:root {
  --night-water: #17343c;
  --deep-water: #0f272e;
  --slate-water: #2c5158;
  --bamboo: #d7b56d;
  --bamboo-light: #e7cb8d;
  --ink: #17201f;
  --paper: #edf0e9;
  --mist: #a9bcb8;
  --copper: #56a696;
  --persimmon: #d77b50;
  --danger: #e89a79;
  --shadow: rgba(5, 18, 22, 0.38);
  --display-font: "STKaiti", "KaiTi", "Kaiti SC", serif;
  --body-font: "Microsoft YaHei UI", "PingFang SC", "Noto Sans CJK SC", sans-serif;
  --utility-font: ui-monospace, "Cascadia Code", "SFMono-Regular", monospace;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  color-scheme: dark;
  background: var(--deep-water);
}

body {
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  color: var(--paper);
  font-family: var(--body-font);
  background:
    radial-gradient(circle at 18% 12%, rgba(86, 166, 150, 0.12), transparent 30rem),
    radial-gradient(circle at 84% 82%, rgba(215, 181, 109, 0.08), transparent 28rem),
    var(--deep-water);
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
}

[hidden] {
  display: none !important;
}

.page-texture {
  position: fixed;
  inset: 0;
  z-index: -1;
  opacity: 0.28;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(93deg, transparent 0 23px, rgba(255, 255, 255, 0.018) 24px),
    repeating-linear-gradient(3deg, transparent 0 31px, rgba(0, 0, 0, 0.025) 32px);
}

.app-shell {
  width: min(1480px, 100%);
  min-height: 100vh;
  margin: 0 auto;
  padding: clamp(20px, 3vw, 46px);
}

.brand-lockup {
  display: grid;
  justify-items: center;
  margin-bottom: clamp(20px, 3vh, 36px);
  text-align: center;
}

.brand-lockup h1 {
  margin: 2px 0 0;
  font-family: var(--display-font);
  font-size: clamp(2.35rem, 5vw, 4.2rem);
  font-weight: 500;
  letter-spacing: 0.16em;
  line-height: 1;
}

.brand-lockup > p:last-child {
  margin: 12px 0 0;
  color: var(--mist);
  font-size: 0.92rem;
  letter-spacing: 0.08em;
}

.brand-kicker,
.section-mark,
.seat-index {
  margin: 0;
  color: var(--copper);
  font-family: var(--utility-font);
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.login-view {
  display: grid;
  min-height: min(620px, 70vh);
  place-items: center;
}

.login-plaque {
  position: relative;
  width: min(100%, 470px);
  padding: clamp(28px, 6vw, 54px);
  border: 1px solid rgba(231, 203, 141, 0.28);
  background: rgba(23, 52, 60, 0.88);
  box-shadow: 0 30px 80px var(--shadow);
}

.login-plaque::before,
.login-plaque::after {
  position: absolute;
  top: 18px;
  width: 5px;
  height: 5px;
  border: 1px solid rgba(231, 203, 141, 0.55);
  border-radius: 50%;
  content: "";
}

.login-plaque::before { left: 18px; }
.login-plaque::after { right: 18px; }

.login-plaque h2 {
  margin: 10px 0 8px;
  font-family: var(--display-font);
  font-size: clamp(1.9rem, 5vw, 2.7rem);
  font-weight: 500;
  letter-spacing: 0.08em;
}

.login-intro {
  margin: 0 0 28px;
  color: var(--mist);
  line-height: 1.7;
}

.login-form,
.password-field {
  display: grid;
  gap: 12px;
}

.seat-picker {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin: 0;
  padding: 0;
  border: 0;
}

.seat-picker legend,
.password-field > span {
  margin-bottom: 9px;
  color: var(--mist);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
}

.seat-option {
  position: relative;
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 10px;
  padding: 12px;
  border: 1px solid rgba(237, 240, 233, 0.14);
  cursor: pointer;
}

.seat-option:has(input:checked) {
  border-color: var(--bamboo);
  background: rgba(215, 181, 109, 0.09);
}

.seat-option input {
  position: absolute;
  opacity: 0;
}

.seat-seal {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border: 1px solid currentColor;
  color: var(--bamboo-light);
  font-family: var(--utility-font);
  font-size: 0.8rem;
}

.password-field {
  margin-top: 14px;
}

.password-field input {
  width: 100%;
  padding: 13px 14px;
  border: 1px solid rgba(237, 240, 233, 0.18);
  border-radius: 0;
  outline: none;
  color: var(--paper);
  background: rgba(8, 28, 34, 0.62);
}

.password-field input:focus {
  border-color: var(--copper);
  box-shadow: 0 0 0 3px rgba(86, 166, 150, 0.16);
}

.form-error {
  min-height: 1.4em;
  margin: 0;
  color: var(--danger);
  font-size: 0.86rem;
}

.primary-action,
.quiet-action,
.text-action {
  min-height: 44px;
  border: 0;
  cursor: pointer;
}

.primary-action {
  padding: 12px 22px;
  color: #10292f;
  font-weight: 700;
  letter-spacing: 0.06em;
  background: var(--bamboo-light);
}

.primary-action:hover:not(:disabled) {
  background: #f0d99f;
}

.primary-action.compact {
  min-width: 132px;
}

.quiet-action {
  padding: 10px 18px;
  border: 1px solid rgba(237, 240, 233, 0.2);
  background: transparent;
}

.text-action {
  padding: 10px 8px;
  color: var(--mist);
  background: transparent;
}

.primary-action:disabled,
.quiet-action:disabled,
.text-action:disabled {
  cursor: not-allowed;
  opacity: 0.42;
}

.board-cell:disabled {
  cursor: not-allowed;
  opacity: 1;
}

button:focus-visible,
input:focus-visible,
.seat-option:has(input:focus-visible) {
  outline: 3px solid var(--copper);
  outline-offset: 3px;
}

.game-view {
  position: relative;
}

.connection-banner {
  position: fixed;
  top: 12px;
  left: 50%;
  z-index: 20;
  padding: 9px 16px;
  color: var(--deep-water);
  font-size: 0.82rem;
  font-weight: 700;
  background: var(--bamboo-light);
  box-shadow: 0 8px 28px var(--shadow);
  transform: translateX(-50%);
}

.notice {
  min-height: 1.5em;
  margin: 0 0 10px;
  color: var(--mist);
  font-size: 0.82rem;
  text-align: center;
}

.notice[data-tone="error"] { color: var(--danger); }
.notice[data-tone="success"] { color: #7bc9b8; }
.notice[data-tone="warning"] { color: var(--bamboo-light); }

.table-layout {
  display: grid;
  grid-template-areas: "seat-a board seat-b";
  grid-template-columns: minmax(150px, 210px) minmax(320px, 720px) minmax(150px, 210px);
  align-items: center;
  justify-content: center;
  gap: clamp(18px, 3vw, 48px);
}

.player-seat {
  position: relative;
  min-height: 230px;
  padding: 20px;
  border-top: 1px solid rgba(237, 240, 233, 0.17);
  border-bottom: 1px solid rgba(237, 240, 233, 0.08);
  background: rgba(23, 52, 60, 0.48);
  transition: border-color 180ms ease, transform 180ms ease, background 180ms ease;
}

.player-seat-a { grid-area: seat-a; }
.player-seat-b { grid-area: seat-b; }

.player-seat.is-online {
  border-top-color: rgba(86, 166, 150, 0.65);
}

.player-seat.is-turn {
  border-top-color: var(--bamboo-light);
  background: rgba(44, 81, 88, 0.62);
  transform: translateY(-4px);
}

.seat-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.presence-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #5c6c69;
  box-shadow: 0 0 0 4px rgba(92, 108, 105, 0.12);
}

.is-online .presence-dot {
  background: var(--copper);
  box-shadow: 0 0 0 4px rgba(86, 166, 150, 0.15);
}

.player-seat h2 {
  margin: 38px 0 4px;
  font-family: var(--display-font);
  font-size: clamp(1.55rem, 3vw, 2.1rem);
  font-weight: 500;
}

.presence-copy,
.score-line {
  color: var(--mist);
  font-size: 0.82rem;
}

.piece-assignment {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-top: 28px;
  font-size: 0.88rem;
}

.mini-piece {
  display: inline-block;
  width: 18px;
  height: 18px;
  border: 1px dashed rgba(237, 240, 233, 0.25);
  border-radius: 50%;
}

.mini-piece-black {
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: #101716;
  box-shadow: inset -3px -3px 4px rgba(255, 255, 255, 0.06);
}

.mini-piece-white {
  border: 1px solid rgba(16, 23, 22, 0.2);
  background: #e9e9df;
  box-shadow: inset -3px -3px 4px rgba(16, 23, 22, 0.15);
}

.board-stage {
  grid-area: board;
  width: 100%;
}

.turn-rail {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 10px;
  width: min(460px, 82%);
  margin: 0 auto 16px;
  color: var(--mist);
  font-family: var(--utility-font);
  font-size: 0.7rem;
}

.rail-line {
  position: relative;
  height: 1px;
  background: rgba(237, 240, 233, 0.2);
}

.turn-marker {
  position: absolute;
  top: 50%;
  left: var(--turn-position, 50%);
  width: 10px;
  height: 10px;
  border: 2px solid var(--deep-water);
  border-radius: 50%;
  background: var(--bamboo-light);
  box-shadow: 0 0 0 2px var(--bamboo-light);
  transform: translate(-50%, -50%);
  transition: left 260ms cubic-bezier(.2, .8, .2, 1);
}

.match-heading {
  margin-bottom: 15px;
  text-align: center;
}

.match-heading h2 {
  margin: 5px 0 0;
  font-family: var(--display-font);
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 500;
  letter-spacing: 0.08em;
}

.board-wrap {
  position: relative;
  width: min(100%, 720px);
  margin: 0 auto;
  aspect-ratio: 1;
  filter: drop-shadow(0 24px 30px rgba(3, 12, 14, 0.32));
}

.board {
  position: absolute;
  inset: 0;
  z-index: 2;
  display: grid;
  grid-template-columns: repeat(15, 1fr);
  grid-template-rows: repeat(15, 1fr);
  padding: 3.33%;
  border: clamp(7px, 1vw, 12px) solid #b78c49;
  background:
    repeating-linear-gradient(88deg, rgba(255, 255, 255, 0.022) 0 2px, transparent 2px 17px),
    linear-gradient(102deg, var(--bamboo-light), var(--bamboo) 54%, #c59a55);
  box-shadow:
    inset 0 0 0 1px rgba(76, 48, 16, 0.42),
    inset 0 0 30px rgba(106, 66, 21, 0.16);
}

.board::before {
  position: absolute;
  inset: 6.44%;
  z-index: -1;
  background-image:
    linear-gradient(rgba(44, 38, 25, 0.6) 1px, transparent 1px),
    linear-gradient(90deg, rgba(44, 38, 25, 0.6) 1px, transparent 1px);
  background-size: calc(100% / 14) calc(100% / 14);
  content: "";
}

.board-cell {
  position: relative;
  z-index: 3;
  min-width: 0;
  min-height: 0;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: transparent;
}

.board-cell::before {
  position: absolute;
  top: 13%;
  left: 13%;
  width: 74%;
  height: 74%;
  border-radius: 50%;
  content: "";
  opacity: 0;
  transform: scale(0.76);
}

.board-cell:not(:disabled):hover::before,
.board-cell.is-pending::before {
  opacity: 0.3;
  background: var(--ink);
  transform: scale(0.82);
}

.board-cell.stone-black::before,
.board-cell.stone-white::before {
  opacity: 1;
  transform: scale(1);
  animation: stone-settle 180ms cubic-bezier(.2, .9, .25, 1.25);
}

.board-cell.stone-black::before {
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: radial-gradient(circle at 34% 28%, #3c4743, #101716 58%, #050908);
  box-shadow: 1px 3px 6px rgba(50, 34, 15, 0.46);
}

.board-cell.stone-white::before {
  border: 1px solid rgba(36, 38, 32, 0.22);
  background: radial-gradient(circle at 34% 28%, #ffffff, #e9e9df 58%, #c8c8bf);
  box-shadow: 1px 3px 6px rgba(50, 34, 15, 0.36);
}

.board-cell.is-last::after {
  position: absolute;
  top: 50%;
  left: 50%;
  z-index: 4;
  width: 18%;
  height: 18%;
  border-radius: 50%;
  background: var(--persimmon);
  box-shadow: 0 0 0 1px rgba(16, 23, 22, 0.26);
  content: "";
  transform: translate(-50%, -50%);
}

.board-cell.is-winning::before {
  box-shadow: 0 0 0 3px var(--persimmon), 0 0 18px rgba(215, 123, 80, 0.7);
}

.board-cell:focus-visible {
  outline: 2px solid var(--persimmon);
  outline-offset: -3px;
}

.board-stars {
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
}

.star {
  position: absolute;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: rgba(44, 38, 25, 0.72);
  transform: translate(-50%, -50%);
}

.star-1 { top: 25%; left: 25%; }
.star-2 { top: 25%; left: 75%; }
.star-3 { top: 50%; left: 50%; }
.star-4 { top: 75%; left: 25%; }
.star-5 { top: 75%; left: 75%; }

.pause-overlay {
  position: absolute;
  inset: 0;
  z-index: 5;
  display: grid;
  place-content: center;
  justify-items: center;
  color: var(--paper);
  text-align: center;
  background: rgba(10, 30, 34, 0.76);
  backdrop-filter: blur(4px);
}

.pause-overlay strong {
  margin-top: 8px;
  font-family: var(--display-font);
  font-size: 1.7rem;
  font-weight: 500;
}

.pause-overlay strong + span {
  margin-top: 4px;
  color: var(--mist);
  font-size: 0.82rem;
}

.pause-overlay .pause-countdown {
  margin-top: 10px;
  color: var(--bamboo-light);
  font-family: var(--utility-font);
  font-size: 0.72rem;
}

.pause-symbol {
  color: var(--bamboo-light);
  font-family: var(--utility-font);
  letter-spacing: 0.18em;
}

.game-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin-top: 18px;
}

@keyframes stone-settle {
  from { opacity: 0.45; transform: scale(1.28); }
  to { opacity: 1; transform: scale(1); }
}

@media (max-width: 900px) {
  .app-shell {
    padding: 18px;
  }

  .brand-lockup {
    margin-bottom: 18px;
  }

  .brand-lockup > p:last-child {
    display: none;
  }

  .table-layout {
    grid-template-areas:
      "seat-a seat-b"
      "board board";
    grid-template-columns: 1fr 1fr;
    align-items: stretch;
    gap: 14px;
  }

  .player-seat {
    min-height: 128px;
    padding: 14px;
  }

  .player-seat.is-turn {
    transform: translateY(-2px);
  }

  .player-seat h2 {
    margin: 16px 0 2px;
    font-size: 1.35rem;
  }

  .piece-assignment {
    position: absolute;
    top: 13px;
    right: 13px;
    margin: 0;
  }

  .score-line {
    margin-bottom: 0;
  }

  .board-stage {
    margin-top: 4px;
  }
}

@media (max-width: 520px) {
  .app-shell {
    padding: 14px 10px 20px;
  }

  .brand-lockup h1 {
    font-size: 2.35rem;
  }

  .brand-kicker {
    font-size: 0.62rem;
  }

  .player-seat {
    min-width: 0;
    min-height: 112px;
    padding: 11px;
  }

  .seat-index {
    font-size: 0.58rem;
  }

  .player-seat h2 {
    overflow: hidden;
    margin-top: 15px;
    font-size: 1.15rem;
    text-overflow: ellipsis;
    white-space: nowrap;
  }

  .presence-copy,
  .score-line,
  .piece-assignment {
    font-size: 0.68rem;
  }

  .piece-assignment {
    top: 10px;
    right: 9px;
  }

  .mini-piece {
    width: 14px;
    height: 14px;
  }

  .turn-rail {
    margin-bottom: 10px;
  }

  .match-heading {
    margin-bottom: 9px;
  }

  .match-heading h2 {
    font-size: 1.3rem;
  }

  .game-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
  }

  .game-actions .text-action {
    grid-column: 1 / -1;
  }

  .primary-action.compact,
  .quiet-action {
    min-width: 0;
    padding-inline: 10px;
  }

  .login-plaque {
    padding: 28px 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}