:root {
  --bg: #0b0d14;
  --bg-elevated: #12151f;
  --bg-card: #161a26;
  --border: #262c3d;
  --text: #eef0f6;
  --text-dim: #8991a8;
  --accent: #7c5cff;
  --accent-2: #21d4c4;
  --accent-grad: linear-gradient(135deg, #7c5cff 0%, #21d4c4 100%);
  --danger: #ff5c72;
  --radius: 14px;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f4f5f9;
    --bg-elevated: #ffffff;
    --bg-card: #ffffff;
    --border: #e2e5ee;
    --text: #14161f;
    --text-dim: #6b7185;
    --shadow: 0 10px 30px rgba(20, 22, 31, 0.08);
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

.app {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.topbar {
  padding: 24px 32px;
  border-bottom: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-mark {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--accent-grad);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  color: white;
  letter-spacing: 0.5px;
  flex-shrink: 0;
}

.brand-text h1 {
  margin: 0;
  font-size: 20px;
  font-weight: 700;
}

.brand-text p {
  margin: 2px 0 0;
  font-size: 13px;
  color: var(--text-dim);
}

main {
  flex: 1;
  max-width: 980px;
  width: 100%;
  margin: 0 auto;
  padding: 40px 24px 80px;
}

.view.hidden { display: none; }

/* Upload */
.dropzone {
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  background: var(--bg-elevated);
  padding: 70px 24px;
  text-align: center;
  cursor: pointer;
  transition: border-color 0.2s ease, background 0.2s ease, transform 0.15s ease;
}

.dropzone:hover, .dropzone.dragover {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 6%, var(--bg-elevated));
}

.dropzone.dragover { transform: scale(1.01); }

.dropzone-icon {
  font-size: 42px;
  margin-bottom: 12px;
  background: var(--accent-grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.dropzone h2 {
  margin: 0 0 8px;
  font-size: 19px;
}

.dropzone p {
  margin: 0;
  color: var(--text-dim);
  font-size: 14px;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  margin-top: 24px;
}

.feature {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  font-size: 13.5px;
  color: var(--text-dim);
  display: flex;
  align-items: center;
  gap: 10px;
}

.feature span { font-size: 18px; }

/* Processing */
.processing-card, .error-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 56px 32px;
  text-align: center;
  box-shadow: var(--shadow);
}

.spinner {
  width: 46px;
  height: 46px;
  margin: 0 auto 24px;
  border-radius: 50%;
  border: 3px solid var(--border);
  border-top-color: var(--accent);
  animation: spin 0.9s linear infinite;
}

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

.processing-card h2 { margin: 0 0 6px; font-size: 18px; }
.processing-card p#processing-message { color: var(--text-dim); margin: 0 0 28px; font-size: 14px; min-height: 20px; }

.steps {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 8px;
  padding: 0;
  margin: 0 0 20px;
  flex-wrap: wrap;
}

.steps li {
  padding: 7px 14px;
  border-radius: 999px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-dim);
  font-size: 12.5px;
}

.steps li.active {
  border-color: var(--accent);
  color: var(--text);
  background: color-mix(in srgb, var(--accent) 14%, var(--bg-elevated));
}

.steps li.complete {
  border-color: var(--accent-2);
  color: var(--accent-2);
}

.hint { color: var(--text-dim); font-size: 12.5px; margin: 0; }

/* Error */
.error-icon {
  width: 46px; height: 46px; line-height: 46px;
  border-radius: 50%;
  background: var(--danger);
  color: white;
  font-weight: 800;
  margin: 0 auto 20px;
}
.error-card p { color: var(--text-dim); margin-bottom: 24px; }

/* Buttons */
.btn {
  border: none;
  border-radius: 10px;
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.1s ease, opacity 0.15s ease;
}
.btn:active { transform: scale(0.97); }
.btn-primary {
  background: var(--accent-grad);
  color: white;
}
.btn-primary:hover { opacity: 0.92; }
.btn-ghost {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--text);
}
.btn-ghost:hover { border-color: var(--accent); }
.btn-small {
  padding: 6px 12px;
  font-size: 12.5px;
  border-radius: 8px;
}
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

/* Result view */
.analysis-bar {
  display: flex;
  align-items: center;
  gap: 24px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.stat { display: flex; flex-direction: column; gap: 4px; min-width: 70px; }
.stat-label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--text-dim); }
.stat-value { font-size: 20px; font-weight: 700; }
.stat-sub { font-size: 10.5px; color: var(--text-dim); }
.analysis-bar .btn { margin-left: auto; }

.transport-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 22px;
  margin-bottom: 20px;
}

#waveform {
  width: 100%;
  height: 80px;
  display: block;
  border-radius: 8px;
  margin-bottom: 14px;
}

.transport-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

.play-btn {
  width: 40px; height: 40px;
  border-radius: 50%;
  border: none;
  background: var(--accent-grad);
  color: white;
  font-size: 14px;
  cursor: pointer;
  flex-shrink: 0;
}

.seek { flex: 1; accent-color: var(--accent); }

#time-current, #time-total {
  font-variant-numeric: tabular-nums;
  font-size: 12.5px;
  color: var(--text-dim);
  min-width: 38px;
}

.speed-control {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-dim);
  padding-left: 12px;
  border-left: 1px solid var(--border);
}
.speed-control input { accent-color: var(--accent-2); width: 80px; }
#speed-value { min-width: 42px; }

.mixer {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 14px;
  margin-bottom: 20px;
}

.channel {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.channel.karaoke { border-color: color-mix(in srgb, var(--accent-2) 40%, var(--border)); }

.channel-title { display: flex; align-items: center; justify-content: space-between; }
.channel-title h3 { margin: 0; font-size: 15px; }
.channel-badge {
  font-size: 10.5px;
  padding: 2px 8px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--accent-2) 20%, transparent);
  color: var(--accent-2);
}

.channel-badge.experimental {
  background: color-mix(in srgb, #ffb020 20%, transparent);
  color: #ffb020;
}

.instrument-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.instrument-tags-empty {
  font-size: 11.5px;
  color: var(--text-dim);
  font-style: italic;
}

.instrument-tags .tag {
  font-size: 11px;
  padding: 3px 8px;
  border-radius: 999px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  color: var(--text-dim);
  white-space: nowrap;
}

.instrument-tags .tag b {
  color: var(--text);
  font-weight: 700;
}

.channel-toggle-row { display: flex; gap: 8px; }

.toggle-btn {
  flex: 1;
  padding: 7px 0;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-dim);
  font-size: 12.5px;
  font-weight: 600;
  cursor: pointer;
}
.toggle-btn.active.mute { background: var(--danger); border-color: var(--danger); color: white; }
.toggle-btn.active.solo { background: var(--accent-2); border-color: var(--accent-2); color: #06231f; }

.volume-row { display: flex; align-items: center; gap: 10px; }
.volume-row input { flex: 1; accent-color: var(--accent); }
.volume-row span { font-size: 11.5px; color: var(--text-dim); width: 32px; text-align: right; }

.channel-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.channel-actions .btn { flex: 1; text-align: center; }

.midi-status { font-size: 11.5px; color: var(--text-dim); min-height: 14px; }

.downloads-bar { display: flex; justify-content: center; margin-top: 8px; }

footer {
  text-align: center;
  padding: 20px;
  color: var(--text-dim);
  font-size: 12px;
  border-top: 1px solid var(--border);
}