:root{--bg:#f5f6f8;--surface:#fff;--border:#d9dce1;--text:#1c1f24;--text-muted:#6b7280;--accent:#2f7fbf;--accent-contrast:#fff;--accent-light:#e9f2fa;--error-bg:#fdeceb;--error-border:#e5534b;--error-text:#8a1f16;--success:#22c55e;--warning:#f59e0b;--key-closed:#2f7fbf;--key-closed-contrast:#fff;--key-open-border:#b9c2cc;--lightningcss-light:initial;--lightningcss-dark: ;color-scheme:light}:root[data-theme=dark]{--bg:#14161a;--surface:#1b1e24;--border:#2e333c;--text:#e6e8eb;--text-muted:#9aa1ac;--accent:#5aa9e6;--accent-contrast:#0b1220;--accent-light:#1c2a36;--error-bg:#3a1c1c;--error-border:#e5534b;--error-text:#ffb4ac;--success:#4ade80;--warning:#fbbf24;--key-closed:#5aa9e6;--key-closed-contrast:#0b1220;--key-open-border:#454c57;--lightningcss-light: ;--lightningcss-dark:initial;color-scheme:dark}*{box-sizing:border-box}body{background:var(--bg);color:var(--text);margin:0;font-family:system-ui,Segoe UI,Roboto,sans-serif}.site-header{align-items:center;gap:10px;margin-bottom:12px;display:flex}.site-header__brand{color:var(--accent);white-space:nowrap;font-size:15px;font-weight:700;text-decoration:none}.site-header__brand:hover{text-decoration:underline}.site-header__divider{color:var(--text-muted);font-weight:400}.site-header__title{color:var(--text-muted);white-space:nowrap;font-size:15px;font-weight:600}.toolbar-spacer{flex:1}.btn,.toggle-btn{border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;border-radius:6px;padding:6px 12px;font-family:inherit;font-size:13px}.btn:hover,.toggle-btn:hover{border-color:var(--accent)}.btn:disabled{opacity:.5;cursor:not-allowed}.btn--primary{background:var(--accent);color:var(--accent-contrast);border-color:var(--accent)}.btn--primary:hover{opacity:.9}.btn--large{padding:12px 28px;font-size:16px}.icon-btn{padding:6px 10px}.app{max-width:1000px;margin:0 auto;padding:20px 20px 48px}.flute-app__title{color:var(--text);margin:8px 0 4px;font-size:28px}.flute-app__intro{color:var(--text-muted);margin:0 0 20px;font-size:15px;line-height:1.5}.section-title{color:var(--text);margin:0 0 8px;font-size:22px}.section-intro{color:var(--text-muted);margin:0 0 20px;font-size:14px;line-height:1.5}.tab-nav{border-bottom:1px solid var(--border);gap:4px;margin-bottom:20px;display:flex;overflow-x:auto}.tab-nav__btn{color:var(--text-muted);cursor:pointer;white-space:nowrap;background:0 0;border:none;border-bottom:3px solid #0000;align-items:center;gap:6px;padding:10px 16px;font-family:inherit;font-size:14px;font-weight:500;display:flex}.tab-nav__btn:hover{color:var(--text)}.tab-nav__btn--active{color:var(--accent);border-bottom-color:var(--accent)}.tab-nav__icon{font-size:16px}.tab-content{min-height:400px}.note-selector{flex-wrap:wrap;align-items:center;gap:6px;margin-bottom:20px;display:flex}.note-selector__label{color:var(--text-muted);font-size:13px}.note-chip{border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;border-radius:20px;padding:4px 10px;font-family:inherit;font-size:12px;font-weight:600}.note-chip:hover,.note-chip--active{border-color:var(--accent);background:var(--accent-light);color:var(--accent)}.filter-btn{border:1px solid var(--border);background:var(--surface);color:var(--text);cursor:pointer;border-radius:20px;padding:6px 14px;font-family:inherit;font-size:13px}.filter-btn:hover{border-color:var(--accent)}.filter-btn--active{background:var(--accent);color:var(--accent-contrast);border-color:var(--accent)}.fingering-chart__display{justify-content:center;display:flex}.fingering-diagram{background:var(--surface);border:1px solid var(--border);border-radius:12px;flex-direction:column;gap:14px;min-width:260px;padding:20px;display:inline-flex}.fingering-diagram--compact{gap:10px;padding:14px}.fingering-diagram--missing{color:var(--text-muted);padding:12px}.fingering-diagram__header{justify-content:space-between;align-items:center;display:flex}.fingering-diagram__note{color:var(--text);font-size:20px;font-weight:700}.fingering-diagram__play{background:var(--accent);color:var(--accent-contrast);cursor:pointer;border:none;border-radius:50%;justify-content:center;align-items:center;width:28px;height:28px;font-size:11px;display:flex}.fingering-diagram__play:hover{opacity:.85}.fingering-diagram__body{flex-direction:column;gap:10px;display:flex}.fingering-diagram__hand-label{color:var(--text-muted);text-transform:uppercase;letter-spacing:.04em;margin-bottom:4px;font-size:11px;display:block}.fingering-diagram__keys{flex-wrap:wrap;gap:6px;display:flex}.fingering-key{border:2px solid var(--key-open-border);min-width:30px;height:30px;color:var(--text-muted);background:var(--surface);border-radius:50%;justify-content:center;align-items:center;padding:0 6px;font-size:11px;font-weight:700;display:flex}.fingering-key--closed{background:var(--key-closed);border-color:var(--key-closed);color:var(--key-closed-contrast)}.fingering-diagram__legend{color:var(--text-muted);margin:0;font-size:11px}.lessons__header{margin-bottom:20px}.lessons__back{margin-bottom:12px}.lessons__progress{background:var(--border);border-radius:14px;height:28px;margin-bottom:20px;position:relative;overflow:hidden}.lessons__progress-bar{background:var(--accent);border-radius:14px;height:100%;transition:width .3s}.lessons__progress-text{color:var(--text);text-shadow:0 1px 2px #ffffff80;font-size:12px;font-weight:600;position:absolute;top:50%;left:50%;transform:translate(-50%,-50%)}.lesson-step{background:var(--surface);border:1px solid var(--border);border-radius:10px;margin-bottom:16px;padding:20px}.lesson-step__title{color:var(--text);margin:0 0 12px;font-size:18px}.lesson-step__description{color:var(--text);margin:0 0 16px;font-size:15px;line-height:1.6}.lesson-step__notes{flex-wrap:wrap;align-items:flex-start;gap:12px;margin-bottom:16px;display:flex}.lesson-step__play-all{align-self:center}.lesson-step__tip{background:var(--accent-light);color:var(--text);border-radius:8px;align-items:flex-start;gap:8px;padding:12px;font-size:14px;line-height:1.5;display:flex}.tip-icon{flex-shrink:0}.lessons__nav{justify-content:space-between;gap:12px;display:flex}.lessons__list{flex-direction:column;gap:12px;display:flex}.lesson-card{background:var(--surface);border:1px solid var(--border);cursor:pointer;text-align:left;border-radius:10px;align-items:center;gap:12px;padding:16px 20px;font-family:inherit;transition:border-color .2s;display:flex}.lesson-card:hover{border-color:var(--accent)}.lesson-card__body{flex:1}.lesson-card__title{color:var(--text);margin:0 0 4px;font-size:16px}.lesson-card__desc{color:var(--text-muted);margin:0 0 6px;font-size:13px}.lesson-card__meta{align-items:center;gap:8px;display:flex}.lesson-card__badge{text-transform:capitalize;border-radius:12px;padding:2px 8px;font-size:11px;font-weight:600}.lesson-card__badge--beginner{color:var(--success);background:#22c55e26}.lesson-card__badge--intermediate{color:var(--warning);background:#f59e0b26}.lesson-card__steps{color:var(--text-muted);font-size:12px}.lesson-card__arrow{color:var(--text-muted);font-size:20px}.metronome__bpm{justify-content:center;align-items:center;gap:16px;margin-bottom:12px;display:flex}.metronome__bpm-value{flex-direction:column;align-items:center;gap:2px;display:flex}.metronome__bpm-value input{text-align:center;width:90px;color:var(--text);background:0 0;border:none;font-family:inherit;font-size:32px;font-weight:800}.metronome__bpm-value span{color:var(--text-muted);font-size:12px}.metronome__slider{width:100%;max-width:400px;margin:0 auto 20px;display:block}.metronome__beats{justify-content:center;align-items:center;gap:8px;margin-bottom:20px;display:flex}.metronome__beats-label{color:var(--text-muted);font-size:13px}.metronome__beat-indicator{justify-content:center;gap:12px;margin-bottom:24px;display:flex}.metronome__beat-dot{border:2px solid var(--border);background:var(--surface);border-radius:50%;width:18px;height:18px;transition:background 50ms,border-color 50ms}.metronome__beat-dot--accent{border-color:var(--text-muted)}.metronome__beat-dot--active{background:var(--accent);border-color:var(--accent)}.metronome__controls{justify-content:center;gap:12px;display:flex}.practice__mode-toggle{gap:8px;margin-bottom:20px;display:flex}.practice__challenge{flex-direction:column;align-items:center;gap:12px;margin:20px 0;display:flex}.practice__challenge-prompt{color:var(--text-muted);margin:0;font-size:14px}.practice__challenge-result{color:var(--success);flex-direction:column;align-items:center;gap:10px;font-size:16px;font-weight:600;display:flex}.tuner__error{background:var(--error-bg);border:1px solid var(--error-border);color:var(--error-text);border-radius:10px;padding:16px}.tuner__display{flex-direction:column;align-items:center;gap:20px;margin-top:20px;display:flex}.tuner__gauge{width:100%;max-width:500px}.tuner__gauge-scale{justify-content:space-between;margin-bottom:4px;padding:0 10px;display:flex}.tuner__gauge-mark{color:var(--text-muted);font-size:11px}.tuner__gauge-mark--center{color:var(--success);font-weight:700}.tuner__gauge-track{background:var(--surface);border:1px solid var(--border);border-radius:20px;height:40px;position:relative;overflow:hidden}.tuner__needle{background:var(--accent);border-radius:2px;width:4px;transition:transform .1s ease-out;position:absolute;top:4px;bottom:4px;left:50%;transform:translate(0)}.tuner__needle.in-tune{background:var(--success)}.tuner__needle.close{background:var(--warning)}.tuner__gauge-center{background:var(--text-muted);opacity:.3;width:2px;position:absolute;top:0;bottom:0;left:50%}.tuner__note-display{background:var(--surface);border:2px solid var(--border);border-radius:12px;flex-direction:column;align-items:center;gap:4px;min-width:200px;padding:20px;display:flex}.tuner__note-display.in-tune{border-color:var(--success)}.tuner__note-display.close{border-color:var(--warning)}.tuner__note-name{color:var(--text);font-size:48px;font-weight:800}.tuner__note-display.in-tune .tuner__note-name{color:var(--success)}.tuner__note-full{color:var(--text-muted);font-size:14px}.tuner__freq{color:var(--text-muted);font-family:monospace;font-size:13px}.tuner__cents{color:var(--accent);font-size:16px;font-weight:600}.tuner__note-display.in-tune .tuner__cents{color:var(--success)}.tuner__status{color:var(--text-muted);margin-top:4px;font-size:14px;font-weight:600}.tuner__note-display.in-tune .tuner__status{color:var(--success)}.tuner__waiting{color:var(--text-muted);padding:20px;font-size:18px}.tuner__hint{color:var(--text-muted);text-align:center;font-size:13px}@media (width<=640px){.app{padding:12px 12px 40px}.flute-app__title{font-size:22px}.tab-nav__label{font-size:13px}.tab-nav__btn{padding:8px 10px}.tuner__note-name{font-size:36px}.metronome__beat-indicator{gap:8px}}