:root {
  color-scheme: light;
  --ink: #17231f;
  --muted: #6e756f;
  --paper: #f3f0e7;
  --paper-deep: #e8e1d2;
  --line: rgba(23, 35, 31, 0.72);
  --vermillion: #a33d2f;
  --gold: #b98a48;
  --board-size: min(69vh, 660px, calc(100vw - 430px));
  font-family: "Noto Serif SC", "Songti SC", SimSun, serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html { background: var(--ink); }

body {
  margin: 0;
  min-height: 100svh;
  color: var(--ink);
  background:
    radial-gradient(circle at 15% 10%, rgba(255,255,255,.88), transparent 34%),
    radial-gradient(circle at 92% 78%, rgba(185,138,72,.1), transparent 28%),
    repeating-linear-gradient(90deg, rgba(49,54,43,.025) 0 1px, transparent 1px 7px),
    var(--paper);
}

button { font: inherit; }

.app-shell {
  width: min(1180px, calc(100% - 48px));
  min-height: 100svh;
  margin: 0 auto;
  padding: 28px 0 36px;
}

.masthead {
  min-height: 84px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid rgba(23,35,31,.2);
  margin-bottom: 24px;
}

.brand-lockup { display: flex; align-items: center; gap: 14px; }
.brand-mark {
  display: grid;
  place-items: center;
  width: 52px;
  height: 52px;
  border: 1px solid rgba(163,61,47,.55);
  color: var(--vermillion);
  font-size: 29px;
  line-height: 1;
  background: rgba(255,255,255,.18);
  box-shadow: inset 0 0 0 4px var(--paper), inset 0 0 0 5px rgba(163,61,47,.22);
}

.eyebrow {
  margin: 0 0 3px;
  font: 600 11px/1.2 ui-sans-serif, system-ui, sans-serif;
  letter-spacing: .22em;
  color: var(--vermillion);
}

h1 {
  margin: 0;
  font-size: clamp(18px, 2vw, 25px);
  font-weight: 600;
  letter-spacing: .08em;
  line-height: 1.2;
}

.icon-button {
  width: 42px;
  height: 42px;
  border: 1px solid rgba(23,35,31,.26);
  border-radius: 50%;
  color: var(--ink);
  background: transparent;
  cursor: pointer;
  transition: background .2s, color .2s, transform .2s;
}

.icon-button:hover { background: var(--ink); color: var(--paper); transform: rotate(-5deg); }
.sound-off { display: none; }
.icon-button.muted .sound-on { display: none; }
.icon-button.muted .sound-off { display: inline; }

.icon-button.muted { opacity: .42; text-decoration: line-through; }

.game-layout {
  display: grid;
  grid-template-columns: minmax(440px, 1fr) 300px;
  gap: clamp(34px, 6vw, 80px);
  align-items: center;
}

.board-panel { min-width: 0; }

.turn-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 32px;
  margin-bottom: 12px;
  font-size: 14px;
  letter-spacing: .15em;
  border-bottom: 1px solid rgba(23,35,31,.1);
}
.turn-main { display: inline-flex; align-items: center; gap: 9px; }
.move-counter { color: var(--muted); font: 10px ui-sans-serif, system-ui, sans-serif; letter-spacing: .08em; }
.move-counter strong { color: var(--ink); font-weight: 650; }

.board-wrap {
  width: var(--board-size);
  height: var(--board-size);
  max-width: 100%;
  margin: auto;
  padding: clamp(16px, 2.5vw, 28px);
  border: 1px solid rgba(23,35,31,.35);
  background:
    linear-gradient(135deg, rgba(255,255,255,.16), transparent 35%),
    repeating-linear-gradient(4deg, rgba(91,55,20,.025) 0 2px, transparent 2px 8px),
    #d1aa70;
  box-shadow: 0 24px 55px rgba(45, 40, 28, .2), inset 0 0 35px rgba(92,55,20,.12);
  position: relative;
}

.board-wrap::before {
  content: "";
  position: absolute;
  inset: 7px;
  border: 1px solid rgba(80,50,22,.25);
  pointer-events: none;
}

.board {
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-columns: repeat(15, 1fr);
  grid-template-rows: repeat(15, 1fr);
  position: relative;
  background-image:
    radial-gradient(circle at 21.43% 21.43%, var(--line) 0 3px, transparent 3.5px),
    radial-gradient(circle at 78.57% 21.43%, var(--line) 0 3px, transparent 3.5px),
    radial-gradient(circle at 50% 50%, var(--line) 0 3px, transparent 3.5px),
    radial-gradient(circle at 21.43% 78.57%, var(--line) 0 3px, transparent 3.5px),
    radial-gradient(circle at 78.57% 78.57%, var(--line) 0 3px, transparent 3.5px),
    linear-gradient(to right, transparent calc(50% - .5px), var(--line) 50%, transparent calc(50% + .5px)),
    linear-gradient(to bottom, transparent calc(50% - .5px), var(--line) 50%, transparent calc(50% + .5px));
  background-size: 100% 100%, 100% 100%, 100% 100%, 100% 100%, 100% 100%, calc(100% / 14) calc(100% / 14), calc(100% / 14) calc(100% / 14);
  background-position: center;
  background-repeat: no-repeat, no-repeat, no-repeat, no-repeat, no-repeat, repeat, repeat;
}

.board-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: var(--board-size);
  max-width: 100%;
  margin: 10px auto 0;
  color: rgba(23,35,31,.48);
  font: 9px ui-sans-serif, system-ui, sans-serif;
  letter-spacing: .2em;
}
.board-footer-mark { color: var(--vermillion); font: 16px/1 serif; }

.cell {
  appearance: none;
  min-width: 0;
  border: 0;
  padding: 0;
  position: relative;
  z-index: 1;
  background: transparent;
  cursor: pointer;
  touch-action: manipulation;
}
.board.locked .cell { cursor: default; }

.cell::after {
  content: "";
  position: absolute;
  width: min(72%, 28px);
  aspect-ratio: 1;
  inset: 50% auto auto 50%;
  border-radius: 50%;
  transform: translate(-50%, -50%) scale(0);
  transition: transform 150ms ease-out;
}

.cell.black::after {
  transform: translate(-50%, -50%) scale(1);
  background: radial-gradient(circle at 35% 28%, #4d534f, #101513 62%);
  box-shadow: 0 2px 4px rgba(0,0,0,.35);
}

.cell.white::after {
  transform: translate(-50%, -50%) scale(1);
  background: radial-gradient(circle at 35% 28%, #fff, #ddd8ca 72%);
  box-shadow: 0 2px 5px rgba(0,0,0,.28), inset 0 0 0 1px rgba(0,0,0,.1);
}

.cell.last::before {
  content: "";
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--vermillion);
  position: absolute;
  z-index: 2;
  left: 50%; top: 50%;
  transform: translate(-50%, -50%);
}

.cell:focus-visible { outline: 2px solid var(--vermillion); outline-offset: -2px; }

.board:not(.locked).black-turn .cell:not(.black):not(.white):hover::after {
  transform: translate(-50%, -50%) scale(.45);
  background: rgba(23,35,31,.18);
}
.board:not(.locked).white-turn .cell:not(.black):not(.white):hover::after {
  transform: translate(-50%, -50%) scale(.45);
  background: rgba(255,255,255,.55);
  box-shadow: inset 0 0 0 1px rgba(0,0,0,.09);
}

.control-panel { padding-top: 22px; }

.intro { display: flex; gap: 14px; margin-bottom: 24px; }
.seal {
  flex: 0 0 auto;
  display: grid; place-items: center;
  width: 42px; height: 42px;
  border: 2px solid var(--vermillion);
  color: var(--vermillion);
  font-size: 23px;
}
.intro-title { margin: 0 0 5px; font-size: 18px; font-weight: 700; }
.intro-copy { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.65; }

.section-label {
  margin: 0 0 8px;
  color: var(--muted);
  font: 600 10px/1.2 ui-sans-serif, system-ui, sans-serif;
  letter-spacing: .14em;
}

.mode-picker {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin-bottom: 18px;
}

.mode {
  min-width: 0;
  padding: 12px 9px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 5px;
  text-align: center;
  border: 1px solid rgba(23,35,31,.16);
  border-radius: 2px;
  color: var(--ink);
  background: rgba(255,255,255,.25);
  cursor: pointer;
}
.mode:hover { border-color: rgba(23,35,31,.5); }
.mode.active { border-color: var(--ink); background: var(--ink); color: var(--paper); box-shadow: 0 8px 22px rgba(23,35,31,.12); }
.mode-icon { display: grid; place-items: center; width: 25px; height: 25px; border: 1px solid currentColor; text-align: center; font-size: 11px; border-radius: 50%; }
.mode strong, .mode small { display: block; white-space: nowrap; }
.mode strong { font-size: 13px; }
.mode small { opacity: .65; margin-top: 2px; font: 10px ui-sans-serif, system-ui, sans-serif; }

.online-panel {
  margin: 2px 0 18px;
  padding: 12px;
  border: 1px solid rgba(23,35,31,.16);
  background: rgba(255,255,255,.25);
}
.create-room-button {
  width: 100%;
  min-height: 54px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 14px;
  border: 0;
  color: var(--paper);
  background: var(--ink);
  text-align: left;
  cursor: pointer;
}
.create-room-button strong, .create-room-button small { display: block; }
.create-room-button strong { font-size: 13px; }
.create-room-button small { margin-top: 3px; opacity: .62; font: 9px ui-sans-serif, system-ui, sans-serif; }
.create-room-button > span:last-child { font: 24px/1 ui-sans-serif, system-ui, sans-serif; font-weight: 200; }
.join-divider { height: 28px; display: flex; align-items: center; color: var(--muted); font: 9px ui-sans-serif, system-ui, sans-serif; }
.join-divider::before, .join-divider::after { content: ""; height: 1px; flex: 1; background: rgba(23,35,31,.12); }
.join-divider span { padding: 0 8px; }
.join-room-form { display: grid; grid-template-columns: 1fr 66px; gap: 7px; }
.join-room-form input {
  min-width: 0;
  height: 42px;
  padding: 0 12px;
  border: 1px solid rgba(23,35,31,.24);
  outline: none;
  color: var(--ink);
  background: rgba(255,255,255,.45);
  font: 650 14px ui-monospace, SFMono-Regular, Consolas, monospace;
  letter-spacing: .14em;
  text-transform: uppercase;
}
.join-room-form input:focus { border-color: var(--vermillion); box-shadow: 0 0 0 2px rgba(163,61,47,.1); }
.join-room-form button, .copy-invite {
  border: 1px solid var(--ink);
  color: var(--ink);
  background: transparent;
  cursor: pointer;
}
.room-error { min-height: 14px; margin: 7px 0 -2px; color: var(--vermillion); font: 10px ui-sans-serif, system-ui, sans-serif; }
.room-lobby { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 10px; }
.room-lobby .section-label { margin-bottom: 4px; }
.room-code { padding: 0; border: 0; color: var(--vermillion); background: transparent; cursor: pointer; font: 700 25px/1 ui-monospace, SFMono-Regular, Consolas, monospace; letter-spacing: .13em; }
.room-lobby-status { grid-column: 1 / -1; display: flex; align-items: center; gap: 7px; padding-top: 10px; border-top: 1px solid rgba(23,35,31,.12); color: var(--muted); font: 10px ui-sans-serif, system-ui, sans-serif; }
.connection-dot { width: 7px; height: 7px; border-radius: 50%; background: var(--gold); box-shadow: 0 0 0 3px rgba(185,138,72,.12); }
.connection-dot.connected { background: #4e7d61; box-shadow: 0 0 0 3px rgba(78,125,97,.12); }
.copy-invite { height: 34px; padding: 0 10px; font-size: 10px; }

.difficulty-section { margin: 2px 0 18px; transition: opacity .2s; }
.difficulty-section.disabled { opacity: .42; }
.setting-heading { display: flex; align-items: center; justify-content: space-between; }
.setting-heading > span { margin-bottom: 8px; color: var(--vermillion); font: 10px ui-sans-serif, system-ui, sans-serif; }
.difficulty-picker {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  padding: 3px;
  border: 1px solid rgba(23,35,31,.15);
  background: rgba(255,255,255,.24);
}
.difficulty-picker button {
  min-width: 0;
  padding: 9px 4px;
  border: 0;
  color: var(--ink);
  background: transparent;
  cursor: pointer;
}
.difficulty-picker button + button { border-left: 1px solid rgba(23,35,31,.1); }
.difficulty-picker button.active { color: var(--paper); background: var(--vermillion); }
.difficulty-picker button:disabled { cursor: not-allowed; }
.difficulty-picker strong, .difficulty-picker small { display: block; }
.difficulty-picker strong { font-size: 12px; }
.difficulty-picker small { margin-top: 3px; opacity: .68; font: 9px ui-sans-serif, system-ui, sans-serif; white-space: nowrap; }

.score-card { border-top: 1px solid rgba(23,35,31,.2); border-bottom: 1px solid rgba(23,35,31,.2); }
.player-row { height: 70px; display: flex; align-items: center; gap: 12px; opacity: .52; transition: opacity .2s; }
.player-row.active { opacity: 1; }
.player-row strong, .player-row small { display: block; }
.player-row strong { font-size: 15px; }
.player-row small { color: var(--muted); font: 11px ui-sans-serif, system-ui, sans-serif; margin-top: 2px; }
.stone {
  display: inline-block;
  width: 28px; height: 28px;
  border-radius: 50%;
  flex: 0 0 auto;
}
.stone.black { background: radial-gradient(circle at 35% 28%, #505651, #0d1210 65%); box-shadow: 0 2px 4px rgba(0,0,0,.35); }
.stone.white { background: radial-gradient(circle at 35% 28%, #fff, #d7d2c5 75%); box-shadow: 0 2px 5px rgba(0,0,0,.25), inset 0 0 0 1px rgba(0,0,0,.08); }
.stone.mini { width: 15px; height: 15px; }
.player-tag, .thinking { margin-left: auto; font: 10px ui-sans-serif, system-ui, sans-serif; letter-spacing: .1em; }
.player-tag { color: var(--vermillion); }
.thinking { display: none; color: var(--muted); }
.thinking.visible { display: inline; }
.divider { height: 1px; position: relative; background: rgba(23,35,31,.12); }
.divider span { position: absolute; left: 50%; top: 50%; transform: translate(-50%,-50%); background: var(--paper); padding: 0 8px; color: var(--muted); font-size: 10px; }

.actions { display: grid; grid-template-columns: 1.35fr 1fr; gap: 10px; margin-top: 20px; }
.primary-button, .secondary-button {
  height: 48px;
  border: 1px solid var(--ink);
  cursor: pointer;
  letter-spacing: .12em;
  transition: transform .15s, opacity .15s;
}
.primary-button { color: var(--paper); background: var(--ink); }
.actions .primary-button { display: flex; align-items: center; justify-content: space-between; padding: 0 18px; }
.primary-button:hover:not(:disabled) { background: #263630; }
.secondary-button:hover:not(:disabled) { background: rgba(23,35,31,.06); }
.secondary-button { color: var(--ink); background: transparent; }
.primary-button:active, .secondary-button:active { transform: translateY(1px); }
.secondary-button:disabled { opacity: .3; cursor: not-allowed; }
.shortcut { text-align: center; color: var(--muted); font: 10px ui-sans-serif, system-ui, sans-serif; }
kbd { border: 1px solid rgba(23,35,31,.25); border-radius: 3px; padding: 1px 4px; background: rgba(255,255,255,.4); }

.dialog-backdrop {
  position: fixed;
  z-index: 10;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(12,20,17,.67);
  backdrop-filter: blur(4px);
}
.dialog-backdrop[hidden] { display: none; }
.result-dialog {
  width: min(390px, 100%);
  padding: 40px;
  text-align: center;
  background: var(--paper);
  box-shadow: 0 30px 80px rgba(0,0,0,.3);
}
.result-mark { display: grid; place-items: center; width: 62px; height: 62px; margin: 0 auto 24px; border: 2px solid var(--vermillion); color: var(--vermillion); font-size: 32px; }
.result-dialog h2 { margin: 8px 0; font-size: 27px; }
.result-dialog > p:not(.eyebrow) { margin: 0 0 24px; color: var(--muted); font-size: 13px; }
.result-dialog .primary-button { width: 100%; }

@media (max-width: 850px) {
  :root { --board-size: min(calc(100vw - 36px), 620px); }
  .app-shell { width: min(620px, calc(100% - 24px)); padding: 10px 0 calc(28px + env(safe-area-inset-bottom)); }
  .masthead { min-height: 64px; margin-bottom: 10px; }
  .brand-mark { width: 40px; height: 40px; font-size: 23px; }
  h1 { font-size: 16px; }
  .game-layout { display: flex; flex-direction: column; gap: 18px; }
  .board-panel { width: 100%; }
  .board-wrap { padding: clamp(12px, 4.5vw, 22px); }
  .control-panel { width: 100%; padding: 0; display: flex; flex-direction: column; }
  .intro { display: none; }
  .control-panel > .section-label { order: 2; margin: 13px 0 7px; }
  .mode-picker { order: 3; margin: 0; }
  .difficulty-section { order: 4; margin: 13px 0 0; }
  .online-panel { order: 4; margin: 13px 0 0; }
  .score-card { order: 1; display: grid; grid-template-columns: 1fr 1px 1fr; }
  .player-row { height: 56px; padding: 0 10px; }
  .player-row:nth-of-type(3) { flex-direction: row-reverse; text-align: right; }
  .player-row:nth-of-type(3) .thinking { margin: 0 auto 0 0; }
  .divider { width: 1px; height: 100%; }
  .divider span { display: none; }
  .player-tag { display: none; }
  .actions { order: 5; margin-top: 10px; }
  .shortcut { display: none; order: 6; }
}

@media (max-width: 420px) {
  .eyebrow { font-size: 9px; }
  .brand-lockup { gap: 9px; }
  .brand-mark { width: 36px; height: 36px; font-size: 20px; }
  h1 { font-size: 14px; letter-spacing: .04em; }
  .turn-banner { margin-bottom: 8px; font-size: 12px; }
  .board-wrap { width: calc(100vw - 24px); height: calc(100vw - 24px); }
  .board-footer { width: calc(100vw - 24px); }
  .mode { justify-content: center; padding-inline: 3px; }
  .mode-icon { display: none; }
  .mode strong { font-size: 12px; }
  .mode small { font-size: 8px; }
  .difficulty-picker small { display: none; }
  .difficulty-picker button { padding: 10px 4px; }
  .result-dialog { padding: 32px 24px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: .01ms !important; }
}