:root {
  --bg-top: #f6e7c8;
  --bg-bottom: #d7b884;
  --panel: rgba(98, 56, 24, 0.14);
  --panel-strong: rgba(255, 246, 225, 0.72);
  --text: #2d1b10;
  --muted: #6f4b34;
  --accent: #a9441d;
  --accent-soft: #db8f4a;
  --line: rgba(72, 42, 18, 0.78);
  --shadow: 0 20px 60px rgba(73, 36, 12, 0.18);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Space Grotesk", sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(255, 246, 224, 0.95), transparent 30%),
    linear-gradient(160deg, var(--bg-top), var(--bg-bottom));
}

body.modal-open {
  overflow: hidden;
}

.mobile-sticky-bar {
  display: none;
}

body::before,
body::after {
  content: "";
  position: fixed;
  inset: auto;
  border-radius: 999px;
  pointer-events: none;
  filter: blur(10px);
}

body::before {
  width: 280px;
  height: 280px;
  top: 3rem;
  right: 6vw;
  background: rgba(255, 226, 169, 0.28);
}

body::after {
  width: 240px;
  height: 240px;
  bottom: 2rem;
  left: 5vw;
  background: rgba(151, 67, 20, 0.12);
}

.app-shell {
  width: min(1180px, calc(100vw - 2rem));
  margin: 0 auto;
  min-height: 100vh;
  display: grid;
  grid-template-columns: minmax(280px, 360px) minmax(0, 1fr);
  gap: 1.5rem;
  padding: 1.5rem 0 2rem;
}

.hero-panel,
.board-panel {
  position: relative;
  overflow: hidden;
  min-width: 0;
  border: 1px solid rgba(107, 61, 26, 0.18);
  border-radius: 28px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.hero-panel {
  padding: 2rem;
  background:
    linear-gradient(180deg, rgba(255, 248, 236, 0.9), rgba(241, 218, 177, 0.78)),
    rgba(255, 248, 236, 0.7);
}

.board-panel {
  padding: 1.25rem;
  background:
    linear-gradient(180deg, rgba(255, 249, 238, 0.72), rgba(235, 207, 157, 0.82)),
    rgba(255, 255, 255, 0.45);
}

.eyebrow,
.board-title,
.label,
.move-counter span {
  margin: 0;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-size: 0.78rem;
  color: var(--muted);
}

h1 {
  margin: 0.5rem 0 1rem;
  font-family: "Noto Serif TC", serif;
  font-size: clamp(2.4rem, 6vw, 4.3rem);
  line-height: 0.95;
}

.intro {
  margin: 0;
  max-width: 26ch;
  color: rgba(45, 27, 16, 0.82);
  font-size: 1rem;
  line-height: 1.7;
}

.hero-points {
  margin: 1.4rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.6rem;
  color: var(--muted);
}

.hero-points li {
  padding: 0.75rem 0.9rem;
  border-radius: 16px;
  background: rgba(255, 248, 233, 0.72);
  border: 1px solid rgba(107, 61, 26, 0.12);
}

.controls {
  display: grid;
  gap: 1rem;
  margin-top: 2rem;
}

.status-card {
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: var(--panel-strong);
  border: 1px solid rgba(100, 57, 25, 0.14);
}

.difficulty-card {
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: rgba(255, 248, 233, 0.72);
  border: 1px solid rgba(100, 57, 25, 0.14);
}

.stats-card {
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: rgba(255, 248, 233, 0.72);
  border: 1px solid rgba(100, 57, 25, 0.14);
}

.badge-rule-card {
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: rgba(255, 248, 233, 0.72);
  border: 1px solid rgba(100, 57, 25, 0.14);
}

.status-card strong {
  display: block;
  margin-top: 0.4rem;
  font-size: 1.1rem;
}

.difficulty-card select {
  width: 100%;
  margin-top: 0.5rem;
  border: 1px solid rgba(107, 61, 26, 0.18);
  border-radius: 14px;
  padding: 0.75rem 0.9rem;
  font: inherit;
  color: var(--text);
  background: rgba(255, 252, 245, 0.92);
  appearance: none;
}

.stats-topline {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-top: 0.55rem;
}

.stats-summary {
  margin: 0.65rem 0 0;
  color: rgba(45, 27, 16, 0.82);
}

.badge-rule-intro {
  margin: 0.55rem 0 0;
  color: rgba(45, 27, 16, 0.82);
  line-height: 1.6;
}

.badge-rule-list {
  margin: 0.75rem 0 0;
  padding-left: 1.15rem;
  color: rgba(45, 27, 16, 0.82);
  line-height: 1.65;
}

.badge-image {
  width: 74px;
  height: auto;
  display: block;
  filter: drop-shadow(0 6px 12px rgba(78, 45, 18, 0.16));
}

.badge-image-large {
  width: 90px;
}

.mobile-sticky-field {
  display: grid;
  gap: 0.35rem;
  min-width: 0;
}

.mobile-sticky-field select {
  width: 100%;
  border: 1px solid rgba(107, 61, 26, 0.16);
  border-radius: 14px;
  padding: 0.72rem 0.85rem;
  font: inherit;
  color: var(--text);
  background: rgba(255, 251, 243, 0.96);
  appearance: none;
}

.mobile-sticky-stats {
  display: none;
}

.button-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

button {
  border: 0;
  border-radius: 999px;
  padding: 0.9rem 1.2rem;
  font: inherit;
  font-weight: 700;
  color: #fff7ee;
  background: linear-gradient(135deg, #9b3c17, #d2752c);
  box-shadow: 0 12px 24px rgba(146, 67, 24, 0.22);
  cursor: pointer;
  transition: transform 180ms ease, box-shadow 180ms ease, opacity 180ms ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 16px 28px rgba(146, 67, 24, 0.28);
}

button.secondary {
  color: var(--text);
  background: rgba(255, 247, 230, 0.88);
}

.legend {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1.6rem;
  color: var(--muted);
}

.legend div {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
}

.stone {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  display: inline-block;
}

.stone.black {
  background: radial-gradient(circle at 30% 30%, #646464, #111 65%);
}

.stone.white {
  background: radial-gradient(circle at 35% 35%, #fff, #dbd2c4 70%);
  border: 1px solid rgba(79, 56, 39, 0.18);
}

.board-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1rem;
}

.seo-copy {
  margin-bottom: 1.2rem;
  padding: 1rem 1.1rem;
  border-radius: 20px;
  background: rgba(255, 247, 230, 0.68);
  border: 1px solid rgba(107, 61, 26, 0.1);
}

.seo-kicker,
.content-label {
  margin: 0 0 0.35rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-size: 0.74rem;
  color: var(--muted);
}

.seo-copy h2,
.content-card h2 {
  margin: 0;
  font-family: "Noto Serif TC", serif;
  font-size: clamp(1.45rem, 3.5vw, 2.2rem);
}

.seo-copy p,
.content-card p,
.faq-list p,
.content-list {
  color: rgba(45, 27, 16, 0.82);
  line-height: 1.75;
}

.board-subtitle,
.hint {
  margin: 0.35rem 0 0;
  color: var(--muted);
}

.move-counter {
  min-width: 76px;
  padding: 0.75rem 0.9rem;
  text-align: center;
  border-radius: 18px;
  background: rgba(255, 250, 241, 0.75);
}

.move-counter strong {
  display: block;
  margin-top: 0.25rem;
  font-size: 1.5rem;
}

.board-wrap {
  position: relative;
  display: grid;
  place-items: center;
  padding: 1rem;
  border-radius: 24px;
  background:
    linear-gradient(180deg, rgba(255, 241, 212, 0.95), rgba(225, 184, 116, 0.92));
  box-shadow: inset 0 2px 12px rgba(114, 66, 28, 0.18);
}

.board {
  width: min(100%, 720px);
  max-width: 100%;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(15, 1fr);
  grid-template-rows: repeat(15, 1fr);
  background:
    linear-gradient(to right, transparent calc(50% - 1px), var(--line) calc(50% - 1px), var(--line) calc(50% + 1px), transparent calc(50% + 1px)),
    linear-gradient(to bottom, transparent calc(50% - 1px), var(--line) calc(50% - 1px), var(--line) calc(50% + 1px), transparent calc(50% + 1px));
  background-size: calc(100% / 15) calc(100% / 15);
  border: 2px solid rgba(71, 39, 15, 0.6);
  border-radius: 14px;
  overflow: hidden;
}

.win-line {
  position: absolute;
  inset: 1rem;
  width: calc(100% - 2rem);
  height: calc(100% - 2rem);
  pointer-events: none;
  overflow: visible;
}

.win-line line {
  stroke: rgba(187, 40, 28, 0.92);
  stroke-width: 1.2;
  stroke-linecap: round;
  filter: drop-shadow(0 2px 6px rgba(118, 18, 18, 0.26));
  opacity: 0;
  transition: opacity 180ms ease;
}

.win-line.active line {
  opacity: 1;
}

.cell {
  position: relative;
  width: 100%;
  height: 100%;
  border: 0;
  padding: 0;
  background: transparent;
  cursor: pointer;
}

.cell::after {
  content: "";
  position: absolute;
  inset: 18%;
  border-radius: 50%;
  opacity: 0;
  transform: scale(0.55);
  transition: opacity 160ms ease, transform 160ms ease;
}

.cell:hover::after {
  opacity: 0.2;
  transform: scale(0.9);
  background: rgba(120, 61, 21, 0.4);
}

.cell.black::after,
.cell.white::after,
.cell.last-move::before {
  opacity: 1;
  transform: scale(1);
}

.cell.black::after {
  background: radial-gradient(circle at 32% 28%, #686868, #181818 68%);
  box-shadow: 0 6px 10px rgba(0, 0, 0, 0.18);
}

.cell.white::after {
  background: radial-gradient(circle at 32% 28%, #fff, #d6ccc1 70%);
  box-shadow: 0 6px 10px rgba(81, 60, 44, 0.15);
}

.cell.last-move::before {
  content: "";
  position: absolute;
  inset: 8%;
  border: 2px solid rgba(169, 68, 29, 0.92);
  border-radius: 50%;
  animation: pulse 1.1s ease-out infinite;
}

.hint {
  min-height: 1.5rem;
  margin-top: 1rem;
}

.content-shell {
  width: min(1180px, calc(100vw - 2rem));
  margin: 0 auto 3rem;
  display: grid;
  gap: 1.5rem;
}

.content-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1.5rem;
}

.content-card {
  padding: 1.5rem;
  border-radius: 28px;
  border: 1px solid rgba(107, 61, 26, 0.18);
  background:
    linear-gradient(180deg, rgba(255, 249, 238, 0.85), rgba(237, 214, 174, 0.82)),
    rgba(255, 255, 255, 0.5);
  box-shadow: var(--shadow);
}

.content-list {
  margin: 1rem 0 0;
  padding-left: 1.2rem;
}

.faq-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 1.5rem;
  margin-top: 1rem;
}

.faq-list article {
  padding: 1rem 1.1rem;
  border-radius: 18px;
  background: rgba(255, 247, 230, 0.68);
  border: 1px solid rgba(107, 61, 26, 0.1);
}

.faq-list h3 {
  margin: 0 0 0.45rem;
  font-size: 1rem;
}

.result-modal {
  position: fixed;
  inset: 0;
  z-index: 40;
  display: grid;
  place-items: center;
  padding: 1rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity 180ms ease, visibility 180ms ease;
}

.result-modal.open {
  opacity: 1;
  visibility: visible;
}

.result-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(33, 20, 12, 0.42);
  backdrop-filter: blur(10px);
}

.result-card {
  position: relative;
  z-index: 1;
  width: min(100%, 420px);
  padding: 1.5rem;
  border-radius: 28px;
  border: 1px solid rgba(107, 61, 26, 0.16);
  background:
    linear-gradient(180deg, rgba(255, 248, 236, 0.97), rgba(236, 206, 158, 0.95)),
    rgba(255, 255, 255, 0.88);
  box-shadow: 0 24px 70px rgba(46, 24, 12, 0.25);
}

.result-kicker {
  margin: 0 0 0.35rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-size: 0.74rem;
  color: var(--muted);
}

.result-card h2 {
  margin: 0;
  font-family: "Noto Serif TC", serif;
  font-size: clamp(1.8rem, 5vw, 2.5rem);
}

.result-card p {
  color: rgba(45, 27, 16, 0.82);
  line-height: 1.7;
}

.result-actions {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-top: 1.2rem;
}

@keyframes pulse {
  0% {
    transform: scale(0.86);
    opacity: 0.95;
  }

  100% {
    transform: scale(1.1);
    opacity: 0;
  }
}

@media (max-width: 900px) {
  .app-shell {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero-panel {
    padding: 1.5rem;
  }

  .board {
    width: min(100%, 680px);
  }

  .content-grid,
  .faq-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 560px) {
  .mobile-sticky-bar {
    position: sticky;
    top: 0;
    z-index: 30;
    display: block;
    padding: 0.2rem 0.45rem 0;
  }

  .mobile-sticky-inner {
    display: grid;
    grid-template-columns: minmax(112px, 1.1fr) auto auto auto;
    align-items: center;
    gap: 0.4rem;
    width: min(100vw - 1rem, 100%);
    margin: 0 auto;
    padding: 0.32rem 0.42rem;
    border-radius: 16px;
    background: rgba(255, 248, 236, 0.78);
    border: 1px solid rgba(107, 61, 26, 0.12);
    box-shadow: 0 6px 16px rgba(58, 29, 14, 0.1);
    backdrop-filter: blur(10px);
  }

  .mobile-sticky-inner button {
    width: auto;
    white-space: nowrap;
    min-height: 36px;
    padding: 0.55rem 0.78rem;
    padding-inline: 0.78rem;
    border-radius: 999px;
    box-shadow: 0 6px 14px rgba(146, 67, 24, 0.16);
  }

  .mobile-sticky-stats {
    display: contents;
  }

  .mobile-sticky-stats .badge {
    width: 52px;
  }

  .mobile-sticky-stats strong {
    display: block;
    min-width: 58px;
    text-align: left;
    font-size: 0.74rem;
    white-space: nowrap;
    color: rgba(45, 27, 16, 0.82);
  }

  .mobile-sticky-field {
    display: grid;
    grid-template-columns: auto minmax(84px, 1fr);
    align-items: center;
    gap: 0.35rem;
  }

  .mobile-sticky-field .label {
    margin: 0;
    font-size: 0.68rem;
    letter-spacing: 0.08em;
    white-space: nowrap;
  }

  .mobile-sticky-field select {
    margin: 0;
    min-height: 36px;
    border-radius: 10px;
    padding: 0.48rem 0.62rem;
  }

  .stats-card {
    display: none;
  }

  .app-shell {
    width: min(100vw - 1rem, 100%);
    padding-top: 0.5rem;
  }

  .hero-panel,
  .board-panel {
    border-radius: 24px;
  }

  .board-wrap {
    padding: 0.75rem;
  }

  .win-line {
    inset: 0.75rem;
    width: calc(100% - 1.5rem);
    height: calc(100% - 1.5rem);
  }

  .button-row {
    flex-direction: column;
  }

  button {
    width: 100%;
  }

  .content-shell {
    width: min(100vw - 1rem, 100%);
    margin-bottom: 2rem;
  }

  .content-card {
    padding: 1.2rem;
    border-radius: 24px;
  }

  .result-card {
    padding: 1.25rem;
    border-radius: 24px;
  }

  .result-actions {
    flex-direction: column;
  }
}