:root {
  --bg: #0b0e14;
  --panel: #141924;
  --panel-2: #1b2230;
  --line: #2a3447;
  --text: #e6ebf4;
  --muted: #8b97b0;
  --accent: #7aa5ff;
  --good: #8de0c9;
  --warn: #ffb35c;
  --bad: #ff7a88;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-tap-highlight-color: transparent;
}

#app {
  max-width: 480px;
  margin: 0 auto;
  padding: 16px 14px 80px;
  min-height: 100vh;
}

header h1 {
  font-size: 1.25rem;
  margin: 0 0 14px;
  letter-spacing: -0.01em;
}

.instrument-selector {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}

.instrument {
  flex: 1;
  background: var(--panel-2);
  border: 1px solid var(--line);
  color: var(--text);
  padding: 12px 8px;
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  font-family: inherit;
  transition: background 0.15s, border-color 0.15s;
}

.instrument.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #0b0e14;
}

.aref {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 10px;
  align-items: center;
  margin-bottom: 16px;
}

.aref label {
  font-size: 0.95rem;
  color: var(--muted);
  font-weight: 600;
}

.aref label sub {
  font-size: 0.7em;
}

#aref-slider {
  width: 100%;
  accent-color: var(--accent);
}

#aref-value {
  font-variant-numeric: tabular-nums;
  font-size: 0.92rem;
  color: var(--text);
  min-width: 72px;
  text-align: right;
}

.presets {
  grid-column: 1 / -1;
  display: flex;
  gap: 8px;
}

.preset, .tuning {
  flex: 1;
  background: var(--panel-2);
  border: 1px solid var(--line);
  color: var(--text);
  padding: 8px 10px;
  font-size: 0.85rem;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  font-family: inherit;
}

.preset.active, .tuning.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #0b0e14;
  font-weight: 600;
}

.tuning-section {
  margin-bottom: 16px;
}

.tuning-presets {
  display: flex;
  gap: 6px;
  margin-bottom: 12px;
  flex-wrap: wrap;
}

.tuning {
  flex: 1 1 calc(33.33% - 4px);
  min-width: 0;
  font-size: 0.78rem;
  padding: 9px 6px;
}

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

.strings .string-btn {
  flex: 1 1 calc(25% - 4.5px);
  min-width: 0;
}

.string-btn {
  flex: 1;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 4px;
  font-family: inherit;
  font-size: 0.95rem;
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

.string-btn:hover {
  background: var(--panel-2);
}

.string-btn.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #0b0e14;
  font-weight: 700;
}

.string-btn .freq {
  display: block;
  font-size: 0.7rem;
  margin-top: 3px;
  opacity: 0.8;
  font-variant-numeric: tabular-nums;
}

.auto-indicator {
  margin-top: 10px;
  padding: 8px 10px;
  background: rgba(141, 224, 201, 0.08);
  border: 1px solid rgba(141, 224, 201, 0.25);
  border-radius: 8px;
  font-size: 0.72rem;
  color: var(--good);
  line-height: 1.4;
}

.auto-indicator.manual {
  background: rgba(122, 165, 255, 0.08);
  border-color: rgba(122, 165, 255, 0.25);
  color: var(--accent);
}

.meter-section {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 18px 16px;
  margin-bottom: 16px;
}

.note-display {
  text-align: center;
  margin-bottom: 16px;
}

.note-name {
  font-size: 3.2rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
  margin-bottom: 6px;
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

.note-target, .note-current {
  font-size: 0.85rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.note-current {
  color: var(--accent);
  margin-top: 2px;
}

.needle-track {
  margin-top: 12px;
}

.needle-scale {
  display: flex;
  justify-content: space-between;
  font-size: 0.7rem;
  color: var(--muted);
  margin-bottom: 4px;
  font-variant-numeric: tabular-nums;
}

.needle-bar {
  position: relative;
  height: 50px;
  background: linear-gradient(90deg,
    rgba(255,122,136,0.20) 0%,
    rgba(255,122,136,0.10) 30%,
    rgba(141,224,201,0.20) 45%,
    rgba(141,224,201,0.40) 50%,
    rgba(141,224,201,0.20) 55%,
    rgba(255,122,136,0.10) 70%,
    rgba(255,122,136,0.20) 100%);
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
}

.needle-zero {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  width: 1px;
  background: var(--muted);
  opacity: 0.5;
}

.needle {
  position: absolute;
  top: 4px;
  bottom: 4px;
  left: 50%;
  width: 4px;
  background: var(--text);
  border-radius: 2px;
  transform: translateX(-50%);
  transition: left 0.08s ease-out, background 0.15s;
  box-shadow: 0 0 12px rgba(122, 165, 255, 0.6);
}

.needle.in-tune {
  background: var(--good);
  box-shadow: 0 0 18px rgba(141, 224, 201, 0.8);
}

.needle.flat {
  background: var(--warn);
}

.needle.sharp {
  background: var(--warn);
}

.needle.way-off {
  background: var(--bad);
}

.cents {
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 8px;
  font-variant-numeric: tabular-nums;
}

.mic-section {
  text-align: center;
  margin-bottom: 16px;
}

.big-btn {
  width: 100%;
  background: var(--accent);
  color: #0b0e14;
  border: 0;
  padding: 16px;
  border-radius: 12px;
  font-size: 1.05rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: opacity 0.15s;
}

.big-btn:active { opacity: 0.85; }

.big-btn.listening {
  background: var(--bad);
}

.mic-status {
  margin-top: 10px;
  font-size: 0.85rem;
  color: var(--accent);
  line-height: 1.4;
}

.mic-status.error {
  color: var(--bad);
  background: rgba(255, 122, 136, 0.08);
  border: 1px solid rgba(255, 122, 136, 0.25);
  padding: 10px 12px;
  border-radius: 8px;
  text-align: left;
}

.hidden { display: none; }

footer {
  text-align: center;
  margin-top: 22px;
}

footer .hint {
  font-size: 0.75rem;
  color: var(--muted);
  line-height: 1.5;
  display: block;
}

.footer-links {
  margin-top: 10px;
  font-size: 0.78rem;
  color: var(--muted);
}

.footer-links a {
  color: var(--accent);
  text-decoration: none;
}

.footer-links a:hover {
  text-decoration: underline;
}

.footer-links .sep {
  margin: 0 6px;
  opacity: 0.4;
}

main.prose {
  padding-top: 24px;
}

main.prose .back {
  display: inline-block;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.85rem;
  margin-bottom: 16px;
}

main.prose h1 {
  font-size: 1.8rem;
  margin: 0 0 8px;
  letter-spacing: -0.02em;
}

main.prose h2 {
  font-size: 1.05rem;
  margin: 1.8rem 0 0.4rem;
  color: var(--text);
}

main.prose p, main.prose li {
  color: var(--text);
  font-size: 0.92rem;
  line-height: 1.6;
}

main.prose .lede {
  color: var(--muted);
  font-size: 0.92rem;
}

main.prose a {
  color: var(--accent);
}

.update-toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--panel-2);
  border: 1px solid var(--accent);
  border-radius: 10px;
  padding: 12px 16px;
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 0.88rem;
  color: var(--text);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
  z-index: 100;
  max-width: calc(100% - 32px);
}

.update-toast button {
  background: var(--accent);
  color: #0b0e14;
  border: 0;
  padding: 6px 12px;
  border-radius: 6px;
  font-family: inherit;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
}

.diag {
  margin-top: 16px;
  text-align: left;
}

.diag summary {
  font-size: 0.7rem;
  color: var(--muted);
  cursor: pointer;
  padding: 4px 0;
  list-style: none;
}

.diag summary::-webkit-details-marker { display: none; }
.diag summary::before { content: "▸ "; }
.diag[open] summary::before { content: "▾ "; }

#diag-log {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px;
  font-size: 0.68rem;
  color: var(--muted);
  white-space: pre-wrap;
  word-break: break-all;
  max-height: 240px;
  overflow-y: auto;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

@media (max-width: 360px) {
  .note-name { font-size: 2.6rem; }
  .preset, .tuning { font-size: 0.75rem; padding: 7px 4px; }
}