/* Waveform Racer — dark, neon, minimal. */

:root {
  --bg: #06070f;
  --neon: #22e6ff;
  --neon-soft: rgba(34, 230, 255, 0.25);
  --magenta: #ff3df0;
  --text: #d7ecf5;
  --text-dim: #6e8698;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
}

#scene {
  position: fixed;
  inset: 0;
  display: block;
}

.hidden { display: none !important; }

/* ---- centre overlay (drop zone / analysing / error) ---- */

#overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
}

.panel {
  pointer-events: auto;
  text-align: center;
  padding: 3rem 3.5rem;
  border: 1px solid var(--neon-soft);
  border-radius: 16px;
  background: rgba(8, 12, 24, 0.82);
  box-shadow: 0 0 40px rgba(34, 230, 255, 0.08),
              inset 0 0 24px rgba(34, 230, 255, 0.04);
  backdrop-filter: blur(6px);
  max-width: min(90vw, 30rem);
}

h1 {
  margin: 0 0 0.75rem;
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #fff;
  text-shadow: 0 0 12px var(--neon), 0 0 40px rgba(34, 230, 255, 0.4);
}

.tagline { margin: 0 0 1.75rem; line-height: 1.5; }

.hint {
  margin: 1rem 0 0;
  font-size: 0.8rem;
  color: var(--text-dim);
}

button {
  font: inherit;
  cursor: pointer;
  color: var(--neon);
  background: transparent;
  border: 1px solid var(--neon);
  border-radius: 999px;
  padding: 0.65rem 1.8rem;
  letter-spacing: 0.06em;
  transition: box-shadow 0.15s, background 0.15s;
}

button:hover {
  background: rgba(34, 230, 255, 0.1);
  box-shadow: 0 0 16px var(--neon-soft);
}

/* ---- analysing spinner ---- */

.spinner {
  width: 44px;
  height: 44px;
  margin: 0 auto 1.25rem;
  border-radius: 50%;
  border: 3px solid rgba(34, 230, 255, 0.15);
  border-top-color: var(--neon);
  animation: spin 0.9s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

#analysing-label::after {
  content: "";
  animation: dots 1.5s steps(4, end) infinite;
}

@keyframes dots {
  0%   { content: ""; }
  25%  { content: "."; }
  50%  { content: ".."; }
  75%  { content: "..."; }
}

/* ---- HUD ---- */

#hud {
  position: fixed;
  left: 50%;
  bottom: 1.25rem;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.5rem 1.25rem;
  border: 1px solid var(--neon-soft);
  border-radius: 999px;
  background: rgba(8, 12, 24, 0.82);
  backdrop-filter: blur(6px);
  white-space: nowrap;
}

#play-pause {
  width: 2.6rem;
  height: 2.6rem;
  padding: 0;
  display: grid;
  place-items: center;
  font-size: 0.9rem;
}

#song-name {
  max-width: 40vw;
  overflow: hidden;
  text-overflow: ellipsis;
}

#bpm {
  color: var(--neon);
  font-variant-numeric: tabular-nums;
}

#notice {
  color: var(--magenta);
  font-size: 0.8rem;
}

#notice:empty { display: none; }