/* Dark is the base theme (used when the system preference is unknown); light overrides the tokens below. */
:root {
  color-scheme: dark;
  --bg: #07061a;
  --panel: #100e2b;
  --ink: #eceaff;
  --dim: #8e8ab8;
  --cyan: #22f3ff;   --cyan-rgb: 34, 243, 255;
  --mag: #ff2bd6;    --mag-rgb: 255, 43, 214;
  --grn: #39ff88;    --grn-rgb: 57, 255, 136;
  --red: #ff3b5c;    --red-rgb: 255, 59, 92;
  --amber: #ffd23f;  --amber-rgb: 255, 210, 63;
  --line: rgba(var(--cyan-rgb), .28);
  --lit-ink: #fff;                       /* number on a lit (active) header */
  --on-accent: var(--bg);                /* text on a solid accent button */
  --cell-bg: rgba(255, 255, 255, .025);
  --settings-bg: rgba(16, 14, 43, .7);
  --shade: rgba(0, 0, 0, .5);            /* inset shadow inside the table */
  --drop: rgba(0, 0, 0, .6);             /* drop shadow under pop-ups */
  --veil: rgba(7, 6, 26, .8);            /* overlay behind the completion card */
  --glow: 1;                             /* multiplier for neon text glows */
  --wash-1: rgba(var(--mag-rgb), .18);   /* page background gradients */
  --wash-2: rgba(var(--cyan-rgb), .14);
  --sans: system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, "Cascadia Mono", Consolas, "SF Mono", Menlo, monospace;
  --n: 13;      /* columns (always 0..12) */
  --rows: 13;   /* rows, set from the range */
  --cell: clamp(28px, min(calc((100vw - 2rem - 16px - var(--n) * 2px) / (var(--n) + 1)), calc(72vh / (var(--rows) + 1))), 64px);
}
/* Light: the same cyberpunk look on a slate-indigo ground instead of near-black; neon stays bright, glows a touch softer. */
/* Light tokens apply when the visitor picks Light, or picks Auto (no data-theme) and the system prefers light. */
:root[data-theme=light] {
  color-scheme: dark;
  --bg: #343a5e;
  --panel: #262b49;
  --ink: #f3f2ff;
  --dim: #aeabd3;
  --cyan: #4ff2ff;   --cyan-rgb: 79, 242, 255;
  --mag: #ff5fe1;    --mag-rgb: 255, 95, 225;
  --grn: #5eff9f;    --grn-rgb: 94, 255, 159;
  --red: #ff6079;    --red-rgb: 255, 96, 121;
  --amber: #ffd95c;  --amber-rgb: 255, 217, 92;
  --line: rgba(var(--cyan-rgb), .35);
  --lit-ink: #fff;
  --on-accent: #1a1d38;
  --cell-bg: rgba(255, 255, 255, .05);
  --settings-bg: rgba(38, 43, 73, .75);
  --shade: rgba(0, 0, 0, .3);
  --drop: rgba(0, 0, 0, .45);
  --veil: rgba(52, 58, 94, .85);
  --glow: .8;
  --wash-1: rgba(var(--mag-rgb), .16);
  --wash-2: rgba(var(--cyan-rgb), .16);
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme=dark]) {
    color-scheme: dark;
    --bg: #343a5e;
    --panel: #262b49;
    --ink: #f3f2ff;
    --dim: #aeabd3;
    --cyan: #4ff2ff;   --cyan-rgb: 79, 242, 255;
    --mag: #ff5fe1;    --mag-rgb: 255, 95, 225;
    --grn: #5eff9f;    --grn-rgb: 94, 255, 159;
    --red: #ff6079;    --red-rgb: 255, 96, 121;
    --amber: #ffd95c;  --amber-rgb: 255, 217, 92;
    --line: rgba(var(--cyan-rgb), .35);
    --lit-ink: #fff;
    --on-accent: #1a1d38;
    --cell-bg: rgba(255, 255, 255, .05);
    --settings-bg: rgba(38, 43, 73, .75);
    --shade: rgba(0, 0, 0, .3);
    --drop: rgba(0, 0, 0, .45);
    --veil: rgba(52, 58, 94, .85);
    --glow: .8;
    --wash-1: rgba(var(--mag-rgb), .16);
    --wash-2: rgba(var(--cyan-rgb), .16);
  }
}
* { box-sizing: border-box; }
html { background: var(--bg); color: var(--ink); font-family: var(--sans); }
body {
  margin: 0; min-height: 100vh; display: flex; flex-direction: column; align-items: center; gap: 1rem;
  padding: 1rem;
  background:
    radial-gradient(ellipse at 50% -20%, var(--wash-1), transparent 55%),
    radial-gradient(ellipse at 50% 120%, var(--wash-2), transparent 55%),
    var(--bg);
}
a { color: var(--cyan); }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, summary:focus-visible { outline: 2px solid var(--amber); outline-offset: 2px; }

.top { display: flex; align-items: baseline; gap: 1.25rem; width: 100%; max-width: 900px; justify-content: space-between; flex-wrap: wrap; }
h1 { margin: 0; font-size: 1.1rem; font-weight: 600; letter-spacing: .12em; color: var(--mag); text-shadow: 0 0 12px rgba(var(--mag-rgb), calc(.7 * var(--glow))); }
.status { margin: 0; color: var(--dim); font-family: var(--mono); display: flex; gap: 1.25rem; }
.status #left { color: var(--ink); }
.timer { color: var(--amber); text-shadow: 0 0 8px rgba(var(--amber-rgb), calc(.6 * var(--glow))); }

main { display: flex; flex-direction: column; align-items: center; gap: 1rem; width: 100%; }

/* --- the table --- */
.board { position: relative; max-width: 100%; }
.grid {
  display: grid;
  grid-template-columns: repeat(calc(var(--n) + 1), var(--cell));
  grid-auto-rows: var(--cell);
  gap: 2px;
  padding: 6px;
  background: var(--panel);
  border: 1px solid var(--line);
  box-shadow: 0 0 24px rgba(var(--cyan-rgb), .18), inset 0 0 40px var(--shade);
  font-family: var(--mono);
  font-size: calc(var(--cell) * .42);
  user-select: none;
}
.corner, .head { display: grid; place-items: center; }
.corner { color: var(--dim); }
.head { color: var(--cyan); text-shadow: 0 0 8px rgba(var(--cyan-rgb), calc(.6 * var(--glow))); border: 1px solid transparent; transition: background .12s, color .12s; }
.head.lit { background: rgba(var(--mag-rgb), .22); border-color: var(--mag); color: var(--lit-ink); }
.head.complete { color: var(--grn); text-shadow: 0 0 10px rgba(var(--grn-rgb), calc(.8 * var(--glow))); }
/* the ✓ is absolutely positioned so the header number never shifts */
.head { position: relative; }
.head.complete::after { content: "✓"; position: absolute; font-size: .5em; line-height: 1; }
.head[role=columnheader].complete::after { top: 2px; left: 50%; transform: translateX(-50%); }  /* above the number */
.head[role=rowheader].complete::after { left: 3px; top: 50%; transform: translateY(-50%); }    /* left of the number */

.cell { position: relative; }
.cell input {
  width: 100%; height: 100%; margin: 0; padding: 0;
  text-align: center; font: inherit; color: var(--ink);
  background: var(--cell-bg);
  border: 1px solid var(--line); border-radius: 0;
  caret-color: var(--amber);
}
.cell input:focus { outline: none; border-color: var(--amber); box-shadow: 0 0 0 1px var(--amber), 0 0 14px rgba(var(--amber-rgb), .55); background: rgba(var(--amber-rgb), .12); }
.cell.given input { color: var(--dim); border-style: dotted; background: transparent; }
.cell.right input { color: var(--grn); border-color: var(--grn); background: rgba(var(--grn-rgb), .08); }
.cell.wrong input { color: var(--red); border: 2px dashed var(--red); background: rgba(var(--red-rgb), .12); text-shadow: 0 0 6px rgba(var(--red-rgb), calc(.7 * var(--glow))); }
.mark { position: absolute; top: 1px; right: 3px; font-size: .5em; pointer-events: none; }
.cell.wrong .mark::before { content: "✗"; color: var(--red); }

/* --- number pad (touch only; pops up beside the cell being edited) --- */
.numpad {
  position: absolute; z-index: 5; display: grid; grid-template-columns: repeat(3, 3.5rem); gap: 6px;
  padding: 6px; background: var(--panel); border: 1px solid var(--amber);
  box-shadow: 0 0 18px rgba(var(--amber-rgb), .45), 0 8px 24px var(--drop);
}
.numpad[hidden] { display: none; }
.numpad button { height: 2.75rem; font: 1.4rem var(--mono); border-radius: 4px; }
.numpad .wide { font-size: 1rem; }

/* --- play bar: the few things you touch during play --- */
.playbar { display: flex; align-items: center; gap: .5rem; flex-wrap: wrap; justify-content: center; }
button { font: .9rem var(--sans); padding: .5rem .9rem; cursor: pointer; color: var(--ink); background: var(--panel); border: 1px solid var(--line); border-radius: 6px; transition: border-color .12s, background .12s, box-shadow .12s, transform .08s; }
button:hover { border-color: var(--cyan); }
button:active { transform: translateY(1px); }
button.primary { color: var(--on-accent); background: var(--cyan); border-color: var(--cyan); font-weight: 600; box-shadow: 0 0 12px rgba(var(--cyan-rgb), .5); }
button.primary:hover { box-shadow: 0 0 20px rgba(var(--cyan-rgb), .75); }
button.big { font-size: 1.05rem; padding: .7rem 1.5rem; letter-spacing: .02em; }
button.icon { display: inline-flex; align-items: center; gap: .45rem; padding: .55rem .8rem; color: var(--dim); }
button.icon svg { width: 1.2em; height: 1.2em; fill: currentColor; flex: none; }
button.icon[aria-pressed=true] { color: var(--cyan); border-color: rgba(var(--cyan-rgb), .6); text-shadow: 0 0 8px rgba(var(--cyan-rgb), calc(.6 * var(--glow))); }
button.icon[aria-pressed=false] svg .wave { opacity: .25; }
button.icon[aria-pressed=false] { text-decoration: line-through; text-decoration-color: rgba(var(--red-rgb), .7); text-decoration-thickness: 2px; }
button.text { background: none; border-color: transparent; color: var(--dim); padding: .5rem .6rem; }
button.text:hover { color: var(--cyan); border-color: transparent; }

/* --- settings drawer: side panel on wide screens, bottom sheet on phones --- */
.backdrop { position: fixed; inset: 0; z-index: 20; background: var(--veil); backdrop-filter: blur(3px); opacity: 0; visibility: hidden; transition: opacity .2s, visibility 0s .2s; }
.backdrop.open { opacity: 1; visibility: visible; transition: opacity .2s; }
.drawer {
  position: fixed; z-index: 21; top: 0; right: 0; bottom: 0; width: min(380px, 100%);
  display: flex; flex-direction: column;
  background: var(--panel); border-left: 1px solid var(--line);
  box-shadow: -8px 0 40px var(--drop), 0 0 30px rgba(var(--cyan-rgb), .12);
  transform: translateX(100%); visibility: hidden; transition: transform .25s cubic-bezier(.2, .8, .2, 1), visibility 0s .25s;
}
.drawer.open { transform: none; visibility: visible; transition: transform .25s cubic-bezier(.2, .8, .2, 1); }
.drawer-head { display: flex; align-items: center; justify-content: space-between; padding: 1rem 1rem 1rem 1.25rem; border-bottom: 1px solid var(--line); }
.drawer-head h2 { margin: 0; font-size: 1rem; font-weight: 600; letter-spacing: .12em; text-transform: uppercase; color: var(--mag); text-shadow: 0 0 10px rgba(var(--mag-rgb), calc(.6 * var(--glow))); }
.drawer-head .icon { padding: .4rem; }
.drawer-body { flex: 1; overflow-y: auto; padding: .25rem 1.25rem 1rem; overscroll-behavior: contain; }
.drawer-foot { display: flex; align-items: center; gap: .25rem; padding: .75rem 1rem; border-top: 1px solid var(--line); background: var(--settings-bg); }
.drawer-foot .primary { margin-left: auto; padding: .65rem 1.6rem; }

.group { padding: 1.1rem 0; border-bottom: 1px solid rgba(var(--cyan-rgb), .12); }
.group:last-child { border-bottom: 0; }
.group h3 { margin: 0 0 .6rem; font-size: .72rem; font-weight: 600; letter-spacing: .16em; text-transform: uppercase; color: var(--cyan); text-shadow: 0 0 8px rgba(var(--cyan-rgb), calc(.5 * var(--glow))); }
.hint { margin: 0 0 .5rem; font-size: .8rem; color: var(--dim); }
.summary { margin: .5rem 0 0; font: .9rem var(--mono); color: var(--ink); min-height: 1.3em; }
.row { display: flex; align-items: center; gap: .75rem; margin-top: .9rem; }
.lbl { flex: 0 0 5.5rem; font-size: .85rem; color: var(--dim); }
.val { font: .85rem var(--mono); color: var(--ink); min-width: 7.5ch; text-align: right; }
.row input[type=range] { flex: 1; min-width: 0; }
input[type=range] { accent-color: var(--mag); }

/* tables picker: tap first and last */
.chips { display: grid; grid-template-columns: repeat(7, 1fr); gap: 6px; }
.chips button { padding: 0; height: 2.5rem; font: 1rem var(--mono); color: var(--dim); background: var(--cell-bg); border-color: var(--line); }
.chips button.in { color: var(--ink); background: rgba(var(--cyan-rgb), .14); border-color: rgba(var(--cyan-rgb), .5); }
.chips button.end { color: var(--on-accent); background: var(--cyan); border-color: var(--cyan); font-weight: 700; box-shadow: 0 0 10px rgba(var(--cyan-rgb), .55); }
.chips button.picking { background: var(--mag); border-color: var(--mag); box-shadow: 0 0 12px rgba(var(--mag-rgb), .7); }

/* segmented control */
.seg { display: inline-flex; border: 1px solid var(--line); border-radius: 6px; overflow: hidden; background: var(--cell-bg); }
.seg button { border: 0; border-radius: 0; background: none; color: var(--dim); padding: .45rem .9rem; font: .85rem var(--sans); min-width: 3rem; }
.seg button + button { border-left: 1px solid var(--line); }
.seg button[aria-checked=true] { color: var(--on-accent); background: var(--cyan); font-weight: 600; box-shadow: inset 0 0 12px rgba(255, 255, 255, .15); }

/* switch */
.switch { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding: .5rem 0; font-size: .9rem; color: var(--ink); cursor: pointer; }
.switch input { position: absolute; opacity: 0; width: 1px; height: 1px; }
.switch i { position: relative; flex: none; width: 2.6rem; height: 1.5rem; border-radius: 1rem; background: var(--cell-bg); border: 1px solid var(--line); transition: background .15s, border-color .15s; }
.switch i::after { content: ""; position: absolute; top: 2px; left: 2px; width: calc(1.5rem - 6px); height: calc(1.5rem - 6px); border-radius: 50%; background: var(--dim); transition: transform .15s, background .15s; }
.switch input:checked + i { background: rgba(var(--grn-rgb), .25); border-color: var(--grn); }
.switch input:checked + i::after { transform: translateX(1.1rem); background: var(--grn); box-shadow: 0 0 8px rgba(var(--grn-rgb), .8); }
.switch input:focus-visible + i { outline: 2px solid var(--amber); outline-offset: 2px; }

@media (max-width: 640px) {
  .drawer { top: auto; left: 0; right: 0; width: 100%; max-height: 88vh; border-left: 0; border-top: 1px solid var(--line); border-radius: 14px 14px 0 0; transform: translateY(100%); box-shadow: 0 -8px 40px var(--drop); }
  .drawer-head::before { content: ""; position: absolute; top: 6px; left: 50%; width: 36px; height: 4px; border-radius: 2px; background: var(--line); transform: translateX(-50%); }
  .drawer-head { position: relative; }
  .playbar .icon span { display: none; }          /* icons only on small screens */
  .playbar .icon { padding: .6rem .7rem; }
  .playbar #openSettings span, .playbar #openHelp span { display: none; }
}
body.drawer-open { overflow: hidden; }

/* --- how to play --- */
.goal { margin: 0; font-size: 1rem; color: var(--ink); line-height: 1.5; }
.goal em { font-style: normal; font-family: var(--mono); color: var(--cyan); text-shadow: 0 0 8px rgba(var(--cyan-rgb), calc(.5 * var(--glow))); }
.keys { display: grid; grid-template-columns: auto 1fr; gap: .7rem 1rem; align-items: center; margin: 0; }
.keys dt { display: flex; align-items: center; gap: .3rem; flex-wrap: wrap; font-size: .8rem; color: var(--dim); }
.keys dd { margin: 0; font-size: .9rem; color: var(--ink); }
.keys .or { font-size: .75rem; }
kbd {
  display: inline-block; min-width: 1.9em; padding: .2em .5em; text-align: center;
  font: .8rem var(--mono); color: var(--ink); background: var(--cell-bg);
  border: 1px solid var(--line); border-bottom-width: 3px; border-radius: 5px;
  box-shadow: 0 0 8px rgba(var(--cyan-rgb), .18);
}
.marks { list-style: none; margin: 0; padding: 0; display: grid; gap: .6rem; }
.marks li { display: flex; align-items: center; gap: .8rem; font-size: .9rem; color: var(--ink); }
.swatch { flex: none; display: grid; place-items: center; width: 2.4rem; height: 2.4rem; font: 1rem var(--mono); border: 1px solid var(--line); background: var(--cell-bg); color: var(--ink); }
.swatch.right { color: var(--grn); border-color: var(--grn); background: rgba(var(--grn-rgb), .08); }
.swatch.wrong { color: var(--red); border: 2px dashed var(--red); background: rgba(var(--red-rgb), .12); }
.swatch.given { color: var(--dim); border-style: dotted; background: transparent; }
.swatch.head { color: var(--grn); border-color: transparent; background: none; text-shadow: 0 0 10px rgba(var(--grn-rgb), calc(.8 * var(--glow))); position: relative; }
.swatch.head::after { content: "✓"; position: absolute; top: 1px; left: 50%; transform: translateX(-50%); font-size: .5em; }
.howto-hint { margin-top: .9rem; }

/* --- completion --- */
.done { position: fixed; inset: 0; display: grid; place-items: center; background: var(--veil); }
.done[hidden] { display: none; }
.done .card { position: relative; display: grid; gap: 1rem; justify-items: center; padding: 2rem 2.5rem; background: var(--panel); border: 1px solid var(--grn); box-shadow: 0 0 40px rgba(var(--grn-rgb), .35); }
.done p { margin: 0; font: 1.4rem var(--mono); color: var(--grn); text-shadow: 0 0 10px rgba(var(--grn-rgb), calc(.8 * var(--glow))); }
.done p.time { font-size: 1.1rem; color: var(--amber); text-shadow: 0 0 8px rgba(var(--amber-rgb), calc(.6 * var(--glow))); }
.confetti { position: absolute; inset: 0; width: 100%; height: 100%; pointer-events: none; }

footer { margin-top: auto; display: flex; gap: 1.25rem; font-size: .8rem; color: var(--dim); flex-wrap: wrap; justify-content: center; }

/* --- policy pages --- */
.doc { max-width: 62ch; line-height: 1.6; align-self: center; }
.doc h1 { font-size: 1.6rem; letter-spacing: .02em; margin: 0 0 .25rem; }
.doc h2 { font-size: 1.05rem; color: var(--cyan); margin: 1.75rem 0 .5rem; }
.doc p, .doc li { color: var(--ink); }
.doc .updated { color: var(--dim); font-size: .85rem; margin-bottom: 1.5rem; }
.doc ul { padding-left: 1.2rem; }
.doc .back { display: inline-block; margin-top: 2rem; }

@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }
@media (max-width: 480px) { .top { justify-content: center; text-align: center; } }