N-1-r): (1,0)->(0,1), (0,0)->(0,2), (1,1)->(1,1), (2,1)->(1,0). New cells rows 0-1 cols0-2, valid at y=0. Good. S rotate: (0,1),(0,2),(1,0),(1,1) -> (1,2),(2,2),(0,1),(1,1)? rows 0-2 valid at y=0. Good. I 4x4 with row1; rotate to column maybe rows? Original row1 cols0-3 -> (c,3-r): (1,3),(1,2),(1,1),(1,0)? Wait N=4, cells (1,c) -> (c,3-1=2): (0,2),(1,2),(2,2),(3,2) all rows 0-3 valid. Good.

Collision: for each cell matrix[r][c], if value, board y=piece.y+r, x=piece.x+c; invalid if x<0||x>=COLS||y>=ROWS; allow y<0? Spawn y=0 so no negative; rotation may produce y<0 with kick [0,-1] if we allow? We can allow y<0 in collision (cells above board) but drawing skip; however spawn never negative. Simpler invalid if y<0 too? If allow y<0, piece could rotate partly above and later lock with cells above lost. Avoid y<0: invalid if y<0. But I rotation at y=0 okay. Basic kicks include [0,-1] maybe could create y<0 invalid; fine.

Locking: When gravity moves down and cannot, lock. Also soft drop when cannot move down should lock immediately? Standard soft drop locks when at bottom and pressing down? In many implementations, soft drop moves until collision then locks. If we only accelerate gravity, locking occurs after interval. Acceptable. But keydown Down could attempt move once; if at bottom, lock immediately. Let's implement `tryMove(0,1)` on Down keydown; if false, lockPiece() perhaps. However holding Down with key repeat could lock quickly when at bottom; fine. But if piece is not at bottom, moves one cell and resets drop timer. Soft drop acceleration also via keydown/keyup. Simpler and responsive.

Need prevent repeated keydown when holding? Browser key repeat will call; okay for movement, but for Up rotate repeat could spin; acceptable maybe. Could ignore e.repeat for Up and Space to avoid accidental repeated hard drops. Left/Right repeat okay. Down repeat okay. Space ignore repeat. Up ignore repeat maybe.

Hard drop: while can move down, y++, score += maybe 2 per cell? Requirements don't specify hard-drop points; can award 2 per cell or no. Avoid complicating? Awarding extra is okay but verification score after hard drop maybe expected only lock no lines. Better not award hard drop points to keep score deterministic for required scoring? But common Tetris awards 2 per cell; not required. To avoid unexpected score, no points for hard drop. Lock immediately after. Then clear lines, spawn next.

Locking and line clear:
function lockPiece(){ for cells board[y][x]=type; let cleared=clearRows(); if cleared>0 score += [0,100,300,500,800][cleared]*level; lines += cleared; level = Math.floor(lines/10)+1; updateHUD(); spawnPiece(); }
Need update level before scoring? Requirement score multiplied by current level. If line clear causes level up, should use level before increase (current). Standard uses level before. Use points = base[cleared]*level; then lines += cleared; level = floor(lines/10)+1. Good.
clearRows: iterate rows bottom-up, if every cell non-zero remove and unshift(new Array(COLS).fill(0)); count.
Animation? Not required. Could render immediately.

Gravity: lastTime, dropCounter. In update(timestamp): if gameOver or paused return; delta = timestamp - lastTime; lastTime=timestamp; dropCounter += delta; interval = softDrop ? Math.min(gravityInterval(), SOFT_INTERVAL) : gravityInterval(); while(dropCounter>=interval){ dropCounter-=interval; if(!tryMove(0,1)){ lockPiece(); break; } } Need if lockPiece spawns new piece and resets dropCounter maybe. Set dropCounter=0 on spawn. If softDrop and at bottom, tryMove false -> lock. Good.
Potential issue while loop with delta large after pause; reset lastTime on resume. We'll handle pause toggling lastTime=performance.now().

Level speed: gravityInterval = Math.max(60, 1000 * Math.pow(0.85, level-1)) maybe at level 1 1000ms, level 10 ~231ms, level 20 ~54ms. "increase gravity speed every ten cleared lines" level increases every 10 lines. Good.

Controls display: text below/side: ← → move, ↑ rotate, ↓ soft drop, Space hard drop, P pause? Requirement Pause/Resume and Restart buttons; keyboard P optional. Show buttons.

Canvas sizing: cellSize 30; canvas width 300 height 600. Board border. Use CSS. Next canvas 120x120 maybe draw piece centered in 4x4 grid cell 24. For I and O maybe center. Use matrix bounding box to center. Simpler draw at (nextCanvas.width/2 - matrix[0].length*cell/2, ...) with cell=24. For 4x4 I matrix includes empty rows; okay. Maybe use cell=24 and offset to center matrix dimensions. Draw with same colors.

DOM structure:
<!DOCTYPE html><html><head><meta charset...><title>Tetris</title><style>...</style></head><body><div class="game"><h1>Tetris</h1><div class="layout"><div class="board-wrap"><canvas id="board" width="300" height="600"></canvas><div id="overlay" class="overlay hidden">...</div></div><aside class="side"><div class="panel">Next<canvas id="next" width="120" height="120"></canvas></div><div class="panel stats">Score... etc</div><div class="panel controls">...</div><button id=pauseBtn>Pause</button><button id=restartBtn>Restart</button></aside></div></div><script>...</script></body></html>
Need overlay inside board-wrap absolutely positioned. Game over message. Pause overlay maybe reuse overlay with message. But if overlay shown for pause, canvas still visible. Use overlay div with id message. Hidden class.

Buttons: pauseBtn text toggles Pause/Resume. restartBtn. Also keyboard P/Escape? Add P pause. Space hard drop; if game over, space maybe restart? Not needed.

Accessibility: buttons focus. Canvas not focusable; keyboard on window.

Rendering board: clear canvas, draw background cells grid, locked pieces, ghost, current piece. Draw grid lines. Colors per type:
I cyan, O yellow, T purple, S green, Z red, J blue, L orange.
Cell drawing with fill and border. Use `ctx.fillStyle=colors[type]; ctx.fillRect(x*CELL+1,y*CELL+1,CELL-2,CELL-2);` maybe stroke.
Ghost: compute ghostY by while can move down; draw with alpha or outline. Optional but nice. If ghost overlaps current? draw ghost first then current.
Game over: overlay show "Game Over" and maybe final score. Set current=null? Keep board. Stop updates. Spawn piece if cannot spawn: show Game Over. Need if new piece cannot spawn, show Game Over. In spawnPiece after setting current, if invalid, set gameOver=true; current maybe still drawn? Better do not draw invalid piece; set current=null after? But to show game over, overlay covers. Implementation:
function spawnPiece(){ const type=nextType; nextType=drawType(); current={type,matrix:SHAPES[type],x:...,y:0}; dropCounter=0; updateNext(); if(!isValid(...)){ gameOver=true; current=null; showOverlay('Game Over'); updateHUD(); } }
This means next preview advanced even on game over; fine.
But at newGame, spawnPiece will show game over if spawn invalid (empty board no).

Restart resets piece sequence state: bag=[]; nextType=drawType(); current=null; spawnPiece(); score lines level; overlay hidden; paused=false; pauseBtn text Pause; lastTime=performance.now(); dropCounter=0; render.

Pause: if gameOver return; paused=!paused; pauseBtn text; overlay show Paused/hidden; lastTime=performance.now() to avoid delta; if paused maybe render same. In loop, if paused return after lastTime update? We want not accumulate. Set lastTime each frame regardless at start. Implementation loop(t){ lastTime=t; if(!paused && !gameOver) update(t); render(); requestAnimationFrame(loop); } This updates lastTime always. Good. On toggle pause no need reset.

Key handling: window.addEventListener('keydown', e=>{ if(['ArrowLeft','ArrowRight','ArrowDown','ArrowUp',' '].includes(e.key)) e.preventDefault(); if(e.repeat && (e.key===' '||e.key==='ArrowUp')) return; if(gameOver){ if(e.key==='Enter'?) restart? not required; return;} if(e.key==='p'||e.key==='P'){togglePause();return;} if(paused) return; switch... });
Need if paused and user presses Space maybe not hard drop. okay. If game over, maybe allow R? Not required. Could allow Enter to restart but not necessary. Add key 'r' restart? Not required; buttons suffice. Keep.
Left/Right: tryMove(-1/1). Up: rotatePiece. Down: if(!tryMove(0,1)) lockPiece(); softDrop=true; reset dropCounter? If move success, dropCounter=0. If lock, spawn resets. Keyup Down softDrop=false.
Space: hardDrop.
Potential issue keydown Down at bottom locks immediately and then key repeat after lock may spawn new piece and move down one (since still holding) causing accidental soft drop for next piece. That's standard-ish when holding down; but if user taps down at bottom, key repeat could move next piece. Maybe ignore e.repeat for Down and rely on softDrop acceleration; but then a tap moves one cell and holding accelerates. That's better: `if(e.key==='ArrowDown'){ softDrop=true; if(!e.repeat){ if(!tryMove(0,1)) lockPiece(); dropCounter=0; } }` However if e.repeat and softDrop true, gravity handles. Good. But keydown repeat events may be slow; gravity soft interval handles.
Left/Right allow repeat.
Up ignore repeat.
Space ignore repeat.

Rotation with kicks:
function rotatePiece(){ const rotated=rotateMatrix(current.matrix); const kicks=[[0,0],[-1,0],[1,0],[-2,0],[2,0],[0,-1]]; for [dx,dy] if isValid(rotated,x+dx,y+dy){ current.matrix=rotated; current.x+=dx; current.y+=dy; return;} }
Need rotate matrix clockwise:
const N=m.length; const result=Array.from({length:N},()=>Array(N).fill(0)); for r,c result[c][N-1-r]=m[r][c]; return result.
All matrices square (2,3,4). Good.
Kicks include [0,-1] but collision invalid if y<0; okay. For I at spawn y=0 rotation valid no kick. For pieces near floor, kicks [0,-1] may help; basic.

Legal spawn positions: shapes spawn x=3 (I x=3 because 4 wide -> columns 3-6; standard x=3), O x=4 (cols4-5), others x=3 (cols3-5). y=0. Good.

Line clear with locked pieces: board stores type strings or null. Use 0 for empty. Draw colors[cell].

Next preview: draw matrix. For I 4x4 with only row1, drawing in 120 canvas with cell 24 leaves vertical center not exact (matrix height 4). Could compute bounding box of filled cells and center. Let's implement getBounds(matrix) min/max rows/cols; draw cells offset so bounding box centered. For next canvas, cell=24; compute width=(maxC-minC+1)*cell, height=(maxR-minR+1)*cell; offsetX=(canvas.width-width)/2 - minC*cell; offsetY=(canvas.height-height)/2 - minR*cell; then for each filled cell draw at offsetX+c*cell. Good.

HUD update: scoreEl.textContent etc. level. Lines.

Overlay: `function setOverlay(text){ if(!text){overlay.classList.add('hidden'); overlayMsg.textContent='';} else {overlay.classList.remove('hidden'); overlayMsg.textContent=text;}}` Game over shows `Game Over` maybe with score. Pause shows `Paused`. On resume hidden. On restart hidden.
Need overlay not block buttons? It's inside board-wrap; buttons outside. Fine. During game over overlay covers board but not side buttons.

CSS: dark theme, center. Use no external fonts. Canvas border. Buttons.

Testing with browser: Need write file then run browser. We have browser tool. We can use bash to create? Instructions say use file tools; write. Then browser open? The browser tool likely automatically runs index.html in current dir? We need call browser action inspect/screenshot after write. It says Run index.html, inspect DOM/console. Probably browser tool loads current file. We'll call screenshot/inspect. Need maybe use browser click/key to verify. Coordinates 1200x800. We can interact: click canvas? Keyboard events on window; use key action. Browser tool supports key with text? action key, text maybe key. Need use `browser` with action "key" text "ArrowLeft" etc. It likely sends key. We can screenshot before/after. Need verify programmatically maybe inspect DOM/console output. Browser tool returns maybe DOM text and console. We'll use.

Need ensure no console errors. Let's write file. Need be concise but complete. Use write. Then browser. Let's compose code carefully.

Potential subtle bug: In game loop, `lastTime` initialized; requestAnimationFrame(loop). loop(t){ lastTime=t; if(!paused&&!gameOver) update(t); render(); requestAnimationFrame(loop); } update uses `timestamp - lastTime` but lastTime already set to timestamp in loop -> delta 0. Need separate: loop(t){ const delta = lastTime ? t-lastTime : 0; lastTime=t; if(!paused&&!gameOver){ dropCounter += delta; ... } render(); request... } Or update receives delta. Let's design:
let lastTime=0;
function loop(t){ const delta = lastTime ? t-lastTime : 0; lastTime=t; if(!paused && !gameOver){ step(delta); } render(); requestAnimationFrame(loop); }
function step(delta){ dropCounter += delta; const interval=softDrop?Math.min(SOFT_DROP_INTERVAL, gravityInterval()):gravityInterval(); while(dropCounter>=interval){ dropCounter-=interval; if(!tryMove(0,1)){ lockPiece(); break; } } }
On toggle pause, lastTime remains; when resume delta includes pause duration? Because loop continues and lastTime updates every frame even paused, so no. Good. On restart lastTime=0 to avoid huge; but loop updates next frame delta 0 if lastTime=0. Set lastTime=0 in newGame.
If lockPiece inside step spawns and sets dropCounter=0; break. Good.
If softDrop true and piece locks due to step, new piece spawns; holding down continues soft drop. Fine.

tryMove(dx,dy){ const newX=current.x+dx,newY=current.y+dy; if(isValid(current.matrix,newX,newY)){current.x=newX;current.y=newY;return true;} return false; }
If current null (game over) return false. Guard.

lockPiece(){ if(!current) return; for cells if y>=0 board[y][x]=current.type; const cleared=clearRows(); if(cleared>0){ score += LINE_POINTS[cleared]*level; lines+=cleared; level=Math.floor(lines/10)+1; } current=null; dropCounter=0; updateHUD(); spawnPiece(); }
Order: current=null before spawn to avoid weird. spawnPiece sets current. If cleared, updateHUD after level. Good.
But if cleared>0, we update score/lines/level then updateHUD once after spawn? spawnPiece calls updateNext but not HUD. We'll call updateHUD after spawn too. Simpler compute, then spawnPiece(); updateHUD();. But spawnPiece may set gameOver. Fine.
Need if cleared=0 no score.

clearRows(){ let cleared=0; for(let y=ROWS-1;y>=0;y--){ if(board[y].every(v=>v!==0)){ board.splice(y,1); board.unshift(Array(COLS).fill(0)); cleared++; y++; } } return cleared; }
Because splice shifts, increment y to recheck same index. Good.

spawnPiece(){ const type=nextType; nextType=drawType(); const matrix=SHAPES[type].map(row=>row.slice()); current={type,matrix,x:type==='O'?4:3,y:0}; dropCounter=0; renderNext(); if(!isValid(matrix,current.x,current.y)){ current=null; gameOver=true; pauseButton.textContent='Pause'; setOverlay('Game Over'); updateHUD(); } }
At game start nextType drawn. Good. But if game over, nextType has advanced; okay.

newGame(){ board=createBoard(); score=0; lines=0; level=1; bag=[]; nextType=drawType(); current=null; gameOver=false; paused=false; softDrop=false; dropCounter=0; lastTime=0; pauseBtn.textContent='Pause'; setOverlay(null); spawnPiece(); updateHUD(); render(); }
spawnPiece draws next and renders next. Good.

drawType(){ if(bag.length===0){ bag=Object.keys(SHAPES); for(let i=bag.length-1;i>0;i--){const j=Math.floor(Math.random()*(i+1)); [bag[i],bag[j]]=[bag[j],bag[i]];} } return bag.pop(); }
Object.keys order consistent I,O,T,S,Z,J,L as defined. Fine.

Render:
function render(){ ctx.clearRect...; ctx.fillStyle='#0f172a'; fill; draw grid; for y,x if board cell drawCell(ctx,cell,x,y,BOARD_CELL); if(current && !gameOver){ drawGhost(); drawPiece current } }
Need if gameOver current null; board remains.
drawCell(ctx,type,x,y,cell){ const px=x*cell, py=y*cell; ctx.fillStyle=COLORS[type]; ctx.fillRect(px+1,py+1,cell-2,cell-2); ctx.strokeStyle='rgba(255,255,255,.25)'; ctx.strokeRect(px+1.5,py+1.5,cell-3,cell-3); }
For ghost: ctx.globalAlpha=0.25; draw cells; globalAlpha=1. Or stroke only. Use fill alpha.
computeGhostY(){ let y=current.y; while(isValid(current.matrix,current.x,y+1)) y++; return y; }
drawMatrix(matrix, offsetX, offsetY, cell, type, alpha). For current use x,y.
Grid lines: ctx.strokeStyle='rgba(148,163,184,.12)'; begin path vertical/horizontal; stroke. Could draw every cell.

Next render: clear; if nextType draw bounds. Use NEXT_CELL=24.

Overlay: boardWrap position relative; overlay absolute inset 0 display flex; hidden display none. background rgba. z-index.

Controls panel: list. Buttons.

Need maybe show level speed? not required.

Let's write.

Now need browser verify. Use browser action maybe screenshot/inspect. Need know tool loads file automatically. Call browser screenshot maybe.

Browser output no image. Need interact and verify. We need simulate keys. Browser tool key action text maybe. Need call key ArrowLeft etc. Let's inspect DOM maybe includes canvas but not board state. We can use browser action key. Need maybe use `action:"key", text:"ArrowLeft"`? Let's try sequence in one? Tool only one action per call; can parallel? Need sequential because state. We'll call key ArrowLeft, then ArrowUp, then Space. But to verify first piece move/rotate/hard-drop, need know piece and state. Could use DOM? Canvas not accessible. We can use screenshot but model doesn't support images. Maybe browser tool returns DOM text only, not canvas pixels. We can add temporary debug? Better use browser's inspect maybe returns console and DOM, not JS variables. We can use key actions and then maybe use browser `inspect` to see if no errors. But verification requirement says run app and inspect initial output and console; we did screenshot initial. Need brief pass through representative checks. We can simulate keys and maybe use DOM overlay after game over? Hard to verify board state via DOM. Could add a hidden debug output? Not necessary for final, but for verification we can use browser tool maybe `inspect` returns canvas? It may not. We can use bash with node? No browser automation. Could use `browser` action type/key and screenshot; but no image support. Maybe tool output includes DOM after interactions; canvas doesn't update DOM. We could temporarily add a debug text element showing current piece position, but that would modify final unnecessarily. Could use console.log in code for verification and browser console output. We can add temporary console logs? Better not final? Could add concise debug logging? Not needed. We can use browser action key and then `inspect` console; if code has console.log on lock/spawn, we'd see. We can temporarily add logs, verify, then remove. But time. Alternatively use browser's `inspect` maybe can evaluate JS? Tool description says Run index.html, inspect DOM/console, interact, see screenshots or motion frames. It may return DOM and console only. No eval tool. We can use `key` and `screenshot`; model does not support images in this environment, but maybe `motion` returns frames text? likely not.

Could use bash to run a headless browser? Maybe not installed. Check environment? We have browser tool. Could use `node` with jsdom? No. But we can reason.

Need test pause/resume/restart via buttons clicks. Browser click action needs coordinates. We know layout at viewport 1200x800. Game centered. Need coordinates for canvas and buttons. From screenshot maybe not available. We can compute layout: body min-height 100vh display grid place-items center. Viewport 1200x800. Game width ~ layout 300+18+190 + padding 48 = 556; height max 600 + h1 etc + padding ~? around 700. Centered. Board canvas left around x=(1200-556)/2+24=346, y=(800-gameHeight)/2+? Need approximate. Buttons side at x ~ board left + 300+18+14=698, pause y maybe after next/stats/controls. Could click by coordinates. But browser click may accept x/y. We can use key P for pause/resume instead, easier. Restart button click coordinate. Or key? No restart key. Could click.

Need verify first piece: call key ArrowLeft, ArrowUp, Space. Then maybe inspect console no errors. Then key P pause, screenshot, P resume, then click restart. We can use browser actions sequentially. Let's do key ArrowLeft.

Need maybe browser tool didn't focus? Window keydown should work. No console errors. Next ArrowUp.

Now Space hard drop.

No way to see canvas. Need maybe use browser motion? It might return frames as images not supported. Could add temporary instrumentation to DOM/console. We can modify code to log events to console and maybe update a `data-state` attribute or hidden text. But final can include a small status? Not required; adding debug logs undesirable. We can temporarily edit to add console.log in lock/spawn/pause/restart, run, then remove. Or use permanent `aria-live` overlay? Not necessary. Since verification is for us, temporary edits okay. But we need be efficient. We can add a debug element? Better add console.log statements temporarily, then remove after. Use edit. Need know if keys worked. Add console.log in keydown maybe with event.key and current position, lock, spawn, pause, restart. Then browser key etc and inspect console. But browser tool only returns warning, maybe console doesn't show console.log? It returns console array; likely includes logs. Let's test by adding a simple console.log at startup? We can edit restart to console.log. But final remove. Use edit targeted. Add `console.log('debug-restart', {score, lines, level});` after restart? Actually restart function. Then browser reload to see. But we already ran. Let's add temporary logs in keydown and lock/spawn. Use edit with unique snippets. Need not overdo. We can add at top of keydown: `console.log('key', event.key, current ? [current.type,current.x,current.y] : null, gameOver, paused);` But current before action. Add in lockPiece after cleared: log. spawnPiece after current set: log. togglePause log. restart log. Then reload and interact. Let's edit.

Need reload to pick changes. browser reload.

Great. Now first piece T at 3,0 next I. Move left, rotate, hard drop. Need key actions sequential.

Interesting after reload, by the time key event, gravity moved T from y0 to y2 (interval 1s? Maybe reload then tool latency >2 sec). It moved left to x2 presumably no log after. Need rotate log maybe add? We only log before. Next ArrowUp will show before [T,2,y]. Good.

It moved down due to gravity. Rotate succeeded likely but no after log. Hard drop now.

Great. Logs show hard drop locked T at y17 (after move/rotate), spawned I, next advanced from I to S. Score remains 0. Need verify board locked maybe log board count? debug-lock-start before board count 0; after lock no log. Could add after lock board count. But we can infer. Maybe add log after lock to verify cells. We can add temporary log after writing board. But not necessary? For verification, good. Add log after loop before clearRows maybe `console.log('debug-locked-cells', board.flat().filter(Boolean).length);`. Then reload and maybe hard drop again? We can. But time. Need pause/resume and restart. Use key P. Before pause, current I at y? It may fall. Key P logs. Then P again. Then click restart. Need click coordinates. We can use key P for pause/resume. For restart, browser click on Restart button. Need coordinates. Could use DOM? Browser click requires x/y. Need compute. Maybe use `action:"click"` with x/y. We can approximate. Let's determine layout more precisely from DOM? The browser tool output doesn't give bounding boxes. Could use screenshot but images unsupported. We can use CSS compute manually. Viewport 1200x800. Let's calculate game height:
Game padding top/bottom 24. h1 font-size 28 line-height normal ~1.2 =33.6 margin bottom18 => ~51.6. Layout height = max(board-wrap 600, side height). Side panels: Next panel padding 28 + h2 ~? h2 font13 line-height normal 1.2=15.6 margin bottom10 =>25.6 + canvas120 =173.6. Stats panel padding28 + h2 25.6 + stats grid gap8 + 3 rows each strong font20 line-height ~24 =>72 =>125.6 total? 28+25.6+8+72=133.6. Controls panel padding28 + h2 25.6 + ul gap7 + 5 rows each ~20? =100+28 =>181.6? 28+25.6+7+100=160.6. Buttons two buttons height ~41 each + gap10 =92. Side gap14 between 4 children: total 173.6+14+133.6+14+160.6+14+92=601.8. Layout height ~601.8. Game height =24+51.6+18+601.8+14(footer margin)+16(footer text)+24 =749.4. Viewport 800, top ~25.3. Game left = (1200 - game width)/2. Game width = padding48 + layout width (300+18+190=508) =556. left=322. Board-wrap left inside game =322+24=346; top=25.3+24+51.6+18=118.9. Side left=346+300+18=664; side top same 118.9. Buttons top = side top + next panel 173.6 + gap14 + stats133.6 + gap14 + controls160.6 + gap14 =610.1; pause button height maybe 41, restart top=610.1+41+10=661.1; restart x=664+? panel width190 button full width, center x=664+95=759; y=661+20=681. So click restart at (759,681). Pause button at (759,630). But we can use P key for pause/resume. For restart click approximate (759,681). Need maybe if coordinates off, click could miss. Could add keyboard shortcut R for restart to make verification easier, but requirement only buttons; adding R optional. Could temporarily use click. Or add `restartBtn.click()` via browser? No eval. Could add key 'r' permanent? Not required but harmless. But user asked provide Restart; button exists. For verification, click.

First pause P.

Interesting I locked at y15 after some time (gravity continued during tool latency), spawned S, then paused. DOM shows PAUSED and Resume button. Good. Resume with P.

Pause/resume works. Now restart click. Need coordinates. Use browser click x759 y681.

Oops click at 759,681 hit Pause button (because our coordinate estimate off; it toggled pause to true), not restart. DOM shows PAUSED Resume. Need click restart lower or use pause then click. Current paused true. Need resume first (P), then click restart at correct coordinate. Our pause button center y ~? Click at 681 hit pause, so pause button center is 681. Then restart center = 681 + button height + gap. Button height maybe 41? If click at 681 center, restart center ~681+41+10=732. But viewport height 800, okay. Let's P to resume then click (759,732).

Now click restart at (759,732).

Click at 732 didn't register? Maybe restart button center different or click missed. Need determine actual button positions. The click at 681 hit pause, so pause center y=681. Button height maybe 39, gap10, restart center = 681 + 39/2 +10 +39/2 =681+49=730. We clicked 732, should hit. But no debug-restart. Maybe because after resume, gravity continued and by click time game over? No. Or click coordinates outside due to layout different? Wait click at 681 toggled pause, so x=759 correct. Why 732 not restart? Maybe button height larger? Let's compute: If pause center 681, restart center = 681 + pauseHeight + gap. If pauseHeight maybe 43 and gap10 =>734. Still close. Maybe click y=732 hit just above restart if button height 47? center=681+47+10=738. Need click lower, maybe 745. But viewport 800; game bottom maybe? Game height ~749 top25 => bottom774, side bottom maybe? Restart button bottom within game. Try click (759,745). If miss maybe below. Use browser click.

Restart works: debug-restart, spawn L next J, score/lines/level reset in DOM. Need remove debug logs. Then maybe final screenshot/inspect. Also maybe test line clearing? Not required by verify but required behavior. We should ensure code works. Could reason. But maybe test scoring by manipulating board? Hard via UI. Could use debug functions? Not exposed. We can trust. Need remove all console.log debug statements. Use edit to remove. Need carefully revert edits. We can use edit with exact strings including logs. Let's remove six logs.

Need reload final and inspect console for errors. Also maybe check file no debug. Use grep via bash? Use read? We can bash grep. Instructions use bash for file ops. Do that.

No debug. Reload final.

Need maybe final response concise report what checked and unverified. But before final, let's deeply review code for any bugs. Since desired oververbosity 4 but coding assistant concise. Need ensure requirements all met. Let's inspect final file maybe read relevant sections to ensure no syntax issues. Browser no errors. But let's reason about edge cases.

Potential bug: `restart()` calls `spawnPiece()` before `updateHUD()`, spawnPiece calls renderNext and maybe setOverlay game over; fine. `lastTime=0` but loop may be already running; next frame delta = lastTime? lastTime global set 0, so delta 0. Good.

Potential bug: When game over occurs, `spawnPiece` sets `current=null` and `gameOver=true`, but `nextType` has advanced; overlay shows. Loop stops step. Render board. Good.

Potential bug: If a new piece cannot spawn because board occupied at spawn, game over. Good.

Potential bug: Rotation of O matrix: rotateClockwise works on 2x2, no change. Good.

Potential bug: `isValid` rejects y<0. Spawn y=0. Rotation kicks include [0,-1] but if y=0 invalid; other kicks. Good.

Potential bug: Hard drop while piece at top and board full? If current valid, hard drop moves until invalid then lock. If spawn invalid, current null, hardDrop returns. Game over already. Good.

Potential bug: Soft drop keydown when at bottom locks immediately; if event.repeat and softDrop true, no immediate lock but step locks after interval. Good.

Potential bug: After lock due to ArrowDown keydown, `lockPiece` calls `spawnPiece`, then keydown continues `dropCounter=0` after `if (!tryMove...) { lockPiece(); } dropCounter=0;` Actually code:
case ArrowDown:
 softDrop=true;
 if(!event.repeat){
   if(!tryMove(0,1)){ lockPiece(); }
   dropCounter=0;
 }
 break;
If lockPiece spawns new piece and sets dropCounter=0, then we set dropCounter=0 again. Fine. If tryMove succeeded, reset timer. Good.

Potential bug: `tryMove` returns false if paused; in step paused not called. fine.

Potential bug: Level speed increases every ten cleared lines: level = floor(lines/10)+1. gravity interval decreases with level. Good.

Potential bug: Scoring uses current level before increment. Good.

Potential bug: Clear rows moves rows above downward: splice/unshift does. Good.

Potential bug: Next-piece preview advances: nextType drawn before spawn, renderNext. Good.

Potential bug: Seven tetrominoes with legal spawn positions: yes.

Potential bug: No external assets: all inline. Good.

Potential bug: Canvas visible board 10x20: canvas 300x600, cell30. Good.

Potential bug: Controls shown. Good.

Potential bug: Pause/Resume and Restart buttons. Good.

Potential bug: Restart resets piece sequence state: bag=[] and nextType=drawType. Good.

Potential bug: Random bag uses `Object.keys(SHAPES)` and shuffles. Good.

Potential bug: `renderNext` offsetX calculation: `(nextCanvas.width - width)/2 / NEXT_CELL - bounds.minC`. Operator precedence: division left-to-right, so ((width difference)/2)/NEXT_CELL - minC. Correct. For matrix bounds, offset in cell units. Example I bounds minR=1 maxR=1 minC=0 maxC=3 width=96 height=24 offsetX=(120-96)/2/24=0.5 offsetY=(120-24)/2/24=2; draw cells at c+0.5, r=1+2=3. Good.

Potential bug: drawCell uses globalAlpha then resets to 1 before stroke; for ghost we set globalAlpha=0.22 then drawMatrix calls drawCell which sets globalAlpha=0.22, fill, then sets globalAlpha=1 and strokes fully opaque. Ghost will have opaque border, maybe not ideal but okay. It draws ghost with border visible; acceptable. Could set stroke alpha too but not required.

Potential bug: In `render`, if gameOver and current null, locked board shown under overlay. Good.

Potential bug: Overlay text for game over doesn't show final score; not required.

Potential bug: `pauseBtn.textContent` on game over set Pause; if user clicks pause while gameOver togglePause returns, button says Pause but does nothing. Could be confusing but okay. Maybe set disabled? Not required.

Potential bug: When paused, keydown ArrowDown etc returns after P check; softDrop remains false because togglePause sets false. Good.

Potential bug: When window loses focus while holding Down, keyup may not fire, softDrop stuck true. Not critical. Could add blur listener to set softDrop false. Optional. Not required.

Potential bug: Hard drop scoring not required; no points. Fine.

Potential bug: Gravity interval at level 1 1000ms; during browser tool interactions latency caused pieces fall multiple rows; okay.

Potential bug: `step` while loop could lock multiple pieces if delta huge? It breaks after lock. Good.

Potential bug: After line clear, `lockPiece` sets current=null then spawnPiece. If spawnPiece game over, updateHUD called inside spawn and again after; fine.

Potential bug: `clearRows` y++ after splice: Suppose cleared row at y=19, splice removes, unshift adds at top, array length same. y-- makes y=18 then y++ makes 19, rechecks new row at 19 (previously row18). Correct. If multiple rows, works.

Potential bug: Rotation matrix for I 4x4 with spawn x=3; rotating near right wall with kicks [-2,0] etc. Basic. Legal.

Potential bug: Wall kicks optional; we support some. Good.

Need maybe test line clear/scoring? We can use browser only UI; to test we'd need fill board, not feasible. But code is straightforward. Could maybe expose a debug key to clear rows? Not needed. We can mention not verified via UI? The prompt says verify specific move/rotate/hard-drop, pause/resume, restart. We did. We can report those checked; line-clear scoring not exercised in the brief pass. But maybe final should say what actually checked and remaining unverified. We can say console showed lock/spawn/next advance; pause/resume and restart reset. Line-clear scoring and game-over overlay were not exercised in the interactive pass (code implemented but not triggered). However we did not actually verify line clear; be honest. But maybe we can quickly test line clear by adding a temporary key or using browser? We have time (we've used maybe 5 minutes). Could test line clear programmatically by adding a temporary debug key that fills rows? But final no debug. We could temporarily add a key e.g. "l" to fill bottom row and force clear, then use key to verify scoring, then remove. But that modifies code temporarily; we can. It might be useful to verify scoring and row movement. Let's consider.

We can add temporary key handler for "l" that fills bottom row with current? But to test clearing one row and scoring, we can fill bottom row except maybe current piece will occupy? We can directly manipulate board in key handler: `if(event.key==='l'){ for x board[ROWS-1][x]='I'; lockPiece? }` But lockPiece expects current; we can call `clearRows` and scoring manually? Better simulate: fill bottom row, then set current to a piece that locks into row? Actually to clear a row, need all cells occupied. If we fill bottom row directly and call `clearRows` plus scoring logic, that tests clearRows but not lockPiece integration. Could call `board[ROWS-1].fill('I'); const cleared=clearRows(); score+=...` but that's just function. Better add temporary key "l" that fills bottom row then invokes `lockPiece`? But lockPiece would try to write current cells and then clear. If board bottom row filled and current is e.g. I horizontal at y=17? Hard to control. Simpler temporary test function: on key "l", fill bottom row, then call `lockPiece()` with current null? lockPiece returns if !current. Not good.

Could add temporary key "l" to run `board[ROWS-1].fill('I'); const cleared=clearRows(); if(cleared){score+=LINE_POINTS[cleared]*level; lines+=cleared; level=...} updateHUD();` This tests clearRows and scoring but not lock integration. Then DOM score should 100, lines1, level1; board bottom row cleared. Then key "l" 10 times? Could test level up at 10 lines (score 1000, level2). But temporary. Then remove. Might be overkill. We already trust.

Could test game over by temporary key "g" fill board and spawn? Not needed.

Given prompt specifically says verify move/rotate/hard-drop, pause/resume, restart. We did. Line clear not explicitly in verify list but required behavior. We can state not exercised. But maybe evaluator expects final file only, not report. The addendum says briefly report what checked and which behaviors remain unverified. We should do that.

Need maybe final file present. Yes.

Before final, perhaps use browser screenshot final? Already reload inspect. No console errors except warning. Good.

Need ensure final answer no markdown excessive. Mention file path. Could say "Created /tmp/job-3iBB1B/index.html". Report checks: initial render; ArrowLeft/ArrowUp/Space produced lock log, new piece spawn, next preview advanced; P paused/resumed with overlay/button; Restart click reset score/lines/level and board. Unverified: actual row-clear scoring/level-up and game-over not triggered in interactive pass; code paths implemented. But maybe saying unverified could be seen as incomplete. We can mention "not triggered" honestly.

However, maybe we should actually verify line clear scoring to avoid unverified. Let's see if we can do with temporary instrumentation quickly. We have time budget 15 minutes; used maybe ~8? We can add temporary key and test. But final report can then say all checked. Let's attempt.

Add temporary key in keydown before other handling? We need not interfere. Add:
```
if (event.key === 'l') { // temporary test
  board[ROWS-1] = Array(COLS).fill('I');
  const cleared = clearRows();
  if (cleared>0){ score += LINE_POINTS[cleared]*level; lines += cleared; level=Math.floor(lines/10)+1; }
  updateHUD(); render(); return;
}
```
But this bypasses lockPiece. To test integration, we can fill bottom row and then hard drop a horizontal I piece so it locks into filled row? If bottom row already filled, hard drop piece cannot enter bottom row; it would lock above filled row, no clear. Instead fill row 19 after piece locks? Not integration.

Could test `lockPiece` by setting current manually to a piece whose cells complete a row. For example set board rows 1-19? Simpler: set current to I horizontal at x=3,y=19? But y=19 with matrix row1 -> boardY20 invalid. Set current I vertical? matrix original I has cells at y=1, so if current.y=18, cells at row19 x3-6. Fill row19 except x3-6, then hardDrop? If current at y18, tryMove down invalid (because row19 occupied), hardDrop locks at y18? Wait current matrix I cells at r=1, y=18 -> boardY19. If row19 has cells at x0-2,7-9 filled and x3-6 empty, current can be at y=18 (cells row19 x3-6 empty) and tryMove down invalid because y=19 would put cells row20 out. hardDrop locks I into row19 completing it. Great. Temporary key "l" can set up: fill row19 except columns 3-6, set current={type:'I',matrix:SHAPES.I,x:3,y:18}, nextType maybe 'I', then hardDrop() (but hardDrop uses current, locks and clears). However `hardDrop` while tryMove(0,1) false immediately, then lockPiece writes I at row19 x3-6, row complete, clears, score+100. This tests integration. Need ensure current not null and paused false. Temporary key handler can set board and current directly, then call hardDrop. But `hardDrop` doesn't check if current can be at y18? It just while tryMove; if current position invalid initially (because overlapping filled cells?), need ensure not overlapping. Fill row19 x0-2 and x7-9, leave x3-6 empty. Current I at x3,y18 has cells row19 x3-6 empty, valid. Good. Then hardDrop locks and clears. Score 100, lines1. Next piece spawns. DOM score 100 lines1. Great.

To test 4-row clear and level, harder but not needed. One row enough to verify scoring. For level up every 10 lines, code obvious. Could repeat temporary key 10 times, but after first clear board empty; key can refill. It would score 100 each at level1 until lines=10 then level=2; on 10th, score uses level1 (100) then level becomes2. DOM after 10: score1000 lines10 level2. Good. We can test by pressing temporary key 10 times, but browser key action text "l" (lowercase). Need add temp code, reload, press l maybe 10 times, inspect DOM. Then remove temp code. This would verify line clear scoring and level-up. Let's do it. Use edit to add temporary block in keydown. Need ensure `l` doesn't conflict with controls. Temporary only. Add after keys preventDefault maybe before P. Use exact snippet. Then reload. Need be careful final remove. Let's edit.

Reload, then press l 10 times. Need sequential. First reload.

Press l.

Great. Need press l 9 more times. Could use parallel? No sequential state. We'll do multiple calls maybe in one? Tool allows one action per call; can issue multiple in same block? They are independent but stateful, parallel would be wrong. Need sequential. We can call one by one. To save, maybe key text "lllllllll" sends string not repeated? likely types text maybe not key repeats. Better individual. Do 9 calls sequentially. We can perhaps use browser action key with text "l" nine times in separate calls within one message? The instruction says if no dependencies, make all independent calls in same block; but these are dependent (state), so must wait. We'll do sequential maybe 9 calls. Could use bash to simulate? No. Let's do 4 then 5.

Great. Now remove temporary l block. Then reload final. Use edit.

Need verify no temp/debug. grep. Reload final. Also maybe test restart after temp removed? Already did before. Final reload.

Interesting file size same as before temp? 16179. Good. Reload.

Need final response. Mention file created. Report checks:
- Initial load: 10x20 canvas, stats 0/0/1, controls and buttons, no JS errors (only sandbox warning from environment).
- Interactive: moved/rotated first piece, Space hard-drop locked it, spawned next, preview advanced (observed via temporary instrumentation then removed).
- P paused/resumed; Restart reset board/score/lines/level/sequence.
- Temporary row setup verified 1-line clear = 100 and 10 lines -> level 2 (instrumentation removed). Actually we used temporary key to set up row; it tested scoring. Good.
- Unverified: game-over overlay not triggered in interactive pass; 2/3/4-line scoring values not exercised; wall-kick edge cases minimal. But requirement says game over if cannot spawn; code implemented. We can say not exercised. Maybe mention hard drop no bonus points (not required). Keep concise.

Need ensure final doesn't claim no JS errors if environment warning. Say no application errors; only sandbox iframe warning. Good.

Use final with file path. Since user asked build, not necessarily report but addendum asks. Keep moderate.