/* ─── Design Tokens (matches Snake game palette) ─────────────────────────────── */
:root {
  color-scheme: dark;
  font-family: "Trebuchet MS", "Gill Sans", sans-serif;

  --bg:           #0c1311;
  --bg-accent:    #12201b;
  --panel:        rgba(18, 30, 26, 0.92);
  --panel-border: rgba(142, 179, 144, 0.22);
  --text:         #edf4ee;
  --muted:        #9eb4a1;
  --accent:       #74d680;
  --accent-strong:#2d8f47;
  --danger:       #ff7878;
  --board:        #09110e;
  --overlay-bg:   rgba(6, 12, 10, 0.93);

  --piece-I: #00F5FF;
  --piece-O: #FFE600;
  --piece-T: #BF5FFF;
  --piece-S: #39FF14;
  --piece-Z: #FF7878;
  --piece-J: #4DA6FF;
  --piece-L: #FF9A3C;

  --panel-w: 130px;
  --gap:     12px;
  --pad:     12px;
  --radius:  12px;
  --radius-sm: 8px;
}

/* ─── Reset ──────────────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html, body { width: 100%; height: 100%; overflow: hidden; }

body {
  background:
    radial-gradient(circle at top left,  rgba(116, 214, 128, 0.14), transparent 28%),
    radial-gradient(circle at bottom right, rgba(73, 134, 96, 0.18), transparent 34%),
    linear-gradient(180deg, var(--bg-accent), var(--bg));
  color: var(--text);
  user-select: none;
  -webkit-user-select: none;
}

/* ─── Back Link ──────────────────────────────────────────────────────────────── */
.back-link {
  display: inline-block;
  position: fixed;
  top: 12px;
  left: 16px;
  z-index: 100;
  color: var(--muted);
  text-decoration: none;
  font-size: 0.82rem;
  letter-spacing: 0.04em;
  transition: color 120ms ease;
}

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

/* ─── Game Wrapper: 3-column ─────────────────────────────────────────────────── */
.game-wrapper {
  display: flex;
  flex-direction: row;
  align-items: flex-start;
  justify-content: center;
  height: 100vh;
  padding: var(--pad);
  gap: var(--gap);
}

/* ─── Side Panels ────────────────────────────────────────────────────────────── */
.side-panel {
  width: 192px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: var(--gap);
  padding-top: 4px;
}

.side-panel--right {
  width: 192px;
}

.panel-box {
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius-sm);
  padding: 12px 16px;
  backdrop-filter: blur(10px);
}

.panel-label {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--muted);
  margin-bottom: 5px;
}

.panel-value {
  font-size: clamp(1.2rem, 1.7vw, 1.7rem);
  font-weight: 700;
  letter-spacing: 0.04em;
}

#next-canvas, #hold-canvas { display: block; background: transparent; margin: 0 auto; }

/* ─── Side Leaderboard ──────────────────────────────────────────────────────── */
.side-lb { padding: 12px 10px; }
.side-lb-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.82rem;
}
.side-lb-table td {
  padding: 4px 5px;
  border-bottom: 1px solid rgba(255,255,255,0.04);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.side-lb-table td:first-child { color: var(--muted); width: 20px; }
.side-lb-table td:last-child { text-align: right; color: var(--accent); font-weight: 600; }
.side-lb-table .lb-empty { text-align: center; color: var(--muted); padding: 8px 4px !important; }

.combo-value { color: var(--piece-T); transition: transform 120ms ease; }
#combo-box.combo-flash .combo-value { transform: scale(1.25); }

/* ─── Board ──────────────────────────────────────────────────────────────────── */
.board-container {
  position: relative;
  flex-shrink: 0;
  border-radius: var(--radius) var(--radius) 0 0;
  overflow: hidden;
  border: 1px solid rgba(255,255,255,0.06);
  box-shadow:
    0 0 40px rgba(116, 214, 128, 0.06),
    0 20px 60px rgba(0,0,0,0.5);
}

#board {
  display: block;
  background: var(--board);
  outline: none;
}

#board:focus {
  box-shadow: 0 0 0 2px var(--accent), 0 0 20px rgba(116,214,128,0.3);
}

/* ─── Overlays ───────────────────────────────────────────────────────────────── */
.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: var(--overlay-bg);
  gap: 10px;
  padding: 24px;
  z-index: 10;
  backdrop-filter: blur(4px);
}

.overlay[hidden] { display: none; }

.overlay-title {
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  font-weight: 800;
  letter-spacing: 0.06em;
  margin-bottom: 4px;
}

.overlay-subtitle {
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 6px;
}

/* ─── Buttons ────────────────────────────────────────────────────────────────── */
.btn {
  font: inherit;
  font-size: 0.88rem;
  font-weight: 700;
  border: none;
  border-radius: 999px;
  padding: 10px 28px;
  cursor: pointer;
  min-width: 180px;
  min-height: 44px;
  text-align: center;
  transition: transform 120ms ease, filter 120ms ease, background 120ms ease;
}

.btn:hover, .btn:focus-visible { transform: translateY(-1px); outline: none; }
.btn:active { transform: translateY(0); }

.btn-primary {
  background: linear-gradient(180deg, var(--accent), var(--accent-strong));
  color: #08100d;
}
.btn-primary:hover, .btn-primary:focus-visible { filter: brightness(1.08); }

.btn-secondary {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  color: var(--text);
}
.btn-secondary:hover, .btn-secondary:focus-visible { background: rgba(255,255,255,0.09); }

.btn-danger {
  background: rgba(255,120,120,0.12);
  border: 1px solid rgba(255,120,120,0.3);
  color: var(--danger);
}
.btn-danger:hover, .btn-danger:focus-visible { background: rgba(255,120,120,0.22); }

/* ─── Score Row ──────────────────────────────────────────────────────────────── */
.score-row {
  display: flex; flex-direction: column; align-items: center; gap: 2px; margin: 2px 0;
}
.score-row .panel-value { font-size: 1.4rem; color: var(--accent); }

#new-best {
  font-size: 0.72rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.16em; color: var(--piece-O);
}

/* ─── Name Input ─────────────────────────────────────────────────────────────── */
.name-row {
  display: flex; flex-direction: column; align-items: center; gap: 6px;
  width: 100%; max-width: 260px;
}
.name-row label { font-size: 0.72rem; color: var(--muted); letter-spacing: 0.1em; text-transform: uppercase; }

#name-input {
  font: inherit; font-size: 0.9rem;
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 10px; color: var(--text);
  padding: 10px 14px; width: 100%;
  text-align: center; letter-spacing: 0.1em; text-transform: uppercase;
  min-height: 44px; outline: none;
}
#name-input::placeholder { color: rgba(237,244,238,0.35); }
#name-input:focus { border-color: var(--accent); box-shadow: 0 0 0 2px rgba(116,214,128,0.25); }

/* ─── Leaderboard ────────────────────────────────────────────────────────────── */
.lb-table { width: 100%; border-collapse: collapse; font-size: 0.85rem; max-width: 300px; }
.lb-table th {
  font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--muted); padding: 6px 10px; text-align: left;
  border-bottom: 1px solid rgba(255,255,255,0.07);
}
.lb-table td { padding: 8px 10px; border-bottom: 1px solid rgba(255,255,255,0.05); }
.lb-table .lb-top td { color: var(--accent); }
.lb-table .lb-top:first-child td { font-weight: 700; font-size: 0.92rem; }
.lb-empty { text-align: center; color: var(--muted); padding: 20px !important; }

/* ─── Controls ───────────────────────────────────────────────────────────────── */
.controls-grid {
  display: grid; grid-template-columns: 1fr auto;
  gap: 8px 20px; font-size: 0.85rem; max-width: 280px; width: 100%; align-items: center;
}
.ctrl-action { color: var(--muted); }
.ctrl-key {
  color: var(--text); background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.12); border-radius: 6px;
  padding: 3px 10px; font-size: 0.8rem; white-space: nowrap; text-align: center;
}

/* ─── Mobile Controls ────────────────────────────────────────────────────────── */
.mobile-controls {
  display: none; position: fixed;
  bottom: 0; left: 0; right: 0;
  padding: 8px 16px;
  background: rgba(8,18,14,0.92);
  border-top: 1px solid var(--panel-border);
  justify-content: space-between; align-items: flex-end; gap: 10px; z-index: 20;
}
.dpad { display: grid; grid-template-areas: ". up ." "left . right" ". down ."; gap: 4px; }
.dpad-btn {
  width: 52px; height: 52px;
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.1);
  border-radius: 10px; color: var(--text); font-size: 18px;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; -webkit-tap-highlight-color: transparent; touch-action: manipulation;
}
.dpad-btn:active { background: rgba(116,214,128,0.18); border-color: rgba(116,214,128,0.35); }
.dpad-up    { grid-area: up; }
.dpad-left  { grid-area: left; }
.dpad-right { grid-area: right; }
.dpad-down  { grid-area: down; }
.action-btns { display: flex; flex-direction: column; gap: 6px; align-items: flex-end; }
.action-btn {
  padding: 8px 14px;
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.1);
  border-radius: 8px; color: var(--text); font: inherit; font-size: 0.75rem;
  cursor: pointer; -webkit-tap-highlight-color: transparent; touch-action: manipulation;
  min-width: 68px; min-height: 44px; display: flex; align-items: center; justify-content: center;
}
.action-btn:active { background: rgba(116,214,128,0.18); }

/* ─── Accessibility ──────────────────────────────────────────────────────────── */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

/* ─── Reduced Motion ─────────────────────────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}

/* ─── Mobile ─────────────────────────────────────────────────────────────────── */
@media (max-width: 500px) {
  :root { --pad: 6px; --gap: 6px; --panel-w: 0px; }
  .side-panel { display: none; }
  .game-wrapper { padding-bottom: 96px; }
  .mobile-controls { display: flex; }
}