:root{color-scheme:light;--paper:#eef0f2;--surface:#fbfbfc;--ink:#353b3c;--muted:#626769;--line:#dcdfe0;--accent:#582630;--soft:#f0e5e7;font-family:"DM Sans",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;color:var(--ink);background:var(--paper);font-synthesis:none}
*{box-sizing:border-box}body{margin:0}button,input,select{font:inherit}button,a,input,select,summary{-webkit-tap-highlight-color:transparent}button{cursor:pointer;color:inherit}button:disabled{opacity:.4;cursor:default}button:focus-visible,select:focus-visible,input:focus-visible,summary:focus-visible,a:focus-visible{outline:3px solid #9a6875;outline-offset:4px}button{min-height:44px}button svg{width:19px;height:19px;fill:none;stroke:currentColor;stroke-width:1.7;stroke-linecap:round}h1,h2,p{margin:0}button,.brand{touch-action:manipulation}[hidden]{display:none!important}.shell{max-width:980px;margin:auto;padding:0 32px max(28px,env(safe-area-inset-bottom))}.masthead{height:100px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}.brand{display:flex;gap:10px;align-items:center;color:var(--ink);text-decoration:none;font-weight:600;font-size:24px;letter-spacing:-1.1px}.brand svg{width:31px;height:31px;fill:none;stroke:var(--accent);stroke-width:2.6;stroke-linecap:round;stroke-linejoin:round}.quiet{border:0;background:transparent;padding:8px 0;font-size:13px;font-weight:550;display:inline-flex;align-items:center;gap:12px;white-space:nowrap}.quiet:hover{color:var(--accent)}.quiet span{font-size:20px}.intro{padding:39px 0 28px}.eyebrow{font-size:10px;letter-spacing:1.8px;font-weight:650;color:var(--muted)}h1{font-size:clamp(36px,5.5vw,54px);font-weight:450;letter-spacing:-2.7px;line-height:1.12;margin:13px 0 12px}.intro>p:last-child{font-size:15px;color:var(--muted)}.instrument{padding:24px 28px;background:var(--surface);border:1px solid #e1e3e5;border-radius:18px}.readout-top{display:flex;justify-content:space-between;align-items:center;font-size:11px}.reference{color:var(--muted);font-variant-numeric:tabular-nums}.status{display:flex;gap:7px;align-items:center;font-weight:600}.status i{width:6px;height:6px;background:#999fa1;border-radius:50%}.status.live i{background:var(--accent);box-shadow:0 0 0 4px var(--soft)}.status.demo i{background:#876cbd}.answer{display:grid;grid-template-columns:1.05fr 1fr;align-items:center;min-height:201px;padding:22px 0}.note{font-size:96px;line-height:1.06;font-weight:450;letter-spacing:-7px;color:var(--accent);min-height:103px;font-variant-numeric:tabular-nums}.note sub{font-size:31px;vertical-align:baseline;letter-spacing:-1px;margin-left:5px;color:#886772}.note-block>p:last-child{font-size:12px;color:var(--muted);margin-top:4px}.frequency{display:flex;align-items:baseline;gap:9px;font-size:15px;color:var(--muted)}.frequency span:first-child{font-size:47px;font-weight:400;letter-spacing:-2px;line-height:1.2;color:var(--ink);font-variant-numeric:tabular-nums}.measure-block>p{font-size:12px;margin:5px 0 17px;color:var(--muted)}.tuner{position:relative;display:flex;justify-content:space-between;font-size:9px;color:var(--muted);padding-top:12px;max-width:290px}.tuner-line{position:absolute;top:0;width:100%;height:1px;background:#d6d9da}.tuner-line:before{content:"";position:absolute;left:50%;height:9px;top:-4px;width:1px;background:#b6bbbd}#tuner-dot{position:absolute;top:-3px;left:50%;height:7px;width:7px;transform:translateX(-50%);background:var(--accent);border-radius:50%;opacity:0}.transport{display:flex;gap:9px;align-items:center;border-top:1px solid var(--line);padding-top:20px}.primary,.secondary{border-radius:9px;padding:11px 19px;display:inline-flex;align-items:center;justify-content:center;gap:10px;font-size:13px;font-weight:550;white-space:nowrap}.primary{border:1px solid var(--accent);background:var(--accent);color:#fff;min-width:163px}.primary:hover{background:#713340}.secondary{border:1px solid var(--line);background:transparent}.secondary:hover{background:var(--paper)}.transport>.quiet{margin-left:auto}.message{font-size:11px;line-height:1.6;color:var(--muted);padding-top:13px;min-height:31px}.message.error{color:#96394d}.hidden-answer{min-height:201px;display:flex;align-items:center;justify-content:center;flex-direction:column}.hidden-symbol{font-size:63px;color:var(--accent);line-height:1.1}.hidden-answer p{margin-top:9px;font-size:18px}.hidden-answer>span:last-child{font-size:12px;color:var(--muted);margin-top:7px}.demo-controls{margin-top:16px;padding-top:16px;border-top:1px solid var(--line);display:flex;gap:12px;align-items:end}.demo-controls label{flex:1}.spectrum-section{margin-top:20px}.section-bar{display:flex;justify-content:space-between;align-items:center;gap:10px;min-height:52px}h2{font-size:14px;letter-spacing:-.2px;font-weight:600}.plot-shell{position:relative;border-radius:14px;background:#111216;overflow:hidden;isolation:isolate;height:310px}.plot-shell canvas{width:100%;height:100%;display:block;cursor:crosshair;touch-action:pan-x pan-y}.plot-empty,.plot-curtain{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;flex-direction:column;pointer-events:none;color:#d4d2d8;font-size:13px;text-align:center;line-height:1.7;background:linear-gradient(115deg,#17151caa,#15171baa)}.plot-empty svg{height:60px;width:160px;stroke:#886575;stroke-width:1;fill:none;margin-bottom:11px}.plot-empty span{color:#97939d;font-size:11px}.plot-curtain{background:#17151c;z-index:2}.plot-foot{display:flex;justify-content:space-between;gap:10px;color:var(--muted);font-size:10px;margin-top:10px;font-variant-numeric:tabular-nums}.inspection{font-size:11px;color:var(--muted);margin-top:12px;min-height:15px}.settings{padding:22px 24px;margin-top:18px;background:#f8f9fa;border:1px solid var(--line);border-radius:14px}.settings-grid{display:grid;grid-template-columns:1fr 1fr;gap:22px 26px}label{display:block;font-size:12px;font-weight:550}select{display:block;width:100%;min-width:0;padding:10px 26px 10px 10px;min-height:42px;border:1px solid #d3d7d9;border-radius:7px;background:var(--surface);color:var(--ink);font-size:12px;margin-top:8px}input[type=range]{display:block;width:100%;height:25px;margin:10px 0 5px;accent-color:var(--accent)}output{float:right;color:var(--accent);font-variant-numeric:tabular-nums}small{font-size:10px;font-weight:400;color:var(--muted);display:block;line-height:1.5;margin-top:6px}.settings-footer{display:flex;align-items:center;justify-content:space-between;gap:20px;border-top:1px solid var(--line);margin-top:20px;padding-top:9px}.settings-footer>span{font-size:10px;color:var(--muted)}.candidates-section{margin-top:17px}.section-bar>span{font-size:10px;color:var(--muted)}.candidates{display:flex;gap:9px;min-height:67px}.candidates>p{font-size:12px;color:var(--muted);align-self:center}.candidate{flex:1;text-align:left;border:1px solid var(--line);background:var(--surface);border-radius:10px;padding:12px 13px;min-width:0;transition:border-color .15s}.candidate.selected{border-color:#aa818b;background:var(--soft)}.candidate b{font-size:19px;font-weight:500;display:block;letter-spacing:-.6px}.candidate span{font-size:10px;color:var(--muted);display:block;margin-top:3px;font-variant-numeric:tabular-nums}.about{margin-top:28px;border-top:1px solid var(--line);border-bottom:1px solid var(--line);font-size:12px}.about summary{cursor:pointer;display:flex;align-items:center;justify-content:space-between;list-style:none;padding:20px 0;min-height:50px}.about summary::-webkit-details-marker{display:none}.about summary span{font-size:20px}.about>div{max-width:700px;padding:0 0 18px;line-height:1.8;color:var(--muted)}.about p+p{margin-top:12px}footer{display:flex;justify-content:space-between;gap:15px;color:var(--muted);font-size:10px;padding-top:22px}footer i{font-style:normal;padding:0 6px}.update{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);background:var(--surface);border:1px solid var(--line);box-shadow:0 5px 30px #0002;padding:12px 18px;display:flex;gap:16px;align-items:center;z-index:10;border-radius:12px;font-size:12px;width:max-content;max-width:94vw}body.answer-hidden #candidates-section{visibility:hidden}body.answer-hidden .inspection,body.answer-hidden .plot-foot{visibility:hidden}body.answer-hidden #view-settings{display:none}body.answer-hidden #view-toggle{visibility:hidden}body.answer-hidden #demo-controls{visibility:hidden}
@media(min-width:1100px){.shell{max-width:920px}.intro{padding-top:42px}.plot-shell{height:325px}}
@media(max-width:600px){.shell{padding-left:20px;padding-right:20px}.masthead{height:77px}.brand{font-size:22px}.masthead .quiet{font-size:12px}.intro{padding:28px 0 23px}h1{font-size:39px;letter-spacing:-2px}.intro>p:last-child{font-size:13px}.instrument{padding:19px 18px;border-radius:15px}.answer{min-height:182px;grid-template-columns:.95fr 1fr;gap:6px;padding:22px 0}.eyebrow{font-size:8px;letter-spacing:1.1px}.note{font-size:79px;letter-spacing:-5px;min-height:84px}.note sub{font-size:25px}.frequency span:first-child{font-size:35px;letter-spacing:-1.5px}.frequency{gap:6px;font-size:12px}.measure-block>p{font-size:10px;line-height:1.6;min-height:32px;margin-bottom:14px}.note-block>p:last-child{font-size:10px;line-height:1.6}.transport{gap:7px;padding-top:17px;flex-wrap:wrap}.primary,.secondary{padding:11px 13px;font-size:12px}.primary{min-width:0;flex:1}.transport>.quiet{font-size:11px;gap:4px;margin-left:3px}.transport>.quiet span{font-size:15px}.message{font-size:10px}.readout-top{font-size:10px}.hidden-answer{min-height:182px}.plot-shell{height:292px}.settings{padding:18px 16px}.settings-grid{grid-template-columns:1fr;gap:21px}.candidate{padding:11px 10px}.candidate b{font-size:17px}.candidate span{font-size:9px}.section-bar>span{font-size:9px}.plot-foot{font-size:9px}.demo-controls{flex-direction:column;align-items:stretch}.demo-controls button{align-self:flex-start}footer{font-size:9px;line-height:1.6}.settings-footer{gap:10px}}
@media(max-width:360px){.shell{padding-left:14px;padding-right:14px}.instrument{padding:17px 14px}.frequency span:first-child{font-size:30px}.note{font-size:70px}.transport>.quiet{flex-basis:100%;justify-content:center;margin:0}.candidate-hint{display:none}.candidates{flex-wrap:wrap}.candidate{flex-basis:40%}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important}}

.page-tabs{display:flex;gap:26px;border-bottom:1px solid var(--line)}.page-tabs a{padding:16px 0 13px;min-height:48px;font-size:12px;text-decoration:none;color:var(--muted);border-bottom:2px solid transparent}.page-tabs a[aria-current=page]{color:var(--accent);border-color:var(--accent);font-weight:650}.page-tabs a:hover{color:var(--accent)}
/* Shared theme and compact listening instruments. */
.header-actions{display:flex;align-items:center;gap:18px}.theme-toggle{display:inline-grid;place-items:center;flex-shrink:0;width:40px;height:40px;min-height:40px;padding:0;border:1px solid var(--line);border-radius:50%;background:var(--surface);color:var(--ink)}.theme-toggle svg{width:18px;height:18px}.theme-toggle:hover{border-color:var(--accent)}
.pitch-panel{margin-top:20px}.pitch-surface{padding:20px;background:var(--surface);border:1px solid var(--line);border-radius:14px}.piano-wrap{position:relative}.piano{position:relative;height:116px;border:1px solid #b5b8bf;border-top:5px solid #34313b;border-radius:5px;overflow:hidden;background:#e0e0e4}.piano-key{position:absolute;top:0;display:flex;align-items:flex-end;justify-content:center;padding-bottom:9px}.white-key{width:calc(100% / 21);height:100%;background:linear-gradient(#eeedf0,#fff 80%);border-right:1px solid #c0c0c8;border-bottom:4px solid #dedee3;border-radius:0 0 3px 3px;color:#777681;z-index:1}.black-key{width:calc(100% / 21 * .62);height:63%;transform:translateX(-50%);z-index:2;background:linear-gradient(90deg,#29272e,#38343f 50%,#1c1b20);border:1px solid #15141a;border-bottom:5px solid #111116;border-radius:0 0 3px 3px;color:#fff}.piano-key>span{font-size:9px;line-height:1}.white-key.middle-c{background:linear-gradient(#b9d3f6,#d9e9ff);border-bottom-color:#689bdf;color:#204f94}.violin-a>span{font-weight:700;color:#49404f}.key-active.white-key{background:linear-gradient(#b98392,#dfb3bf);border-bottom-color:#582630;color:#522733}.key-active.black-key{background:linear-gradient(#74394d,#b56e85);border-bottom-color:#582630}.key-active.middle-c{background:linear-gradient(#87b0e9,#bad7ff);border-bottom-color:#285ea3;color:#183f75}.key-dot{position:absolute;bottom:28px;display:none;width:6px;height:6px;background:#582630;border-radius:50%}.black-key .key-dot{bottom:12px;background:#fff}.key-active .key-dot{display:block}.middle-c .key-dot{background:#204f94}.piano-foot{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-top:11px;font-size:10px;color:var(--muted)}.piano-references{display:flex;align-items:center;gap:18px}.middle-c-reference{display:flex;align-items:center;gap:5px;white-space:nowrap}.middle-c-reference i{width:6px;height:6px;background:#6397dc;border-radius:50%}.reference-tip{font-size:10px;padding:6px 0;min-height:32px;border:0;background:transparent;color:var(--muted);white-space:nowrap}.reference-tip:hover{color:var(--accent)}.violin-tip{font-size:12px;line-height:1.7;padding:12px 15px;margin-top:8px;background:var(--soft);border-radius:8px;color:var(--ink)}.piano-curtain{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:var(--surface);color:var(--muted);font-size:13px;border:1px dashed var(--line);border-radius:7px;z-index:3}
.level-section{margin-top:13px;padding-top:18px;border-top:1px solid var(--line)}.level-heading{display:flex;align-items:baseline;gap:12px;margin-bottom:12px}.level-heading h3{font-weight:550;font-size:12px;margin:0}.level-heading>span{font-size:10px;color:var(--muted)}.level-heading>strong{margin-left:auto;display:flex;align-items:baseline;gap:7px;font-size:20px;font-weight:500;font-variant-numeric:tabular-nums;letter-spacing:-.5px}.level-heading small{margin:0;font-size:9px;letter-spacing:0}.level-meter{position:relative;height:17px;background:#111816;border:1px solid #29322f;border-radius:3px;overflow:hidden}.level-colour{position:absolute;inset:0;background:linear-gradient(to right,#369566 0%,#62c775 66.6%,#dcc75a 83.3%,#e9ac4e 91.6%,#e87565 100%)}.level-mask{position:absolute;top:0;bottom:0;left:0;right:0;background:#18221e}.level-segments{position:absolute;inset:0;background:repeating-linear-gradient(to right,transparent 0,transparent calc(100% / 48 - 2px),#111816 calc(100% / 48 - 2px),#111816 calc(100% / 48))}.level-meter>i{position:absolute;top:0;bottom:0;width:2px;background:#f0f4d1;box-shadow:0 0 3px #ffffd0}.level-scale{display:flex;justify-content:space-between;font-size:9px;margin-top:6px;color:var(--muted);font-variant-numeric:tabular-nums}.level-help{font-size:10px;line-height:1.6;color:var(--muted);margin-top:10px}body.answer-hidden #piano,body.answer-hidden #piano-caption,body.answer-hidden #level-section{visibility:hidden}
:root[data-theme=dark]{color-scheme:dark;--paper:#17181c;--surface:#202126;--ink:#eee9ed;--muted:#aaa6af;--line:#39373f;--accent:#e0a2b4;--soft:#352730}
[data-theme=dark] .instrument{border-color:var(--line)}[data-theme=dark] .primary{color:#24171d}[data-theme=dark] .primary:hover{background:#eab8c6}[data-theme=dark] .settings{background:#1d1e23}[data-theme=dark] select{border-color:var(--line)}[data-theme=dark] .note sub{color:#c594a4}[data-theme=dark] .tuner-line{background:#55515b}[data-theme=dark] .tuner-line:before{background:#88818d}[data-theme=dark] .message.error{color:#f2a0af}[data-theme=dark] .candidate.selected{border-color:#aa7789}[data-theme=dark] .piano{border-color:#514d59}[data-theme=dark] .weight-track i{background:#a47387}[data-theme=dark] .weight-row:first-child .weight-track i{background:var(--accent)}[data-theme=dark] .axis{stroke:#504b58}[data-theme=dark] .floor-curve{stroke:#c899b0}[data-theme=dark] .harmonic-tokens span{border-color:#765465}[data-theme=dark] .time-strip span:after{background:#65515d}[data-theme=dark] .time-strip i{background:#947b89}
@media(max-width:600px){.header-actions{gap:12px}.theme-toggle{width:36px;height:36px;min-height:36px}.pitch-surface{padding:16px}.piano{height:106px}.piano-key>span{font-size:8px}.piano-foot{flex-direction:column;align-items:flex-start;gap:3px}.piano-references{width:100%;justify-content:space-between;gap:10px}.level-heading{gap:8px;flex-wrap:wrap}.level-heading h3{font-size:11px}.level-heading>span{font-size:9px}.level-heading>strong{font-size:19px;gap:5px}.level-heading small{font-size:8px}.level-help{font-size:9px}.masthead-note{display:none}}
@media(max-width:360px){.header-actions{gap:9px}.brand{font-size:20px;gap:7px}.brand svg{width:27px;height:27px}.masthead #hide-answer{font-size:10px;gap:6px}.level-heading>strong{flex-basis:100%;margin-left:0}.piano-key>span{font-size:7px}}

.brand-figure{display:block;width:40px;height:40px;border-radius:9px;flex-shrink:0;background:#fff}.brand{gap:9px}@media(max-width:600px){.brand-figure{width:36px;height:36px}}@media(max-width:360px){.brand-figure{width:32px;height:32px}.brand{gap:7px}}