:root {
  --bg: #071a12;
  --panel: rgba(255, 255, 255, 0.08);
  --panel-border: rgba(255, 255, 255, 0.12);
  --text: #f5fff9;
  --sub: #b8cec0;
  --green: #117a4a;
  --green-dark: #075733;
  --green-light: #31d180;
  --board-line: rgba(0, 0, 0, 0.38);
  --accent: #ddff4f;
  --danger: #ff8b8b;
  --shadow: 0 22px 50px rgba(0, 0, 0, 0.28);
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background:
    radial-gradient(circle at 20% 0%, rgba(34, 141, 88, 0.25), transparent 34rem),
    linear-gradient(180deg, #092519 0%, var(--bg) 70%);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", sans-serif;
}

body {
  min-height: 100dvh;
  display: flex;
  justify-content: center;
}

button,
select,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

.app {
  width: min(100%, 760px);
  padding: max(18px, env(safe-area-inset-top)) 16px max(24px, env(safe-area-inset-bottom));
}

.title-area {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin: 8px 0 18px;
}

.eyebrow {
  margin: 0 0 2px;
  color: var(--green-light);
  font-size: 0.74rem;
  font-weight: 800;
  letter-spacing: 0.18em;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: clamp(2rem, 8vw, 3.4rem);
  line-height: 1;
  letter-spacing: 0.02em;
}

h2 {
  margin-bottom: 22px;
  font-size: 1.35rem;
}

.panel {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 24px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.setup-panel {
  padding: 22px;
}

.setting-block + .setting-block {
  margin-top: 24px;
}

.setting-label {
  display: block;
  margin-bottom: 10px;
  color: var(--sub);
  font-size: 0.9rem;
  font-weight: 700;
}

.segmented {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}

.segmented.five {
  grid-template-columns: repeat(5, 1fr);
}

.segmented button {
  min-height: 48px;
  border: 1px solid rgba(255, 255, 255, 0.13);
  border-radius: 14px;
  background: rgba(0, 0, 0, 0.18);
  color: var(--text);
  font-weight: 800;
  transition: transform 0.12s ease, background 0.15s ease, border-color 0.15s ease;
}

.segmented button:active {
  transform: scale(0.98);
}

.segmented button.active {
  background: var(--green-light);
  color: #042214;
  border-color: var(--green-light);
}

.setting-note {
  margin: 10px 2px 0;
  color: var(--sub);
  font-size: 0.82rem;
  line-height: 1.55;
}

.primary-button,
.secondary-button,
.ghost-button {
  min-height: 48px;
  border-radius: 14px;
  font-weight: 800;
}

.primary-button {
  width: 100%;
  margin-top: 26px;
  border: 0;
  background: var(--accent);
  color: #122000;
  box-shadow: 0 12px 24px rgba(221, 255, 79, 0.16);
}

.secondary-button {
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.07);
  color: var(--text);
}

.ghost-button {
  padding: 0 14px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: transparent;
  color: var(--sub);
}

.game-panel {
  animation: fadeIn 0.24s ease;
}

.hidden {
  display: none !important;
}

.score-row {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 10px;
  align-items: center;
  margin-bottom: 12px;
}

.score-card {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  padding: 10px 12px;
  border: 1px solid rgba(255, 255, 255, 0.11);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.06);
}

.score-card strong {
  display: block;
  font-size: 1.4rem;
  line-height: 1.1;
}

.score-label {
  display: block;
  overflow: hidden;
  color: var(--sub);
  font-size: 0.76rem;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.stone {
  flex: 0 0 auto;
  width: 30px;
  aspect-ratio: 1;
  border-radius: 50%;
}

.stone.black,
.disc.black {
  background: radial-gradient(circle at 32% 27%, #5a5a5a 0%, #171717 28%, #020202 75%);
  box-shadow: inset -2px -3px 5px rgba(255, 255, 255, 0.08), 0 3px 6px rgba(0, 0, 0, 0.32);
}

.stone.white,
.disc.white {
  background: radial-gradient(circle at 32% 27%, #fff 0%, #f7f7f7 38%, #c8c8c8 100%);
  box-shadow: inset -2px -3px 5px rgba(0, 0, 0, 0.08), 0 3px 6px rgba(0, 0, 0, 0.22);
}

.turn-badge {
  padding: 8px 10px;
  border-radius: 999px;
  background: rgba(49, 209, 128, 0.13);
  color: #9ff6c9;
  font-size: 0.78rem;
  font-weight: 800;
  text-align: center;
  white-space: nowrap;
}

.status-message {
  min-height: 25px;
  margin: 10px 0 12px;
  color: var(--sub);
  font-size: 0.9rem;
  font-weight: 700;
  text-align: center;
}

.board-wrap {
  width: 100%;
  display: flex;
  justify-content: center;
}

.board {
  position: relative;
  width: min(94vw, 620px);
  max-width: 100%;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  border: 5px solid #06371f;
  border-radius: 12px;
  overflow: hidden;
  background: var(--green);
  box-shadow: var(--shadow), inset 0 0 20px rgba(0, 0, 0, 0.18);
  touch-action: manipulation;
}

.cell {
  position: relative;
  display: grid;
  place-items: center;
  padding: 0;
  border: 0;
  border-right: 1px solid var(--board-line);
  border-bottom: 1px solid var(--board-line);
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.025), rgba(0, 0, 0, 0.025)),
    var(--green);
}

.cell:nth-child(8n) {
  border-right: 0;
}

.cell:nth-last-child(-n + 8) {
  border-bottom: 0;
}

.cell.legal::after {
  content: "";
  width: 22%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.36);
  box-shadow: 0 0 0 4px rgba(255, 255, 255, 0.04);
}

.cell.legal:active {
  background: #15965b;
}

.disc {
  width: 78%;
  aspect-ratio: 1;
  border-radius: 50%;
  transform: scale(1);
  backface-visibility: hidden;
  transform-style: preserve-3d;
}

.disc.placed {
  animation: placeDisc 0.28s cubic-bezier(.18, .9, .2, 1.25) both;
}

.disc.flip-out {
  animation: flipOut 0.09s ease-in both;
}

.disc.flip-in {
  animation: flipIn 0.11s ease-out both;
}

.cell.cpu-preview {
  z-index: 1;
  background: #1ca865;
  animation: cpuTargetPulse 0.52s ease-in-out infinite alternate;
}

.cell.cpu-preview::before {
  content: "";
  width: 72%;
  aspect-ratio: 1;
  border: 3px solid var(--accent);
  border-radius: 50%;
  box-shadow: 0 0 0 5px rgba(221, 255, 79, 0.14), 0 0 18px rgba(221, 255, 79, 0.42);
}

.cell.cpu-preview::after {
  display: none;
}

.game-actions {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 14px;
}

.legend {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 12px;
  color: var(--sub);
  font-size: 0.78rem;
}

.legend span {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.legal-dot {
  width: 9px;
  aspect-ratio: 1;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.48);
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 10;
  display: grid;
  place-items: center;
  padding: 20px;
  background: rgba(0, 0, 0, 0.66);
  backdrop-filter: blur(8px);
}

.modal-card {
  width: min(100%, 440px);
  padding: 26px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 24px;
  background: #0d2419;
  box-shadow: var(--shadow);
  text-align: center;
}

.modal-card .primary-button {
  margin-top: 0;
}

.result-score {
  margin: 16px 0 6px;
  font-size: 2rem;
  font-weight: 900;
}

.result-text {
  color: var(--sub);
}

.modal-actions {
  display: grid;
  gap: 10px;
  margin-top: 22px;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes placeDisc {
  from { transform: scale(0); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}

@keyframes flipOut {
  from { transform: rotateY(0deg) scale(1); }
  to { transform: rotateY(90deg) scale(0.96); }
}

@keyframes flipIn {
  from { transform: rotateY(90deg) scale(0.96); }
  to { transform: rotateY(0deg) scale(1); }
}

@keyframes cpuTargetPulse {
  from { filter: brightness(1); }
  to { filter: brightness(1.18); }
}

@media (max-width: 520px) {
  .app {
    padding-left: 10px;
    padding-right: 10px;
  }

  .title-area {
    margin-top: 2px;
  }

  .ghost-button {
    min-height: 42px;
    padding: 0 10px;
    font-size: 0.78rem;
  }

  .setup-panel {
    padding: 18px;
    border-radius: 20px;
  }

  .score-row {
    gap: 6px;
  }

  .score-card {
    gap: 7px;
    padding: 8px;
  }

  .stone {
    width: 24px;
  }

  .score-card strong {
    font-size: 1.18rem;
  }

  .turn-badge {
    padding: 7px;
    font-size: 0.7rem;
  }

  .board {
    width: min(96vw, 620px);
    border-width: 4px;
    border-radius: 9px;
  }

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

@media (max-width: 360px) {
  .segmented.five {
    gap: 5px;
  }

  .segmented button {
    min-height: 44px;
    border-radius: 11px;
    font-size: 0.9rem;
  }

  .score-label {
    font-size: 0.68rem;
  }
}