@charset "UTF-8";
.site-banner{display:block;margin-top:24px;overflow:hidden;border-radius:12px;background:var(--surface)}
.site-banner img{display:block;width:100%;height:auto}
.banner-en,html[lang="en"] .banner-zh{display:none}
html[lang="en"] .banner-en{display:block}
@media(max-width:680px){.site-banner{margin-top:12px;border-radius:8px}}
:root{color-scheme:light;--bg:#f3f3ec;--surface:#fffefa;--soft:#f0f2eb;--soft-2:#e9eee4;--ink:#263c31;--muted:#69776b;--line:#dce2d6;--accent:#365b46;--accent-hover:#294b38;--accent-ink:#fffefa;--accent-tint:#e5ede0;--warm:#b48448;--shadow:0 12px 42px #273d2e08;--danger:#a14135;--danger-bg:#fcf0eb;--good:#326c49;--good-bg:#eaf3e7;--focus:#b88231}
[data-theme="sand"]{--bg:#f5f0e7;--surface:#fffcf6;--soft:#f4ecdf;--soft-2:#ebe1d1;--ink:#483d30;--muted:#7c6d5c;--line:#e6dccc;--accent:#826044;--accent-hover:#684b35;--accent-tint:#efe2d2;--warm:#ac783a}
[data-theme="ocean"]{--bg:#edf3f5;--surface:#fbfefe;--soft:#eaf2f5;--soft-2:#dfeaf0;--ink:#273f4a;--muted:#657e88;--line:#d5e3e8;--accent:#356274;--accent-hover:#264f60;--accent-tint:#e0eef2;--warm:#a5814d}
[data-theme="lavender"]{--bg:#f3f0f6;--surface:#fefbff;--soft:#efebf5;--soft-2:#e8e1f0;--ink:#42354e;--muted:#7a6d84;--line:#e2d9e9;--accent:#735784;--accent-hover:#5e426e;--accent-tint:#eee3f3;--warm:#9a7948}
[data-theme="rose"]{--bg:#f7f0ee;--surface:#fffcfa;--soft:#f7ece8;--soft-2:#f0e2dc;--ink:#503c3c;--muted:#8a7270;--line:#eadbd7;--accent:#96665f;--accent-hover:#7e514b;--accent-tint:#f2e1da;--warm:#ac7f4c}
[data-theme="night"]{color-scheme:dark;--bg:#19221f;--surface:#222f28;--soft:#29362e;--soft-2:#334338;--ink:#edf1e7;--muted:#acb9ab;--line:#3c4a3f;--accent:#afcca7;--accent-hover:#c9dfbf;--accent-ink:#1c2b21;--accent-tint:#374d39;--warm:#d5b17d;--danger:#f1b4a4;--danger-bg:#4d302a;--good:#b3d8ac;--good-bg:#314833;--focus:#e5bf87;--shadow:0 12px 42px #00000016}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;font-size:14px;line-height:1.65;-webkit-font-smoothing:antialiased}button,input,select{font:inherit}button,a,input,select,summary{-webkit-tap-highlight-color:transparent}button{cursor:pointer}button{color:inherit}button:disabled{cursor:default;opacity:.43}button,a,select{touch-action:manipulation}a{color:inherit;text-decoration:none}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid var(--focus);outline-offset:4px}button{border:0;background:none}svg{display:block}h1,h2,h3,p{margin:0}button{transition:background .15s,transform .15s,border-color .15s}button:active:not(:disabled){transform:translateY(1px)}[hidden]{display:none!important}.page-shell{max-width:1200px;margin:0 auto;padding:0 36px}.site-header{height:108px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:13px}.brand-icon{height:46px;width:46px;display:grid;place-items:center;background:var(--accent);border-radius:13px;color:var(--accent-ink)}.brand-icon svg{height:30px;width:30px;stroke:currentColor;fill:currentColor;stroke-width:1.8;stroke-linecap:round}.brand-icon svg path{fill:none}.brand strong{font-size:22px;letter-spacing:3px;font-weight:650}.brand-sub{display:block;font-size:8px;letter-spacing:2.45px;line-height:1.3;color:var(--muted);margin-top:2px}.header-actions{display:flex;align-items:center;gap:16px}.series-label{font-size:12px;color:var(--muted);margin-right:12px}.icon-button{width:34px;height:34px;border:1px solid var(--line);border-radius:50%;display:inline-grid;place-items:center;font-size:17px;background:var(--surface)}.theme-trigger{display:flex;align-items:center;gap:8px;font-size:12px;padding:7px 10px;border-radius:6px}.theme-trigger:hover,.text-button:hover{background:var(--soft-2)}.theme-dot{width:15px;height:15px;border-radius:50%;background:linear-gradient(135deg,var(--accent) 50%,var(--warm) 50%);border:1px solid var(--line)}.intro{display:flex;align-items:center;justify-content:space-between;padding:38px 4px 32px;gap:20px}.eyebrow{font-size:11px;letter-spacing:3px;display:flex;align-items:center;gap:9px;color:var(--muted);margin-bottom:12px}.eyebrow>span:first-child{display:inline-block;width:18px;height:1px;background:var(--warm)}h1{font-family:"Songti SC","Noto Serif CJK SC",STSong,serif;font-weight:600;font-size:34px;letter-spacing:1px;line-height:1.5}.intro p{color:var(--muted);font-size:13px;margin-top:10px}.mobile-break{display:none}.intro-art{width:280px;position:relative;padding-top:8px;flex-shrink:0;transform:rotate(-3deg)}.intro-art svg{width:100%;height:auto}.art-staff path{stroke:var(--line);fill:none;stroke-width:1}.art-path{stroke:var(--warm);stroke-width:1.1;fill:none;stroke-dasharray:4 5;opacity:.6}.art-notes{stroke:var(--accent);fill:var(--accent);stroke-width:2}.intro-art>span{display:block;text-align:right;margin-top:0;font-size:10px;color:var(--muted);letter-spacing:2px}.progress-strip{display:flex;align-items:center;gap:28px;background:var(--soft-2);padding:13px 23px;border:1px solid var(--line);border-radius:12px;margin-bottom:24px}.progress-label{font-size:12px;display:flex;align-items:center;gap:9px;color:var(--muted);margin-right:6px}.small-sun{font-size:24px;color:var(--warm);line-height:1}.progress-strip>div{display:flex;gap:9px;align-items:baseline}.progress-strip strong{font-size:21px;font-weight:500;font-variant-numeric:tabular-nums}.progress-strip>div>span{font-size:11px;color:var(--muted)}.progress-strip>.text-button{margin-left:auto;font-size:11px}.text-button{padding:5px 8px;border-radius:5px;font-size:12px;color:var(--muted)}.practice-app{background:var(--surface);border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);overflow:hidden;scroll-margin-top:16px}.main-tabs{display:flex;gap:32px;padding:0 30px;border-bottom:1px solid var(--line)}.main-tabs>button{position:relative;padding:22px 4px 18px;color:var(--muted);font-size:14px;white-space:nowrap}.main-tabs>button>span:first-child{font-size:10px;opacity:.65;font-variant-numeric:tabular-nums;margin-right:7px}.main-tabs>button.active{color:var(--accent);font-weight:650}.main-tabs>button.active::after{content:"";position:absolute;height:3px;bottom:0;left:0;right:0;background:var(--accent);border-radius:3px 3px 0 0}.workspace-grid{display:grid;grid-template-columns:minmax(0,1fr) 268px;min-height:530px}.practice-main{padding:26px 32px 29px;min-width:0}.settings-panel{background:var(--soft);border-left:1px solid var(--line);padding:23px 24px}.settings-panel details>summary{font-size:12px;list-style:none;font-weight:650;letter-spacing:1px;cursor:pointer;margin-bottom:23px;display:flex;justify-content:space-between}.settings-panel summary::-webkit-details-marker{display:none}.settings-panel summary>span[aria-hidden]{display:none}.setting-group{margin-bottom:19px}.setting-label{display:flex;align-items:center;justify-content:space-between;font-size:11px;color:var(--muted);margin-bottom:8px}.setting-label>output{font-size:11px;font-variant-numeric:tabular-nums}.setting-group select{display:block;width:100%;min-height:38px;border-radius:7px;border:1px solid var(--line);background:var(--surface);color:var(--ink);padding:6px 9px;font-size:12px}.mini-segment{display:flex;gap:3px;border:1px solid var(--line);border-radius:7px;padding:3px;background:var(--surface)}.mini-segment button{flex:1;min-height:30px;font-size:11px;border-radius:5px;color:var(--muted);padding:3px 6px}.mini-segment button.active{background:var(--accent-tint);color:var(--accent);font-weight:600}.interval-picks{display:grid;grid-template-columns:repeat(3,1fr);gap:5px}.interval-pick{min-height:34px;font-size:11px;border:1px solid var(--line);border-radius:5px;background:var(--surface);color:var(--muted);padding:4px 2px}.interval-pick.active{background:var(--accent-tint);color:var(--accent);border-color:var(--accent)}.interval-presets{display:flex;gap:6px;margin:9px 0 0;flex-wrap:wrap}.interval-presets button{font-size:10px;padding:2px 4px;text-decoration:underline;text-underline-offset:3px;color:var(--muted)}.setting-divider{height:1px;background:var(--line);margin:21px 0}.range{width:100%;accent-color:var(--accent);cursor:pointer;height:19px;margin:0}.setting-help{font-size:10px;color:var(--muted);line-height:1.8;margin-top:7px}.setting-check{display:flex;align-items:flex-start;gap:7px;font-size:11px;color:var(--muted);cursor:pointer}.setting-check input{accent-color:var(--accent);margin:4px 0 0}.stage-header{display:flex;justify-content:space-between;align-items:center;gap:14px;margin-bottom:23px}.section-label{font-size:10px;letter-spacing:1.7px;color:var(--muted)}.badge{padding:3px 9px;border-radius:20px;font-size:10px;color:var(--accent);background:var(--accent-tint);white-space:nowrap}.stage-title{font-size:21px;font-weight:550;letter-spacing:.3px;line-height:1.5}.stage-description{font-size:12px;color:var(--muted);margin-top:7px}.listening-stage{background:var(--soft);border:1px solid var(--line);border-radius:12px;margin:22px 0 19px;position:relative;overflow:hidden;min-height:164px;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:19px 16px;gap:19px}.blind-notes{display:flex;align-items:center;justify-content:center;gap:18px;min-height:23px}.blind-note{width:10px;height:10px;border:1.5px solid var(--muted);opacity:.4;border-radius:50%;position:relative}.blind-note:not(:last-child)::after{content:"";position:absolute;left:15px;top:3px;width:9px;height:1px;background:var(--line)}.blind-note.sounding{background:var(--accent);border-color:var(--accent);opacity:1;box-shadow:0 0 0 6px var(--accent-tint)}.play-main{display:flex;align-items:center;justify-content:center;gap:13px;background:var(--accent);color:var(--accent-ink);border-radius:10px;min-width:180px;min-height:52px;padding:12px 24px;font-weight:550;font-size:15px;box-shadow:0 4px 9px #00000009}.play-main:hover{background:var(--accent-hover)}.play-symbol{font-size:14px}.listening-hint{font-size:10px;color:var(--muted);min-height:16px}.reference-row{display:flex;justify-content:center;gap:15px;margin:0 0 22px;flex-wrap:wrap}.reference-row .text-button{font-size:11px}.answer-heading{display:flex;align-items:center;justify-content:space-between;font-size:11px;color:var(--muted);margin-bottom:10px;gap:10px}.answer-heading small{font-size:10px}.choice-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:9px}.choice-grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}.answer-choice{border:1px solid var(--line);border-radius:8px;background:var(--surface);min-height:48px;padding:10px 13px;text-align:left;display:flex;align-items:center;justify-content:space-between;gap:5px;font-size:13px}.answer-choice small{font-size:10px;color:var(--muted)}.answer-choice:hover:not(:disabled){border-color:var(--accent);background:var(--soft)}.answer-choice.chosen{border-color:var(--accent);background:var(--accent-tint)}.answer-choice.is-correct{border-color:var(--good);background:var(--good-bg);color:var(--good)}.answer-choice.is-wrong{border-color:var(--danger);background:var(--danger-bg);color:var(--danger)}.candidate-card{padding:12px;border:1px solid var(--line);border-radius:9px;display:flex;flex-direction:column;gap:11px}.candidate-card.selected{border-color:var(--accent);background:var(--accent-tint)}.candidate-card.correct{border-color:var(--good);background:var(--good-bg)}.candidate-card.wrong{border-color:var(--danger);background:var(--danger-bg)}.candidate-top{display:flex;align-items:center;justify-content:space-between;font-size:12px}.candidate-top strong{font-family:Georgia,serif;font-size:21px;font-weight:500}.candidate-select{border:1px solid var(--line);border-radius:6px;min-height:36px;font-size:12px;background:var(--surface)}.candidate-select[aria-pressed="true"]{border-color:var(--accent);color:var(--accent);font-weight:600}.candidate-play{padding:6px 10px;font-size:11px;background:var(--surface);border-radius:6px;border:1px solid var(--line)}.button-row{display:flex;align-items:center;justify-content:flex-end;gap:10px;margin-top:18px;flex-wrap:wrap}.primary-button{background:var(--accent);color:var(--accent-ink);min-height:42px;border-radius:8px;padding:9px 19px;font-size:12px;font-weight:550}.primary-button:hover:not(:disabled){background:var(--accent-hover)}.secondary-button{border:1px solid var(--line);border-radius:7px;padding:8px 13px;min-height:38px;font-size:11px;background:var(--surface)}.secondary-button:hover:not(:disabled){border-color:var(--accent)}.feedback{margin-top:20px;padding:15px 17px;border-radius:9px;border:1px solid var(--line);background:var(--soft)}.feedback.good{background:var(--good-bg);border-color:var(--good)}.feedback.bad{background:var(--danger-bg);border-color:var(--danger)}.feedback h3{font-size:14px;font-weight:600;margin-bottom:4px}.feedback p{font-size:11px;line-height:1.9}.feedback .muted{color:var(--muted)}.staff-box{margin-top:15px;background:var(--surface);border:1px solid var(--line);border-radius:9px;overflow:hidden}.staff-caption{padding:10px 14px 0;font-size:10px;color:var(--muted);display:flex;justify-content:space-between}.staff-svg{width:100%;height:auto;max-height:195px;min-height:105px}.step-list{display:flex;gap:6px;flex-wrap:wrap;margin:12px 0 0}.step-button{padding:7px 9px;border:1px solid var(--line);background:var(--surface);border-radius:6px;font-size:10px}.step-button.problem{border-color:var(--danger);color:var(--danger)}.step-button:hover{border-color:var(--accent)}.note-slots{display:flex;align-items:center;justify-content:center;gap:8px;margin:19px 0;flex-wrap:wrap}.note-slot{height:55px;min-width:55px;border:1px dashed var(--line);border-radius:9px;display:flex;flex-direction:column;align-items:center;justify-content:center;font-size:15px;color:var(--muted);padding:5px}.note-slot.filled{border:1px solid var(--line);background:var(--soft);color:var(--ink)}.note-slot.locked{border-style:solid;background:var(--accent-tint);color:var(--accent)}.note-slot.selected{border:2px solid var(--accent);background:var(--accent-tint)}.note-slot small{font-size:9px;color:var(--muted)}.solfege-grid{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));gap:5px}.solfege-key{border:1px solid var(--line);background:var(--surface);border-radius:7px;min-height:58px;font-size:14px;display:flex;align-items:center;justify-content:center;flex-direction:column;gap:3px;padding:4px 0}.solfege-key small{font-size:8px;color:var(--muted)}.solfege-key:hover:not(:disabled){border-color:var(--accent);background:var(--accent-tint)}.input-mode-row{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-bottom:11px}.input-mode-row .mini-segment{max-width:150px;flex:1}.input-mode-row>span{font-size:10px;color:var(--muted)}.keyboard-viewport{overflow-x:auto;padding:4px 3px 10px;scrollbar-width:thin}.keyboard{display:flex;position:relative;height:125px;min-width:420px;width:100%;border:1px solid #d3d3cc;border-radius:6px;overflow:hidden;background:#f9f8f2;isolation:isolate}.piano-key{position:relative;border:0;border-right:1px solid #d3d3cc;border-bottom:4px solid #dddcd3;background:linear-gradient(#fffef8,#f1f1e9);color:#556256;border-radius:0 0 4px 4px;display:flex;justify-content:flex-end;align-items:center;flex-direction:column;padding:0 0 8px;font-size:10px;line-height:1.5}.piano-key.white{height:100%;flex:1}.piano-key.black{position:absolute;height:64%;width:4.3%;background:linear-gradient(#39453d,#202a23);color:#e9eee5;z-index:2;border:1px solid #172018;border-bottom:5px solid #111b14;top:0;padding-bottom:5px;transform:translateX(-50%);font-size:9px}.piano-key:disabled{opacity:1;color:#b9beb6}.piano-key.black:disabled{color:#768076}.piano-key.enabled:hover{background:var(--accent-tint);color:var(--accent)}.piano-key.black.enabled:hover{background:var(--accent);color:var(--accent-ink)}.piano-key small{font-size:8px}.explore-heading{display:flex;justify-content:space-between;align-items:center;gap:15px;margin-bottom:20px}.explore-heading .mini-segment{width:165px}.interval-display{display:flex;align-items:center;justify-content:center;gap:22px;min-height:90px;margin:10px 0 0}.pitch-display{text-align:center;font-family:Georgia,serif;font-size:30px;min-width:66px}.pitch-display small{display:block;font-family:inherit;font-size:11px;color:var(--muted)}.interval-bridge{font-size:10px;color:var(--muted);text-align:center}.interval-bridge>span{font-size:21px;display:block;color:var(--warm)}.explore-actions{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;margin-top:18px}.explore-note{font-size:11px;color:var(--muted);margin:13px 0 0;line-height:1.9}.app-bottom{padding:12px 28px;border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:10px;color:var(--muted);font-size:10px;min-height:48px}.app-bottom>span{display:flex;align-items:center;gap:7px}.status-dot{width:5px;height:5px;border-radius:50%;background:var(--accent);flex-shrink:0}.stop-button{font-size:10px;white-space:nowrap}.practice-tip{display:flex;align-items:center;gap:14px;margin:20px 3px 37px;color:var(--muted)}.practice-tip>span{font-size:27px;color:var(--warm)}.practice-tip p{font-size:11px;line-height:1.9;flex:1}.practice-tip .text-button{font-size:11px;white-space:nowrap}footer{border-top:1px solid var(--line);padding:23px 2px 28px;display:flex;justify-content:space-between;gap:20px;font-size:9px;color:var(--muted)}footer>div{display:flex;flex-direction:column;gap:5px}.footer-links{flex-direction:row;align-items:flex-start;gap:17px;font-size:10px}.footer-links a:hover{text-decoration:underline;text-underline-offset:4px}dialog{color:var(--ink);background:var(--surface);border:1px solid var(--line);border-radius:17px;width:min(570px,calc(100% - 28px));max-height:85dvh;padding:25px;box-shadow:0 22px 90px #0000002c}dialog::backdrop{background:#14251c65;backdrop-filter:blur(3px)}.dialog-head{display:flex;align-items:center;justify-content:space-between;margin-bottom:21px}.dialog-head h2{font-size:19px;font-weight:600}.dialog-head .icon-button{font-size:22px;flex-shrink:0}#dialog-body{font-size:12px;line-height:1.95}#dialog-body h3{font-size:13px;margin:20px 0 7px}#dialog-body p{margin:9px 0}#dialog-body ul{padding-left:21px}.theme-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}.theme-option{padding:13px 9px;border:1px solid var(--line);border-radius:9px;display:flex;align-items:center;gap:9px;min-height:59px;font-size:12px}.theme-option[aria-pressed="true"]{border-color:var(--accent);background:var(--soft)}.theme-swatch{width:23px;height:23px;border-radius:50%;flex-shrink:0}.stats-overview{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-bottom:20px}.stats-overview>div{background:var(--soft);padding:13px;border-radius:8px;text-align:center}.stats-overview strong{display:block;font-size:25px;font-weight:500}.stats-overview span{font-size:10px;color:var(--muted)}.stat-line{display:grid;grid-template-columns:90px 1fr 75px;gap:9px;align-items:center;font-size:11px;margin:10px 0}.stat-track{height:5px;border-radius:5px;background:var(--soft-2);overflow:hidden}.stat-track>span{display:block;height:100%;background:var(--accent);border-radius:5px}.stat-line>small{font-size:10px;text-align:right;color:var(--muted)}.empty-state{padding:24px;text-align:center;color:var(--muted);background:var(--soft);border-radius:9px}.toast{position:fixed;bottom:25px;left:50%;transform:translateX(-50%);background:var(--ink);color:var(--surface);padding:11px 20px;border-radius:9px;max-width:min(90%,520px);box-shadow:var(--shadow);font-size:12px;z-index:5;text-align:center}.skip-link{position:absolute;left:12px;top:-80px;z-index:6;padding:8px 14px;background:var(--accent);color:var(--accent-ink);border-radius:6px}.skip-link:focus{top:12px}.noscript{position:fixed;bottom:0;background:var(--danger-bg);padding:20px;width:100%;color:var(--danger);text-align:center}.storage-message{font-size:10px;color:var(--danger);margin-top:8px}.subtle{color:var(--muted);font-size:11px}.compare-line{display:flex;gap:8px;flex-wrap:wrap;margin-top:11px}.shortcuts{font-size:10px;color:var(--muted);margin-top:14px;text-align:center}.settings-panel select,.setting-check,.interval-pick,.mini-segment button{min-height:36px}
.staff-svg g.sounding{color:var(--warm)}.note-slot.sounding{border-color:var(--warm);box-shadow:0 0 0 2px var(--accent-tint)}
@media(min-width:1400px){.page-shell{max-width:1270px}.intro{padding-top:46px;padding-bottom:38px}.workspace-grid{grid-template-columns:minmax(0,1fr) 280px}.practice-main{padding:30px 39px}}
@media(max-width:980px){.page-shell{padding:0 24px}.series-label{display:none}.workspace-grid{grid-template-columns:minmax(0,1fr) 235px}.settings-panel{padding:22px 17px}.practice-main{padding:24px}.intro-art{width:220px}h1{font-size:30px}.progress-strip{gap:19px;padding:12px 17px}.footer-links{gap:11px}.progress-label{margin:0}.solfege-key{font-size:12px}.note-slot{min-width:48px;height:50px}}
@media(max-width:700px){.page-shell{padding:0 16px}.site-header{height:84px}.brand strong{font-size:20px}.brand-icon{width:41px;height:41px}.brand-sub{font-size:7px;letter-spacing:2.1px}.brand{gap:10px}.header-actions{gap:8px}.theme-trigger{padding:7px 3px}.theme-trigger>span:last-child{display:none}.intro{padding:28px 2px 24px;gap:7px}.intro-art{width:135px}.intro-art>span{display:none}h1{font-size:28px;line-height:1.5;letter-spacing:1px}.mobile-break{display:block}.intro p{font-size:11px;max-width:260px;margin-top:11px;line-height:1.9}.eyebrow{font-size:10px;letter-spacing:2px;margin-bottom:10px}.progress-strip{gap:17px;padding:12px 14px;margin-bottom:19px;position:relative}.progress-label{display:none}.progress-strip>div{gap:5px;flex-direction:column;line-height:1.3}.progress-strip strong{font-size:20px}.progress-strip>div>span{font-size:9px}.progress-strip>.text-button{font-size:10px}.main-tabs{gap:0;padding:0 11px;justify-content:space-between}.main-tabs>button{padding:18px 8px 15px;font-size:12px}.main-tabs>button>span:first-child{font-size:9px;margin-right:4px}.workspace-grid{grid-template-columns:1fr;min-height:0}.practice-main{padding:22px 20px 24px}.settings-panel{border-left:0;border-top:1px solid var(--line);padding:0 20px}.settings-panel details>summary{min-height:49px;margin:0;align-items:center;font-size:11px}.settings-panel summary>span[aria-hidden]{display:inline}.settings-panel details[open]>summary{margin-bottom:12px}#settings-body{display:grid;grid-template-columns:1fr 1fr;gap:0 20px;padding-bottom:10px}#settings-body .full-width,#settings-body .setting-divider{grid-column:1/-1}.setting-group{margin-bottom:16px}.setting-divider{margin:2px 0 17px}.interval-picks{grid-template-columns:repeat(5,1fr)}.interval-pick{font-size:10px;min-height:34px}.stage-header{margin-bottom:20px}.stage-title{font-size:19px}.stage-description{font-size:11px}.listening-stage{margin-top:20px;min-height:163px;padding:18px 12px;gap:18px}.play-main{min-height:50px;min-width:175px;font-size:14px}.reference-row{gap:8px;margin-bottom:20px}.reference-row .text-button{font-size:10px}.answer-choice{font-size:12px;padding:10px}.app-bottom{padding:11px 17px;font-size:9px}.practice-tip{margin:15px 2px 26px;gap:9px;align-items:flex-start}.practice-tip p{font-size:10px}.practice-tip>.text-button{font-size:10px;padding:3px;flex-shrink:0}.practice-tip>span{font-size:23px;line-height:1.2}footer{flex-direction:column;gap:15px;padding-bottom:max(23px,env(safe-area-inset-bottom))}.footer-links{gap:21px;font-size:10px}.solfege-grid{gap:4px}.solfege-key{font-size:12px;min-height:54px}.solfege-key small{font-size:7px}.note-slots{gap:6px}.note-slot{min-width:43px;height:49px;font-size:13px}.note-slot small{font-size:8px}.theme-grid{grid-template-columns:repeat(2,1fr)}.step-button{font-size:9px;padding:7px}.staff-svg{min-height:85px}.listening-hint{font-size:9px}.button-row{gap:8px}.shortcuts{display:none}.stat-line{grid-template-columns:85px 1fr 65px}.explore-heading{margin-bottom:18px}.explore-heading .mini-segment{width:146px}.setting-help{font-size:9px}}
@media(max-width:360px){.page-shell{padding:0 10px}.practice-main{padding:20px 14px}.brand strong{font-size:18px}.brand-sub{letter-spacing:1.5px}.intro-art{width:100px}h1{font-size:25px}.progress-strip{gap:14px}.main-tabs>button{padding-left:6px;padding-right:6px}.solfege-key{font-size:11px}.choice-grid.three{grid-template-columns:1fr}.note-slot{min-width:39px}.interval-picks{grid-template-columns:repeat(4,1fr)}}
@media(prefers-reduced-motion:reduce){*{scroll-behavior:auto!important;transition:none!important;animation:none!important}}

/* Bilingual reading sizes, touch controls and source attribution. */
body{font-size:15px}
.header-actions{gap:10px}.brand-sub{font-size:9px}.series-label{font-size:13px;margin-right:4px}
.icon-button{width:44px;height:44px}.theme-trigger{min-height:44px;font-size:14px}
.language-button{border:1px solid var(--line);background:var(--surface);border-radius:8px;padding:8px 12px;min-height:44px;font-size:14px;font-weight:600;white-space:nowrap}
.language-button:hover{border-color:var(--accent);background:var(--accent-tint)}
.intro p{font-size:15px}.intro-art>span{font-size:12px}.eyebrow{font-size:12px}
.progress-strip>div>span,.progress-strip>.text-button,.progress-label{font-size:13px}
.text-button{min-height:44px;display:inline-flex;align-items:center;justify-content:center;font-size:14px}
.main-tabs>button{font-size:16px;min-height:54px}.main-tabs>button>span:first-child{font-size:12px}
.settings-panel details>summary{font-size:15px;letter-spacing:0}
.setting-label,.setting-label>output{font-size:13px}.setting-group select{font-size:15px;padding:9px;min-height:44px}
.mini-segment button{min-height:44px;font-size:13px;line-height:1.5;padding:5px 7px}
.interval-pick{min-height:44px;font-size:12px;line-height:1.4;padding:6px 3px;overflow-wrap:normal}
.interval-presets{gap:4px}.interval-presets button{font-size:12px;min-height:36px;padding:5px}
.setting-check{font-size:13px;min-height:44px;align-items:center}.setting-check input{width:18px;height:18px;flex-shrink:0;margin:0}
.setting-help,.storage-message{font-size:12px;line-height:1.85}.range{height:32px}
.section-label{font-size:12px;letter-spacing:1.3px}.badge{font-size:12px;white-space:normal;text-align:right}
.stage-title{font-size:23px}.stage-description{font-size:14px;line-height:1.85}
.play-main{font-size:17px;min-height:56px}.listening-hint{font-size:13px;text-align:center}
.reference-row .text-button{font-size:13px}.answer-heading{font-size:14px;align-items:flex-start}.answer-heading small{font-size:12px;text-align:right}
.answer-choice{font-size:15px;min-height:52px;padding:12px}.answer-choice small{font-size:12px;flex-shrink:0}
.candidate-play,.candidate-select{font-size:14px;min-height:44px;padding:8px 10px}.candidate-top{font-size:14px}
.primary-button{font-size:15px;min-height:46px}.secondary-button{font-size:14px;min-height:44px}
.feedback h3{font-size:17px}.feedback p{font-size:14px;line-height:1.85}.staff-caption{font-size:12px;gap:10px;flex-wrap:wrap}
.staff-svg{max-height:240px;min-height:140px}.step-button{font-size:13px;min-height:44px;padding:9px 10px;line-height:1.5;text-align:left}
.note-slot{min-width:55px;min-height:60px;font-size:17px}.note-slot small{font-size:11px}
.solfege-key{font-size:16px;min-height:64px}.solfege-key small{font-size:11px}
.input-mode-row{align-items:flex-start;flex-wrap:wrap}.input-mode-row>span{font-size:12px}.input-mode-row .mini-segment{max-width:210px}
.keyboard{height:148px}.piano-key{font-size:13px}.piano-key.black{font-size:12px}.piano-key small{font-size:11px}
.pitch-display small,.interval-bridge{font-size:13px}.interval-bridge{line-height:1.6}.explore-note{font-size:14px}.explore-reference{margin-top:22px}
.app-bottom{font-size:13px;padding:12px 24px}.stop-button{font-size:13px}
.practice-tip p,.practice-tip .text-button{font-size:13px}.practice-tip{align-items:flex-start}
footer{font-size:12px;line-height:1.85}.footer-links{font-size:13px;flex-wrap:wrap;justify-content:flex-end}.footer-links a{min-height:44px;display:inline-flex;align-items:center}.footer-links .text-button{padding:0;font-size:13px}
.copyright-note{max-width:580px}.footer-note{font-size:12px}
#dialog-body{font-size:15px;line-height:1.85}#dialog-body h3{font-size:16px}.dialog-head h2{font-size:21px}
.theme-option{font-size:14px}.theme-help{margin-top:17px!important}.stats-overview span{font-size:12px}.stat-line{font-size:13px;grid-template-columns:minmax(100px,1.4fr) 1fr 88px}.stat-line>small{font-size:12px}.subtle{font-size:13px}.toast{font-size:14px}
.source-strip{border-top:1px solid var(--line);padding:8px 24px;display:flex;align-items:center;flex-wrap:wrap;gap:2px 16px;color:var(--muted);font-size:12px;line-height:1.6}
.source-strip>span:first-child{color:var(--accent)}#source-build{font-variant-numeric:tabular-nums;letter-spacing:.3px}.source-strip .text-button{margin-left:auto;font-size:12px}
.source-notice{padding:14px 18px;border:1px solid var(--warm);background:var(--surface);border-radius:10px;margin-bottom:20px;font-size:14px}.source-notice a,.source-link{text-decoration:underline;text-underline-offset:4px}
.source-details{display:grid;grid-template-columns:auto minmax(0,1fr);gap:8px 16px;padding:15px 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}.source-details dt{color:var(--muted)}.source-details dd{margin:0;overflow-wrap:anywhere}.source-details code{font-size:14px}.copyright-card>strong{font-size:16px}
.practice-app{position:relative;isolation:isolate}
.practice-app::after{content:"";position:absolute;inset:0;z-index:3;pointer-events:none;opacity:.055;background-repeat:repeat;background-size:350px 210px;background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='350' height='210' viewBox='0 0 350 210'%3E%3Cg fill='%23263c31' font-family='Arial,sans-serif' text-anchor='middle' transform='rotate(-20 175 105)'%3E%3Ctext x='175' y='98' font-size='15'%3E%C2%A9 Geoffrey Chen %C2%B7 Hear the Melody%3C/text%3E%3Ctext x='175' y='118' font-size='11' letter-spacing='2'%3EHTM-GC-2026%3C/text%3E%3C/g%3E%3C/svg%3E")}
[data-theme="night"] .practice-app::after{filter:invert(1);opacity:.075}
html[lang="en"] .brand strong{font-size:22px;letter-spacing:-.4px}html[lang="en"] .brand-sub{font-size:9px;letter-spacing:1.7px}
html[lang="en"] h1{font-size:32px;letter-spacing:0;max-width:650px}html[lang="en"] .eyebrow{letter-spacing:1.7px}
html[lang="en"] .interval-picks{grid-template-columns:repeat(2,minmax(0,1fr))}
@media(max-width:980px) and (min-width:701px){html[lang="en"] .brand strong{font-size:21px}.intro-art{width:180px}.settings-panel{padding-left:14px;padding-right:14px}.main-tabs{gap:20px}.mini-segment button{padding:5px;font-size:12px}}
@media(max-width:700px){
  body{font-size:16px}.site-header{height:auto;min-height:88px;gap:10px}.brand{gap:8px}.brand strong{font-size:21px}.brand-sub{font-size:8px}.brand-icon{width:39px;height:39px;flex-shrink:0}.header-actions{gap:6px}.language-button{padding:8px;font-size:14px}.icon-button{width:40px;height:44px}.theme-trigger{width:32px;justify-content:center;padding:8px 0}
  .intro{padding:28px 0 24px;position:relative}.intro-art{position:absolute;right:0;top:33px;width:110px;opacity:.35;z-index:-1}.intro>div:first-child{min-width:0}.intro p{font-size:15px;max-width:100%;line-height:1.85}h1{font-size:29px}.eyebrow{font-size:12px}html[lang="en"] h1{font-size:30px}html[lang="en"] .brand strong{font-size:17px;letter-spacing:-.5px;white-space:nowrap}html[lang="en"] .brand-sub{font-size:7px;letter-spacing:1px}
  .progress-strip{gap:14px;padding:13px 14px}.progress-strip strong{font-size:23px}.progress-strip>div>span{font-size:12px}.progress-strip>.text-button{font-size:13px;line-height:1.4;max-width:90px;text-align:center;padding:4px}
  .main-tabs{padding:0 8px}.main-tabs>button{padding:17px 6px 14px;font-size:15px;white-space:normal;line-height:1.5;min-height:56px}.main-tabs>button>span:first-child{font-size:11px;margin-right:3px}
  .practice-main{padding:24px 18px}.stage-title{font-size:22px}.stage-description{font-size:15px}.stage-header{gap:8px}.section-label{font-size:11px}.badge{font-size:12px;max-width:48%}
  .answer-heading{font-size:14px;gap:12px}.answer-heading small{font-size:12px;max-width:43%}.answer-choice{font-size:16px;padding:12px 10px}.answer-choice small{font-size:12px}.choice-grid.three{grid-template-columns:1fr}.play-main{font-size:17px}.listening-hint{font-size:13px;line-height:1.7}.reference-row{gap:0 8px}.reference-row .text-button{font-size:14px;padding:6px}.primary-button{font-size:16px}.secondary-button{font-size:14px}.button-row>.text-button{font-size:14px}
  .settings-panel{padding:0 18px}.settings-panel details>summary{font-size:16px;min-height:56px}#settings-body{gap:0 16px}.setting-label,.setting-label>output{font-size:14px}.setting-group select{font-size:16px;min-height:46px}.mini-segment button{font-size:14px;min-height:46px}.interval-picks{grid-template-columns:repeat(4,minmax(0,1fr))}html[lang="en"] .interval-picks{grid-template-columns:repeat(3,minmax(0,1fr))}.interval-pick{font-size:13px;min-height:46px}.interval-presets button{font-size:13px;min-height:40px}.setting-help,.storage-message{font-size:13px}.setting-check{font-size:14px;line-height:1.6}.range{height:38px}
  .feedback{padding:15px}.feedback p{font-size:15px}.feedback h3{font-size:18px}.staff-svg{min-height:150px}.staff-caption{font-size:12px;padding:11px 12px 0}.step-button{font-size:13px;min-height:46px}.solfege-grid{gap:5px;grid-template-columns:repeat(4,minmax(0,1fr))}.solfege-key{font-size:17px;min-height:64px}.solfege-key small{font-size:12px}.note-slots{gap:7px}.note-slot{min-width:50px;min-height:60px;font-size:17px}.note-slot small{font-size:11px}.input-mode-row{gap:10px}.input-mode-row>span{font-size:13px}.input-mode-row .mini-segment{flex:auto;max-width:220px}.keyboard{min-width:360px;height:160px}
  .interval-display{gap:12px}.pitch-display{font-size:29px;min-width:58px}.interval-bridge{font-size:13px}.explore-note{font-size:15px}.explore-heading .mini-segment{width:180px}.explore-heading{flex-wrap:wrap;gap:10px}
  .app-bottom{font-size:13px;padding:10px 16px}.app-bottom>span{min-width:0}.stop-button{font-size:13px}.source-strip{padding:9px 16px;font-size:12px;gap:0 10px}.source-strip .text-button{font-size:12px;margin-left:0;padding:5px 0}
  .practice-tip{flex-wrap:wrap;gap:4px 10px;margin:20px 2px 27px}.practice-tip p{font-size:14px}.practice-tip .text-button{font-size:14px;margin-left:28px;min-height:44px}footer{font-size:13px;padding-top:21px;gap:12px}.footer-note{font-size:12px}.footer-links{gap:8px 24px;justify-content:flex-start;font-size:14px}.footer-links .text-button{font-size:14px}
  dialog{padding:22px 20px}.dialog-head h2{font-size:21px}#dialog-body{font-size:16px}#dialog-body h3{font-size:17px}.subtle{font-size:14px}.theme-option{font-size:15px;padding:12px 9px}.stats-overview{gap:7px}.stats-overview>div{padding:12px 6px}.stats-overview span{font-size:12px}.stat-line{grid-template-columns:minmax(95px,1.3fr) 1fr 83px;gap:7px;font-size:13px}.source-details{grid-template-columns:1fr;gap:2px}.source-details dd{margin-bottom:9px}.source-details code{font-size:15px}
}
@media(max-width:380px){.page-shell{padding:0 12px}.brand-icon{display:none}html[lang="en"] .brand strong{font-size:18px}.site-header{gap:6px}.header-actions{gap:4px}.progress-strip{gap:12px}.progress-strip>div>span{font-size:11px}.practice-main{padding:22px 15px}.main-tabs>button{font-size:14px;padding-left:4px;padding-right:4px}.main-tabs>button>span:first-child{display:none}#settings-body{grid-template-columns:1fr}.choice-grid{gap:8px}.answer-choice{font-size:15px}.interval-picks{grid-template-columns:repeat(3,minmax(0,1fr))}.stat-line{grid-template-columns:1fr 70px}.stat-track{display:none}}
@media print{.practice-app::after{opacity:.12}.header-actions,.practice-tip,.button-row,.reference-row,.settings-panel,.app-bottom{display:none}.workspace-grid{display:block}.practice-app{box-shadow:none}.source-strip{color:#263c31}body{background:white}}