/* Backgammon, a classic green-felt board in a walnut frame, cream and terracotta points,
   ivory and ebony checkers, on calm warm paper. Fixed palette. */
:root {
  color-scheme: light;
  --bg: #f1ece2;
  --card: #fffdf8;
  --ink: #2a2620;
  --muted: #776f63;
  --line: #e2dacb;
  --wood: #6b4429;
  --wood-2: #573520;
  --wood-3: #3f2615;
  --felt: #2e6a4e;
  --felt-2: #275c43;
  --pt-a: #eadcbc;       /* cream points */
  --pt-b: #b24d34;       /* terracotta points */
  --w: #fbf6ea;          /* White checkers */
  --w-2: #e6dac2;
  --w-rim: #b9a67f;
  --k: #34343b;          /* Black checkers */
  --k-2: #1c1c21;
  --k-rim: #5f5f69;
  --gold: #ffcf4a;
  --glow: rgba(255, 214, 90, .95);
  /* tutorial kit (tutorial.css) */
  --tut-accent: #ffcf4a;
  --tut-accent-ink: #2a2620;
  --tut-bubble: #fffdf8;
  --tut-ink: #2a2620;
  --tut-muted: #776f63;
  --tut-dim: rgba(30, 22, 14, .55);
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.45 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  touch-action: manipulation;
  overflow-x: hidden;
  -webkit-tap-highlight-color: transparent;
}
button { font: inherit; color: inherit; touch-action: manipulation; }
[hidden] { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ---------- bar ---------- */
.app {
  display: flex; flex-direction: column;
  height: 100vh; height: 100dvh;
  max-width: 1100px; margin: 0 auto;
  padding: env(safe-area-inset-top) max(14px, env(safe-area-inset-right)) env(safe-area-inset-bottom) max(14px, env(safe-area-inset-left));
}
.bar { flex: none; display: flex; align-items: center; justify-content: space-between; gap: 10px; min-height: 60px; }
.back { color: var(--muted); text-decoration: none; font-size: 14px; white-space: nowrap; padding: 12px 2px; }
.back:hover, .back:focus-visible { color: var(--ink); }
.bar-actions { display: flex; gap: 8px; }

.btn {
  min-height: 44px; min-width: 44px; padding: 0 18px; border-radius: 22px;
  border: 0; background: var(--card); color: var(--ink);
  font-weight: 650; cursor: pointer; box-shadow: 0 1px 2px rgba(42, 38, 32, .1), 0 0 0 1px var(--line);
  transition: transform .12s, background .15s, opacity .15s;
}
.btn:active { transform: scale(.97); }
.btn.icon { padding: 0; width: 44px; font-size: 22px; line-height: 1; letter-spacing: .04em; }
.btn.ghost { background: transparent; box-shadow: none; }
.btn.primary { background: var(--ink); color: var(--card); box-shadow: none; }
.btn.wide { width: 100%; min-height: 50px; font-size: 17px; }
.btn:disabled, .row:disabled { opacity: .35; cursor: default; transform: none; }
.btn:focus-visible, .seg button:focus-visible, .row:focus-visible, .link:focus-visible,
.pt:focus-visible, .tray:focus-visible, .roll:focus-visible, .cube:focus-visible, .undo-chip:focus-visible, .barzone:focus-visible {
  outline: 3px solid var(--gold); outline-offset: 2px;
}

/* ---------- game column ---------- */
.game {
  flex: 1; min-height: 0;
  display: grid; grid-template-rows: auto minmax(0, 1fr) auto auto;
  gap: 10px; padding-bottom: 12px;
}
.turn {
  justify-self: center; display: inline-flex; align-items: center; gap: 10px;
  padding: 8px 18px; border-radius: 999px; background: var(--card);
  box-shadow: 0 0 0 1px var(--line); font-weight: 650; font-size: 16px; min-height: 40px;
}
.turn.thinking #turn-text::after { content: ''; display: inline-block; width: 1.1em; text-align: left; animation: dots 1.2s steps(4) infinite; }
@keyframes dots { 0% { content: ''; } 25% { content: '.'; } 50% { content: '..'; } 75% { content: '...'; } }
.hint {
  justify-self: center; min-height: 22px; font-size: 15px; color: var(--muted); text-align: center;
  opacity: 0; transform: translateY(3px); transition: opacity .25s, transform .25s;
}
.hint.show { opacity: 1; transform: none; }
.info { justify-self: center; font-size: 13px; color: var(--muted); text-align: center; margin-top: -6px; }

/* ---------- checker icon (turn pill, game over) ---------- */
.chk-icon { display: inline-block; flex: none; width: 20px; height: 20px; border-radius: 50%; }
.chk-icon.c0 { background: radial-gradient(circle at 50% 42%, var(--w) 0 45%, var(--w-2) 70%); box-shadow: inset 0 0 0 2px var(--w-rim); }
.chk-icon.c1 { background: radial-gradient(circle at 50% 42%, var(--k) 0 45%, var(--k-2) 70%); box-shadow: inset 0 0 0 2px var(--k-rim); }
.chk-icon.big { width: 58px; height: 58px; box-shadow: inset 0 0 0 4px var(--w-rim), 0 4px 10px rgba(0, 0, 0, .18); }
.chk-icon.big.c1 { box-shadow: inset 0 0 0 4px var(--k-rim), 0 4px 10px rgba(0, 0, 0, .25); }

/* ---------- board ---------- */
.board-wrap { min-height: 0; min-width: 0; display: flex; align-items: center; justify-content: center; }
.board {
  --u: 40px;
  position: relative; flex: none;
  border-radius: calc(var(--u) * .38);
  background:
    repeating-linear-gradient(97deg, rgba(255, 255, 255, .035) 0 3px, transparent 3px 11px),
    linear-gradient(160deg, var(--wood), var(--wood-2));
  box-shadow: 0 calc(var(--u) * .14) 0 var(--wood-3), 0 calc(var(--u) * .4) calc(var(--u) * .8) rgba(42, 38, 32, .25);
  user-select: none; -webkit-user-select: none;
}
.felt {
  position: absolute; border-radius: calc(var(--u) * .12);
  background: radial-gradient(120% 90% at 50% 40%, var(--felt), var(--felt-2));
  box-shadow: inset 0 2px 6px rgba(0, 0, 0, .35);
}
.tray, .barzone, .pt {
  position: absolute; border: 0; margin: 0; padding: 0; background: transparent; cursor: default;
}
.tray {
  border-radius: calc(var(--u) * .12);
  background: linear-gradient(180deg, #2f1c10, #3b2416);
  box-shadow: inset 0 2px 5px rgba(0, 0, 0, .5);
  transition: box-shadow .2s;
}
.tray.dest { cursor: pointer; box-shadow: inset 0 2px 5px rgba(0, 0, 0, .5), 0 0 0 3px var(--glow), 0 0 14px var(--glow); animation: pulse 1.1s ease-in-out infinite alternate; }

/* points: a triangle drawn inside a full-size tap target */
.pt::before {
  content: ''; position: absolute; inset: 0; background: var(--pt-a);
  transition: filter .2s, background .2s;
}
.pt.c1::before { background: var(--pt-b); }
.pt.tri-L::before { clip-path: polygon(0 3%, 94% 50%, 0 97%); }
.pt.tri-R::before { clip-path: polygon(100% 3%, 6% 50%, 100% 97%); }
.pt.tri-T::before { clip-path: polygon(3% 0, 97% 0, 50% 94%); }
.pt.tri-B::before { clip-path: polygon(3% 100%, 97% 100%, 50% 6%); }
.pt.src, .pt.dest, .barzone.src, .tray.dest { cursor: pointer; }
.pt.from::before { filter: brightness(1.12) saturate(.8); }
.pt.dest::before { filter: brightness(1.18); }

/* checkers */
.chk {
  position: absolute; left: 0; top: 0; width: var(--u); height: var(--u);
  border-radius: 50%; pointer-events: none;
  transition: transform .3s cubic-bezier(.3, .7, .3, 1), width .3s, height .3s, border-radius .3s;
  will-change: transform;
}
.chk.c0 {
  background: radial-gradient(circle at 50% 42%, var(--w) 0 42%, var(--w-2) 72%);
  box-shadow: inset 0 0 0 calc(var(--u) * .06) var(--w-rim), inset 0 0 0 calc(var(--u) * .2) rgba(185, 166, 127, .25), 0 calc(var(--u) * .04) calc(var(--u) * .06) rgba(0, 0, 0, .35);
}
.chk.c1 {
  background: radial-gradient(circle at 50% 42%, var(--k) 0 42%, var(--k-2) 72%);
  box-shadow: inset 0 0 0 calc(var(--u) * .06) var(--k-rim), inset 0 0 0 calc(var(--u) * .2) rgba(255, 255, 255, .05), 0 calc(var(--u) * .04) calc(var(--u) * .06) rgba(0, 0, 0, .45);
}
.chk[data-n]:not([data-n=""])::after {
  content: attr(data-n); position: absolute; inset: 0; display: grid; place-items: center;
  font: normal 800 calc(var(--u) * .42) / 1 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
.chk.c0::after { color: #6d5a37; }
.chk.c1::after { color: #e9e4d8; }
.chk.can { box-shadow: inset 0 0 0 calc(var(--u) * .06) var(--w-rim), 0 0 0 calc(var(--u) * .07) rgba(255, 214, 90, .75), 0 0 calc(var(--u) * .3) rgba(255, 214, 90, .6); }
.chk.c1.can { box-shadow: inset 0 0 0 calc(var(--u) * .06) var(--k-rim), 0 0 0 calc(var(--u) * .07) rgba(255, 214, 90, .75), 0 0 calc(var(--u) * .3) rgba(255, 214, 90, .6); }
.chk.sel { box-shadow: inset 0 0 0 calc(var(--u) * .06) var(--w-rim), 0 0 0 calc(var(--u) * .1) var(--gold), 0 0 calc(var(--u) * .45) var(--gold); }
.chk.c1.sel { box-shadow: inset 0 0 0 calc(var(--u) * .06) var(--k-rim), 0 0 0 calc(var(--u) * .1) var(--gold), 0 0 calc(var(--u) * .45) var(--gold); }
.chk.moved::before {
  content: ''; position: absolute; left: 39%; top: 39%; width: 22%; height: 22%; border-radius: 50%;
  background: var(--gold); box-shadow: 0 0 0 2px rgba(0, 0, 0, .15);
}
/* borne-off checkers are slivers seen edge-on */
.portrait .chk.off { width: calc(var(--u) * .17); height: calc(var(--u) * .8); border-radius: calc(var(--u) * .05); }
.landscape .chk.off { width: calc(var(--u) * .9); height: calc(var(--u) * .24); border-radius: calc(var(--u) * .05); }
.chk.off { box-shadow: inset 0 0 0 1px rgba(0, 0, 0, .25); }
.chk.c0.off { background: linear-gradient(90deg, var(--w-2), var(--w)); }
.chk.c1.off { background: linear-gradient(90deg, #4a4a52, #6a6a73); box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .22); }

/* landing markers */
.mark {
  position: absolute; left: 0; top: 0; width: var(--u); height: var(--u); border-radius: 50%;
  pointer-events: none; opacity: 0; z-index: 30;
}
.mark.on {
  opacity: 1;
  border: calc(var(--u) * .08) dashed var(--gold);
  background: rgba(255, 214, 90, .22);
  animation: pulse 1.1s ease-in-out infinite alternate;
}
.mark.far { background: rgba(255, 214, 90, .1); border-style: dotted; }
@keyframes pulse { from { opacity: .55; } to { opacity: 1; } }

/* dice */
.die {
  position: absolute; left: 0; top: 0; width: calc(var(--u) * .9); height: calc(var(--u) * .9);
  border-radius: calc(var(--u) * .18); pointer-events: none; opacity: 0;
  display: grid; grid-template: repeat(3, 1fr) / repeat(3, 1fr); padding: calc(var(--u) * .12);
  transition: opacity .25s, transform .3s;
}
.die.on { opacity: 1; z-index: 20; }
.die.d0 { background: linear-gradient(145deg, #fffdf7, #eee3cc); box-shadow: 0 calc(var(--u) * .05) 0 #c9b893, 0 calc(var(--u) * .1) calc(var(--u) * .15) rgba(0, 0, 0, .35); }
.die.d1 { background: linear-gradient(145deg, #3d3d45, #202026); box-shadow: 0 calc(var(--u) * .05) 0 #0d0d10, 0 calc(var(--u) * .1) calc(var(--u) * .15) rgba(0, 0, 0, .4); }
.die .pip { width: 72%; height: 72%; margin: auto; border-radius: 50%; }
.die.d0 .pip { background: #2a2620; }
.die.d1 .pip { background: #f4efe3; }
.pip.q0 { grid-area: 1 / 1; } .pip.q1 { grid-area: 1 / 2; } .pip.q2 { grid-area: 1 / 3; }
.pip.q3 { grid-area: 2 / 1; } .pip.q4 { grid-area: 2 / 2; } .pip.q5 { grid-area: 2 / 3; }
.pip.q6 { grid-area: 3 / 1; } .pip.q7 { grid-area: 3 / 2; } .pip.q8 { grid-area: 3 / 3; }
.die.used { opacity: .32; }
.die.old { opacity: .78; filter: saturate(.7); }
.die.rolling { animation: tumble .48s cubic-bezier(.2, .8, .3, 1); }
@keyframes tumble {
  0% { rotate: -200deg; scale: .6; }
  60% { rotate: 20deg; scale: 1.08; }
  100% { rotate: 0deg; scale: 1; }
}

/* roll button: two blank dice on the roller's side */
.roll {
  position: absolute; display: none; border: 0; padding: 0; background: transparent; cursor: pointer;
  z-index: 25; align-items: center; justify-content: center; gap: calc(var(--u) * .16);
  color: #f6efdc; font-weight: 750; font-size: calc(var(--u) * .34); letter-spacing: .02em;
}
.roll.on { display: flex; }
.roll.vert { flex-direction: column; }
.roll .die { position: static; opacity: 1; animation: bob 1.4s ease-in-out infinite alternate; }
.roll .die + .die { animation-delay: .2s; }
.roll .die.blank { background: linear-gradient(145deg, #fffdf7, #eee3cc); box-shadow: 0 calc(var(--u) * .05) 0 #c9b893, 0 0 0 calc(var(--u) * .06) rgba(255, 214, 90, .7), 0 0 calc(var(--u) * .35) rgba(255, 214, 90, .5); }
.roll.r1 .die.blank { background: linear-gradient(145deg, #3d3d45, #202026); box-shadow: 0 calc(var(--u) * .05) 0 #0d0d10, 0 0 0 calc(var(--u) * .06) rgba(255, 214, 90, .7), 0 0 calc(var(--u) * .35) rgba(255, 214, 90, .5); }
@keyframes bob { from { transform: translateY(0) rotate(-4deg); } to { transform: translateY(calc(var(--u) * -.06)) rotate(4deg); } }
.roll:active .die { transform: scale(.94); }

/* doubling cube and take-back chip */
.cube {
  position: absolute; display: none; border: 0; padding: 0; cursor: default; z-index: 22;
  border-radius: calc(var(--u) * .14);
  background: linear-gradient(145deg, #fffaf0, #e6dbc3); color: var(--ink);
  font-weight: 800; font-size: calc(var(--u) * .36); line-height: 1;
  box-shadow: 0 calc(var(--u) * .05) 0 #b9a67f;
}
.cube.on { display: grid; place-items: center; }
.cube.o1 { background: linear-gradient(145deg, #45454d, #26262c); color: #f4efe3; box-shadow: 0 calc(var(--u) * .05) 0 #111; }
.cube.can { cursor: pointer; box-shadow: 0 calc(var(--u) * .05) 0 #b9a67f, 0 0 0 calc(var(--u) * .07) var(--glow), 0 0 calc(var(--u) * .3) var(--glow); }
.cube.dead { opacity: .45; }
.cube-big {
  display: inline-grid; place-items: center; width: 56px; height: 56px; border-radius: 12px;
  background: linear-gradient(145deg, #fffaf0, #e6dbc3); font-weight: 800; font-size: 24px;
  box-shadow: 0 4px 0 #b9a67f, 0 0 0 1px var(--line);
}
.undo-chip {
  position: absolute; display: none; border: 0; padding: 0; z-index: 26; cursor: pointer;
  border-radius: 50%; background: rgba(255, 253, 248, .92); color: var(--ink);
  font-size: calc(var(--u) * .46); font-weight: 700; line-height: 1;
  box-shadow: 0 2px 6px rgba(0, 0, 0, .3);
}
.undo-chip.on { display: grid; place-items: center; }
.undo-chip::after { content: ''; position: absolute; inset: calc(var(--u) * -.15); }   /* bigger tap target */

.still .chk, .still .die { transition: none; }

/* ---------- overlays ---------- */
.overlay {
  position: fixed; inset: 0; z-index: 50;
  background: rgba(42, 38, 32, .36);
  display: flex; align-items: flex-end; justify-content: center;
  padding: 12px;
  animation: fade .2s ease-out;
}
.overlay.soft { background: rgba(241, 236, 226, .55); align-items: center; }
@keyframes fade { from { opacity: 0; } to { opacity: 1; } }
.sheet, .card {
  background: var(--card); color: var(--ink);
  width: 100%; max-width: 440px; max-height: calc(100vh - 24px); max-height: calc(100dvh - 24px);
  overflow: auto; overscroll-behavior: contain;
  border-radius: 24px; padding: 8px 20px 20px;
  box-shadow: 0 20px 50px rgba(42, 38, 32, .22);
  animation: rise .22s ease-out;
}
@keyframes rise { from { transform: translateY(16px); opacity: .6; } to { transform: none; opacity: 1; } }
@media (min-width: 600px) { .overlay { align-items: center; } }
.sheet-head { display: flex; align-items: center; justify-content: space-between; min-height: 52px; }
.sheet-head h2 { margin: 0; font-size: 20px; }
.row {
  display: block; width: 100%; text-align: left; min-height: 50px; padding: 0 4px;
  border: 0; border-bottom: 1px solid var(--line); background: transparent; font-weight: 600; cursor: pointer;
}
.group { padding: 10px 0 2px; }
.label { font-size: 13px; color: var(--muted); margin-bottom: 6px; }
.seg { display: flex; gap: 4px; padding: 4px; border-radius: 16px; background: var(--bg); }
.seg button {
  flex: 1 1 0; min-height: 42px; border: 0; border-radius: 12px; background: transparent; padding: 0 4px;
  font-weight: 600; cursor: pointer; color: var(--muted); transition: background .15s, color .15s;
}
.seg button[aria-pressed="true"] { background: var(--card); color: var(--ink); box-shadow: 0 1px 3px rgba(42, 38, 32, .16); }
.note { font-size: 13px; color: var(--muted); margin: 8px 0 0; }
.menu-sheet .row:first-of-type { border-top: 1px solid var(--line); }
.menu-sheet #menu-help { margin-top: 10px; border-top: 1px solid var(--line); }
.menu-sheet .btn.wide { margin-top: 16px; }

.over-card { max-width: 340px; text-align: center; padding: 24px 22px 14px; }
.over-mark { display: flex; justify-content: center; gap: 8px; margin-bottom: 10px; }
.over-title { font-size: 28px; font-weight: 800; }
.over-sub { color: var(--muted); margin: 4px 0 20px; }
.two { display: flex; gap: 10px; padding-bottom: 8px; }
.link { display: block; margin: 8px auto 0; min-height: 44px; padding: 0 16px; border: 0; background: transparent; color: var(--muted); cursor: pointer; }

.help-sheet { max-width: 560px; }
.help-body { padding-bottom: 6px; }
.help-body h3 { font-size: 16px; margin: 18px 0 4px; }
.help-body p, .help-body li { font-size: 15px; margin: 4px 0; }
.fine { font-size: 13px; color: var(--muted); margin-top: 14px; }

/* ---------- small and landscape screens ---------- */
@media (max-width: 380px) {
  .app { padding-left: max(10px, env(safe-area-inset-left)); padding-right: max(10px, env(safe-area-inset-right)); }
  .btn { padding: 0 14px; }
  .back { font-size: 13px; }
}
@media (max-height: 700px) {
  .bar { min-height: 52px; }
  .game { gap: 6px; padding-bottom: 8px; }
  .turn { min-height: 36px; padding: 5px 16px; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* Online play (online.js): no New game while a friend is playing; a presence line under the turn. */
body.is-online #btn-new { display: none; }
.top { display: flex; flex-direction: column; align-items: center; gap: 6px; }
.net { color: var(--muted, #767a86); }
/* The online rows sit above How to play: they carry its divider (one line), and it joins them. */
.menu-sheet #menu-online, .menu-sheet #menu-leave { margin-top: 10px; border-top: 1px solid var(--line); }
.menu-sheet #menu-online + #menu-leave + #menu-help, .menu-sheet #menu-leave + #menu-help { margin-top: 0; border-top: 0; }
#over-leave { margin-top: 8px; }