:root{
  --bg:#f6f2ea;
  --paper:#fffdf8;
  --ink:#1e2433;
  --muted:#6f7789;
  --line:#e5ded1;
  --accent:#4f46e5;
  --accent-soft:#eef0ff;
  --warm:#b45309;
  --good:#0f766e;
  --shadow:0 18px 40px rgba(30,36,51,.08);
  --radius:18px;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;color:var(--ink);background:
    radial-gradient(900px 460px at 10% -10%, #fffaf0 0%, transparent 60%),
    radial-gradient(700px 420px at 95% 0%, #eef0ff 0%, transparent 55%),
    var(--bg);
  font:16px/1.65 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"PingFang SC","Microsoft YaHei",sans-serif;
  -webkit-font-smoothing:antialiased;
}
img,svg{max-width:100%}
a{color:var(--accent);text-underline-offset:3px}
a:hover{text-decoration-thickness:2px}
.wrap{width:min(1120px,calc(100% - 40px));margin-inline:auto}
.skip-link{
  position:absolute;left:12px;top:-60px;z-index:50;background:var(--ink);color:#fff;
  padding:10px 14px;border-radius:8px;text-decoration:none;
}
.skip-link:focus{top:12px}
.site-header{
  position:sticky;top:0;z-index:20;background:rgba(246,242,234,.9);
  backdrop-filter:blur(14px);border-bottom:1px solid rgba(229,222,209,.7);
}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:18px;min-height:64px}
.brand{display:inline-flex;align-items:center;gap:8px;color:var(--ink);font-weight:750;text-decoration:none;letter-spacing:-.01em}
.brand-mark{font-family:Georgia,serif;font-size:24px;color:var(--accent);line-height:1}
.site-nav{display:flex;align-items:center;gap:18px;font-size:13px;flex-wrap:wrap}
.site-nav a{color:var(--muted);text-decoration:none;font-weight:650}
.site-nav a:hover{color:var(--ink)}
.lang-switch{display:inline-flex;gap:6px;padding-left:14px;border-left:1px solid var(--line)}
.lang-switch a{padding:3px 6px;border-radius:7px}
.lang-switch a.active{background:var(--accent-soft);color:var(--accent)}
.hero{padding:44px 0 20px}
.breadcrumb{font-size:12px;color:var(--muted);margin-bottom:22px}
.breadcrumb ol{display:flex;gap:8px;list-style:none;margin:0;padding:0;flex-wrap:wrap}
.breadcrumb li+li::before{content:"/";margin-right:8px;color:#b8b0a1}
.breadcrumb a{color:var(--muted)}
.eyebrow{font:700 11px/1 var(--mono);letter-spacing:.14em;text-transform:uppercase;color:var(--accent);margin:0 0 10px}
h1,h2,h3{letter-spacing:-.02em}
h1{font-family:Georgia,"Times New Roman",serif;font-size:clamp(36px,5vw,58px);line-height:1.05;margin:0 0 14px;font-weight:700}
h2{font-family:Georgia,"Times New Roman",serif;font-size:clamp(24px,3vw,34px);line-height:1.15;margin:0 0 14px}
h3{font-size:15px;margin:0 0 6px}
.lede{font-size:clamp(17px,2vw,20px);line-height:1.55;color:#3d4558;max-width:760px;margin:0 0 14px}
.byline{font-size:12px;color:var(--muted);margin:0}
.section{padding:36px 0;border-top:1px solid rgba(229,222,209,.8)}
.section-head{max-width:780px;margin-bottom:16px}
.section-intro{color:var(--muted);margin:0}
.prose{max-width:820px}
.prose p{color:#3d4558;margin:0 0 12px}
.tool-section{padding:26px 0 34px}
.tool-grid{display:grid;grid-template-columns:1.35fr .65fr;gap:16px;align-items:start}
.tool-card,.notes-card{
  background:var(--paper);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);
}
.tool-card{padding:16px 16px 8px}
.tool-controls{display:flex;flex-wrap:wrap;gap:10px;align-items:end;padding-bottom:12px;border-bottom:1px solid var(--line)}
.field{display:grid;gap:4px}
.field span{font-size:10px;font-weight:750;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
select{
  appearance:none;background:#fff;border:1px solid var(--line);border-radius:10px;
  padding:9px 32px 9px 11px;font:650 13px/1.2 inherit;color:var(--ink);
  background-image:linear-gradient(45deg,transparent 50%,var(--muted) 50%),linear-gradient(135deg,var(--muted) 50%,transparent 50%);
  background-position:calc(100% - 15px) 50%,calc(100% - 10px) 50%;
  background-size:5px 5px,5px 5px;background-repeat:no-repeat;min-width:118px;min-height:40px;
}
.switch{display:flex;align-items:center;gap:7px;font-size:12px;color:var(--muted);padding:9px 0}
.switch input{width:17px;height:17px;accent-color:var(--accent)}
.btn{
  appearance:none;border:1px solid var(--line);background:#fff;color:var(--ink);
  padding:9px 13px;border-radius:10px;font:700 12px/1 inherit;cursor:pointer;min-height:40px;
}
.btn.primary{background:var(--accent);border-color:var(--accent);color:#fff}
.btn:hover{transform:translateY(-1px)}
.sound-status{
  display:inline-flex;align-items:center;justify-content:center;
  font:700 10px/1 var(--mono);letter-spacing:.04em;color:var(--accent);
  background:var(--accent-soft);border-radius:999px;padding:7px 9px;min-height:28px;white-space:nowrap;
}
.sound-status.loading{color:var(--warm);background:#fdf3e2}
.sound-status.fallback{color:var(--muted);background:#f0ede6}
.staff-head{display:flex;justify-content:space-between;align-items:baseline;gap:12px;padding:12px 4px 2px}
.scale-name{font-family:Georgia,serif;font-size:19px}
.range{font:650 11px/1 var(--mono);color:var(--muted)}
#staffMount{padding-bottom:4px}
#staffMount svg{width:100%;height:auto;display:block}
.staff-line{stroke:#c9c2b4;stroke-width:1.4}
.ledger{stroke:#b9b2a4;stroke-width:1.2}
.clef{font-family:Georgia,serif;font-size:112px;fill:#2b3244}
.staff-cap{font-family:var(--mono);font-size:11px;fill:#8b8577;letter-spacing:.08em}
.accidental{font-family:Georgia,serif;font-size:18px;font-weight:700;fill:var(--accent)}
.notehead{fill:#202636}
.stem{stroke:#202636;stroke-width:1.8}
.note-label{text-anchor:middle;font-family:var(--mono);font-size:12px;fill:var(--muted)}
.notes-card{padding:16px}
.notes-card h3{font-size:14px}
.hint{font-size:12px;color:var(--muted);margin:0 0 12px}
.note-list{display:grid;gap:6px}
.note-row{
  display:grid;grid-template-columns:34px 1fr auto;gap:10px;align-items:center;
  border:1px solid var(--line);border-radius:12px;padding:8px 10px;background:#fff;
  cursor:pointer;min-height:42px;font:inherit;color:inherit;text-align:left;width:100%;
}
.note-row:hover{border-color:#c7cbea;background:var(--accent-soft)}
.note-row .nn{font-family:Georgia,serif;font-weight:700;font-size:16px}
.note-row .ns{font-size:12px;color:var(--muted)}
.note-row .nf{font:700 11px/1 var(--mono);color:var(--accent);background:var(--accent-soft);padding:5px 7px;border-radius:999px}
.noscript{font-size:12px;color:var(--warm);margin:10px 0 0}
.practice-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.step{background:var(--paper);border:1px solid var(--line);border-radius:14px;padding:16px}
.step-num{font:700 11px/1 var(--mono);color:var(--accent);letter-spacing:.08em}
.step h3{margin-top:8px;font-size:15px}
.step p{margin:0;color:var(--muted);font-size:14px}
.mistakes{padding-left:20px;color:#3d4558}
.mistakes li{margin:8px 0}
.refs{padding-left:20px;color:#3d4558;font-size:14px}
.refs li{margin:7px 0}
.refs a{color:var(--accent)}
.faq-list{display:grid;gap:8px;max-width:920px}
.faq-item{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:0}
.faq-item summary{cursor:pointer;padding:14px 16px;font-weight:650;list-style:none}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"+";float:right;color:var(--accent);font-weight:700}
.faq-item[open] summary::after{content:"−"}
.faq-item p{margin:0;padding:0 16px 16px;color:var(--muted);font-size:14px}
.table-wrap{overflow:auto;border:1px solid var(--line);border-radius:14px;background:var(--paper)}
.scale-table{width:100%;border-collapse:collapse;font-size:14px;min-width:720px}
.scale-table caption{text-align:left;padding:12px 14px;color:var(--muted);font-size:12px}
.scale-table th,.scale-table td{padding:10px 14px;border-bottom:1px solid var(--line);text-align:left;vertical-align:top}
.scale-table thead th{background:#fbf7ef;color:var(--muted);font-size:11px;text-transform:uppercase;letter-spacing:.06em}
.scale-table tbody th{font-weight:700;white-space:nowrap}
.scale-table tr:last-child td,.scale-table tr:last-child th{border-bottom:0}
.scale-notes{font-family:var(--mono);font-size:12px;color:#3d4558}
.site-footer{border-top:1px solid var(--line);padding:26px 0 42px;color:var(--muted);font-size:12px}
.footer-inner{display:grid;gap:6px}
.footer-note{max-width:760px;margin:0}
.footer-meta,.footer-links{margin:0}
.footer-links a{color:var(--muted)}

:focus-visible{outline:3px solid #a5b4fc;outline-offset:2px}
@media (max-width:960px){
  .tool-grid{grid-template-columns:1fr}
  .practice-grid{grid-template-columns:1fr}
  .header-inner{align-items:flex-start;padding:10px 0}
}
@media (max-width:620px){
  .wrap{width:calc(100% - 28px)}
  .site-nav{gap:10px}
  .lang-switch{padding-left:8px}
  .tool-card{padding:10px 8px 4px}
  .tool-controls{gap:8px}
  .field,.btn{flex:1 1 130px}
  .switch{flex:1 1 100%}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *{transition:none!important;animation:none!important}
}
@media print{
  body{background:#fff}
  .site-header,.site-footer,.tool-controls,.notes-card,.skip-link,.breadcrumb,.byline,.noscript{display:none!important}
  .section{border:0;padding:14px 0}
  .tool-card{box-shadow:none;border:0;padding:0}
  .staff-head{padding:0}
  #staffMount svg{max-height:260px}
  .practice-grid{grid-template-columns:1fr 1fr}
  .faq-item{break-inside:avoid}
}