:root {
  --bg: #0f1419;
  --panel: #1a2332;
  --text: #e8eef5;
  --muted: #8b9bb4;
  --accent: #3ddc97;
  --focus: #6eb5ff;
  --danger: #ff6b6b;
}

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

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Segoe UI", system-ui, sans-serif;
  background: radial-gradient(1200px 800px at 50% 0%, #1b2636, var(--bg));
  color: var(--text);
}

.app {
  max-width: 640px;
  margin: 0 auto;
  padding: clamp(12px, 3vw, 24px);
}

.topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 16px;
  padding: 12px 16px;
  background: var(--panel);
  border-radius: 12px;
  border: 1px solid rgba(255, 255, 255, 0.06);
}

.topbar__back {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.88rem;
  transition: color 0.15s;
}

.topbar__back:hover {
  color: var(--accent);
}

.topbar__back:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
  border-radius: 4px;
}

.brand {
  font-weight: 700;
  letter-spacing: 0.02em;
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
}

.stats {
  display: flex;
  gap: 20px;
  margin-left: auto;
  font-size: 0.95rem;
  color: var(--muted);
}

.stats strong {
  color: var(--text);
  font-weight: 700;
}

.hint {
  color: var(--muted);
  font-size: 0.88rem;
  text-align: center;
  margin: 12px 0 10px;
  min-height: 1.3em;
}

.board-wrap {
  position: relative;
  width: min(92vw, 560px);
  margin: 0 auto;
  border-radius: 14px;
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.06);
  background: var(--panel);
  padding: 10px;
  touch-action: none;
}

.board-wrap.is-shaking {
  animation: shake 0.45s ease;
}

@keyframes shake {
  0%,
  100% {
    transform: translate(0, 0);
  }
  20% {
    transform: translate(-4px, 2px);
  }
  40% {
    transform: translate(4px, -2px);
  }
  60% {
    transform: translate(-3px, -2px);
  }
  80% {
    transform: translate(3px, 2px);
  }
}

#canvas {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 8px;
}

.death-flash {
  position: absolute;
  inset: 10px;
  border-radius: 8px;
  background: var(--danger);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.12s ease;
}

.death-flash.is-active {
  opacity: 0.35;
}

.status {
  text-align: center;
  min-height: 1.4em;
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.9rem;
}

.overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  background: rgba(8, 12, 18, 0.82);
  backdrop-filter: blur(6px);
  z-index: 100;
}

.overlay--board {
  background: rgba(8, 12, 18, 0.72);
}

.overlay--hidden {
  display: none;
}

.overlay__panel {
  width: min(100%, 400px);
  padding: 28px 24px;
  background: var(--panel);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 16px;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.45);
}

.overlay__panel--compact {
  text-align: center;
}

.overlay__title {
  margin: 0 0 20px;
  font-size: 1.35rem;
  font-weight: 700;
}

.overlay__score {
  margin: 0 0 8px;
  color: var(--muted);
  font-size: 1.05rem;
}

.overlay__score strong {
  color: var(--text);
  font-size: 1.4rem;
}

.overlay__new-best {
  margin: 0 0 16px;
  color: var(--accent);
  font-weight: 600;
  animation: statusPop 0.45s ease;
}

.overlay__hint {
  margin: 0 0 4px;
  color: var(--muted);
  font-size: 0.9rem;
}

.overlay__hint kbd {
  display: inline-block;
  padding: 2px 7px;
  border-radius: 5px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  background: rgba(255, 255, 255, 0.06);
  font-family: inherit;
  font-size: 0.85em;
}

.overlay__actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 20px;
}

@keyframes statusPop {
  from {
    opacity: 0;
    transform: translateY(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.settings-form {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.field {
  border: none;
  margin: 0;
  padding: 0;
}

.field legend {
  font-weight: 600;
  font-size: 0.92rem;
  margin-bottom: 10px;
  color: var(--text);
}

.radio-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 8px;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.radio-label:hover {
  background: rgba(255, 255, 255, 0.07);
}

.radio-label:has(input:checked) {
  border-color: color-mix(in srgb, var(--accent) 60%, transparent);
  background: color-mix(in srgb, var(--accent) 10%, transparent);
}

.radio-label input {
  accent-color: var(--accent);
}

.radio-label small {
  color: var(--muted);
}

.theme-group {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
}

.theme-option {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  padding: 12px 10px;
  background: rgba(255, 255, 255, 0.04);
  border: 2px solid rgba(255, 255, 255, 0.06);
  border-radius: 10px;
  cursor: pointer;
  transition: border-color 0.15s, transform 0.12s;
}

.theme-option:hover {
  transform: translateY(-1px);
}

.theme-option:has(input:checked) {
  border-color: var(--accent);
}

.theme-option input {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.theme-option__swatch {
  display: flex;
  gap: 4px;
}

.theme-option__swatch span {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
}

.theme-option__name {
  font-size: 0.82rem;
  font-weight: 600;
}

.btn {
  cursor: pointer;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text);
  padding: 10px 16px;
  border-radius: 8px;
  font: inherit;
  font-weight: 600;
  transition: background 0.15s, border-color 0.15s;
}

.btn:hover {
  background: rgba(255, 255, 255, 0.1);
  border-color: rgba(255, 255, 255, 0.2);
}

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

.btn--primary {
  background: color-mix(in srgb, var(--accent) 25%, transparent);
  border-color: color-mix(in srgb, var(--accent) 50%, transparent);
  color: var(--text);
}

.btn--primary:hover {
  background: color-mix(in srgb, var(--accent) 35%, transparent);
}

@media (prefers-reduced-motion: reduce) {
  .board-wrap.is-shaking,
  .overlay__new-best {
    animation: none;
  }

  .death-flash {
    transition: none;
  }

  .theme-option:hover {
    transform: none;
  }
}