/* Kaizen Desk. One stylesheet, no build step. */

@font-face { font-family: "Bricolage Grotesque"; src: url("../fonts/bricolage.woff2") format("woff2"); font-weight: 200 800; font-display: swap; }
@font-face { font-family: "Atkinson Hyperlegible"; src: url("../fonts/atkinson-400.woff2") format("woff2"); font-weight: 400; font-display: swap; }
@font-face { font-family: "Atkinson Hyperlegible"; src: url("../fonts/atkinson-400i.woff2") format("woff2"); font-weight: 400; font-style: italic; font-display: swap; }
@font-face { font-family: "Atkinson Hyperlegible"; src: url("../fonts/atkinson-700.woff2") format("woff2"); font-weight: 700; font-display: swap; }
@font-face { font-family: "IBM Plex Mono"; src: url("../fonts/plexmono-400.woff2") format("woff2"); font-weight: 400; font-display: swap; }
@font-face { font-family: "IBM Plex Mono"; src: url("../fonts/plexmono-500.woff2") format("woff2"); font-weight: 500; font-display: swap; }

:root {
  --page: #f1f4fa;
  --surface: #ffffff;
  --ink: #14213d;
  --ink-soft: #55627f;
  --line: #d5dcea;
  --grid: #e8ecf4;
  --sun: #ffc53d;
  --sun-deep: #b37400;
  --on-sun: #14213d;
  --class-a: #2f5bea;
  --class-b: #ee5446;
  --leaf: #0f8f66;
  --violet: #7a4fd6;
  --warn: #b24a00;
  --nav: #14213d;
  --nav-ink: #e9edf7;
  --nav-soft: #9aa7c7;
  --code-bg: #f6f8fc;

  --font-display: "Bricolage Grotesque", "Atkinson Hyperlegible", system-ui, sans-serif;
  --font-body: "Atkinson Hyperlegible", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;

  --nav-w: 264px;
  --measure: 68ch;
  --r-lg: 18px;
  --r-md: 12px;
  --r-sm: 8px;
  color-scheme: light;
}

:root[data-theme="dark"] {
  --page: #0d1530;
  --surface: #151f40;
  --ink: #eef2fb;
  --ink-soft: #a5b1ce;
  --line: #2c3963;
  --grid: #212c52;
  --sun: #ffc53d;
  --sun-deep: #ffd66e;
  --on-sun: #14213d;
  --class-a: #7391ff;
  --class-b: #ff7d70;
  --leaf: #3fcf9f;
  --violet: #ab8eff;
  --warn: #ffb169;
  --nav: #091026;
  --code-bg: #0f1834;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--page);
  color: var(--ink);
  font: 400 1.0625rem/1.6 var(--font-body);
}
h1, h2, h3 { font-family: var(--font-display); line-height: 1.08; letter-spacing: -0.02em; margin: 0; text-wrap: balance; }
h1 { font-size: clamp(2.5rem, 6.2vw, 4.4rem); font-weight: 750; }
h2 { font-size: clamp(1.55rem, 3vw, 2.1rem); font-weight: 700; }
h3 { font-size: 1.2rem; font-weight: 700; letter-spacing: -0.01em; }
p { margin: 0; }
a { color: inherit; text-decoration-thickness: 2px; text-underline-offset: 3px; text-decoration-color: var(--sun); }
a:hover { text-decoration-color: currentColor; }
code { font-family: var(--font-mono); font-size: 0.88em; background: var(--code-bg); border: 1px solid var(--line); border-radius: 5px; padding: 0.05em 0.35em; }
button { font: inherit; color: inherit; }
:focus-visible { outline: 3px solid var(--class-a); outline-offset: 2px; border-radius: 4px; }
h1[tabindex="-1"]:focus { outline: none; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

/* ------------------------------------------------------------------ shell */
.shell { display: grid; grid-template-columns: var(--nav-w) minmax(0, 1fr); min-height: 100vh; }
.nav {
  background: var(--nav);
  color: var(--nav-ink);
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  padding: 26px 18px 20px;
  display: flex;
  flex-direction: column;
  gap: 22px;
}
.brand { font: 750 1.55rem/1 var(--font-display); letter-spacing: -0.03em; text-decoration: none; display: inline-flex; align-items: center; gap: 10px; }
.brand-mark { width: 26px; height: 26px; border-radius: 50%; background: var(--sun); box-shadow: inset -7px -7px 0 rgba(20, 33, 61, 0.16); flex: none; }
.nav-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 2px; }
.nav-list a {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: baseline;
  gap: 8px;
  padding: 9px 12px;
  border-radius: var(--r-sm);
  text-decoration: none;
  color: var(--nav-ink);
  border-left: 4px solid transparent;
}
.nav-list a:hover { background: rgba(255, 255, 255, 0.07); }
.nav-list a[aria-current="page"] { background: rgba(255, 255, 255, 0.1); border-left-color: var(--sun); font-weight: 700; }
.nav-count { font-size: 0.82rem; color: var(--nav-soft); font-variant-numeric: tabular-nums; }
.nav-heading { font-size: 0.85rem; color: var(--nav-soft); padding: 0 12px 4px; }
.nav-foot { margin-top: auto; display: grid; gap: 8px; }
.nav-btn {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14);
  color: var(--nav-ink);
  border-radius: var(--r-sm);
  padding: 9px 12px;
  text-align: left;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  gap: 8px;
}
.nav-btn:hover { background: rgba(255, 255, 255, 0.14); }
.nav-btn kbd { font: 500 0.78rem var(--font-mono); color: var(--nav-soft); }
.nav :focus-visible { outline-color: var(--sun); }

.topbar { display: none; }
.main { min-width: 0; padding: clamp(20px, 4vw, 56px) clamp(16px, 4vw, 56px) 80px; }
.page { max-width: 1180px; margin: 0 auto; }
.prose { max-width: var(--measure); }

@media (max-width: 900px) {
  .shell { grid-template-columns: 1fr; }
  .topbar {
    display: flex; align-items: center; justify-content: space-between;
    background: var(--nav); color: var(--nav-ink); padding: 12px 16px; position: sticky; top: 0; z-index: 30;
  }
  .topbar .brand { font-size: 1.3rem; }
  .menu-btn { background: none; border: 1px solid rgba(255, 255, 255, 0.25); color: var(--nav-ink); border-radius: var(--r-sm); padding: 6px 12px; cursor: pointer; }
  .nav { position: fixed; inset: 0 auto 0 0; width: min(86vw, 320px); z-index: 40; transform: translateX(-102%); transition: transform 0.2s ease; }
  .nav.open { transform: none; box-shadow: 0 0 0 100vmax rgba(9, 16, 38, 0.55); }
  .nav > .brand { display: none; }
}

/* ------------------------------------------------------------------- home */
.hero { display: grid; gap: 26px; margin-bottom: 72px; }
.hero h1 { max-width: 13ch; }
.hero h1 .glow { background: linear-gradient(transparent 62%, var(--sun) 62%); }
.hero-lede { font-size: 1.25rem; max-width: 46ch; color: var(--ink-soft); }
.hero-lab-note { font: 700 1rem var(--font-display); display: flex; align-items: center; gap: 10px; }
.hero-lab-note::before { content: ""; width: 34px; height: 3px; background: var(--ink); border-radius: 2px; }

.tracks { list-style: none; padding: 0; margin: 24px 0 72px; border-top: 2px solid var(--ink); }
.tracks a {
  display: grid;
  grid-template-columns: minmax(8ch, 14ch) minmax(0, 1fr) auto;
  gap: 8px 28px;
  align-items: baseline;
  padding: 22px 6px;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}
.tracks a:hover { background: var(--surface); }
.tracks a:hover .track-name { text-decoration: underline; text-decoration-color: var(--sun); text-decoration-thickness: 5px; text-underline-offset: 5px; }
.track-name { font: 700 clamp(1.5rem, 3.4vw, 2.3rem)/1 var(--font-display); letter-spacing: -0.02em; }
.track-blurb { color: var(--ink-soft); }
.track-meta { font-variant-numeric: tabular-nums; white-space: nowrap; color: var(--ink-soft); }
@media (max-width: 640px) { .tracks a { grid-template-columns: 1fr auto; } .track-blurb { grid-column: 1 / -1; } }

.steps { counter-reset: step; list-style: none; padding: 0; margin: 24px 0 72px; display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 0; border-top: 2px solid var(--ink); }
.steps li { counter-increment: step; padding: 18px 18px 18px 0; }
.steps li::before { content: counter(step); font: 750 2.6rem/1 var(--font-display); color: var(--sun-deep); display: block; margin-bottom: 8px; }
.steps b { display: block; font-family: var(--font-display); font-size: 1.15rem; }
.steps span { color: var(--ink-soft); font-size: 0.98rem; }

.section-head { display: grid; gap: 8px; max-width: var(--measure); }
.section-head p { color: var(--ink-soft); }

/* ------------------------------------------------------------ track index */
.track-hero { display: grid; gap: 14px; margin-bottom: 44px; max-width: var(--measure); }
.track-hero p { font-size: 1.2rem; color: var(--ink-soft); }
.group { margin-bottom: 44px; }
.group-head { display: grid; gap: 4px; padding-bottom: 12px; border-bottom: 2px solid var(--ink); }
.group-head p { color: var(--ink-soft); }
.lesson-list { list-style: none; margin: 0; padding: 0; }
.lesson-list a {
  display: grid;
  grid-template-columns: 26px minmax(0, 22ch) minmax(0, 1fr) auto;
  gap: 6px 18px;
  align-items: baseline;
  padding: 15px 6px;
  border-bottom: 1px solid var(--line);
  text-decoration: none;
}
.lesson-list a:hover { background: var(--surface); }
.lesson-list .l-title { font: 700 1.15rem var(--font-display); }
.lesson-list .l-tag { color: var(--ink-soft); }
.tick { width: 20px; height: 20px; border-radius: 50%; border: 2px solid var(--line); align-self: center; position: relative; }
.tick.done { background: var(--leaf); border-color: var(--leaf); }
.tick.done::after { content: ""; position: absolute; left: 5px; top: 1px; width: 5px; height: 10px; border: solid #fff; border-width: 0 2.5px 2.5px 0; transform: rotate(45deg); }
.level { display: inline-flex; gap: 3px; align-items: center; }
.level i { width: 7px; height: 7px; border-radius: 50%; background: var(--line); }
.level i.on { background: var(--ink); }
@media (max-width: 720px) { .lesson-list a { grid-template-columns: 26px minmax(0, 1fr) auto; } .lesson-list .l-tag { grid-column: 2 / -1; } }

/* ----------------------------------------------------------------- lesson */
.crumb { color: var(--ink-soft); font-size: 0.95rem; margin-bottom: 14px; }
.crumb a { text-decoration: none; }
.crumb a:hover { text-decoration: underline; }
.lesson-head { display: grid; gap: 14px; margin-bottom: 34px; }
.lesson-head .tagline { font-size: 1.3rem; color: var(--ink-soft); max-width: 44ch; }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 8px 18px; align-items: center; color: var(--ink-soft); font-size: 0.95rem; }

.story {
  background: var(--sun);
  color: var(--on-sun);
  border-radius: var(--r-lg);
  padding: clamp(22px, 4vw, 40px);
  margin-bottom: 52px;
  display: grid;
  gap: 12px;
}
.story h2 { font-size: 1.05rem; letter-spacing: 0; font-weight: 700; }
.story p { font-size: clamp(1.15rem, 2.1vw, 1.42rem); line-height: 1.5; max-width: 60ch; }
.story code { background: rgba(255, 255, 255, 0.55); border-color: rgba(20, 33, 61, 0.2); color: var(--on-sun); }

.block { margin-bottom: 56px; display: grid; gap: 18px; }
.how { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; max-width: var(--measure); }
.how li { padding-left: 22px; position: relative; }
.how li::before { content: ""; position: absolute; left: 0; top: 0.62em; width: 10px; height: 10px; border-radius: 50%; background: var(--sun); border: 2px solid var(--ink); }

.try { border-left: 5px solid var(--class-a); padding: 4px 0 4px 20px; display: grid; gap: 8px; max-width: var(--measure); }
.try ol { margin: 0; padding-left: 1.3em; display: grid; gap: 8px; }
.try ol li::marker { font-weight: 700; font-family: var(--font-display); }

.surprise { background: var(--ink); color: var(--page); border-radius: var(--r-lg); padding: clamp(22px, 4vw, 40px); display: grid; gap: 14px; }
.surprise .kicker { font: 700 1rem var(--font-display); color: var(--sun); }
.surprise h2 { max-width: 24ch; }
.surprise p { max-width: 64ch; font-size: 1.1rem; }
:root[data-theme="dark"] .surprise { background: #060b1c; color: var(--ink); border: 1px solid var(--line); }

details.fold { border: 1px solid var(--line); border-radius: var(--r-lg); background: var(--surface); }
details.fold > summary { cursor: pointer; padding: 18px 22px; font: 700 1.3rem var(--font-display); list-style: none; display: flex; justify-content: space-between; align-items: center; gap: 12px; }
details.fold > summary::-webkit-details-marker { display: none; }
details.fold > summary::after { content: "+"; font: 400 1.8rem/1 var(--font-display); color: var(--ink-soft); }
details.fold[open] > summary::after { content: "\2212"; }
details.fold > summary small { font: 400 0.95rem var(--font-body); color: var(--ink-soft); display: block; margin-top: 2px; }
.fold-body { padding: 0 22px 22px; }

.formulas { list-style: none; margin: 0; padding: 0; }
.formulas li { display: grid; grid-template-columns: minmax(0, 15ch) minmax(0, 1fr); gap: 6px 24px; padding: 18px 0; border-top: 1px solid var(--line); align-items: start; }
.formulas .f-name { font: 700 1.02rem var(--font-display); }
.formulas .f-tex { overflow-x: auto; overflow-y: hidden; padding: 2px 0 6px; }
.formulas .f-plain { grid-column: 2; color: var(--ink-soft); max-width: 60ch; }
.katex-display { margin: 0 !important; text-align: left !important; }
.katex-display > .katex { text-align: left !important; }
@media (max-width: 640px) { .formulas li { grid-template-columns: 1fr; } .formulas .f-plain { grid-column: 1; } }

.use { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 12px 40px; }
.use ul { margin: 8px 0 0; padding-left: 1.1em; display: grid; gap: 5px; }
.use .good h3 { color: var(--leaf); }
.use .bad h3 { color: var(--warn); }

.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; border-top: 2px solid var(--ink); padding-top: 22px; }
.pager a { text-decoration: none; display: grid; gap: 2px; }
.pager a span { color: var(--ink-soft); font-size: 0.95rem; }
.pager a b { font: 700 1.3rem var(--font-display); }
.pager a:hover b { text-decoration: underline; text-decoration-color: var(--sun); text-decoration-thickness: 4px; }
.pager .next { text-align: right; }

/* -------------------------------------------------------------------- lab */
.lab {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  display: grid;
  grid-template-columns: 248px minmax(0, 1fr) 236px;
  grid-template-areas: "controls stage side" "footer footer footer";
  overflow: hidden;
}
.lab-controls { grid-area: controls; padding: 18px; display: grid; gap: 16px; align-content: start; border-right: 1px solid var(--line); }
.lab-stage { grid-area: stage; padding: 14px; min-width: 0; display: grid; gap: 8px; align-content: start; }
.lab-stage-stack { display: grid; gap: 8px; min-width: 0; }
.lab-side { grid-area: side; padding: 18px; display: grid; gap: 14px; align-content: start; border-left: 1px solid var(--line); min-width: 0; }
.lab-footer { grid-area: footer; padding: 14px 18px; border-top: 1px solid var(--line); }
@media (max-width: 1240px) {
  .lab { grid-template-columns: 248px minmax(0, 1fr); grid-template-areas: "controls stage" "side side"; }
  .lab-side { border-left: 0; border-top: 1px solid var(--line); grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
}
@media (max-width: 760px) {
  .lab { grid-template-columns: minmax(0, 1fr); grid-template-areas: "stage" "controls" "side"; }
  .lab-controls { border-right: 0; border-top: 1px solid var(--line); }
}
.plot-host { min-width: 0; position: relative; }
.plot { display: block; width: 100%; border-radius: var(--r-sm); }
.lab-loading { padding: 60px 20px; text-align: center; color: var(--ink-soft); }

.ctl { display: grid; gap: 6px; }
.ctl-head { display: flex; justify-content: space-between; gap: 10px; align-items: baseline; }
.ctl label, .ctl-label { font-size: 0.95rem; font-weight: 700; }
.ctl-value { font: 500 0.9rem var(--font-mono); color: var(--ink-soft); white-space: nowrap; }
.ctl-hint { font-size: 0.88rem; color: var(--ink-soft); line-height: 1.4; }
input[type="range"] { width: 100%; accent-color: var(--class-a); height: 22px; margin: 0; cursor: pointer; }
.seg { display: flex; flex-wrap: wrap; gap: 4px; }
.seg button {
  flex: 1 1 auto;
  border: 1px solid var(--line);
  background: var(--page);
  border-radius: 999px;
  padding: 5px 11px;
  font-size: 0.88rem;
  cursor: pointer;
  white-space: nowrap;
}
.seg button:hover { border-color: var(--ink); }
.seg button[aria-pressed="true"] { background: var(--ink); color: var(--surface); border-color: var(--ink); font-weight: 700; }
.btn {
  border: 2px solid var(--ink);
  background: var(--surface);
  border-radius: 999px;
  padding: 7px 16px;
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
}
.btn:hover { background: var(--sun); color: var(--on-sun); border-color: var(--on-sun); }
.btn.primary { background: var(--ink); color: var(--surface); }
.btn.primary:hover { background: var(--sun); color: var(--on-sun); }
.btn.quiet { border-color: var(--line); font-weight: 400; }
.btn[disabled] { opacity: 0.5; cursor: progress; }
.btn-row { display: flex; flex-wrap: wrap; gap: 8px; }

.stats { margin: 0; display: grid; gap: 14px; }
.stat { display: grid; gap: 1px; padding-left: 12px; border-left: 4px solid var(--line); }
.stat dt { font-size: 0.86rem; color: var(--ink-soft); line-height: 1.3; }
.stat dd { margin: 0; font: 700 1.5rem/1.15 var(--font-display); letter-spacing: -0.01em; font-variant-numeric: tabular-nums; overflow-wrap: anywhere; }
.stat.good { border-left-color: var(--leaf); }
.stat.warn { border-left-color: var(--class-b); }
.stat-note { font-size: 0.86rem; color: var(--ink-soft); line-height: 1.35; margin-top: 3px; }
.legend { font-size: 0.86rem; color: var(--ink-soft); display: flex; flex-wrap: wrap; gap: 4px 6px; align-items: center; line-height: 1.4; }
.legend-item { display: inline-flex; align-items: center; gap: 6px; white-space: nowrap; margin-right: 10px; }
.key { display: inline-block; width: 11px; height: 11px; border-radius: 50%; flex: none; }
.key.filled { background: var(--ink-soft); }
.key.hollow { border: 2px solid var(--ink-soft); }
.key.dash { width: 18px; height: 0; border-radius: 0; border-top: 2px dashed var(--ink-soft); }
.replay { display: grid; grid-template-columns: auto minmax(0, 1fr) auto; gap: 12px; align-items: center; padding-top: 4px; }
.replay-label { font: 500 0.88rem var(--font-mono); color: var(--ink-soft); min-width: 9ch; text-align: right; }

.statements { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.statements table { width: 100%; border-collapse: collapse; font-size: 0.93rem; }
.statements caption { text-align: left; font: 700 0.98rem var(--font-display); padding-bottom: 6px; line-height: 1.25; }
.statements th { text-align: left; font-weight: 400; padding: 5px 8px 5px 0; }
.statements td { text-align: right; font-variant-numeric: tabular-nums; padding: 5px 0; white-space: nowrap; }
.statements tr { border-top: 1px solid var(--line); }
.statements tr.total th, .statements tr.total td { font-weight: 700; border-top: 2px solid var(--ink); }

/* ------------------------------------------------------------------- code */
.runner { border: 1px solid var(--line); border-radius: var(--r-md); background: var(--surface); overflow: hidden; }
.runner-bar { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; padding: 10px 12px; border-top: 1px solid var(--line); }
.runner-bar .spacer { flex: 1; }
.runner-status { font-size: 0.9rem; color: var(--ink-soft); }
.editor {
  display: block; width: 100%; border: 0; resize: vertical; min-height: 3.2em;
  background: var(--code-bg); color: var(--ink);
  font: 400 0.92rem/1.55 var(--font-mono);
  padding: 14px 16px; tab-size: 2; white-space: pre; overflow: auto;
}
.editor:focus-visible { outline-offset: -3px; border-radius: 0; }
.output { margin: 0; padding: 14px 16px; border-top: 1px solid var(--line); font: 400 0.9rem/1.5 var(--font-mono); white-space: pre; overflow: auto; max-height: 340px; }
.output.error { color: var(--class-b); white-space: pre-wrap; }
.output:empty { display: none; }
.result-table { border-collapse: collapse; font: 400 0.88rem/1.4 var(--font-mono); }
.result-table th, .result-table td { text-align: left; padding: 3px 18px 3px 0; white-space: nowrap; }
.result-table th { border-bottom: 2px solid var(--ink); font-weight: 500; }
.result-table td { border-bottom: 1px solid var(--grid); }
.result-table td.null { color: var(--ink-soft); font-style: italic; }
.verdict { padding: 10px 16px; border-top: 1px solid var(--line); font-weight: 700; }
.verdict.pass { background: color-mix(in srgb, var(--leaf) 16%, var(--surface)); }
.verdict.fail { background: color-mix(in srgb, var(--class-b) 12%, var(--surface)); font-weight: 400; }

.lang-tabs { display: flex; gap: 4px; }
.lang-tabs button { border: 0; background: none; padding: 8px 14px; border-bottom: 4px solid transparent; cursor: pointer; font: 700 1.05rem var(--font-display); color: var(--ink-soft); }
.lang-tabs button[aria-selected="true"] { color: var(--ink); border-bottom-color: var(--sun); }
.note { font-size: 0.95rem; color: var(--ink-soft); max-width: var(--measure); }

.points { margin: 0; padding-left: 1.2em; display: grid; gap: 8px; max-width: var(--measure); }
.task { display: grid; gap: 12px; padding-top: 22px; border-top: 2px solid var(--ink); }
.task-head { display: flex; gap: 12px; align-items: baseline; }
.task-head h3 { white-space: nowrap; }
.task-prompt { max-width: var(--measure); }
.schema { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 18px; }
.schema h3 { font-family: var(--font-mono); font-size: 1rem; letter-spacing: 0; }
.schema ul { list-style: none; padding: 0; margin: 6px 0 0; font: 400 0.88rem/1.6 var(--font-mono); }
.schema p { font-size: 0.9rem; color: var(--ink-soft); }

/* ------------------------------------------------------------------- quiz */
.quiz { display: grid; gap: 26px; max-width: var(--measure); }
.quiz fieldset { border: 0; margin: 0; padding: 0; display: grid; gap: 8px; }
.quiz legend { font: 700 1.1rem/1.3 var(--font-display); padding: 0; margin-bottom: 8px; }
.opt { text-align: left; border: 2px solid var(--line); background: var(--surface); border-radius: var(--r-md); padding: 10px 14px; cursor: pointer; }
.opt:hover:not([disabled]) { border-color: var(--ink); }
.opt[disabled] { cursor: default; }
.opt.right { border-color: var(--leaf); background: color-mix(in srgb, var(--leaf) 14%, var(--surface)); font-weight: 700; }
.opt.wrong { border-color: var(--class-b); background: color-mix(in srgb, var(--class-b) 10%, var(--surface)); }
.why { color: var(--ink-soft); padding-left: 14px; border-left: 4px solid var(--sun); }
.done-banner { background: color-mix(in srgb, var(--leaf) 16%, var(--surface)); border: 2px solid var(--leaf); border-radius: var(--r-md); padding: 12px 16px; font-weight: 700; }

/* --------------------------------------------------------------- glossary */
.search-field { width: 100%; font: 400 1.3rem var(--font-body); padding: 14px 4px; border: 0; border-bottom: 3px solid var(--ink); background: none; color: var(--ink); }
.search-field::placeholder { color: var(--ink-soft); }
.search-field:focus-visible { outline: none; border-bottom-color: var(--class-a); }
.gloss { margin: 28px 0 0; display: grid; grid-template-columns: repeat(auto-fill, minmax(min(100%, 420px), 1fr)); gap: 0 44px; }
.gloss > div { padding: 14px 0; border-bottom: 1px solid var(--line); }
.gloss dt { font: 700 1.12rem var(--font-display); display: flex; flex-wrap: wrap; justify-content: space-between; gap: 2px 12px; align-items: baseline; }
.gloss dt a { font: 400 0.88rem var(--font-body); color: var(--ink-soft); white-space: nowrap; }
.gloss dd { margin: 3px 0 0; color: var(--ink-soft); }
.empty { padding: 30px 0; color: var(--ink-soft); }

dialog.search { border: 0; border-radius: var(--r-lg); padding: 0; width: min(640px, 92vw); background: var(--surface); color: var(--ink); box-shadow: 0 30px 80px rgba(9, 16, 38, 0.4); margin-top: 12vh; }
dialog.search::backdrop { background: rgba(9, 16, 38, 0.55); }
dialog.search .search-field { padding: 18px 22px; font-size: 1.15rem; }
.hits { list-style: none; margin: 0; padding: 6px; max-height: 52vh; overflow: auto; }
.hits a { display: grid; grid-template-columns: 1fr auto; gap: 12px; padding: 10px 16px; border-radius: var(--r-sm); text-decoration: none; }
.hits a:hover, .hits a.active { background: var(--page); }
.hits span { color: var(--ink-soft); font-size: 0.9rem; }

.footer { margin-top: 80px; padding-top: 22px; border-top: 1px solid var(--line); color: var(--ink-soft); font-size: 0.95rem; display: flex; flex-wrap: wrap; gap: 6px 22px; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .nav { transition: none; }
}
@media print {
  .nav, .topbar, .pager, .runner-bar { display: none; }
  .shell { display: block; }
}

/* ------------------------------------------------------------ explanations */
.tip {
  position: fixed; z-index: 100; max-width: min(340px, calc(100vw - 16px));
  background: var(--ink); color: var(--surface);
  padding: 10px 13px; border-radius: var(--r-sm);
  font: 400 0.92rem/1.45 var(--font-body);
  box-shadow: 0 10px 30px rgba(9, 16, 38, 0.35);
  pointer-events: none;
}
:root[data-theme="dark"] .tip { background: #f3f5fb; color: #14213d; }
.ctl [data-tip]:not(button), .stat dt[data-tip] > span, .term {
  text-decoration: underline dotted var(--ink-soft) 1.5px; text-underline-offset: 4px; cursor: help;
}
.term:focus-visible { outline-offset: 1px; }

/* ============================================================ Kaizen Desk layer */
:root { --t-mba: #2f5bea; --t-ai: #7a4fd6; --t-sql: #0f8f66; --t-python: #c98a00; --t-r: #d6453a; --t-git: #14213d; }
:root[data-theme="dark"] { --t-mba: #7391ff; --t-ai: #ab8eff; --t-sql: #3fcf9f; --t-python: #ffc53d; --t-r: #ff7d70; --t-git: #c9d3ee; }
.t-models { --tc: var(--t-mba); } .t-mba { --tc: var(--t-mba); } .t-ai { --tc: var(--t-ai); } .t-sql { --tc: var(--t-sql); } .t-python { --tc: var(--t-python); } .t-r { --tc: var(--t-r); } .t-git { --tc: var(--t-git); }

.hero { margin-bottom: 40px; gap: 20px; }
.hero h1 { max-width: 15ch; }
.hero-kicker { font: 700 .8rem var(--font-mono); letter-spacing: .08em; text-transform: uppercase; color: var(--sun-deep); margin: 0; }
.hero-lab { display: grid; gap: 18px; margin-bottom: 64px; }
.tracks li { border-left: 6px solid var(--tc, transparent); }

/* today tiles */
.today { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 12px; }
.tile { display: grid; gap: 4px; align-content: start; padding: 18px; border-radius: var(--r-lg); text-decoration: none; color: var(--ink); background: var(--surface); border: 1px solid var(--line); transition: transform .15s ease, box-shadow .15s ease; min-height: 138px; }
.tile:hover { transform: translateY(-3px); box-shadow: 0 10px 24px rgba(20,33,61,.12); }
.tile-big { font: 800 2.6rem/1 var(--font-display); letter-spacing: -.03em; font-variant-numeric: tabular-nums; }
.tile-label { font-size: .95rem; color: var(--ink-soft); }
.tile-cta { margin-top: auto; font: 700 .85rem var(--font-display); text-decoration: underline; text-decoration-color: var(--sun); text-decoration-thickness: 3px; text-underline-offset: 4px; }
.t-streak { background: var(--sun); border-color: var(--sun); color: var(--on-sun); }
.t-streak .tile-label { color: var(--on-sun); }
.t-streak .tile-cta { text-decoration-color: var(--on-sun); }
.t-review .tile-big { color: var(--class-a); } .t-mission .tile-big { color: var(--leaf); } .t-next .tile-big { color: var(--class-b); }
@media (max-width: 900px) { .today { grid-template-columns: repeat(2, minmax(0, 1fr)); } }

/* progress map */
.map { display: grid; gap: 10px; margin: 20px 0 64px; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg); padding: 20px; }
.map-row { display: grid; grid-template-columns: 11rem 1fr auto; gap: 14px; align-items: center; }
.map-name { font: 700 .95rem var(--font-display); text-decoration: none; color: var(--ink); border-left: 5px solid var(--tc); padding-left: 10px; }
.map-dots { display: flex; flex-wrap: wrap; gap: 12px; }
.map-group { display: inline-flex; gap: 5px; }
.dot { width: 18px; height: 18px; border-radius: 50%; border: 2px solid var(--tc); background: transparent; display: block; transition: transform .12s ease; }
.dot:hover { transform: scale(1.35); }
.dot.done { background: var(--tc); }
.dot.won { box-shadow: 0 0 0 3px var(--sun); }
.map-count { font: 500 .8rem var(--font-mono); color: var(--ink-soft); }
@media (max-width: 640px) { .map-row { grid-template-columns: 1fr auto; } .map-dots { grid-column: 1 / -1; grid-row: 2; } }

/* mission banner */
.mission { display: grid; grid-template-columns: auto 1fr auto; gap: 6px 14px; align-items: center; padding: 14px 18px; margin-bottom: 10px; border-radius: var(--r-md); border: 2px dashed var(--sun-deep); background: color-mix(in srgb, var(--sun) 16%, var(--surface)); }
.mission-tag { font: 700 .72rem var(--font-mono); letter-spacing: .08em; text-transform: uppercase; background: var(--ink); color: var(--surface); border-radius: 6px; padding: 4px 8px; }
.mission-goal { margin: 0; font: 700 1.05rem/1.35 var(--font-display); }
.mission-status { font: 700 .85rem var(--font-display); color: var(--ink-soft); }
.mission-win { grid-column: 1 / -1; margin: 0; color: var(--ink); }
.mission-win:empty { display: none; }
.mission.solved { border-style: solid; border-color: var(--leaf); background: color-mix(in srgb, var(--leaf) 16%, var(--surface)); }
.mission.solved .mission-tag { background: var(--leaf); color: #fff; }
.mission.solved .mission-status { color: var(--leaf); }
.mission.solved .mission-status::before { content: "✓ "; }
@keyframes mission-pop { 0% { transform: scale(1); } 30% { transform: scale(1.025); box-shadow: 0 0 0 10px color-mix(in srgb, var(--leaf) 30%, transparent); } 100% { transform: scale(1); box-shadow: 0 0 0 0 transparent; } }
.mission.pop { animation: mission-pop .6s ease-out; }
@media (max-width: 640px) { .mission { grid-template-columns: 1fr; } }

/* nav counters */
.nav-today { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.nav-today a { display: grid; gap: 2px; padding: 10px 12px; border-radius: var(--r-md); text-decoration: none; color: var(--nav-ink); background: rgba(255,255,255,.07); font-size: .78rem; }
.nav-today a:hover, .nav-today a[aria-current="page"] { background: rgba(255,255,255,.14); }
.streak-n, .due-n { font: 800 1.5rem/1 var(--font-display); font-variant-numeric: tabular-nums; }
.streak-n { color: var(--sun); }

/* review */
.review-stage { max-width: var(--measure); }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: var(--r-lg); padding: clamp(18px, 3vw, 30px); display: grid; gap: 16px; box-shadow: 0 8px 0 -4px var(--line), 0 16px 0 -8px var(--grid); }
.card fieldset { border: 0; margin: 0; padding: 0; display: grid; gap: 10px; }
.card legend { font: 700 1.3rem/1.3 var(--font-display); padding: 0; margin-bottom: 10px; }
.card .options { display: grid; gap: 8px; }
.card-meta { margin: 0; font: 500 .8rem var(--font-mono); color: var(--ink-soft); }
.review-done { background: color-mix(in srgb, var(--leaf) 14%, var(--surface)); border: 2px solid var(--leaf); border-radius: var(--r-lg); padding: 28px; }

/* gentle entrance for lesson blocks */
@keyframes rise { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: none; } }
.page > * { animation: rise .35s ease-out both; }
.page > *:nth-child(2) { animation-delay: .04s; } .page > *:nth-child(3) { animation-delay: .08s; } .page > *:nth-child(4) { animation-delay: .12s; }
@media (prefers-reduced-motion: reduce) { .page > *, .mission.pop { animation: none; } .tile, .dot { transition: none; } }