/* Minesweeper Reforged — flat, modern, high contrast. No framework.
   Every color pair used for text is checked against WCAG 2.1 AA (4.5:1) by
   tests/test_game.js, so do not tweak a swatch without re-running the suite. */

:root {
  --bg: #f4f6fb;
  --bg-panel: #ffffff;
  --bg-sunken: #eef1f7;
  --ink: #1a1f2b;
  --ink-soft: #4a5468;
  --ink-faint: #626d82;
  --line: #d7dde8;
  --line-strong: #b9c2d2;
  --accent: #1d4ed8;
  --accent-ink: #ffffff;
  --accent-soft: #e5ecfd;
  --danger: #b91c1c;
  --danger-soft: #fde8e8;
  --good: #15803d;

  /* Board */
  --cell-covered: #dfe5ef;
  --cell-covered-top: #f0f3f9;
  --cell-hover: #d3dbe9;
  --cell-open: #e8ecf3;
  --cell-open-line: #d5dbe6;
  --cell-shadow: 0 1px 0 rgba(255, 255, 255, .9) inset, 0 2px 4px rgba(24, 32, 52, .14);
  --flag: #b91c1c;
  --mine: #4a5468;
  --mine-blame: #dc2626;
  --mine-blame-ink: #ffffff;
  --hint: #15803d;

  --n1: #1d4ed8;
  --n2: #146c34;
  --n3: #b91c1c;
  --n4: #6d28d9;
  --n5: #9a4a08;
  --n6: #0e6b64;
  --n7: #a8175a;
  --n8: #333e52;

  --radius: 12px;
  --radius-sm: 5px;
  --shadow-panel: 0 1px 2px rgba(24, 32, 52, .05), 0 10px 30px rgba(24, 32, 52, .07);
  --focus: #1d4ed8;
  --stagger: 0ms;
}

[data-theme="dark"] {
  --bg: #12151d;
  --bg-panel: #1a1f2a;
  --bg-sunken: #151a23;
  --ink: #eef2f9;
  --ink-soft: #b3bdcd;
  --ink-faint: #97a2b4;
  --line: #2a3140;
  --line-strong: #3a4354;
  --accent: #6ea0ff;
  --accent-ink: #0d1220;
  --accent-soft: #1e2941;
  --danger: #f87171;
  --danger-soft: #341c1c;
  --good: #4ade80;

  --cell-covered: #2b3343;
  --cell-covered-top: #38425600;
  --cell-hover: #354056;
  --cell-open: #202634;
  --cell-open-line: #2c3444;
  --cell-shadow: 0 1px 0 rgba(255, 255, 255, .06) inset, 0 2px 5px rgba(0, 0, 0, .35);
  --flag: #fca5a5;
  --mine: #8b95a8;
  --mine-blame: #f87171;
  --mine-blame-ink: #2a0b0b;
  --hint: #4ade80;

  --n1: #7dd3fc;
  --n2: #86efac;
  --n3: #fca5a5;
  --n4: #c4b5fd;
  --n5: #fcd34d;
  --n6: #5eead4;
  --n7: #f9a8d4;
  --n8: #cbd5e1;

  --focus: #8ab4ff;
  --shadow-panel: 0 1px 2px rgba(0, 0, 0, .3), 0 12px 34px rgba(0, 0, 0, .35);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 400 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3 { line-height: 1.2; letter-spacing: -.015em; margin: 0 0 .5em; }
h1 { font-size: clamp(2rem, 1.4rem + 2.4vw, 3rem); font-weight: 800; }
h2 { font-size: clamp(1.35rem, 1.1rem + 1vw, 1.85rem); font-weight: 750; }
h3 { font-size: 1.1rem; font-weight: 700; margin-top: 1.8em; }
p { margin: 0 0 1em; }
a { color: var(--accent); text-underline-offset: .18em; }
a:hover { text-decoration-thickness: 2px; }

kbd {
  font: 600 .78em/1 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  background: var(--bg-sunken);
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: .2em .4em;
  color: var(--ink-soft);
  white-space: nowrap;
}

.wrap { max-width: 72rem; margin: 0 auto; padding: 0 1.25rem; }
.section { padding: 2.5rem 1.25rem 1rem; }
.section-sub { margin-top: 2.5rem; }

.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

.skip-link {
  position: absolute; left: 1rem; top: -3rem; z-index: 50;
  background: var(--accent); color: var(--accent-ink);
  padding: .6rem 1rem; border-radius: 0 0 8px 8px; font-weight: 600;
  transition: top .15s ease;
}
.skip-link:focus { top: 0; }

/* Focus is always visible, everywhere. */
:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ------------------------------------------------------------------ header */

.site-header {
  border-bottom: 1px solid var(--line);
  background: var(--bg-panel);
  position: sticky; top: 0; z-index: 20;
}
.header-inner {
  display: flex; align-items: center; gap: 1rem;
  min-height: 60px; flex-wrap: wrap;
}
.brand {
  display: inline-flex; align-items: center; gap: .55rem;
  font-weight: 700; font-size: 1.05rem; color: var(--ink); text-decoration: none;
}
.brand-mark { color: var(--accent); font-size: 1.15em; }
.brand-name b { color: var(--accent); font-weight: 800; }
.header-nav { margin-left: auto; display: flex; gap: 1.1rem; font-size: .93rem; }
.header-nav a { color: var(--ink-soft); text-decoration: none; }
.header-nav a:hover { color: var(--accent); text-decoration: underline; }

/* ------------------------------------------------------------------ buttons */

.btn {
  display: inline-flex; align-items: center; gap: .45rem;
  font: inherit; font-size: .92rem; font-weight: 600;
  padding: .5rem .85rem;
  border: 1px solid var(--line-strong);
  border-radius: 9px;
  background: var(--bg-panel);
  color: var(--ink);
  cursor: pointer;
  transition: background .12s ease, border-color .12s ease, transform .08s ease;
}
.btn:hover { background: var(--bg-sunken); }
.btn:active { transform: translateY(1px); }
.btn:disabled { opacity: .45; cursor: not-allowed; transform: none; }
.btn kbd { margin-left: .1rem; }
.btn-primary {
  background: var(--accent); border-color: var(--accent); color: var(--accent-ink);
}
.btn-primary:hover { background: var(--accent); filter: brightness(1.08); }
.btn-primary kbd { background: rgba(255,255,255,.16); border-color: rgba(255,255,255,.3); color: inherit; }
.btn-ghost { background: transparent; border-color: transparent; color: var(--ink-soft); }
.btn-ghost:hover { background: var(--bg-sunken); color: var(--ink); }
.btn-danger { border-color: var(--danger); color: var(--danger); background: transparent; }
.btn-danger:hover { background: var(--danger-soft); }
.btn-lg { font-size: 1.02rem; padding: .7rem 1.6rem; }
.btn-toggle[aria-pressed="true"] {
  background: var(--accent-soft); border-color: var(--accent); color: var(--accent);
}

.chip {
  font: inherit; font-size: .86rem; font-weight: 600;
  padding: .4rem .75rem; border-radius: 999px;
  border: 1px solid var(--line-strong); background: var(--bg-panel);
  color: var(--ink-soft); cursor: pointer;
}
.chip:hover { background: var(--bg-sunken); color: var(--ink); }
.chip[aria-pressed="true"] {
  background: var(--accent); border-color: var(--accent); color: var(--accent-ink);
}

/* ------------------------------------------------------------------ intro */

.intro {
  font-size: 1.06rem; color: var(--ink-soft);
  max-width: 62ch; margin-bottom: 2rem;
}
.intro em { color: var(--ink); font-style: italic; }

/* ------------------------------------------------------------------ game */

.game-shell {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-panel);
  padding: 1rem;
}

.hud {
  display: flex; flex-wrap: wrap; gap: 1rem; align-items: flex-end;
  justify-content: space-between; margin-bottom: 1rem;
}
.hud-stats { display: flex; flex-wrap: wrap; gap: .4rem .5rem; }
.stat {
  background: var(--bg-sunken);
  border: 1px solid var(--line);
  border-radius: 9px;
  padding: .35rem .7rem;
  min-width: 5.4rem;
}
.stat-label {
  display: block; font-size: .68rem; letter-spacing: .07em;
  text-transform: uppercase; color: var(--ink-faint); font-weight: 700;
}
.stat-value {
  display: block; font-size: 1.25rem; font-weight: 700;
  font-variant-numeric: tabular-nums; line-height: 1.25;
}
#hud-mines.is-negative { color: var(--danger); }
#hud-timer.is-urgent { color: var(--danger); }
.stat-state .stat-value { font-size: 1rem; padding-top: .16rem; }

.hud-actions { display: flex; flex-wrap: wrap; gap: .45rem; }

/* ------------------------------------------------------------------ board */

.board-wrap {
  position: relative;
  background: var(--bg-sunken);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 8px;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  --avail: min(100vw - 4.5rem, 66rem);
  --cell: clamp(24px, calc(var(--avail) / var(--cols)), 42px);
}

/* Explicit row and column tracks mean the board's box is the right size before
   game.js has created a single cell — that is what keeps CLS at zero. */
.board {
  display: grid;
  grid-template-columns: repeat(var(--cols, 16), var(--cell));
  grid-template-rows: repeat(var(--rows, 16), var(--cell));
  gap: 2px;
  width: max-content;
  margin: 0 auto;
  touch-action: manipulation;
}
.row { display: contents; }

.cell {
  appearance: none;
  border: 0;
  padding: 0;
  margin: 0;
  font: 700 clamp(12px, calc(var(--cell) * .55), 22px)/1 system-ui, sans-serif;
  border-radius: var(--radius-sm);
  background: linear-gradient(180deg, var(--cell-covered-top), var(--cell-covered));
  box-shadow: var(--cell-shadow);
  color: var(--ink);
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  user-select: none; -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
  transition: background .1s ease, transform .08s ease;
}
.cell:hover:not(.is-open) { background: var(--cell-hover); }
.cell.is-pressing { transform: scale(.93); }

.cell.is-open {
  background: var(--cell-open);
  box-shadow: inset 0 0 0 1px var(--cell-open-line);
  cursor: default;
}
.cell.is-open:hover { background: var(--cell-open); }

.cell.n1 { color: var(--n1); }
.cell.n2 { color: var(--n2); }
.cell.n3 { color: var(--n3); }
.cell.n4 { color: var(--n4); }
.cell.n5 { color: var(--n5); }
.cell.n6 { color: var(--n6); }
.cell.n7 { color: var(--n7); }
.cell.n8 { color: var(--n8); }

.cell.is-flag { color: var(--flag); }
.cell.is-question { color: var(--ink-faint); }
.cell.is-mine { color: var(--mine); background: var(--cell-open); box-shadow: inset 0 0 0 1px var(--cell-open-line); }
.cell.is-blame {
  color: var(--mine-blame-ink);
  background: var(--mine-blame);
  box-shadow: inset 0 0 0 1px var(--mine-blame);
}
.cell.is-wrong { position: relative; color: var(--ink-faint); }
.cell.is-wrong::after {
  content: "";
  position: absolute; inset: 12%;
  background:
    linear-gradient(to bottom right, transparent 44%, var(--danger) 44%, var(--danger) 56%, transparent 56%),
    linear-gradient(to bottom left, transparent 44%, var(--danger) 44%, var(--danger) 56%, transparent 56%);
}
.cell.is-hint {
  box-shadow: var(--cell-shadow), 0 0 0 2px var(--hint);
}

.board.is-lost .cell.is-open:not(.is-blame) { filter: grayscale(1) opacity(.82); }
.board.is-lost .cell.is-mine:not(.is-blame) { filter: grayscale(1) opacity(.7); }

@keyframes msr-pop {
  from { opacity: 0; transform: scale(.72); }
  to   { opacity: 1; transform: scale(1); }
}
.cell.is-popping {
  animation: msr-pop 150ms ease-out both;
  animation-delay: var(--reveal-delay, 0ms);
}
@keyframes msr-nudge {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-2px); }
  75% { transform: translateX(2px); }
}
.cell.is-nudge { animation: msr-nudge 160ms ease-in-out; }

body.flag-mode .cell:not(.is-open) { cursor: crosshair; }

/* ------------------------------------------------------------------ overlay */

.overlay {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  padding: 1rem;
  background: color-mix(in srgb, var(--bg-panel) 88%, transparent);
  backdrop-filter: blur(3px);
  border-radius: 10px;
  z-index: 5;
}
.overlay[hidden] { display: none; }

.screen {
  width: min(100%, 34rem);
  max-height: 100%;
  overflow-y: auto;
  text-align: center;
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-panel);
  padding: 1.4rem 1.3rem;
}
.screen h2 { margin-bottom: .35rem; }
.screen-lead { color: var(--ink-soft); font-size: .95rem; }
.screen-note { color: var(--ink-faint); font-size: .84rem; margin: .8rem 0 0; }
.screen-tier {
  font-size: .82rem; font-weight: 700; letter-spacing: .05em;
  text-transform: uppercase; color: var(--ink-faint); margin-bottom: .6rem;
}
.screen-actions { display: flex; gap: .5rem; justify-content: center; margin-top: 1rem; flex-wrap: wrap; }
#screen-end.is-win h2 { color: var(--good); }

.tier-list { list-style: none; margin: 1rem 0; padding: 0; display: grid; gap: .5rem; text-align: left; }
.tier {
  display: block; width: 100%; text-align: left;
  font: inherit; cursor: pointer;
  background: var(--bg-sunken);
  border: 1px solid var(--line);
  border-left: 4px solid var(--line-strong);
  border-radius: 10px;
  padding: .7rem .85rem;
  color: var(--ink);
}
.tier:hover { border-color: var(--accent); background: var(--accent-soft); }
.tier.is-selected, .tier[aria-pressed="true"] {
  border-color: var(--accent); border-left-color: var(--accent); background: var(--accent-soft);
}
.tier-name { display: block; font-weight: 700; font-size: 1.02rem; }
.tier-name em { font-style: normal; font-weight: 600; color: var(--ink-faint); font-size: .82rem; }
.tier-blurb { display: block; font-size: .88rem; color: var(--ink-soft); margin-top: .15rem; }
.tier-meta {
  display: block; font-size: .75rem; color: var(--ink-faint);
  margin-top: .3rem; font-variant-numeric: tabular-nums;
}
.pause-tiers { display: flex; flex-wrap: wrap; gap: .4rem; justify-content: center; margin: .9rem 0 0; }

.gen-note {
  margin: .6rem 0 0; text-align: center;
  font-size: .82rem; color: var(--ink-faint); min-height: 1.2em;
}

.board-picker {
  display: flex; flex-wrap: wrap; align-items: center; gap: .5rem;
  margin-top: 1rem; padding-top: 1rem; border-top: 1px solid var(--line);
}
.board-picker-label {
  font-size: .7rem; letter-spacing: .07em; text-transform: uppercase;
  font-weight: 700; color: var(--ink-faint);
}
.board-buttons { display: flex; flex-wrap: wrap; gap: .4rem; }

/* ------------------------------------------------------------------ tables */

.table-scroll { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; font-size: .92rem; }
th, td { text-align: left; padding: .55rem .7rem; border-bottom: 1px solid var(--line); }
thead th {
  font-size: .72rem; letter-spacing: .06em; text-transform: uppercase;
  color: var(--ink-faint); border-bottom: 2px solid var(--line-strong);
}
tbody th { font-weight: 600; }
.scores td { font-variant-numeric: tabular-nums; }
.scores tr.is-current { background: var(--accent-soft); }
.scores tr.is-current th { color: var(--accent); }

/* ------------------------------------------------------------------ prose */

.steps { padding-left: 1.3rem; max-width: 68ch; }
.steps li { margin-bottom: .6rem; }
.tier-explainer { padding-left: 1.3rem; max-width: 72ch; }
.tier-explainer li { margin-bottom: .5rem; }
.features { list-style: none; padding: 0; display: grid; gap: .7rem; grid-template-columns: repeat(auto-fit, minmax(19rem, 1fr)); }
.features li {
  background: var(--bg-panel); border: 1px solid var(--line);
  border-radius: 10px; padding: .8rem .95rem; font-size: .93rem; color: var(--ink-soft);
}
.features li strong { color: var(--ink); display: block; }
#faq p { max-width: 74ch; color: var(--ink-soft); }
#about-build p { max-width: 74ch; color: var(--ink-soft); }

/* ------------------------------------------------------------------ dialogs */

.dialog {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0;
  background: var(--bg-panel);
  color: var(--ink);
  box-shadow: var(--shadow-panel);
  width: min(100% - 2rem, 26rem);
}
.dialog::backdrop { background: rgba(12, 16, 25, .55); }
.dialog-body { padding: 1.3rem; }
.dialog-lead { color: var(--ink-soft); font-size: .9rem; }
.field { margin-bottom: .9rem; }
.field label { display: block; font-weight: 600; font-size: .9rem; margin-bottom: .3rem; }
.field input[type="number"] {
  font: inherit; width: 100%; padding: .5rem .6rem;
  border: 1px solid var(--line-strong); border-radius: 8px;
  background: var(--bg-sunken); color: var(--ink);
}
.field-check label { display: flex; align-items: center; gap: .5rem; font-weight: 600; }
.field-help { font-size: .8rem; color: var(--ink-faint); margin: .25rem 0 0; }
.field-error {
  background: var(--danger-soft); border: 1px solid var(--danger);
  color: var(--danger); border-radius: 8px; padding: .5rem .7rem;
  font-size: .87rem; margin: 0 0 .8rem;
}
.dialog-actions { display: flex; gap: .5rem; justify-content: flex-end; margin-top: 1rem; }

/* ------------------------------------------------------------------ footer */

.site-footer {
  margin-top: 3rem; padding: 2rem 0 2.5rem;
  border-top: 1px solid var(--line); background: var(--bg-panel);
}
.footer-inner { display: grid; gap: .6rem; }
.footer-attribution { font-size: 1rem; font-weight: 600; margin: 0; }
.footer-nav { display: flex; gap: 1rem; font-size: .9rem; }
.footer-note { color: var(--ink-faint); font-size: .85rem; margin: 0; }

/* ------------------------------------------------------------------ motion */

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-delay: 0ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}

@media (max-width: 640px) {
  .section { padding-top: 1.75rem; }
  .header-nav { order: 3; width: 100%; margin-left: 0; }
  .hud { gap: .6rem; }
  .stat { min-width: 4.6rem; padding: .3rem .55rem; }
  .stat-value { font-size: 1.1rem; }
  .board-wrap { --avail: calc(100vw - 3.5rem); }
}