:root {
  --bg: #0a0d12;
  --bg-elevated: #11151c;
  --bg-card: #141922;
  --border: #1f2630;
  --border-strong: #2a3340;

  --fg: #e6ecf3;
  --fg-muted: #8b96a5;
  --fg-dim: #566271;

  --accent: #00e5a0;
  --accent-dim: #00b37d;
  --accent-glow: rgba(0, 229, 160, 0.18);

  --red: #ff5a5f;
  --red-glow: rgba(255, 90, 95, 0.15);
  --amber: #ffb84d;
  --blue: #5ca2ff;

  --font-ui: 'Geist', 'Helvetica Neue', Helvetica, Arial, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, Menlo, monospace;
}

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

html, body {
  width: 100%;
  min-height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-ui);
  overflow: hidden;
  -webkit-user-select: none;
  user-select: none;
}

body {
  display: grid;
  grid-template-rows: auto auto 1fr;
  height: 100vh;
  height: 100dvh;
  position: relative;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 40% at 50% 0%, var(--accent-glow), transparent 70%),
    linear-gradient(to bottom, rgba(17, 21, 28, 0.5), transparent 40%);
  pointer-events: none;
  z-index: 0;
}

body::after {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(to right, var(--border) 1px, transparent 1px),
    linear-gradient(to bottom, var(--border) 1px, transparent 1px);
  background-size: 80px 80px;
  opacity: 0.15;
  pointer-events: none;
  z-index: 0;
}

/* ------------------------------------------------------------
   Topbar
   ------------------------------------------------------------ */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border);
  background: rgba(10, 13, 18, 0.6);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  position: relative;
  z-index: 10;
}

.back {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 0.5rem 0.85rem;
  color: var(--fg-muted);
  text-decoration: none;
  border: 1px solid var(--border);
  border-radius: 4px;
  transition: all 0.2s ease;
  white-space: nowrap;
}
.back:hover { color: var(--accent); border-color: var(--accent); }

.title {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--fg);
}
.title .sub { color: var(--fg-dim); font-weight: 400; }

/* ------------------------------------------------------------
   HUD
   ------------------------------------------------------------ */
.hud {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--border);
  border-bottom: 1px solid var(--border);
  position: relative;
  z-index: 5;
}
.stat {
  background: var(--bg-elevated);
  padding: 0.85rem 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.35rem;
}
.stat-label {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  color: var(--fg-dim);
}
.stat-value {
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 600;
  color: var(--fg);
  line-height: 1;
  letter-spacing: -0.02em;
}

.sound-btn {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--accent);
  background: transparent;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  padding: 0.3rem 0.7rem;
  cursor: pointer;
  transition: all 0.2s ease;
}
.sound-btn:hover { border-color: var(--accent); }
.sound-btn.off { color: var(--fg-dim); }

/* ------------------------------------------------------------
   Stage: status line + tiles
   ------------------------------------------------------------ */
.stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  padding: 1.25rem;
  position: relative;
  z-index: 2;
  overflow: hidden;
}

.status {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--fg-dim);
  min-height: 1.4em;
  text-align: center;
}
.status.speaking { color: var(--blue); }
.status.echoing { color: var(--accent); }
.status.wrong { color: var(--red); }

.tiles {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  grid-template-rows: repeat(2, 1fr);
  gap: clamp(0.6rem, 2.5vw, 1rem);
  width: clamp(180px, min(84vw, calc(100vh - 300px)), 400px);
  width: clamp(180px, min(84vw, calc(100dvh - 300px)), 400px);
  aspect-ratio: 1 / 1;
  touch-action: manipulation;
}

.tile {
  position: relative;
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  background: var(--bg-card);
  cursor: pointer;
  padding: 0;
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
  transition: border-color 0.15s ease, box-shadow 0.15s ease, transform 0.08s ease;
}
.tile::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--tc);
  opacity: 0.12;
  transition: opacity 0.12s ease;
}

.tile-0 { --tc: var(--accent); --tg: rgba(0, 229, 160, 0.4); }
.tile-1 { --tc: var(--blue);   --tg: rgba(92, 162, 255, 0.4); }
.tile-2 { --tc: var(--amber);  --tg: rgba(255, 184, 77, 0.4); }
.tile-3 { --tc: var(--red);    --tg: rgba(255, 90, 95, 0.4); }

.tile:hover { border-color: var(--tc); }
.tile:focus-visible { outline: 2px solid var(--tc); outline-offset: 2px; }
.tiles.locked .tile { cursor: default; }
.tiles.locked .tile:hover { border-color: var(--border-strong); }

.tile.lit,
.tiles:not(.locked) .tile:active {
  border-color: var(--tc);
  box-shadow: 0 0 34px var(--tg), inset 0 0 26px var(--tg);
}
.tile.lit::before,
.tiles:not(.locked) .tile:active::before { opacity: 0.75; }
.tiles:not(.locked) .tile:active { transform: scale(0.97); }

.tile.wrong {
  border-color: var(--red);
  box-shadow: 0 0 34px var(--red-glow), inset 0 0 34px var(--red-glow);
  animation: shake 0.45s ease;
}
.tile.wrong::before { background: var(--red); opacity: 0.55; }

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  20% { transform: translateX(-7px); }
  40% { transform: translateX(6px); }
  60% { transform: translateX(-4px); }
  80% { transform: translateX(3px); }
}

.tile .kbd {
  position: absolute;
  bottom: 0.55rem;
  right: 0.65rem;
  color: var(--tc);
  background: rgba(10, 13, 18, 0.55);
  border-color: var(--border-strong);
  z-index: 1;
  pointer-events: none;
}

/* Diamond arrangement on roomy desktop viewports */
@media (min-width: 900px) and (min-height: 680px) {
  .stage { gap: 2.75rem; }
  .tiles {
    width: min(40vh, 340px);
    width: min(40dvh, 340px);
    transform: rotate(45deg);
    margin: calc(min(40vh, 340px) * 0.21);
    margin: calc(min(40dvh, 340px) * 0.21);
  }
  .tile .kbd {
    bottom: 50%;
    right: 50%;
    transform: translate(50%, 50%) rotate(-45deg);
  }
}

/* ------------------------------------------------------------
   Overlays (start / end)
   ------------------------------------------------------------ */
.overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  background: rgba(10, 13, 18, 0.85);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  animation: fadeIn 0.3s ease-out;
  overflow-y: auto;
}
.overlay[hidden] { display: none; }
@keyframes fadeIn { from { opacity: 0; } }

.overlay-inner {
  max-width: 560px;
  width: 100%;
  text-align: center;
  background: var(--bg-card);
  border: 1px solid var(--border-strong);
  border-radius: 10px;
  padding: 2.5rem 2rem;
  margin: auto;
}

.overlay .eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--accent);
  margin-bottom: 1rem;
}
.overlay h1 {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4vw, 2.2rem);
  font-weight: 600;
  color: var(--fg);
  line-height: 1.15;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}
.overlay h1 .accent { color: var(--accent); }
.overlay .lede {
  color: var(--fg-muted);
  font-size: 0.95rem;
  line-height: 1.55;
  margin-bottom: 1.5rem;
}

.keys {
  display: flex;
  justify-content: center;
  gap: 1.1rem;
  margin-bottom: 1.75rem;
  flex-wrap: wrap;
}
.key-group {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--fg-muted);
  letter-spacing: 0.08em;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}
.kbd {
  display: inline-block;
  min-width: 1.8em;
  padding: 2px 6px;
  border: 1px solid var(--border-strong);
  border-bottom-width: 2px;
  border-radius: 3px;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  text-align: center;
}
.key-tone { font-weight: 600; }
.key-green { color: var(--accent); }
.key-blue { color: var(--blue); }
.key-amber { color: var(--amber); }
.key-red { color: var(--red); }

.primary {
  background: var(--accent);
  color: var(--bg);
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: 0.1em;
  padding: 0.9rem 2.2rem;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  transition: all 0.2s ease;
}
.primary:hover {
  background: var(--fg);
  transform: translateY(-1px);
}

.overlay-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.ghost {
  background: transparent;
  color: var(--fg-muted);
  font-family: var(--font-mono);
  font-weight: 500;
  font-size: 0.85rem;
  letter-spacing: 0.08em;
  padding: 0.9rem 1.4rem;
  border: 1px solid var(--border-strong);
  border-radius: 4px;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.2s ease;
  display: inline-block;
}
.ghost:hover {
  color: var(--fg);
  border-color: var(--fg-muted);
}

.pb {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.66rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  color: var(--bg);
  background: var(--accent);
  border-radius: 3px;
  padding: 0.28rem 0.65rem;
  margin-bottom: 1rem;
}

.note {
  color: var(--fg-muted);
  font-size: 0.85rem;
  line-height: 1.4;
  margin-bottom: 0.25rem;
}

#standings { margin-bottom: 1.5rem; }

/* ------------------------------------------------------------
   Responsive
   ------------------------------------------------------------ */
@media (max-width: 640px) {
  .topbar { padding: 0.75rem 1rem; }
  .title { font-size: 0.75rem; }
  .title .sub { display: none; }

  .stat { padding: 0.6rem 0.75rem; }
  .stat-label { font-size: 0.56rem; }
  .stat-value { font-size: 1.1rem; }
  .sound-btn { font-size: 0.7rem; padding: 0.22rem 0.55rem; }

  .stage { gap: 1.1rem; padding: 1rem; }
  .overlay-inner { padding: 1.75rem 1.25rem; }
  .keys { gap: 0.6rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}