/* Towers. Monochrome; the board is an isometric block drawn in SVG. Luke Steuber. */
@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);--mono:"Plex Mono",monospace;--sans:"Plex Sans",sans-serif;
  /* The three faces of a tower: top, left, right. */
  --face-top:var(--bg);--face-left:var(--line);--face-right:var(--guide)}
@media(prefers-color-scheme:dark){:root:not([data-theme=light]){color-scheme:dark;--bg:#000000;--ink:#ffffff;--text:#ededed;--sub:#a6a6a6;--line:#2f2f2f;--guide:#8f8f8f;--frame:#ededed;--band:rgba(255,255,255,.06);--scrim:rgba(0,0,0,.8)}}
:root[data-theme=dark]{color-scheme:dark;--bg:#000000;--ink:#ffffff;--text:#ededed;--sub:#a6a6a6;--line:#2f2f2f;--guide:#8f8f8f;--frame:#ededed;--band:rgba(255,255,255,.06);--scrim:rgba(0,0,0,.8)}

*{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,summary:focus-visible{outline:2px solid var(--ink);outline-offset:2px}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%);white-space:nowrap}
.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}

#board-shell{position:absolute;inset:52px 12px 120px;display:flex;overflow:hidden}
.board-stage{flex:none;margin:auto;display:flex;flex-direction:column;align-items:center}
.board{flex:none;line-height:0;user-select:none;-webkit-user-select:none;-webkit-touch-callout:none}
.board svg{display:block;overflow:visible}

/* Ground, numbers at the edge, towers, then the labels above everything. */
.ground path{fill:var(--bg);stroke:var(--guide);stroke-width:1}
.cell{cursor:pointer;outline:none}
.cell path{stroke:var(--ink);stroke-width:1.25;stroke-linejoin:round}
.cell .tile{fill:transparent;stroke:none}
.cell .top{fill:var(--face-top)}
.cell .left{fill:var(--face-left)}
.cell .right{fill:var(--face-right)}
.cell.given .top{fill:var(--ink)}
.board.flat .cell .top{stroke:none;fill:transparent}
.board.flat .cell.given .top{fill:var(--ink)}
.labels,.clues,.ground,.focus-ring{pointer-events:none}
.labels text,.clues text{font-family:var(--mono);font-weight:500;text-anchor:middle;dominant-baseline:central}
.labels text{fill:var(--ink);stroke:var(--face-top);stroke-width:3px;paint-order:stroke;stroke-linejoin:round}
.labels .given text{fill:var(--bg);stroke:var(--ink)}
.board.flat .labels text{stroke:none}
.mark{fill:none;stroke:var(--ink)}
.given .mark{stroke:var(--bg)}
.mark.repeat{stroke-width:2;stroke-dasharray:5 4}
.mark.evidence{stroke-width:1.25;stroke:var(--guide)}
.mark.target{stroke-width:3;animation:pulse 650ms 2}
.clue text{fill:var(--ink)}
.clue.met text{fill:var(--sub)}
.clue circle{fill:none;stroke:var(--ink);stroke-width:1.5;display:none}
.clue.broken circle{display:inline;stroke-dasharray:4 3}
.clue.evidence circle{display:inline;stroke-dasharray:none;stroke-width:2;animation:pulse 650ms 2}
.focus-ring{display:none;fill:none;stroke:var(--ink);stroke-width:3.5;stroke-linejoin:round}
.focus-ring.on-given{stroke:var(--bg);stroke-width:3}
.board:has(.cell:focus-visible) .focus-ring{display:inline}
/* At the solve the edge numbers and the ground lines let go; the skyline stands alone. */
.clues,.ground path{transition:opacity .6s}
.board.solved .clues{opacity:0}
.board.solved .ground path{stroke-opacity:0}
.board.solved .cell{cursor:default}

.completion{display:flex;justify-content:center;height:48px;animation:next-reveal .45s .15s both}
.completion[hidden]{display:none}
#completion #next-btn{border:1px solid var(--ink)!important;background:var(--bg)}
@keyframes next-reveal{from{opacity:0;translate:0 4px}to{opacity:1;translate:0 0}}
@keyframes pulse{50%{opacity:.3}}

#feedback{position:fixed;bottom:60px;left:16px;right:16px;margin:0;min-height:0;text-align:center;color:var(--sub);font:14px/1.3 var(--sans);pointer-events:none}
.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)}

.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;padding:8px 16px;gap:12px;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}
.help-more{border-top:1px solid var(--line);margin-top:16px;padding-top:4px}
.help-more summary{cursor:pointer;min-height:44px;padding:12px 0;color:var(--sub)}
.help-more p{font-size:14px}
.sheet-body .help-more p:last-child{margin-bottom:0}
kbd{font-family:var(--mono)}
@media(max-width:480px){.sheet-head{padding:8px 12px}.sheet-body{padding:16px}}

@media(orientation:landscape) and (max-height:520px){
  #board-shell{inset:40px 72px 66px 12px}
  .toolbar{left:auto;right:8px;top:12px;bottom:12px;flex-direction:column;width:48px}
  .toolbar>div{flex-direction:column}
  #feedback{left:64px;right:72px;bottom:4px;font-size:12px}
  .readout{left:calc(50% - 32px)}
}
@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 path,.mark,.focus-ring,.clue circle{stroke:CanvasText}
  .cell .top{fill:Canvas}.cell .left,.cell .right{fill:GrayText}.cell.given .top{fill:CanvasText}
  .labels text,.clue text{fill:CanvasText;stroke:Canvas}.labels .given text{fill:Canvas;stroke:CanvasText}.given .mark{stroke:Canvas}
  .ground path{fill:Canvas;stroke:GrayText}.sheet{border-color:CanvasText}
}