/* ============================================================
   流光 · 贪吃蛇  —  极光星海 × 玻璃拟态 UI
   ============================================================ */
:root {
  --bg0: #05060f;
  --bg1: #0a0a1c;
  --glass: rgba(255, 255, 255, 0.055);
  --glass-brd: rgba(255, 255, 255, 0.12);
  --txt: #e8ecff;
  --muted: #9aa3c7;
  --cyan: #7dd3fc;
  --vio: #a78bfa;
  --pink: #f0abfc;
  --gold: #ffd36e;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html, body { height: 100%; }

body {
  font-family: 'Noto Sans SC', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  color: var(--txt);
  background:
    radial-gradient(1100px 750px at 15% 8%, rgba(88, 64, 180, 0.28), transparent 60%),
    radial-gradient(900px 700px at 85% 92%, rgba(14, 90, 140, 0.25), transparent 55%),
    radial-gradient(700px 500px at 70% 15%, rgba(190, 60, 160, 0.14), transparent 60%),
    linear-gradient(160deg, #05060f, #0a0a1c 55%, #04040e);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 18px;
}

#app { width: min(96vw, 1000px); }

#stage { position: relative; border-radius: 24px; }

#game {
  display: block;
  width: 100%;
  aspect-ratio: 24 / 16;
  border-radius: 24px;
  background: #07081a;
  border: 1px solid rgba(140, 170, 255, 0.16);
  box-shadow:
    0 40px 90px rgba(0, 0, 0, 0.6),
    0 0 0 1px rgba(120, 160, 255, 0.06),
    inset 0 0 140px rgba(0, 0, 0, 0.4);
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
}

/* ---------------- 浮层 ---------------- */
.overlay {
  position: absolute;
  inset: 0;
  z-index: 10;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 16px;
  border-radius: 24px;
  background: rgba(6, 8, 24, 0.55);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: opacity 0.35s ease;
}
.overlay.hidden { opacity: 0; pointer-events: none; }

/* 主菜单更通透，让背后的演示蛇可见 */
#menu {
  background: linear-gradient(180deg, rgba(6, 8, 24, 0.28), rgba(6, 8, 24, 0.62));
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.title {
  font-family: 'ZCOOL KuaiLe', 'Noto Sans SC', sans-serif;
  font-weight: 400;
  letter-spacing: 0.06em;
  line-height: 1.2;
  text-align: center;
  font-size: clamp(2.2rem, 7vw, 4rem);
  background: linear-gradient(90deg, #7dd3fc, #c4b5fd, #f0abfc, #ffd36e, #7dd3fc);
  background-size: 300% 100%;
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: shimmer 7s linear infinite;
  filter: drop-shadow(0 6px 26px rgba(167, 139, 250, 0.35));
}
@keyframes shimmer { to { background-position: 300% 0; } }

.subtitle {
  color: var(--muted);
  letter-spacing: 0.42em;
  font-size: 0.8rem;
  text-transform: uppercase;
  text-indent: 0.42em;
}

.menu-best { color: var(--muted); font-size: 0.85rem; letter-spacing: 0.18em; }
.menu-best b {
  font-family: 'Orbitron', monospace;
  color: var(--gold);
  font-size: 1.15rem;
  margin-left: 0.3em;
}

/* ---------------- 按钮 ---------------- */
.btn {
  font-family: inherit;
  font-size: 1.02rem;
  letter-spacing: 0.3em;
  text-indent: 0.3em;
  padding: 14px 44px;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  color: #fff;
  background: linear-gradient(135deg, #6366f1, #a855f7 45%, #ec4899);
  background-size: 180% 180%;
  box-shadow: 0 12px 36px rgba(168, 85, 247, 0.4), inset 0 1px 0 rgba(255, 255, 255, 0.25);
  transition: transform 0.25s, box-shadow 0.25s, background-position 0.4s;
}
.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 16px 46px rgba(168, 85, 247, 0.55);
  background-position: 100% 50%;
}
.btn:active { transform: translateY(0) scale(0.97); }
.btn.ghost { background: transparent; border: 1px solid rgba(255, 255, 255, 0.28); box-shadow: none; }
.btn.ghost:hover { border-color: rgba(125, 211, 252, 0.6); box-shadow: 0 0 24px rgba(125, 211, 252, 0.2); }

/* ---------------- 开关 ---------------- */
.switch-row {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-size: 0.88rem;
  letter-spacing: 0.06em;
  cursor: pointer;
  user-select: none;
}
.switch { position: relative; width: 46px; height: 26px; flex: none; }
.switch input { opacity: 0; width: 0; height: 0; position: absolute; }
.slider {
  position: absolute;
  inset: 0;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.12);
  border: 1px solid var(--glass-brd);
  transition: 0.25s;
}
.slider::before {
  content: '';
  position: absolute;
  left: 3px; top: 3px;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: #cfe0ff;
  transition: transform 0.25s;
}
.switch input:checked + .slider {
  background: linear-gradient(135deg, #6366f1, #ec4899);
  border-color: transparent;
  box-shadow: 0 0 14px rgba(168, 85, 247, 0.6);
}
.switch input:checked + .slider::before { transform: translateX(20px); background: #fff; }

/* ---------------- 提示 ---------------- */
.hint {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.05em;
}
kbd {
  font-family: 'Orbitron', monospace;
  padding: 3px 8px;
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-bottom-width: 3px;
  font-size: 0.68rem;
  color: #cdd6ff;
}

/* ---------------- HUD ---------------- */
#hud {
  position: absolute;
  top: 0; left: 0; right: 0;
  z-index: 5;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 16px 20px;
  pointer-events: none;
}
.hud-group { display: flex; gap: 10px; align-items: center; }
.stat { display: flex; flex-direction: column; }
.stat .label { font-size: 0.6rem; letter-spacing: 0.28em; color: var(--muted); }
.stat .value {
  font-family: 'Orbitron', monospace;
  font-size: clamp(1.05rem, 3vw, 1.5rem);
  font-weight: 700;
  color: #fff;
  text-shadow: 0 0 18px rgba(125, 211, 252, 0.55);
  line-height: 1.15;
}
#best { color: var(--gold); text-shadow: 0 0 18px rgba(255, 211, 110, 0.45); }
.stat .value.pop { animation: pop 0.35s ease; }
@keyframes pop { 50% { transform: scale(1.28); color: var(--gold); } }

.chip {
  font-family: 'Orbitron', monospace;
  padding: 6px 13px;
  border-radius: 999px;
  background: var(--glass);
  border: 1px solid var(--glass-brd);
  font-size: 0.74rem;
  color: #cdd6ff;
  letter-spacing: 0.08em;
}

.icon-btn {
  pointer-events: auto;
  width: 38px; height: 38px;
  border-radius: 50%;
  border: 1px solid var(--glass-brd);
  background: var(--glass);
  color: #dfe6ff;
  font-size: 0.95rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: 0.2s;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
}
.icon-btn:hover {
  border-color: rgba(125, 211, 252, 0.55);
  box-shadow: 0 0 18px rgba(125, 211, 252, 0.28);
  transform: translateY(-1px);
}
.icon-btn:active { transform: scale(0.94); }

/* ---------------- 结算 ---------------- */
.final-score {
  font-family: 'Orbitron', monospace;
  font-size: clamp(2.6rem, 9vw, 4.4rem);
  font-weight: 900;
  line-height: 1;
  color: #fff;
  text-shadow: 0 0 30px rgba(125, 211, 252, 0.6);
}
.badge {
  font-size: 0.78rem;
  letter-spacing: 0.24em;
  padding: 6px 18px;
  border-radius: 999px;
  color: var(--gold);
  border: 1px solid rgba(255, 211, 110, 0.5);
  background: rgba(255, 211, 110, 0.08);
  box-shadow: 0 0 20px rgba(255, 211, 110, 0.25);
  animation: bob 1.6s ease-in-out infinite;
}
@keyframes bob { 50% { transform: translateY(-4px); } }

/* ---------------- 提示条 ---------------- */
#toast {
  position: absolute;
  top: 72px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 12;
  padding: 10px 24px;
  border-radius: 999px;
  font-size: 0.88rem;
  letter-spacing: 0.1em;
  white-space: nowrap;
  background: var(--glass);
  border: 1px solid var(--glass-brd);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.45);
  transition: opacity 0.4s, transform 0.4s;
}
#toast.hidden { opacity: 0; transform: translate(-50%, -12px); pointer-events: none; }

/* ---------------- 入场动效 ---------------- */
.overlay.enter .title,
.overlay.enter .subtitle,
.overlay.enter .final-score,
.overlay.enter .badge,
.overlay.enter .menu-best,
.overlay.enter .switch-row,
.overlay.enter .hint,
.overlay.enter .btn {
  animation: rise 0.55s cubic-bezier(0.2, 0.8, 0.3, 1) both;
}
.overlay.enter .subtitle { animation-delay: 0.05s; }
.overlay.enter .menu-best { animation-delay: 0.1s; }
.overlay.enter .switch-row { animation-delay: 0.15s; }
.overlay.enter .btn { animation-delay: 0.2s; }
.overlay.enter .hint { animation-delay: 0.28s; }
.overlay.enter .final-score { animation-delay: 0.05s; }
.overlay.enter .badge { animation-delay: 0.18s; }
@keyframes rise {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: none; }
}

footer {
  text-align: center;
  margin-top: 14px;
  color: rgba(154, 163, 199, 0.5);
  font-size: 0.72rem;
  letter-spacing: 0.22em;
}

/* ---------------- 移动端 ---------------- */
@media (max-width: 560px) {
  body { padding: 10px; }
  #hud { padding: 10px 12px; }
  .icon-btn { width: 32px; height: 32px; font-size: 0.82rem; }
  .stat .value { font-size: 0.98rem; }
  .chip { display: none; }
  .btn { padding: 12px 34px; font-size: 0.92rem; }
  .overlay { gap: 12px; }
  #toast { top: 58px; }
}

/* ---------------- 返回大厅 ---------------- */
.back-chip {
  pointer-events: auto;
  padding: 6px 13px;
  border-radius: 999px;
  font-size: 0.74rem;
  letter-spacing: 0.1em;
  color: #cdd6ff;
  text-decoration: none;
  background: var(--glass);
  border: 1px solid var(--glass-brd);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  transition: 0.2s;
  white-space: nowrap;
}
.back-chip:hover {
  color: #fff;
  border-color: rgba(125, 211, 252, 0.55);
  box-shadow: 0 0 16px rgba(125, 211, 252, 0.28);
}