body.fifteen-page {
  --fifteen-ink: #17242d;
  --fifteen-muted: #53636d;
  --fifteen-paper: #f6f2ea;
  --fifteen-panel: #ffffff;
  --fifteen-line: #26343d;
  --fifteen-soft-line: #d3cec4;
  --fifteen-accent: #c94d2c;
  --fifteen-accent-dark: #96371f;
  --fifteen-tile: #fff8e8;
  --fifteen-good: #e2f0ec;
  margin: 0;
  min-height: 100vh;
  background: linear-gradient(180deg, #f6f2ea 0%, #e8f1ef 100%);
  color: var(--fifteen-ink);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", sans-serif;
}

.fifteen-page *,
.fifteen-page *::before,
.fifteen-page *::after {
  box-sizing: border-box;
}

.fifteen-page button,
.fifteen-page a {
  font: inherit;
}

.fifteen-page button {
  color: inherit;
  touch-action: manipulation;
}

.fifteen-app {
  width: min(760px, 100%);
  margin: 0 auto;
  padding: max(14px, env(safe-area-inset-top)) 14px max(22px, env(safe-area-inset-bottom));
}

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

.fifteen-back-link,
.fifteen-level-badge {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 2px solid var(--fifteen-line);
  border-radius: 8px;
  background: var(--fifteen-panel);
  color: var(--fifteen-ink);
  padding: 8px 10px;
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 900;
  white-space: nowrap;
}

.fifteen-title-block {
  min-width: 0;
}

.fifteen-kicker {
  margin: 0 0 2px;
  color: var(--fifteen-accent-dark);
  font-size: 0.92rem;
  font-weight: 900;
}

.fifteen-page h1,
.fifteen-page h2 {
  margin: 0;
  letter-spacing: 0;
  line-height: 1.18;
}

.fifteen-page h1 {
  font-size: clamp(1.45rem, 6vw, 2.25rem);
}

.fifteen-page h2 {
  font-size: 1.22rem;
}

.fifteen-start-panel,
.fifteen-status,
.fifteen-controls {
  border: 2px solid var(--fifteen-soft-line);
  border-radius: 8px;
  background: var(--fifteen-panel);
  padding: 12px;
}

.fifteen-start-panel {
  display: grid;
  gap: 10px;
  margin-bottom: 12px;
}

.fifteen-start-panel p {
  margin: 6px 0 0;
  color: var(--fifteen-muted);
  font-size: 1rem;
  line-height: 1.55;
}

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

.fifteen-status-title,
.fifteen-message {
  margin: 0;
}

.fifteen-status-title {
  font-size: 1.08rem;
  font-weight: 900;
}

.fifteen-message {
  color: var(--fifteen-muted);
  font-size: 1rem;
  line-height: 1.5;
}

.fifteen-message.is-error {
  color: #a72f22;
  font-weight: 900;
}

.fifteen-stats {
  display: grid;
  gap: 6px;
  min-width: 104px;
  font-weight: 900;
  text-align: right;
}

.fifteen-board-section {
  display: grid;
  place-items: center;
  margin-bottom: 12px;
}

.fifteen-board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 7px;
  width: min(100%, 560px);
  aspect-ratio: 1;
  border: 3px solid var(--fifteen-line);
  border-radius: 8px;
  background: var(--fifteen-line);
  padding: 7px;
}

.fifteen-tile {
  display: grid;
  place-items: center;
  width: 100%;
  min-width: 0;
  border: 2px solid #8c7a57;
  border-radius: 8px;
  background: var(--fifteen-tile);
  box-shadow: inset 0 -4px 0 rgba(23, 36, 45, 0.1);
  color: var(--fifteen-ink);
  font-size: clamp(1.7rem, 12vw, 3.2rem);
  font-weight: 900;
  line-height: 1;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.fifteen-tile.can-move {
  background: #ffe6b1;
  border-color: var(--fifteen-accent);
}

.fifteen-empty {
  border: 2px dashed rgba(255, 255, 255, 0.45);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.12);
}

.fifteen-controls {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.fifteen-primary,
.fifteen-secondary {
  min-height: 52px;
  border-radius: 8px;
  border: 2px solid var(--fifteen-line);
  padding: 8px 10px;
  font-weight: 900;
  text-align: center;
}

.fifteen-primary {
  background: var(--fifteen-accent);
  color: #ffffff;
}

.fifteen-secondary {
  background: #ffffff;
  color: var(--fifteen-ink);
}

.fifteen-wide {
  width: 100%;
}

.fifteen-modal-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
}

.fifteen-control-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
}

.fifteen-modal {
  position: fixed;
  inset: 0;
  z-index: 20;
  display: grid;
  place-items: center;
  padding: 18px;
  background: rgba(23, 36, 45, 0.58);
}

.fifteen-modal[hidden] {
  display: none;
}

.fifteen-modal-box {
  display: grid;
  gap: 12px;
  width: min(440px, 100%);
  border: 3px solid var(--fifteen-line);
  border-radius: 8px;
  background: var(--fifteen-panel);
  padding: 18px;
}

.fifteen-result-list {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 8px;
  margin: 0;
}

.fifteen-result-list div {
  border: 2px solid var(--fifteen-soft-line);
  border-radius: 8px;
  padding: 10px;
  background: var(--fifteen-paper);
}

.fifteen-result-list dt {
  color: var(--fifteen-muted);
  font-size: 0.9rem;
  font-weight: 800;
}

.fifteen-result-list dd {
  margin: 4px 0 0;
  font-size: 1.18rem;
  font-weight: 900;
}

.fifteen-clear-message {
  margin: 0;
  color: var(--fifteen-muted);
  line-height: 1.5;
}

@media (max-width: 720px) {
  .fifteen-header {
    grid-template-columns: 1fr auto;
  }

  .fifteen-back-link {
    grid-column: 1 / -1;
    justify-self: start;
  }

  .fifteen-status {
    grid-template-columns: 1fr;
  }

  .fifteen-stats {
    grid-template-columns: auto auto;
    justify-content: space-between;
    text-align: left;
  }
}

@media (max-width: 430px) {
  .fifteen-app {
    padding-left: 10px;
    padding-right: 10px;
  }

  .fifteen-header {
    grid-template-columns: 1fr;
  }

  .fifteen-level-badge {
    justify-self: start;
  }

  .fifteen-controls {
    grid-template-columns: 1fr 1fr;
  }

  .fifteen-board {
    gap: 5px;
    padding: 5px;
  }

  .fifteen-tile {
    font-size: clamp(1.45rem, 13vw, 2.35rem);
  }

  .fifteen-result-list {
    grid-template-columns: 1fr;
  }
}