:root{font-family:system-ui,"Segoe UI",Arial,sans-serif;color-scheme:dark}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);min-height:100vh;line-height:1.55}button,a{font:inherit}button{cursor:pointer}a{color:inherit}button:focus-visible,a:focus-visible{outline:3px solid var(--accent);outline-offset:3px}
@font-face{font-family:Bravura;src:url("assets/Bravura.woff2") format("woff2");font-weight:normal;font-style:normal;font-display:block}
body[data-theme="slate"]{--bg:#172333;--panel:#223247;--panel-alt:#1b293a;--text:#f6f1e8;--muted:#bfcbda;--line:#455870;--accent:#f3c775;--blue:#8ccfff;--coral:#ffad92;--key:#fffdfa;--key-ink:#18283b;--shadow:#0a111d66;color-scheme:dark}
body[data-theme="cream"]{--bg:#f5efe1;--panel:#fffaf0;--panel-alt:#eee3d2;--text:#2b2117;--muted:#6b5844;--line:#b8a58d;--accent:#a65324;--blue:#176c9b;--coral:#a14c3b;--key:#fffdfa;--key-ink:#2b2117;--shadow:#78614733;color-scheme:light}
body[data-theme="midnight"]{--bg:#090f1b;--panel:#151f30;--panel-alt:#0f1929;--text:#f7f9ff;--muted:#b5c3db;--line:#3f5573;--accent:#eac779;--blue:#8fc8ff;--coral:#ffb59b;--key:#fffdfa;--key-ink:#18283b;--shadow:#0008;color-scheme:dark}
.app-shell{max-width:1480px;margin:auto}.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:15px clamp(16px,3vw,40px);border-bottom:1px solid var(--line);background:var(--panel-alt)}.brand,.top-actions{display:flex;align-items:center;gap:12px}.brand-copy{display:grid;min-width:0}.brand-kicker{font-size:.72rem;color:var(--muted);letter-spacing:.1em}.brand-copy strong{font-size:1rem}.icon-button{width:42px;height:42px;display:grid;place-items:center;flex:0 0 42px;border:1px solid var(--line);border-radius:11px;background:var(--panel);color:var(--text);text-decoration:none;font-size:1.15rem}.icon-button:hover,.language-button:hover{border-color:var(--accent)}.language-button{padding:8px 13px;border:1px solid var(--line);border-radius:10px;background:var(--panel);text-decoration:none;font-weight:700}.theme-wrap{position:relative}.tone-wheel{width:20px;height:20px;border-radius:50%;background:conic-gradient(#ee614e,#f5b444,#d8e462,#58c390,#59abdf,#9b73d7,#ee614e);box-shadow:inset 0 0 0 2px #ffffff38}.theme-menu{position:absolute;top:calc(100% + 10px);inset-inline-end:0;width:180px;z-index:20;background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:7px;box-shadow:0 15px 35px var(--shadow)}.theme-menu[hidden]{display:none}.theme-menu button{width:100%;border:0;border-radius:8px;background:transparent;color:var(--text);padding:9px;text-align:start}.theme-menu button:hover,.theme-menu button[aria-pressed="true"]{background:var(--panel-alt)}
main{padding:24px clamp(14px,3vw,40px) 50px}.hero{display:flex;align-items:center;justify-content:space-between;gap:22px;padding:24px clamp(20px,4vw,42px);border:1px solid var(--line);border-radius:22px;background:radial-gradient(circle at 80% 20%,#80bbd626,transparent 40%),var(--panel);box-shadow:0 12px 32px var(--shadow)}.eyebrow{color:var(--accent);font-weight:900;font-size:.76rem;letter-spacing:.08em}.hero h1{font-size:clamp(2rem,4vw,3.6rem);line-height:1.1;margin:7px 0 12px}.hero p{max-width:760px;color:var(--muted);margin:0;font-size:1.05rem}.steps{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px;margin:20px 0}.step-button{display:flex;align-items:center;gap:12px;text-align:start;padding:13px 15px;border:1px solid var(--line);border-radius:13px;background:var(--panel);color:var(--text);font-weight:750}.step-button[aria-pressed="true"]{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent);background:var(--panel-alt)}.step-num{display:grid;place-items:center;flex:0 0 30px;width:30px;height:30px;border-radius:9px;background:var(--accent);color:#1d2330;font-weight:900}.lesson-grid{display:grid;grid-template-columns:minmax(0,1.35fr) minmax(320px,.85fr);gap:16px;align-items:start}.panel{border:1px solid var(--line);border-radius:18px;background:var(--panel);padding:20px;box-shadow:0 10px 28px var(--shadow)}.panel-heading{display:flex;justify-content:space-between;align-items:start;gap:14px}.panel h2{font-size:1.25rem;margin:3px 0 0}.lead{color:var(--muted);margin:11px 0 15px}.play-button{white-space:nowrap;padding:8px 12px;border:1px solid var(--accent);border-radius:10px;background:var(--accent);color:#1c2230;font-weight:850}.note-chips{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 15px}.note-chip{padding:7px 10px;border-radius:999px;border:1px solid var(--line);background:var(--panel-alt);font-weight:800;font-size:.86rem}.note-chip.left{color:var(--blue)}.note-chip.right{color:var(--coral)}.note-chip.center{color:var(--accent)}.keyboard-layout{display:grid;gap:14px}.keyboard-layout.split{grid-template-columns:repeat(2,minmax(0,1fr))}.hand-keyboard{min-width:0;border:1px solid var(--line);border-radius:13px;background:var(--panel-alt);padding:12px 12px 14px}.hand-label{display:flex;justify-content:space-between;gap:8px;font-size:.82rem;font-weight:850;margin-bottom:6px}.hand-label .left{color:var(--blue)}.hand-label .right{color:var(--coral)}.key-stack{position:relative}.keyboard{position:relative;display:flex;height:146px;direction:ltr;overflow:hidden;border:1px solid #738095;border-radius:8px;background:#1d2530}.white-key{flex:1;min-width:0;display:flex;align-items:end;justify-content:center;padding:4px 0 8px;border:0;border-inline-end:1px solid #97a0aa;border-radius:0 0 5px 5px;background:linear-gradient(#fff,var(--key));color:var(--key-ink);font-size:.72rem;font-weight:850;position:relative;z-index:1}.white-key:last-of-type{border-inline-end:0}.white-key.anchor{background:linear-gradient(#fff6de,#efca78)}.white-key.pinky-left{background:linear-gradient(#dff5ff,#96d6f4)}.white-key.pinky-right{background:linear-gradient(#ffeae3,#f8af9a)}.white-key:active,.white-key.playing{filter:brightness(.87)}.key-label{display:grid;justify-items:center;line-height:1.1}.key-label small{font-size:.63rem}.black-key{position:absolute;top:0;height:57%;width:7%;z-index:2;border:1px solid #05080d;border-radius:0 0 5px 5px;background:linear-gradient(90deg,#111b2b,#36465b 58%,#0d1522);box-shadow:1px 3px 4px #0006}.black-key:active,.black-key.playing{background:#73869e}.hand-caption{text-align:center;color:var(--muted);font-size:.78rem;margin-top:8px}.tip{margin:14px 0 0;color:var(--muted);font-size:.84rem}.panel-collapse-bar{display:flex;align-items:center;justify-content:space-between;gap:14px;cursor:pointer;user-select:none;border-radius:10px}.panel-collapse-bar:hover .collapse-icon{background:var(--accent);color:#1c2230}.panel-collapse-bar:focus-visible{outline:2px solid var(--accent);outline-offset:4px}.panel-collapse-title{display:block;min-width:0}.collapse-icon{flex:0 0 auto;display:grid;place-items:center;width:34px;height:34px;border-radius:999px;background:var(--panel-alt);border:1.5px solid var(--accent);color:var(--accent);font-size:1.05rem;font-weight:900;line-height:1}.panel.is-collapsed .panel-collapse-bar{margin:0}.panel.is-collapsed .panel-body{display:none}.staff-wrap{overflow-x:auto}.grand-staff{display:block;width:100%;min-width:360px;max-height:340px;border:1px solid var(--line);border-radius:12px;background:#f9f8f3}.staff-legend{display:flex;gap:10px;flex-wrap:wrap;margin-top:10px;font-size:.78rem}.staff-legend span{display:inline-flex;align-items:center;gap:5px}.legend-dot{width:10px;height:10px;border-radius:50%;display:inline-block}.legend-dot.left{background:#2580b5}.legend-dot.right{background:#c66e52}.legend-dot.center{background:#b4862a}
.landmark-panel{margin-top:16px}.landmark-panel .panel-body{display:flex;align-items:center;gap:30px}.landmark-panel h2{margin:4px 0 6px}.landmark-panel p{margin:0;color:var(--muted)}.landmark-keys{direction:ltr;position:relative;display:flex;flex:0 0 204px;height:105px;border-radius:7px;overflow:hidden;background:#fff}.mini-white{display:flex;align-items:end;justify-content:center;flex:1;padding-bottom:8px;border:1px solid #8d9bac;background:#fff;color:#263345;font-weight:900}.mini-white.c-key{background:#f0c776}.mini-black{position:absolute;top:0;height:63px;width:27px;background:#1a2534;border-radius:0 0 4px 4px}.mini-black.one{left:53px}.mini-black.two{left:120px}.interval-panel{margin-top:16px}.interval-options{display:flex;flex-wrap:wrap;gap:8px;margin:18px 0}.interval-options button{padding:8px 12px;border:1px solid var(--line);border-radius:9px;background:var(--panel-alt);color:var(--text);font-weight:800}.interval-options button[aria-pressed="true"]{border-color:var(--accent);background:var(--accent);color:#1c2230}.interval-display{display:grid;grid-template-columns:minmax(240px,.6fr) 1fr;align-items:center;gap:20px}.mini-staff svg{display:block;width:100%;max-height:190px;border:1px solid var(--line);border-radius:12px;background:#f9f8f3}.interval-copy h3{margin:0 0 7px;font-size:1.2rem}.interval-copy p{margin:0;color:var(--muted)}@media(max-width:980px){.lesson-grid{grid-template-columns:minmax(0,1fr)}.lesson-grid>.panel{min-width:0}.staff-panel{order:2}}
@media(max-width:700px){.keyboard-layout.split{grid-template-columns:1fr}.steps{grid-template-columns:1fr}.interval-display{grid-template-columns:1fr}.landmark-panel .panel-body{flex-direction:column;align-items:stretch}.landmark-keys{flex-basis:auto;width:204px}.panel{padding:16px}.topbar{padding:12px 14px}.brand-copy strong{font-size:.88rem}.language-button{font-size:.8rem;padding:7px 9px}}
@media(max-width:380px){.brand-kicker{display:none}.top-actions{gap:7px}.brand{gap:7px}}
.keyboard-layout{direction:ltr}
.hand-keyboard{direction:rtl}
.hand-label{direction:ltr}
.note-chips[hidden]{display:none}
.finger-role-row{display:grid;grid-template-columns:repeat(var(--finger-count),minmax(0,1fr));align-items:center;direction:ltr;min-height:42px;margin:7px 0 2px}
.finger-role{white-space:nowrap;justify-self:center;font-size:.78rem;padding:6px 8px}
.finger-role.at-start{justify-self:start}
.finger-role.at-end{justify-self:end}
.key-solfege{font-size:.72rem;font-weight:900;line-height:1.2}
.fifth-rule{margin:22px 0 12px;color:var(--text);font-weight:800}
.fifth-examples{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}
.fifth-example{min-width:0;padding:12px;border:1px solid var(--line);border-radius:13px;background:var(--panel-alt)}
.fifth-example strong{display:block;margin-bottom:9px;color:var(--accent)}
.fifth-example svg{display:block;width:100%;border-radius:9px;background:#f9f8f3}.comparison-tabs{display:flex;gap:8px;margin:22px 0 0}.comparison-tab{padding:8px 14px;border:1px solid var(--line);border-radius:9px;background:var(--panel-alt);color:var(--text);font-weight:800}.comparison-tab[aria-selected="true"]{border-color:var(--accent);background:var(--accent);color:#1c2230}.comparison-panel .fifth-rule{margin-top:14px}
@media(max-width:700px){.fifth-examples{grid-template-columns:1fr}}
.parity-block{margin-top:22px;padding:18px;border:1px solid var(--line);border-radius:15px;background:var(--panel-alt)}
.parity-block h3{margin:0 0 12px;font-size:1.12rem}
.parity-table{width:100%;border-collapse:separate;border-spacing:0 6px;table-layout:fixed}
.parity-table th{padding:10px 12px;text-align:start;color:var(--accent);font-size:.88rem}
.parity-table td{padding:10px 12px;background:var(--panel);border:1px solid var(--line);font-weight:750}
.parity-table td:first-child{border-radius:0 10px 10px 0}
.parity-table td:last-child{border-radius:10px 0 0 10px}
.interval-number{display:inline-grid;place-items:center;width:27px;height:27px;margin-inline-end:9px;border-radius:8px;background:var(--accent);color:#1d2330;font-weight:900}
.parity-table td:nth-child(2) .interval-number{background:var(--blue)}
.octave-note{margin:14px 0 0;padding:12px 14px;border-inline-start:3px solid var(--blue);background:var(--panel);border-radius:8px;line-height:1.55}
.triad-summary{margin-top:20px;padding-top:18px;border-top:1px solid var(--line)}
.triad-degrees{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}
.triad-degree{display:flex;align-items:center;gap:9px;padding:7px 12px;border:1px solid var(--line);border-radius:12px;background:var(--panel)}
.triad-degree b{font-size:1.3rem;color:var(--accent)}
.triad-degree small{font-size:.84rem;font-weight:750}
.triad-summary p{margin:8px 0 0;line-height:1.5}
.triad-fingers{color:var(--muted)}
@media(max-width:700px){.parity-block{padding:12px}.parity-table th,.parity-table td{padding:8px 6px;font-size:.82rem}.interval-number{width:24px;height:24px;margin-inline-end:5px}}
.interval-controls{display:flex;align-items:center;gap:12px;flex-wrap:wrap;margin:12px 0 4px}.interval-controls label{font-weight:800}.interval-controls select{min-width:130px;padding:9px 12px;border:1px solid var(--line);border-radius:10px;background:var(--panel-alt);color:var(--text);font:inherit;font-weight:750}.interval-controls select:focus-visible{outline:3px solid var(--accent);outline-offset:3px}
.major-panel{margin-top:16px}.major-panel h2{margin:3px 0 0}.major-choices{display:flex;gap:9px;flex-wrap:wrap;margin:16px 0}.major-choices button{display:flex;align-items:center;gap:10px;flex-wrap:wrap;padding:9px 14px;border:1px solid var(--line);border-radius:11px;background:var(--panel-alt);color:var(--text);font-weight:800}.major-choices button[aria-pressed="true"]{border-color:var(--accent);background:var(--accent);color:#1c2230}.major-choices button span{font-size:.86rem}.major-visual{display:grid;grid-template-columns:minmax(300px,1fr) minmax(230px,.85fr);gap:20px;align-items:center}.major-keyboard{direction:ltr;display:flex;position:relative;height:150px;overflow:hidden;border:1px solid #77869a;border-radius:10px;background:#fff}.major-white-key{flex:1;min-width:0;display:flex;flex-direction:column;align-items:center;justify-content:end;padding-bottom:10px;border-right:1px solid #9ca8b5;background:#fff;color:#243143;font-size:.9rem;line-height:1.1}.major-white-key:last-of-type{border-right:0}.major-white-key.degree-1{background:#f3cf83}.major-white-key.degree-3{background:#c4e6b4}.major-white-key.degree-5{background:#addbf3}.major-white-key small{font-size:.72rem;font-weight:900}.major-black-key{position:absolute;top:0;width:5.6%;height:58%;border-radius:0 0 5px 5px;background:linear-gradient(90deg,#111b2b,#36465b 58%,#0d1522);box-shadow:1px 3px 4px #0006;pointer-events:none}.major-copy h3{margin:0 0 10px;font-size:1.15rem}.major-copy p{margin:7px 0;color:var(--muted)}.major-copy p:last-child{color:var(--accent);font-weight:800}@media(max-width:700px){.major-visual{grid-template-columns:1fr}.major-keyboard{height:135px}}