@font-face{font-family:"Plex Mono";src:url("fonts/IBMPlexMono-500.woff2") format("woff2");font-weight:500;font-display:swap}
@font-face{font-family:"Plex Sans";src:url("fonts/IBMPlexSans-400.woff2") format("woff2");font-weight:400;font-display:swap}
:root{color-scheme:light;--bg:#ffffff;--ink:#000000;--text:#111111;--sub:#5e5e5e;--line:#d4d4d4;--guide:#8f8f8f;--frame:#1c1c1c;--band:rgba(0,0,0,.05);--scrim:rgba(255,255,255,.84);--empty:#cdcdcd;--grid:#8f8f8f;--mono:"Plex Mono",ui-monospace,Menlo,Consolas,monospace;--sans:"Plex Sans",system-ui,-apple-system,"Segoe UI",sans-serif}
@media(prefers-color-scheme:dark){:root:not([data-theme="light"]){color-scheme:dark;--bg:#000000;--ink:#ffffff;--text:#ededed;--sub:#a6a6a6;--line:#2f2f2f;--frame:#ededed;--band:rgba(255,255,255,.06);--scrim:rgba(0,0,0,.8);--empty:#484848;--grid:#8f8f8f}}
:root[data-theme="dark"]{color-scheme:dark;--bg:#000000;--ink:#ffffff;--text:#ededed;--sub:#a6a6a6;--line:#2f2f2f;--frame:#ededed;--band:rgba(255,255,255,.06);--scrim:rgba(0,0,0,.8);--empty:#484848;--grid:#8f8f8f}

*,*::before,*::after{box-sizing:border-box;border-radius:0}
html,body{touch-action:manipulation}
body{margin:0;height:100dvh;overflow:hidden;background:var(--bg);color:var(--text);font:16px/1.45 var(--sans);-webkit-text-size-adjust:100%;-webkit-tap-highlight-color:transparent}
button,select{font:inherit;color:inherit}
button{cursor:pointer}
button:disabled{opacity:.35;cursor:default}
button:focus-visible,select:focus-visible,a:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
.sr-only{position:absolute!important;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip-path:inset(50%);white-space:nowrap;border:0}
kbd{font:500 14px/1 var(--mono)}

.readout{position:fixed;top:calc(max(0px,env(safe-area-inset-top)) + 18px);left:50%;transform:translateX(-50%);font:500 13px/1 var(--mono);letter-spacing:.02em;color:var(--sub);font-variant-numeric:tabular-nums;white-space:nowrap}
#restart-btn{position:fixed;top:max(0px,env(safe-area-inset-top));left:8px;z-index:2}

/* The board. Cells are literally black or white in both themes; an empty cell is a mid grey. */
#board-shell{position:absolute;inset:58px 6px 120px;display:flex}
.board-stage{flex:none;margin:auto;position:relative}
.board{display:flex;flex-direction:column;border:1px solid var(--frame);user-select:none;-webkit-user-select:none;-webkit-touch-callout:none}
.grid-row{display:flex;flex:none}
.cell{flex:none;position:relative;display:grid;place-items:center;width:var(--cell);height:var(--cell);--on:var(--ink);background-color:var(--empty);background-repeat:no-repeat;background-position:center;box-shadow:inset -1px 0 var(--grid),inset 0 -1px var(--grid);cursor:pointer;transition:background-color .12s ease-out,box-shadow .6s}
.cell:last-child{box-shadow:inset 0 -1px var(--grid)}
.grid-row:last-child .cell{box-shadow:inset -1px 0 var(--grid)}
.grid-row:last-child .cell:last-child{box-shadow:none}
.cell.b{background-color:#000;--on:#fff}
.cell.w{background-color:#fff;--on:#000}
/* A given carries a small square dot; a player's mark is plain. */
.cell.given{cursor:default}
.cell.given::before{content:"";width:clamp(5px,14%,9px);aspect-ratio:1;background:var(--on);transition:opacity .6s}
/* Three alike: one thin line through the three. */
.cell.run-h{background-image:linear-gradient(var(--on),var(--on));background-size:100% 2px}
.cell.run-v{background-image:linear-gradient(var(--on),var(--on));background-size:2px 100%}
.cell.run-h.run-v{background-image:linear-gradient(var(--on),var(--on)),linear-gradient(var(--on),var(--on));background-size:100% 2px,2px 100%}
.cell:focus{outline:none}
.cell:focus-visible{outline:2px solid var(--on);outline-offset:-4px;z-index:2}
.cell.evidence::after,.cell.hint-target::after{content:"";position:absolute;inset:6px;pointer-events:none}
.cell.evidence::after{border:2px dashed var(--on)}
.cell.hint-target::after{border:3px solid var(--on);animation:pulse 650ms 2}
@keyframes pulse{50%{opacity:.3}}
/* A full row or column with unequal counts: one small square past its end. */
.marks{position:absolute;inset:0;pointer-events:none}
.marks i{position:absolute;width:8px;height:8px;background:var(--ink)}
.marks .end-row{left:calc(100% + 5px)}
.marks .end-column{top:calc(100% + 5px)}
/* Solved: the grid lines and dots go, and the finished pattern stands alone. */
.board.solved .cell{box-shadow:none;cursor:default}
.board.solved .cell.given::before{opacity:0}

.completion{position:fixed;left:50%;bottom:64px;transform:translateX(-50%);display:flex;justify-content:center}
.completion[hidden]{display:none}
.completion .ib{outline:1px solid var(--ink);outline-offset:-1px;animation:next-reveal .45s .15s both}
.completion .ib:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
@keyframes next-reveal{from{opacity:0;translate:0 4px}to{opacity:1;translate:0 0}}

#feedback{position:fixed;bottom:62px;left:16px;right:16px;margin:0;text-align:center;color:var(--sub);font:14px/1.3 var(--sans);pointer-events:none;min-height:1.3em}
.toolbar{position:fixed;bottom:max(6px,env(safe-area-inset-bottom));left:8px;right:8px;display:flex;justify-content:space-between}
.toolbar>div{display:flex}
.ib{display:inline-grid;place-items:center;width:48px;height:48px;min-width:48px;min-height:48px;border:0;background:none;padding:12px;color:var(--ink);transition:opacity .15s,transform .1s}
.ib svg{width:24px;height:24px;stroke:currentColor;fill:none;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.ib:active{transform:scale(.94)}
header,.toolbar,button{-webkit-user-select:none;user-select:none;-webkit-touch-callout:none}

.sheet{width:min(32rem,calc(100vw - 16px));max-height:calc(100dvh - 16px);border:1px solid var(--frame);padding:0;background:var(--bg);color:var(--text)}
.sheet[open]{display:flex;flex-direction:column}
.sheet::backdrop{background:var(--scrim)}
.sheet-head{display:flex;justify-content:space-between;align-items:center;gap:12px;padding:8px 16px;flex:none;border-bottom:1px solid var(--line)}
.sheet-head h2{margin:0;font:500 16px/1.3 var(--mono)}
.sheet-head form{margin:0}
.sheet-x{width:44px;height:44px;min-width:44px;min-height:44px;padding:10px}
.sheet-body{padding:20px 24px;overflow:auto;min-height:0;overscroll-behavior:contain}
.sheet-body p{margin:0 0 16px;max-width:60ch}
.row{display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:52px;border-bottom:1px solid var(--line)}
.row select{max-width:65%;min-height:44px;background:var(--bg);border:0;padding:4px 8px}
.row button{min-height:44px;background:none;border:0;padding:8px}
.row button:not(:disabled){text-decoration:underline;text-underline-offset:4px}
.sheet-foot{padding:12px 24px;border-top:1px solid var(--line);flex:none;color:var(--sub);font-size:14px}
.sheet-foot a{color:inherit}
.text-action{min-height:44px;padding:8px 12px;border:1px solid var(--line);background:none;font:500 14px/1.3 var(--mono);color:var(--text)}
.controls{border-top:1px solid var(--line);padding-top:16px}
.controls p{margin:0 0 6px}
.sheet-body .controls p:last-child{margin-bottom:0}
@media(max-width:480px){.sheet-head{padding:8px 12px}.sheet-body{padding:16px}}

@media(max-height:520px) and (min-width:560px){
  #board-shell{inset:50px 72px 64px 12px}
  .toolbar{left:auto;right:8px;top:12px;bottom:12px;flex-direction:column;width:48px}
  .toolbar>div{flex-direction:column}
  .completion{bottom:12px}
  #feedback{left:12px;right:72px;bottom:6px;font-size:12px}
}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation:none!important;transition:none!important}}
:root[data-motion="reduce"] *,:root[data-motion="reduce"] *::before,:root[data-motion="reduce"] *::after{animation:none!important;transition:none!important}
@media(forced-colors:active){
  .cell{forced-color-adjust:none}
  .sheet{border-color:CanvasText}
}