.frequency-page{--lab-blue:#174be8;--lab-ink:#16243c;max-width:1400px;margin:auto;padding:65px 5vw 75px}.frequency-intro{max-width:930px}.frequency-intro h1{font-size:clamp(52px,7.5vw,105px);font-weight:450;letter-spacing:-.07em;line-height:1.02;margin:24px 0 28px}.frequency-intro .lede{max-width:660px;font-size:19px}.frequency-back{font-size:11px;display:inline-block;margin-bottom:38px;color:#596779}.lab-intro-links{display:flex;gap:26px;font-size:12px;margin:30px 0 48px}.frequency-page button,.frequency-page input{font:inherit}.frequency-page button:focus-visible,.frequency-page input:focus-visible{outline:3px solid #174be8;outline-offset:4px}.frequency-page button:disabled{opacity:.45;cursor:not-allowed}.lab-panel{background:#edf3ff;padding:40px;color:var(--lab-ink)}.lab-panel-top{display:flex;justify-content:space-between;gap:20px;font-size:10px;letter-spacing:1px;text-transform:uppercase;color:#4d6182}.lab-readout{display:flex;justify-content:space-between;align-items:flex-end;margin-top:42px;gap:30px}.frequency-display output{display:block;font-size:clamp(58px,7vw,98px);letter-spacing:-.075em;font-weight:450;line-height:1.1;font-variant-numeric:tabular-nums;color:#1644c3}.frequency-display>span{font-size:11px;display:block;margin-top:14px;color:#516784}.region-description{max-width:300px}.region-description h2{font-size:27px;font-weight:500;letter-spacing:-.04em;margin:0 0 10px}.region-description p{font-size:13px;line-height:1.7;margin:0;color:#52637c}.lab-wave{width:100%;height:135px;display:block;margin:25px 0 0;opacity:.8}.lab-wave path{stroke:var(--lab-blue);stroke-width:1.5;fill:none;vector-effect:non-scaling-stroke}.lab-spectrum{position:relative;height:9px;background:linear-gradient(90deg,#bed1eb,#aec7ec,#89b1ef,#648bea,#5277d5,#2d499b);margin:8px 0 20px}.lab-spectrum>span{position:absolute;width:2px;height:25px;top:-8px;background:#173977;transform:translateX(-1px);pointer-events:none}.lab-slider-label{display:flex;justify-content:space-between;gap:20px;align-items:center;font-size:12px}.lab-slider-label small{font-size:10px;color:#576f91}.frequency-range{width:100%;height:38px;margin:10px 0 0;accent-color:var(--lab-blue);cursor:pointer}.lab-ticks{display:flex;justify-content:space-between;font-size:10px;color:#576982;margin:0 0 24px}.lab-ticks span{position:relative}.lab-presets{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:32px}.lab-presets button{border:1px solid #b9c9e2;background:transparent;color:#3d5a8b;padding:9px 12px;font-size:11px;min-height:36px}.lab-presets button:hover{background:#dce7fa}.lab-actions{display:flex;gap:12px;flex-wrap:wrap;align-items:center}.lab-primary,.lab-stop,.quiz-next,.quiz-repeat{border:1px solid var(--lab-blue);padding:15px 21px;font-size:12px;min-height:46px}.lab-primary,.quiz-next{background:var(--lab-blue);color:#fff}.lab-stop,.quiz-repeat{background:transparent;color:var(--lab-blue)}.lab-primary:hover,.quiz-next:hover{background:#143cb1}.lab-stop:hover,.quiz-repeat:hover{background:#dbe7fc}.lab-volume{display:flex;gap:12px;align-items:center;margin-left:auto;font-size:11px}.lab-volume input{width:100px;accent-color:var(--lab-blue)}.lab-volume output{min-width:30px;text-align:right;font-variant-numeric:tabular-nums}.lab-audio-state{font-size:11px;min-height:18px;color:#58729a;margin:20px 0 0}.lab-audio-state:before{content:'';display:inline-block;width:5px;height:5px;border-radius:50%;background:#91a4be;margin-right:8px;vertical-align:middle}.tone-playing .lab-audio-state:before{background:#174be8}.lab-note{font-size:12px;line-height:1.8;color:#687380;margin:20px 0 0;max-width:860px}.lab-quiz{display:grid;grid-template-columns:.85fr 1.15fr;gap:70px;margin:85px 0;padding-top:50px;border-top:1px solid #d7dee8}.lab-quiz h2,.lab-context h2{font-size:clamp(34px,4vw,49px);font-weight:450;letter-spacing:-.06em;line-height:1.08;margin:18px 0 22px}.lab-quiz-intro p{font-size:15px;line-height:1.85;color:#616d7b;max-width:380px}.quiz-range-key{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;border-top:1px solid #d5deec;padding-top:20px;margin-top:28px;font-size:10px;color:#667389}.quiz-range-key strong{display:block;color:#263952;font-size:13px;margin-bottom:8px;font-weight:550}.quiz-card{background:#f6f8fc;padding:30px;align-self:start}.quiz-controls{display:flex;flex-wrap:wrap;gap:10px}.quiz-options{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin-top:26px}.quiz-options button{min-height:70px;border:1px solid #c6d3e8;background:white;color:#2d4770;font-size:18px;letter-spacing:-.03em}.quiz-options button:not(:disabled):hover{background:#e5edff}.quiz-options button[data-result=correct]{border:2px solid #174be8;background:#e3ecff;opacity:1;color:#174be8}.quiz-options button[data-result=chosen]{text-decoration:line-through;opacity:.65}.quiz-feedback{font-size:14px;line-height:1.7;min-height:72px;color:#435876;margin:22px 0 15px}.quiz-session{display:flex;justify-content:space-between;align-items:center;gap:18px;border-top:1px solid #dce3ed;padding-top:20px;font-size:11px;color:#6b7890}.quiz-session button{border:0;background:transparent;padding:6px 0;color:#4d668a;text-decoration:underline;text-underline-offset:4px;font-size:11px}.lab-context{border-top:1px solid #d7dee8;padding:55px 0 30px}.lab-context-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:38px;margin-top:40px}.lab-context-grid>article{border-top:1px solid #d7dee8;padding-top:20px}.lab-context-grid span{font-size:11px;color:#9aa7b7}.lab-context-grid h3{font-size:23px;font-weight:500;letter-spacing:-.04em;line-height:1.2}.lab-context-grid p{font-size:14px;line-height:1.9;color:#65707d}.lab-method{font-size:11px;line-height:1.8;color:#7a8594;padding-top:20px;max-width:800px}.lab-method a{text-decoration:underline;text-underline-offset:3px}.frequency-page .guide-next{margin-top:55px}.lab-noscript{padding:20px;background:#fff5dc;font-size:14px;line-height:1.7}
@media(max-width:760px){.frequency-page{padding:40px 5vw 50px}.frequency-back{margin-bottom:20px}.lab-panel{padding:25px 20px}.lab-readout{align-items:flex-start;flex-direction:column;gap:22px;margin-top:30px}.region-description{max-width:100%;min-height:94px}.region-description h2{font-size:23px}.lab-wave{height:100px;margin-top:0}.lab-volume{margin-left:0;width:100%;margin-top:14px}.lab-volume input{flex:1}.lab-slider-label{flex-wrap:wrap;gap:6px}.lab-quiz{grid-template-columns:1fr;gap:25px;margin:55px 0;padding-top:35px}.lab-quiz-intro p{max-width:100%}.quiz-card{padding:23px 20px}.lab-context-grid{grid-template-columns:1fr;gap:16px}.lab-context{padding-top:35px}.lab-intro-links{margin-bottom:32px}.lab-panel-top{font-size:9px}.lab-context-grid h3{margin:15px 0}.lab-context-grid p{margin-top:0}.quiz-next,.quiz-repeat{padding:13px 14px}.lab-ticks{font-size:9px}.frequency-page .guide-next{gap:20px;flex-wrap:wrap}}
.tone-settings{display:grid;grid-template-columns:1fr 1fr;gap:24px;margin:12px 0 28px}.tone-settings label,.quiz-mode-label{display:block;font-size:12px;font-weight:550;margin-bottom:10px}.tone-settings input,.tone-settings select,#quiz-mode{font:inherit;background:#fff;border:1px solid #b9c9e2;border-radius:0;padding:12px;color:#203b66;max-width:100%;min-height:46px}.tone-settings select{width:100%}.frequency-entry{display:flex;gap:6px}.frequency-entry input{width:130px;min-width:0;flex:1}.frequency-entry button{border:1px solid #b9c9e2;background:white;color:#203b66;min-width:50px;padding:10px}.harmonic-panel{padding:24px;background:#fff9;margin:0 0 25px}.harmonic-heading{display:flex;justify-content:space-between;gap:10px;font-size:12px}.harmonic-heading span{font-size:9px;letter-spacing:.06em;color:#63718b}.harmonic-bars{display:grid;grid-template-columns:repeat(8,1fr);gap:12px;margin-top:20px;text-align:center}.harmonic-track{height:80px;background:#dce6f7;display:flex;align-items:flex-end;justify-content:center}.harmonic-track span{width:100%;background:#426ee7;min-height:0}.harmonic strong,.harmonic small{display:block;font-size:10px;margin-top:8px;font-weight:400}.harmonic small{color:#6b7890;font-size:9px}.harmonic-panel p,#quiz-mode-note{font-size:12px;line-height:1.7;color:#596c88}.harmonic-panel p{margin-bottom:0}#quiz-mode{width:100%;font-size:13px}#quiz-mode-note{margin:12px 0 24px}.frequency-page select:focus-visible{outline:3px solid #174be8;outline-offset:4px}
@media(max-width:600px){.tone-settings{grid-template-columns:1fr;gap:16px}.harmonic-panel{padding:18px 12px}.harmonic-heading{flex-direction:column}.harmonic-bars{gap:5px}.harmonic-track{height:65px}.harmonic small{font-size:8px}.quiz-options button{font-size:15px}.lab-intro-links{flex-wrap:wrap}}