:root {
  --font: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --color-bg: #f8f9fa;
  --color-surface: #ffffff;
  --color-primary: #1db954;
  --color-primary-hover: #17a349;
  --color-text: #212529;
  --color-text-muted: #6c757d;
  --color-border: #dee2e6;
  --color-error: #dc3545;
  --color-error-bg: #fff5f5;
  --color-seg-a: #e8f4f8;
  --color-seg-b: #f8f0e8;
  --color-visited: #1db954;
  --color-bpm: #4a9eff;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,.1);
}

*, *::before, *::after { box-sizing: border-box; }

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  margin: 0;
  padding: 0;
  min-height: 100vh;
}

header {
  background: #191414;
  color: #fff;
  padding: 1.5rem 2rem;
}

header h1 {
  margin: 0;
  font-size: 1.75rem;
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 0.25rem 0 0;
  color: rgba(255,255,255,0.6);
  font-size: 0.875rem;
}

.tabs {
  display: flex;
  gap: 0;
  background: var(--color-surface);
  border-bottom: 2px solid var(--color-border);
  padding: 0 2rem;
}

.tab {
  background: none;
  border: none;
  border-bottom: 3px solid transparent;
  margin-bottom: -2px;
  padding: 0.75rem 1.5rem;
  cursor: pointer;
  font: inherit;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  transition: color 0.15s, border-color 0.15s;
}

.tab:hover { color: var(--color-text); }
.tab.active { color: var(--color-primary); border-bottom-color: var(--color-primary); }

main {
  max-width: 960px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* Forms */
.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 0.375rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font: inherit;
  font-size: 0.95rem;
  background: var(--color-surface);
  color: var(--color-text);
  transition: border-color 0.15s;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--color-primary);
}

.form-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.form-row .form-group {
  flex: 1;
  min-width: 160px;
}

fieldset {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1rem 0;
}

legend {
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0 0.5rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
  border: none;
  border-radius: var(--radius);
  padding: 0.625rem 1.5rem;
  font: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s;
  position: relative;
}

.btn-primary:hover { background: var(--color-primary-hover); }

.htmx-indicator { display: none; }
.htmx-request .htmx-indicator { display: inline; }
.htmx-request .btn-label { display: none; }

/* Results */
.results {
  margin-top: 2rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.results h2 {
  margin: 0 0 1rem;
  font-size: 1.25rem;
}

.stats-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.stat {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 0.75rem 1rem;
  flex: 1;
  min-width: 120px;
}

.stat-label {
  display: block;
  font-size: 0.75rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  margin-bottom: 0.25rem;
}

.stat-value {
  display: block;
  font-size: 1.25rem;
  font-weight: 700;
}

/* Tables */
.track-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin-bottom: 1.5rem;
}

.track-table th {
  text-align: left;
  padding: 0.5rem 0.75rem;
  border-bottom: 2px solid var(--color-border);
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-muted);
}

.track-table td {
  padding: 0.5rem 0.75rem;
  border-bottom: 1px solid var(--color-border);
}

.track-table tr:last-child td { border-bottom: none; }
.track-table tr:hover td { background: var(--color-bg); }

.camelot-badge {
  background: var(--color-primary);
  color: #fff;
  border-radius: 4px;
  padding: 2px 6px;
  font-size: 0.8rem;
  font-weight: 700;
}

/* Viz */
.viz-row {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

.viz-panel {
  flex: 1;
  min-width: 280px;
}

.viz-panel h3 {
  margin: 0 0 0.5rem;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.viz-panel svg {
  width: 100%;
  height: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

/* Decode */
.message-box {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  font-size: 1.1rem;
  font-weight: 500;
  margin-bottom: 1.5rem;
  word-break: break-all;
  white-space: pre-wrap;
}

/* Error */
.alert-error {
  background: var(--color-error-bg);
  border: 1px solid var(--color-error);
  border-radius: var(--radius);
  color: var(--color-error);
  padding: 1rem 1.25rem;
  margin-top: 1rem;
  font-size: 0.9rem;
}

code {
  font-family: ui-monospace, "SF Mono", "Fira Code", monospace;
  font-size: 0.85em;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  padding: 1px 4px;
}

/* Musicality score */
.score-excellent  { color: #1db954; }
.score-good       { color: #4a9eff; }
.score-fair       { color: #f0a500; }
.score-needs-work { color: var(--color-error); }
.stat-unavailable { color: var(--color-text-muted); font-size: 0.9rem; font-weight: 400; }

.score-detail summary {
  font-size: 0.8rem;
  color: var(--color-text-muted);
  cursor: pointer;
  margin-top: 0.25rem;
}

.score-detail p {
  margin: 0.5rem 0 0;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}

/* Secondary button */
.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius);
  padding: 0.625rem 1.5rem;
  font: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, color 0.15s;
  margin-top: 1rem;
  display: inline-block;
}

.btn-secondary:hover {
  background: var(--color-primary);
  color: #fff;
}

/* Save result partial */
.save-success {
  margin-top: 0.75rem;
  color: var(--color-primary);
  font-weight: 600;
}