:root{color-scheme:dark;--bg:#0e1016;--panel:#161a24;--line:#2a3042;--text:#eef1f8;--muted:#a3abc0;--accent:#4fc8f2;--on-accent:#0e1016}
@media (prefers-color-scheme:light){:root{color-scheme:light;--bg:#f6f7fb;--panel:#fff;--line:#d3dae8;--text:#141824;--muted:#5d6883;--accent:#0a72a3;--on-accent:#fff}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
a{color:var(--accent)}
a:hover{text-decoration:none}
a:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:4px}
header.site,footer.site,main{max-width:760px;margin:0 auto;padding-left:16px;padding-right:16px}
header.site{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px 16px;padding-top:14px;padding-bottom:14px;border-bottom:1px solid var(--line)}
.brand{font-weight:800;font-size:1.25rem;letter-spacing:.01em;color:var(--text);text-decoration:none}
.brand::before{content:"";display:inline-block;width:.7em;height:.7em;margin-right:.45em;border-radius:50%;background:var(--accent);box-shadow:0 0 12px color-mix(in srgb,var(--accent) 60%,transparent)}
header.site nav{display:flex;flex-wrap:wrap;gap:4px 16px}
header.site nav a{color:var(--muted);text-decoration:none;padding:4px 0}
header.site nav a:hover{color:var(--text)}
header.site nav a.open{color:var(--accent)}
main{padding-top:20px;padding-bottom:40px}
h1{font-size:1.9rem;line-height:1.2;margin:.3em 0 .2em}
h2{font-size:1.25rem;margin:1.8em 0 .5em}
h3{font-size:1rem;margin:1.2em 0 .3em;color:var(--muted);font-weight:600}
p{margin:.6em 0}
.crumbs{font-size:.875rem;color:var(--muted)}
.crumbs a{color:var(--muted)}
.kicker{margin:.8em 0 0;font-size:.875rem;color:var(--accent);font-weight:600}
.byline{margin:0;color:var(--muted);font-size:1.05rem}
.lead{font-size:1.1rem;margin:.9em 0}
.tagline{color:var(--accent);margin:0 0 .3em;font-weight:600}
.meta{color:var(--muted);font-size:.875rem}
.can{color:var(--muted);font-size:.95rem}
.cta-row{display:flex;flex-wrap:wrap;align-items:center;gap:10px 16px;margin:1.2em 0}
.cta{display:inline-block;background:var(--accent);color:var(--on-accent);font-weight:700;font-size:1.05rem;text-decoration:none;padding:13px 24px;border-radius:12px}
.cta:hover{filter:brightness(1.1)}
.facts{display:grid;gap:1px;margin:.6em 0;background:var(--line);border:1px solid var(--line);border-radius:12px;overflow:hidden}
.facts>div{display:grid;grid-template-columns:minmax(7.5rem,32%) 1fr;gap:12px;padding:9px 14px;background:var(--panel)}
.facts dt{color:var(--muted)}
.facts dd{margin:0}
.tips,.lessons,.units{padding-left:1.4em}
.tips li,.lessons li,.units li{margin:.6em 0;padding-left:.2em}
.list{list-style:none;padding:0;margin:.4em 0}
.list li{padding:8px 0;border-bottom:1px solid var(--line)}
.chips{display:flex;flex-wrap:wrap;gap:6px;list-style:none;padding:0;margin:.3em 0}
.chips li{background:var(--panel);border:1px solid var(--line);border-radius:999px;padding:3px 12px;font-size:.9rem}
.credit{margin-top:2em;padding:12px 14px;background:var(--panel);border:1px solid var(--line);border-radius:12px;color:var(--muted);font-size:.9rem}
.unit-nav{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:2.2em}
.unit-nav a{display:block;padding:12px 14px;background:var(--panel);border:1px solid var(--line);border-radius:12px;text-decoration:none;color:var(--text)}
.unit-nav .next{text-align:right}
footer.site{padding-top:20px;padding-bottom:36px;border-top:1px solid var(--line);color:var(--muted);font-size:.9rem}
footer.site a{color:var(--muted)}
@font-face{font-family:"Pianuvo Music";src:url(/seo/music-symbols.woff2) format("woff2");font-display:block;unicode-range:U+1D11E,U+1D122,U+1D13D-1D13F}
.article{margin-top:1em}
.article ul,.article ol{padding-left:1.4em}
.article li{margin:.35em 0}
.callout{margin:1.2em 0;padding:12px 16px;background:var(--panel);border:1px solid var(--line);border-left:4px solid var(--accent);border-radius:10px}
.callout p{margin:0}
.diagram{margin:1.4em 0;padding:14px 12px 10px;background:var(--panel);border:1px solid var(--line);border-radius:12px;text-align:center;overflow-x:auto}
.diagram svg{max-width:100%;height:auto;color:var(--text)}
.diagram figcaption{margin-top:8px;color:var(--muted);font-size:.9rem;text-align:left}
.kb-w{fill:#fbfbfd;stroke:#7a8296;stroke-width:1}
.kb-b{fill:#1b1e27;stroke:#1b1e27}
.kb-on{fill:var(--accent);stroke:#7a8296}
.kb-b.kb-on{stroke:var(--accent)}
.kb-t{font:600 12px system-ui,sans-serif;text-anchor:middle;fill:#3d4558}
.kb-t-on{fill:var(--on-accent)}
.kb-t-small{font-size:10px}
.kb-under{font:600 11px system-ui,sans-serif;text-anchor:middle;fill:var(--text)}
.m-line{stroke:currentColor;stroke-width:1;opacity:.75}
.m-ledger{stroke:currentColor;stroke-width:1;opacity:.9}
.m-bar{stroke:currentColor;stroke-width:1.2}
.m-stem{stroke:currentColor;stroke-width:1.3;fill:none}
.m-fill{fill:currentColor}
.m-hollow{fill:none;stroke:currentColor;stroke-width:1.7}
.m-acc{stroke:currentColor;stroke-width:1.3;fill:none}
.m-accb{stroke:currentColor;stroke-width:3}
.m-tie{stroke:currentColor;stroke-width:1.4;fill:none}
.m-glyph{font-family:"Pianuvo Music","Noto Music","Segoe UI Symbol","Apple Symbols",serif;fill:currentColor}
.m-clef,.m-rest{font-size:40px}
.m-time{font:700 21px/1 Georgia,"Times New Roman",serif;text-anchor:middle;dominant-baseline:central;fill:currentColor}
.m-label{font:12px system-ui,sans-serif;text-anchor:middle;fill:var(--muted)}
.m-dyn{font:italic 700 15px Georgia,"Times New Roman",serif;text-anchor:middle;fill:currentColor}
.dg-play{display:flex;width:fit-content;align-items:center;gap:6px;margin:8px auto 0;padding:6px 14px;border:1px solid var(--line);border-radius:999px;background:var(--bg);color:var(--accent);font:600 .9rem system-ui,sans-serif;cursor:pointer}
.dg-play::before{content:"";width:0;height:0;border-style:solid;border-width:5px 0 5px 9px;border-color:transparent transparent transparent currentColor}
.dg-play.on::before{width:9px;height:9px;border:0;background:currentColor}
.dg-play[hidden]{display:none}
.dg-play:hover{border-color:var(--accent)}
.dg-play:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.m-fill.dg-on{fill:#f5b83d}
.m-hollow.dg-on{stroke:#f5b83d;stroke-width:2.4}
.kb-w.dg-on,.kb-b.dg-on{fill:#f5b83d}
.ad{margin:1.8em 0;min-height:120px}
.ad-label{margin:0 0 4px;color:var(--muted);font-size:.75rem;text-transform:uppercase;letter-spacing:.06em}
.ad ins.adsbygoogle{display:block}
@media (max-width:520px){h1{font-size:1.55rem}.facts>div{grid-template-columns:1fr;gap:0}.unit-nav{grid-template-columns:1fr}.unit-nav .next{text-align:left}}