:root {
  --bg: #f6efe2;
  --bg2: #efe4cf;
  --panel: #fffaf0;
  --panel2: #f4ead6;
  --ink: #2a2118;
  --muted: #6e5c45;
  --rule: #d9c9a8;
  --gold: #a67c2e;
  --gold-soft: #c9a45c;
  --ember: #9b3d24;
  --sage: #48664c;
  --wine: #7b2d26;
  --good: #48664c;
  --bad: #7b2d26;
  --glow: #fbf6ea;
  --string: #c45c32;
  --wood: #8a6238;
  --shadow: 0 1px 2px rgba(60,45,20,.08), 0 10px 28px rgba(60,45,20,.07);
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, "EB Garamond", "Times New Roman", serif;
  --sans: ui-sans-serif, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color-scheme: light;
}
html[data-theme="dark"] {
  --bg: #16110c;
  --bg2: #120e0a;
  --panel: #221b14;
  --panel2: #2a2219;
  --ink: #f0e4d0;
  --muted: #b59a78;
  --rule: #3d3024;
  --gold: #d4a04a;
  --gold-soft: #c9a45c;
  --ember: #e07a4a;
  --sage: #8fbf95;
  --wine: #e08373;
  --good: #8fbf95;
  --bad: #e08373;
  --glow: #231c14;
  --string: #e08a55;
  --wood: #c4a06a;
  --shadow: 0 1px 2px rgba(0,0,0,.45), 0 12px 32px rgba(0,0,0,.4);
  color-scheme: dark;
}
* { box-sizing: border-box; }
html, body { margin: 0; height: 100%; }
html {
  background: var(--bg2);
  scrollbar-color: var(--gold-soft) var(--bg2);
  scrollbar-width: thin;
}
::-webkit-scrollbar { width: 12px; height: 12px; }
::-webkit-scrollbar-track { background: var(--bg2); }
::-webkit-scrollbar-thumb {
  background: var(--gold-soft);
  border-radius: 8px;
  border: 3px solid var(--bg2);
}
body {
  background:
    radial-gradient(1000px 480px at 50% -80px, var(--glow) 0%, transparent 58%),
    linear-gradient(180deg, var(--bg) 0%, var(--bg2) 100%);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 17.5px;
  line-height: 1.58;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
  height: 100dvh;
}
button, input, select { font-family: var(--sans); color: inherit; }
a { color: var(--gold); }
.app {
  display: grid;
  grid-template-columns: 272px 1fr;
  grid-template-rows: auto 1fr;
  grid-template-areas:
    "head head"
    "nav main";
  height: 100%;
  height: 100dvh;
  max-width: 100vw;
  overflow: hidden;
}
header {
  grid-area: head;
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 18px;
  padding-left: max(18px, env(safe-area-inset-left));
  padding-right: max(18px, env(safe-area-inset-right));
  background: var(--panel);
  border-bottom: 1px solid var(--rule);
  min-width: 0;
  z-index: 20;
}
header h1 {
  font-size: 19px;
  margin: 0;
  font-weight: 600;
  letter-spacing: .01em;
  min-width: 0;
  flex: 1 1 auto;
  line-height: 1.25;
}
header h1 small {
  font-weight: 400;
  color: var(--muted);
  font-size: 13px;
  font-family: var(--sans);
  margin-left: 8px;
}
.progress {
  font-family: var(--sans);
  font-size: 12px;
  color: var(--muted);
  padding: 4px 8px;
  border: 1px solid var(--rule);
  border-radius: 999px;
  white-space: nowrap;
  flex-shrink: 0;
}
.tbtn {
  background: var(--panel2);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 6px 11px;
  font-size: 13px;
  cursor: pointer;
  white-space: nowrap;
}
.tbtn:hover { border-color: var(--gold); }
.tbtn.icon { padding: 6px 9px; font-size: 15px; }
.tbtn.on, .tbtn[aria-pressed="true"] {
  background: color-mix(in srgb, var(--gold) 28%, var(--panel2));
  border-color: var(--gold);
}
#b-speak[aria-pressed="true"] {
  color: var(--ember);
}
#b-nav { display: none; flex-shrink: 0; }
nav {
  grid-area: nav;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  border-right: 1px solid var(--rule);
  background: var(--panel);
  padding: 10px 0 0;
  min-width: 0;
}
nav .find { margin: 4px 12px 10px; flex-shrink: 0; }
nav .find input {
  width: 100%;
  padding: 7px 10px;
  border-radius: 8px;
  border: 1px solid var(--rule);
  background: var(--bg);
  font-size: 13px;
}
#nav-list { flex: 1 1 auto; min-height: 0; overflow: auto; padding-bottom: 8px; }
nav h3 {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: .09em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 16px 14px 6px;
}
nav a {
  display: flex;
  gap: 8px;
  padding: 5px 14px;
  text-decoration: none;
  color: var(--ink);
  font-size: 14.5px;
  line-height: 1.35;
  cursor: pointer;
}
nav a:hover { background: var(--panel2); }
nav a.on { background: var(--panel2); box-shadow: inset 3px 0 0 var(--ember); }
nav a b {
  font-weight: 600;
  color: var(--muted);
  min-width: 22px;
  font-family: var(--sans);
  font-size: 12px;
  padding-top: 2px;
}
nav a.on b { color: var(--ember); }
nav a.done span::after {
  content: " ✓";
  color: var(--sage);
  font-size: 12px;
}
.snaps {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}
.snaps button {
  font-family: var(--sans);
  font-size: 12px;
  padding: 4px 9px;
  border-radius: 999px;
  border: 1px solid var(--rule);
  background: var(--panel2);
  cursor: pointer;
}
.snaps button:hover, .snaps button.on {
  border-color: var(--gold);
  color: var(--gold);
}
.colophon {
  flex-shrink: 0;
  padding: 12px 14px 14px;
  border-top: 1px solid var(--rule);
  font-family: var(--sans);
  font-size: 11px;
  line-height: 1.45;
  color: color-mix(in srgb, var(--muted) 70%, var(--ink));
}
.nav-backdrop { display: none; }
main {
  grid-area: main;
  overflow: auto;
  padding: 28px 36px 110px;
  scroll-behavior: smooth;
  min-width: 0;
}
.wrap { max-width: 780px; margin: 0 auto; min-width: 0; }
.kicker {
  font-family: var(--sans);
  font-size: 12px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ember);
  margin-bottom: 6px;
}
h2.lesson {
  font-size: 28px;
  font-weight: 600;
  margin: 0 0 18px;
  line-height: 1.25;
  letter-spacing: .01em;
}
.prose p { margin: 0 0 1em; }
.prose p:last-child { margin-bottom: 0; }
.prose em { font-style: italic; }
.prose strong { font-weight: 600; }
.latin {
  font-style: italic;
  color: color-mix(in srgb, var(--ink) 88%, var(--gold));
}
.cite {
  font-family: var(--sans);
  font-size: 12.5px;
  color: var(--muted);
  letter-spacing: .01em;
}
blockquote.note, .remark {
  background: var(--panel);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--gold);
  border-radius: 0 10px 10px 0;
  padding: 12px 16px;
  margin: 18px 0;
  box-shadow: var(--shadow);
}
.remark h4, .check h4, .lab h4 {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--gold);
  margin: 0 0 8px;
}
.dl {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 6px 16px;
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 12px 16px;
  margin: 16px 0 20px;
  font-size: 16px;
}
.dl dt { font-weight: 600; color: var(--ember); }
.dl dd { margin: 0; color: var(--ink); }
.widget, .lab {
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 14px 16px 16px;
  margin: 20px 0 24px;
  box-shadow: var(--shadow);
}
.widget .whead, .lab .whead {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}
.widget .whead span, .readout {
  font-family: var(--sans);
  font-size: 12.5px;
  color: var(--muted);
}
.playrow {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}
.pbtn {
  background: var(--panel2);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 7px 13px;
  font-size: 13px;
  cursor: pointer;
}
.pbtn:hover { border-color: var(--gold); color: var(--gold); }
.pbtn.primary {
  background: color-mix(in srgb, var(--ember) 86%, black);
  border-color: transparent;
  color: #fff8ee;
}
html[data-theme="dark"] .pbtn.primary {
  background: color-mix(in srgb, var(--ember) 70%, #3a2014);
  color: #fff6ea;
}
.mono-svg { width: 100%; height: auto; display: block; touch-action: none; }
.mono-svg .board { fill: color-mix(in srgb, var(--wood) 28%, var(--panel2)); stroke: var(--rule); }
.mono-svg .string { stroke: var(--string); stroke-linecap: round; }
.mono-svg .tick { stroke: var(--muted); }
.mono-svg .ticklab {
  fill: var(--muted);
  font-family: var(--sans);
  font-size: 11px;
}
.mono-svg .bridge { fill: var(--ember); cursor: ew-resize; }
.mono-svg .nut { fill: var(--wood); }
.ratio-row {
  display: flex;
  align-items: stretch;
  gap: 10px;
  margin: 8px 0 4px;
  min-height: 52px;
}
.bar {
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--sans);
  font-size: 12px;
  color: #fff8ee;
  min-width: 28px;
}
.bar.a { background: color-mix(in srgb, var(--ember) 80%, #4a2418); }
.bar.b { background: color-mix(in srgb, var(--gold) 80%, #5a4010); }
.tetractys {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  padding: 8px 0 4px;
  font-family: var(--sans);
}
.tetractys .row { display: flex; gap: 14px; }
.dot {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--gold) 25%, transparent);
}
.check {
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: 12px;
  padding: 16px 18px 18px;
  margin: 28px 0 12px;
}
.check .q { font-size: 18px; margin: 0 0 12px; }
.opts { display: flex; flex-direction: column; gap: 8px; }
.opt {
  text-align: left;
  background: var(--panel2);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 10px 12px;
  cursor: pointer;
  font-size: 15.5px;
  font-family: var(--serif);
  line-height: 1.4;
}
.opt:hover { border-color: var(--gold); }
.opt.sel { border-color: var(--gold); background: color-mix(in srgb, var(--gold) 16%, var(--panel2)); }
.opt.right { border-color: var(--good); background: color-mix(in srgb, var(--good) 16%, var(--panel2)); }
.opt.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 14%, var(--panel2)); }
.explain {
  margin-top: 12px;
  font-size: 15.5px;
  color: var(--ink);
  display: none;
}
.explain.show { display: block; }
.pager {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-top: 28px;
}
.pager button { min-width: 120px; }
.sound-banner {
  display: none;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: var(--panel2);
  border: 1px dashed var(--gold);
  border-radius: 10px;
  padding: 10px 14px;
  margin: 0 0 22px;
  font-family: var(--sans);
  font-size: 13.5px;
}
.sound-banner.show { display: flex; }
.toast {
  position: fixed;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  background: var(--ink);
  color: var(--bg);
  font-family: var(--sans);
  font-size: 13px;
  padding: 8px 14px;
  border-radius: 999px;
  opacity: 0;
  transition: opacity .2s;
  pointer-events: none;
  z-index: 80;
}
.toast.show { opacity: .94; }
kbd {
  font-family: var(--sans);
  font-size: 11px;
  border: 1px solid var(--rule);
  border-bottom-width: 2px;
  border-radius: 5px;
  padding: 1px 5px;
  background: var(--panel2);
  color: var(--muted);
}
.scale-keys {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 8px;
}
.key {
  flex: 1 1 52px;
  min-width: 52px;
  background: var(--panel2);
  border: 1px solid var(--rule);
  border-radius: 8px;
  padding: 10px 6px 8px;
  cursor: pointer;
  text-align: center;
}
.key:hover { border-color: var(--gold); }
.key .nm { display: block; font-family: var(--sans); font-size: 11px; color: var(--muted); }
.key .rt { display: block; font-size: 13px; margin-top: 2px; }
.widget.study { border-left: 3px solid var(--sage); }
.study-body .opts { margin-top: 12px; }
.study-body .opt.ruled {
  opacity: .58;
  text-decoration: line-through;
  text-decoration-color: color-mix(in srgb, var(--bad) 70%, transparent);
  text-decoration-thickness: 1px;
}
.study-said .explain { margin: 12px 0 0; }
.study-said .explain + .explain { border-top: 1px dashed var(--rule); padding-top: 10px; }
.study-body b.good { color: var(--good); }
.study-body b.bad { color: var(--bad); }
.tune-tab {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  border-radius: 10px;
  overflow: hidden;
  margin-top: 6px;
}
.tune-tab .trow {
  display: grid;
  grid-template-columns: 1fr 8.5em auto;
  align-items: center;
  gap: 10px;
  padding: 9px 12px;
  background: var(--panel2);
  font-size: 15px;
}
.tune-tab.wide .trow { grid-template-columns: 1fr 6.5em 6.5em auto; }
.tune-tab .trow.th {
  background: color-mix(in srgb, var(--gold) 14%, var(--panel2));
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
}
.tune-tab .trow small {
  display: block;
  font-family: var(--sans);
  font-size: 11.5px;
  color: var(--muted);
}
.tune-tab .num {
  font-family: var(--sans);
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}
.tune-tab .tbtns { display: flex; gap: 6px; flex-wrap: wrap; justify-content: flex-end; }
.tune-tab .tbtns .pbtn { padding: 5px 10px; font-size: 12px; }
.prose h4.sec {
  font-family: var(--sans);
  font-size: 12px;
  letter-spacing: .09em;
  text-transform: uppercase;
  color: var(--ember);
  margin: 30px 0 10px;
  padding-top: 14px;
  border-top: 1px solid var(--rule);
  font-weight: 600;
}
.prose h4.sec:first-child { margin-top: 4px; border-top: 0; padding-top: 0; }
blockquote.note p:first-child { margin-top: 0; }
blockquote.note p:last-child { margin-bottom: 0; }
code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: .88em;
  background: var(--panel2);
  border: 1px solid var(--rule);
  border-radius: 5px;
  padding: 1px 5px;
}
.xref {
  color: var(--gold);
  border-bottom: 1px dotted var(--gold-soft);
  cursor: pointer;
  white-space: nowrap;
}
.xref:hover { color: var(--ember); border-bottom-color: var(--ember); }
.gps {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
  border-radius: 10px;
  overflow: hidden;
  margin-top: 6px;
}
.gps-row {
  display: grid;
  grid-template-columns: 1fr 5.5em 6em;
  gap: 10px;
  align-items: center;
  text-align: left;
  background: var(--panel2);
  border: 0;
  padding: 7px 12px;
  font-family: var(--serif);
  font-size: 15px;
  cursor: pointer;
}
.gps-row:hover { background: color-mix(in srgb, var(--gold) 16%, var(--panel2)); }
.gps-row.fixed .gname { font-weight: 600; color: var(--ember); }
.gps-row .gstep, .gps-row .grat {
  font-family: var(--sans);
  font-size: 12px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}
.gps-row .grat { text-align: right; }
.dots { display: flex; gap: 5px; margin: 0 0 14px; flex-wrap: wrap; }
.dots i {
  width: 9px; height: 9px; border-radius: 50%;
  background: var(--rule);
  display: block;
}
.dots i.dot-ok { background: var(--good); }
.dots i.dot-no { background: var(--bad); }
.dots i.dot-now { background: var(--gold); box-shadow: 0 0 0 3px color-mix(in srgb, var(--gold) 25%, transparent); }
.drill-body .q { font-size: 18px; margin: 0 0 12px; line-height: 1.45; }
.drill-body .opts { margin-top: 12px; }
.drill-body .opt:disabled { cursor: default; }
.drill-input { display: flex; gap: 8px; margin-top: 12px; flex-wrap: wrap; }
.drill-input input {
  flex: 1 1 180px;
  min-width: 140px;
  padding: 9px 12px;
  border-radius: 10px;
  border: 1px solid var(--rule);
  background: var(--bg);
  font-size: 16px;
  font-family: var(--sans);
}
.drill-input input:focus { outline: none; border-color: var(--gold); }
.drill-input input.right { border-color: var(--good); background: color-mix(in srgb, var(--good) 14%, var(--bg)); }
.drill-input input.wrong { border-color: var(--bad); background: color-mix(in srgb, var(--bad) 12%, var(--bg)); }
.drill-body .explain { margin-top: 14px; }
.drill-body b.good { color: var(--good); }
.drill-body b.bad { color: var(--bad); }
.mark {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: .04em;
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 2px 8px;
  margin-left: 8px;
  white-space: nowrap;
}
.mark.good { border-color: var(--good); color: var(--good); }
.why-block {
  background: var(--panel);
  border: 1px solid var(--rule);
  border-left: 3px solid var(--ember);
  border-radius: 0 10px 10px 0;
  padding: 14px 18px;
  margin: 18px 0 22px;
  box-shadow: var(--shadow);
}
.why-block h4 {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ember);
  margin: 0 0 8px;
}
.why-block p:last-child { margin-bottom: 0; }
.era {
  display: grid;
  grid-template-columns: 7.5em 1fr;
  gap: 4px 14px;
  background: var(--panel);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 12px 16px;
  margin: 16px 0 20px;
  font-size: 15.5px;
}
.era b {
  font-family: var(--sans);
  font-size: 12.5px;
  color: var(--ember);
  font-weight: 600;
  padding-top: 3px;
}
.sources {
  font-family: var(--sans);
  font-size: 12.5px;
  color: var(--muted);
  margin-top: 22px;
  line-height: 1.5;
}
.tbtn:disabled { opacity: .4; cursor: default; }
@media (max-width: 860px) {
  .app {
    grid-template-columns: 1fr;
    grid-template-areas:
      "head"
      "main";
  }
  header h1 small { display: none; }
  nav {
    grid-area: auto;
    position: fixed;
    inset: 0 auto 0 0;
    width: min(320px, 88vw);
    transform: translateX(-105%);
    transition: transform .22s ease;
    z-index: 40;
    box-shadow: var(--shadow);
  }
  nav.open { transform: none; }
  #b-nav { display: inline-flex; }
  .nav-backdrop {
    display: block;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,.4);
    opacity: 0;
    pointer-events: none;
    z-index: 30;
  }
  .nav-backdrop.show { opacity: 1; pointer-events: auto; }
  main { padding: 20px 16px 100px; }
  h2.lesson { font-size: 24px; }
}
@media (max-width: 640px) {
  .tune-tab .trow,
  .tune-tab.wide .trow { grid-template-columns: 1fr; gap: 6px; }
  .tune-tab .trow.th { display: none; }
  .tune-tab .tbtns { justify-content: flex-start; }
  .era { grid-template-columns: 1fr; }
  .era b { padding-top: 8px; }
  .gps-row { grid-template-columns: 1fr auto; }
  .gps-row .gstep { display: none; }
}