:root {
    --mt-bg: #0f172a;
    --mt-card: #1e293b;
    --mt-card-hi: #2a3a52;
    --mt-border: #334155;
    --mt-text: #e2e8f0;
    --mt-text-mute: #94a3b8;
    --mt-accent: #818cf8;
    --mt-accent-solid: #6366f1;
    --mt-accent-bg: rgba(99,102,241,0.15);
    --mt-success: #34d399;
    --mt-warning: #fbbf24;
    --mt-danger: #ef4444;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', sans-serif;
    background: var(--mt-bg); color: var(--mt-text); min-height: 100vh;
}
.mt-fullscreen { min-height: 100vh; display: flex; flex-direction: column; }
.mt-header {
    background: rgba(15,23,42,0.85); backdrop-filter: blur(8px);
    border-bottom: 1px solid var(--mt-border); height: 56px;
    padding: 0 16px; display: flex; align-items: center; gap: 12px;
    position: sticky; top: 0; z-index: 100;
}
.mt-back { color: var(--mt-text-mute); text-decoration: none; display: inline-flex; align-items: center; gap: 6px; font-size: 14px; }
.mt-back:hover { color: var(--mt-text); }
.mt-title { font-size: 16px; font-weight: 600; }
.mt-spacer { flex: 1; }

.mt-main { flex: 1; padding: 24px 16px 60px; max-width: 760px; width: 100%; margin: 0 auto; }
.mt-card { background: var(--mt-card); border: 1px solid var(--mt-border); border-radius: 16px; padding: 24px; }

.mt-tabs {
    display: flex; gap: 4px; background: var(--mt-bg);
    border: 1px solid var(--mt-border); border-radius: 10px;
    padding: 4px; margin-bottom: 24px;
}
.mt-tab {
    flex: 1; background: transparent; color: var(--mt-text-mute);
    border: none; padding: 10px 8px; border-radius: 7px; cursor: pointer;
    font-size: 14px; font-family: inherit;
    display: inline-flex; align-items: center; justify-content: center; gap: 6px;
}
.mt-tab:hover { color: var(--mt-text); }
.mt-tab.active { background: var(--mt-accent-bg); color: var(--mt-accent); font-weight: 500; }

.mt-pane.hidden { display: none; }

.mt-row { margin-bottom: 16px; }
.mt-label { display: block; font-size: 13px; color: var(--mt-text-mute); margin-bottom: 8px; }

/* BPM */
.mt-bpm-display {
    text-align: center; margin: 8px 0 18px;
    padding: 24px; border: 1px solid var(--mt-border); border-radius: 14px;
    background: linear-gradient(180deg, var(--mt-card-hi), var(--mt-card));
}
.mt-bpm-num {
    font-size: 64px; font-weight: 700; color: var(--mt-accent);
    font-variant-numeric: tabular-nums; line-height: 1;
}
.mt-bpm-unit { font-size: 13px; color: var(--mt-text-mute); margin-top: 6px; letter-spacing: 1px; }

.mt-range {
    width: 100%; -webkit-appearance: none; appearance: none;
    height: 6px; background: var(--mt-border); border-radius: 4px; outline: none;
}
.mt-range::-webkit-slider-thumb {
    -webkit-appearance: none; appearance: none;
    width: 22px; height: 22px; border-radius: 50%;
    background: var(--mt-accent-solid); cursor: pointer;
    box-shadow: 0 0 0 4px var(--mt-accent-bg);
}
.mt-range::-moz-range-thumb {
    width: 22px; height: 22px; border-radius: 50%;
    background: var(--mt-accent-solid); cursor: pointer; border: none;
}

.mt-bpm-quick {
    display: flex; flex-wrap: wrap; gap: 8px;
    margin-bottom: 18px;
}
.mt-chip {
    background: transparent; color: var(--mt-text-mute);
    border: 1px solid var(--mt-border); padding: 6px 12px;
    border-radius: 999px; cursor: pointer;
    font-size: 12px; font-family: inherit;
}
.mt-chip:hover { color: var(--mt-text); border-color: var(--mt-accent-solid); }
.mt-chip-tap { background: var(--mt-accent-bg); color: var(--mt-accent); border-color: var(--mt-accent-solid); }
.mt-chip-tap.taping { background: var(--mt-accent-solid); color: #fff; }

.mt-segment {
    display: inline-flex; gap: 4px;
    background: var(--mt-bg); border: 1px solid var(--mt-border);
    border-radius: 8px; padding: 3px;
}
.mt-seg {
    background: transparent; color: var(--mt-text-mute);
    border: none; padding: 8px 16px; border-radius: 5px;
    cursor: pointer; font-size: 13px; font-family: inherit;
}
.mt-seg:hover { color: var(--mt-text); }
.mt-seg.active { background: var(--mt-accent-bg); color: var(--mt-accent); font-weight: 500; }

.mt-beats {
    display: flex; gap: 6px; justify-content: center;
    padding: 16px 0;
}
.mt-beat {
    width: 28px; height: 28px; border-radius: 50%;
    background: var(--mt-card-hi); border: 1px solid var(--mt-border);
    transition: transform .08s, background .08s;
}
.mt-beat.first { width: 36px; height: 36px; }
.mt-beat.active {
    background: var(--mt-accent-solid);
    transform: scale(1.2);
    box-shadow: 0 0 16px var(--mt-accent-bg);
}
.mt-beat.first.active {
    background: var(--mt-warning);
    box-shadow: 0 0 18px rgba(251,191,36,0.4);
}

.mt-actions { display: flex; justify-content: center; margin-top: 8px; }
.mt-btn {
    background: transparent; color: var(--mt-text);
    border: 1px solid var(--mt-border); padding: 10px 18px;
    border-radius: 10px; cursor: pointer; font-size: 14px; font-family: inherit;
    display: inline-flex; align-items: center; gap: 8px;
}
.mt-btn:hover { background: var(--mt-card-hi); border-color: var(--mt-accent-solid); }
.mt-btn-primary { background: var(--mt-accent-solid); color: #fff; border-color: var(--mt-accent-solid); }
.mt-btn-primary:hover { background: var(--mt-accent); }
.mt-btn-lg { padding: 14px 36px; font-size: 16px; min-width: 180px; justify-content: center; }
.mt-btn-primary.running { background: var(--mt-danger); border-color: var(--mt-danger); }
.mt-btn-primary.running:hover { background: #dc2626; }

/* Tuner */
.mt-tuner {
    background: linear-gradient(180deg, var(--mt-card-hi), var(--mt-card));
    border: 1px solid var(--mt-border); border-radius: 14px;
    padding: 24px; margin-bottom: 18px; text-align: center;
}
.mt-tuner-status { color: var(--mt-text-mute); font-size: 13px; margin-bottom: 14px; }
.mt-tuner-note {
    font-size: 64px; font-weight: 700; color: var(--mt-accent);
    line-height: 1; min-height: 64px;
    font-variant-numeric: tabular-nums;
}
.mt-tuner-note.in-tune { color: var(--mt-success); }
.mt-tuner-note.flat, .mt-tuner-note.sharp { color: var(--mt-warning); }
.mt-tuner-freq { font-size: 15px; color: var(--mt-text-mute); margin-top: 6px; font-variant-numeric: tabular-nums; }

.mt-tuner-meter { margin-top: 22px; }
.mt-tuner-scale {
    display: flex; justify-content: space-between;
    font-size: 11px; color: var(--mt-text-mute);
    margin-bottom: 6px;
}
.mt-tuner-tick-mid { color: var(--mt-success); font-weight: 600; }
.mt-tuner-bar {
    position: relative; height: 14px;
    background: var(--mt-bg); border: 1px solid var(--mt-border);
    border-radius: 7px; overflow: hidden;
}
.mt-tuner-bar::before {
    content: ''; position: absolute; left: 50%; top: 0; bottom: 0;
    width: 2px; background: var(--mt-success); transform: translateX(-50%);
}
.mt-tuner-needle {
    position: absolute; top: 0; bottom: 0; left: 50%;
    width: 4px; background: var(--mt-accent-solid);
    border-radius: 2px;
    transition: left .08s ease-out;
    transform: translateX(-50%);
}
.mt-tuner-cents { font-size: 12px; color: var(--mt-text-mute); margin-top: 8px; font-variant-numeric: tabular-nums; }

.mt-tuner-tip {
    margin-top: 18px; padding: 14px 16px;
    background: var(--mt-card-hi); border: 1px solid var(--mt-border);
    border-radius: 8px; color: var(--mt-text-mute);
    font-size: 12px; line-height: 1.7;
}

.mt-foot { margin-top: 18px; color: var(--mt-text-mute); font-size: 12px; }
.mt-seo {
    margin-top: 32px; padding: 20px 24px;
    background: var(--mt-card); border: 1px solid var(--mt-border);
    border-radius: 12px; color: var(--mt-text-mute); font-size: 14px; line-height: 1.7;
}
.mt-seo h2 { color: var(--mt-text); font-size: 16px; margin-bottom: 10px; }
.mt-seo b { color: var(--mt-text); font-weight: 500; }

@media (max-width: 540px) {
    .mt-card { padding: 18px; }
    .mt-bpm-num { font-size: 48px; }
    .mt-tuner-note { font-size: 48px; min-height: 48px; }
    .mt-btn-lg { padding: 12px 24px; min-width: 140px; }
}