:root {
  color-scheme: dark;
  font-family: Inter, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-synthesis: none;
  --bg: #0a0e1b;
  --panel: #11182a;
  --panel-soft: #151d31;
  --line: rgba(204, 216, 255, .13);
  --text: #f3f5ff;
  --muted: #a6b0c8;
  --soft: #7d8aa6;
  --violet: #c9b7ff;
  --cyan: #78dfd7;
  --amber: #f2c384;
  background: var(--bg);
  color: var(--text);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  min-width: 320px;
  margin: 0;
  background:
    radial-gradient(circle at 82% 5%, rgba(121, 94, 220, .17), transparent 27rem),
    radial-gradient(circle at 2% 29%, rgba(74, 155, 172, .09), transparent 25rem),
    var(--bg);
}
a { color: inherit; }
a:focus-visible, summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 4px;
  border-radius: 4px;
}
button, input { font: inherit; }
.skip-link {
  position: absolute;
  top: -80px;
  left: 16px;
  z-index: 20;
  padding: 10px 14px;
  border-radius: 8px;
  background: var(--cyan);
  color: #08111c;
}
.skip-link:focus { top: 12px; }
.container { width: min(1160px, calc(100% - 48px)); margin-inline: auto; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid var(--line);
  background: rgba(10, 14, 27, .9);
  backdrop-filter: blur(16px);
}
.header-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand { display: inline-flex; align-items: center; gap: 12px; text-decoration: none; white-space: nowrap; }
.brand-mark {
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(201, 183, 255, .4);
  border-radius: 10px;
  background: rgba(201, 183, 255, .1);
  color: var(--violet);
  font-family: Georgia, serif;
  font-size: 21px;
  font-style: italic;
}
.brand-label { font-size: 11px; font-weight: 800; letter-spacing: .16em; }
.site-nav { display: flex; align-items: center; justify-content: flex-end; gap: clamp(12px, 2.8vw, 32px); }
.site-nav a { color: var(--muted); font-size: 13px; text-decoration: none; white-space: nowrap; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--text); }
.site-nav .nav-cta {
  padding: 9px 13px;
  border: 1px solid rgba(201, 183, 255, .35);
  border-radius: 9px;
  color: var(--violet);
}
.site-nav .nav-cta:hover { background: rgba(201, 183, 255, .11); }

main { overflow: hidden; }
.eyebrow { margin: 0 0 18px; color: var(--cyan); font-size: 11px; font-weight: 800; letter-spacing: .18em; text-transform: uppercase; }
.eyebrow::before { content: ""; display: inline-block; width: 7px; height: 7px; margin-right: 10px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 12px rgba(120, 223, 215, .6); vertical-align: 1px; }
.hero { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(310px, .8fr); align-items: center; gap: 7%; padding-top: 106px; padding-bottom: 105px; }
.hero h1, .page-hero h1 { max-width: 12em; margin: 0; font-size: clamp(42px, 5.6vw, 72px); line-height: 1.16; letter-spacing: -.055em; }
.hero h1 em, .page-hero h1 em { color: var(--violet); font-style: normal; }
.hero-copy { max-width: 38em; margin: 27px 0 0; color: var(--muted); font-size: 17px; line-height: 1.9; }
.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 34px; }
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 10px;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}
.button-primary { background: var(--violet); color: #171126; }
.button-primary:hover { background: #ded3ff; }
.button-ghost { border-color: var(--line); color: var(--text); background: rgba(255, 255, 255, .035); }
.button-ghost:hover { border-color: rgba(201, 183, 255, .4); }
.hero-note { margin: 20px 0 0; color: var(--soft); font-size: 12px; }
.hero-visual {
  position: relative;
  padding: 23px;
  border: 1px solid rgba(201, 183, 255, .23);
  border-radius: 24px;
  background: linear-gradient(145deg, rgba(145, 114, 236, .12), rgba(28, 41, 68, .55) 52%, rgba(22, 46, 57, .5));
  box-shadow: 0 30px 95px rgba(0, 0, 0, .24);
}
.visual-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 20px; color: var(--soft); font-size: 10px; font-weight: 750; letter-spacing: .14em; }
.visual-status { display: inline-flex; align-items: center; gap: 7px; color: var(--cyan); letter-spacing: 0; }
.visual-status::before { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--cyan); }
.visual-step { display: flex; align-items: center; gap: 15px; padding: 15px 16px; border: 1px solid var(--line); border-radius: 13px; background: rgba(9, 14, 25, .55); }
.visual-step + .visual-step { margin-top: 10px; }
.visual-step:nth-of-type(3) { border-color: rgba(201, 183, 255, .38); }
.step-number { min-width: 28px; color: var(--cyan); font-family: ui-monospace, Consolas, monospace; font-size: 11px; }
.visual-step strong { display: block; font-size: 14px; }
.visual-step small { display: block; margin-top: 5px; color: var(--soft); font-size: 11px; }
.visual-parallel { margin-top: 15px; padding: 13px 15px; border: 1px dashed rgba(242, 195, 132, .4); border-radius: 12px; color: var(--amber); font-size: 12px; line-height: 1.6; }
.visual-parallel span { display: block; margin-bottom: 3px; font-size: 10px; letter-spacing: .12em; }

.section { padding-top: 82px; padding-bottom: 90px; border-top: 1px solid var(--line); }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 28px; margin-bottom: 30px; }
.section-head h2, .component-section h2 { margin: 0; font-size: clamp(29px, 3vw, 40px); letter-spacing: -.04em; line-height: 1.25; }
.section-intro { max-width: 34em; margin: 0; color: var(--muted); font-size: 14px; line-height: 1.8; }
.route-strip { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 30px; }
.route-stop { position: relative; min-height: 124px; padding: 19px 22px; border: 1px solid var(--line); border-radius: 15px; background: var(--panel); }
.route-stop span { color: var(--cyan); font-family: ui-monospace, Consolas, monospace; font-size: 11px; }
.route-stop strong { display: block; margin-top: 13px; font-size: 19px; }
.route-stop small { display: block; margin-top: 7px; color: var(--soft); font-size: 12px; }
.route-stop:not(:last-child)::after { content: "→"; position: absolute; top: 48px; right: -18px; z-index: 1; color: var(--violet); font-size: 22px; }
.phase-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 16px; }
.phase-card { padding: 28px; border: 1px solid var(--line); border-radius: 17px; background: rgba(17, 24, 42, .86); }
.phase-top { display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.phase-index { color: var(--cyan); font-family: ui-monospace, Consolas, monospace; font-size: 11px; font-weight: 700; letter-spacing: .1em; }
.phase-lane { padding: 6px 9px; border: 1px solid rgba(201, 183, 255, .2); border-radius: 99px; color: var(--violet); font-size: 10px; }
.phase-card h3 { margin: 17px 0 11px; font-size: 23px; letter-spacing: -.035em; }
.phase-card > p { min-height: 3.5em; margin: 0; color: var(--muted); font-size: 13px; line-height: 1.75; }
.topic-list { display: flex; gap: 7px; flex-wrap: wrap; min-height: 57px; margin: 20px 0 18px; padding: 0; list-style: none; }
.topic-list li { height: fit-content; padding: 5px 8px; border-radius: 6px; background: rgba(255, 255, 255, .055); color: #c7d0e1; font-size: 10px; }
.phase-result { padding-top: 15px; border-top: 1px solid var(--line); color: var(--text); font-size: 12px; line-height: 1.7; }
.phase-result strong { color: var(--cyan); }
.phase-hardware { margin-top: 8px; color: var(--amber); font-size: 11px; line-height: 1.7; }
.phase-link { display: inline-flex; margin-top: 19px; color: var(--violet); font-size: 12px; font-weight: 750; text-decoration: none; }
.phase-link:hover { color: #e6deff; text-decoration: underline; text-underline-offset: 4px; }
.divider-note { margin: 19px 0 0; color: var(--soft); font-size: 12px; line-height: 1.7; }

.hardware-section { background: linear-gradient(180deg, rgba(28, 32, 54, .28), transparent); }
.hardware-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 14px; }
.hardware-card { padding: 23px; border: 1px solid var(--line); border-radius: 15px; background: var(--panel); }
.hardware-card .hardware-index { color: var(--amber); font-family: ui-monospace, Consolas, monospace; font-size: 11px; }
.hardware-card h3 { min-height: 2.5em; margin: 16px 0 9px; font-size: 18px; line-height: 1.3; }
.hardware-card p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.8; }
.hardware-card .hardware-output { margin-top: 18px; padding-top: 12px; border-top: 1px solid var(--line); color: var(--amber); }
.callout { margin-top: 20px; padding: 17px 19px; border: 1px solid rgba(242, 195, 132, .27); border-radius: 12px; background: rgba(242, 195, 132, .06); color: #dfd0bb; font-size: 12px; line-height: 1.8; }
.callout strong { color: var(--amber); }
.feature-card { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 30px; padding: 34px; border: 1px solid rgba(201, 183, 255, .27); border-radius: 18px; background: linear-gradient(115deg, rgba(63, 49, 108, .33), rgba(15, 30, 42, .9)); }
.feature-card h3 { margin: 0 0 11px; font-size: 25px; letter-spacing: -.03em; }
.feature-card p { max-width: 43em; margin: 0; color: var(--muted); font-size: 13px; line-height: 1.8; }
.task-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; }
.task-card { padding: 20px; border: 1px solid var(--line); border-radius: 13px; background: var(--panel); }
.task-card span { color: var(--cyan); font-family: ui-monospace, Consolas, monospace; font-size: 11px; }
.task-card h3 { margin: 13px 0 8px; font-size: 15px; }
.task-card p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.7; }
.reference-list { display: flex; flex-wrap: wrap; gap: 10px 18px; margin: 0; padding: 0; list-style: none; }
.reference-list a { color: var(--violet); font-size: 12px; line-height: 1.7; text-underline-offset: 4px; }
.reference-list a:hover { color: #e6deff; }

.page-hero { padding-top: 88px; padding-bottom: 57px; }
.page-hero h1 { max-width: 14em; font-size: clamp(40px, 5vw, 63px); }
.page-hero p:last-child { max-width: 46em; margin: 24px 0 0; color: var(--muted); font-size: 15px; line-height: 1.9; }
.component-nav { display: flex; flex-wrap: wrap; gap: 9px; padding-bottom: 45px; }
.component-nav a { padding: 10px 13px; border: 1px solid var(--line); border-radius: 9px; color: var(--muted); font-size: 12px; text-decoration: none; }
.component-nav a:hover { border-color: rgba(201, 183, 255, .4); color: var(--text); }
.reading-guide { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; padding: 22px; border: 1px solid rgba(120, 223, 215, .25); border-radius: 15px; background: rgba(120, 223, 215, .055); }
.reading-guide div { padding: 0 12px; }
.reading-guide div + div { border-left: 1px solid var(--line); }
.reading-guide strong { display: block; color: var(--cyan); font-size: 13px; }
.reading-guide span { display: block; margin-top: 7px; color: var(--muted); font-size: 11px; line-height: 1.7; }
.component-section { padding: 75px 0 0; scroll-margin-top: 90px; }
.component-section-head { display: flex; align-items: end; justify-content: space-between; gap: 20px; margin-bottom: 20px; }
.component-section-head p { max-width: 30em; margin: 0; color: var(--muted); font-size: 12px; line-height: 1.7; }
.component-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; }
.component-card { align-self: start; border: 1px solid var(--line); border-radius: 13px; background: var(--panel); }
.component-card[open] { border-color: rgba(201, 183, 255, .35); }
.component-card summary { display: flex; align-items: start; gap: 12px; min-height: 85px; padding: 19px 18px; cursor: pointer; list-style: none; }
.component-card summary::-webkit-details-marker { display: none; }
.component-card summary::after { content: "+"; margin-left: auto; color: var(--violet); font-size: 20px; line-height: 1; }
.component-card[open] summary::after { content: "−"; }
.component-icon { flex: 0 0 auto; display: grid; place-items: center; width: 34px; height: 34px; border: 1px solid rgba(201, 183, 255, .23); border-radius: 9px; background: rgba(201, 183, 255, .075); color: var(--violet); font-family: ui-monospace, Consolas, monospace; font-size: 12px; }
.component-name { display: block; font-size: 15px; font-weight: 700; }
.component-teaser { display: block; margin-top: 6px; color: var(--soft); font-size: 11px; line-height: 1.6; }
.component-body { padding: 0 19px 18px 64px; }
.component-body dl { margin: 0; }
.component-body dt { margin-top: 14px; color: var(--cyan); font-size: 10px; font-weight: 800; letter-spacing: .1em; }
.component-body dd { margin: 5px 0 0; color: var(--muted); font-size: 12px; line-height: 1.75; }
.component-body a { display: inline-block; margin-top: 16px; color: var(--violet); font-size: 11px; text-underline-offset: 3px; }
.advanced-card { margin-top: 18px; padding: 23px; border: 1px dashed rgba(242, 195, 132, .42); border-radius: 14px; background: rgba(242, 195, 132, .05); }
.advanced-card h3 { margin: 0 0 10px; color: var(--amber); font-size: 17px; }
.advanced-card p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.8; }

/* C language course */
.course-page main, .lesson-page main { overflow: visible; }
.course-breadcrumb { display: flex; align-items: center; gap: 10px; color: var(--soft); font-size: 12px; }
.course-breadcrumb a { color: var(--muted); text-decoration: none; }
.course-breadcrumb a:hover { color: var(--violet); }
.course-breadcrumb span:last-child { color: var(--text); }
.course-hero { padding-top: 43px; padding-bottom: 88px; }
.course-hero-grid { display: grid; grid-template-columns: minmax(0, 1.08fr) minmax(330px, .92fr); align-items: center; gap: 6%; padding-top: 64px; }
.course-hero h1 { margin: 0; font-size: clamp(44px, 5.5vw, 69px); line-height: 1.15; letter-spacing: -.055em; }
.course-hero h1 em { color: var(--violet); font-style: normal; }
.course-lead { max-width: 38em; margin: 23px 0 0; color: var(--muted); font-size: 16px; line-height: 1.9; }
.course-visual { overflow: hidden; border: 1px solid rgba(201, 183, 255, .31); border-radius: 18px; background: #0d1425; box-shadow: 0 35px 100px rgba(0, 0, 0, .25); }
.course-visual-top { display: flex; align-items: center; justify-content: space-between; gap: 15px; padding: 15px 20px; border-bottom: 1px solid var(--line); color: var(--soft); font: 11px ui-monospace, Consolas, monospace; letter-spacing: .06em; }
.course-visual-top span:first-child { color: var(--cyan); }
.course-visual pre { overflow-x: auto; margin: 0; padding: 28px 23px; color: #dfe8f8; font: 13px/1.85 ui-monospace, Consolas, "Courier New", monospace; tab-size: 4; }
.course-visual code { font: inherit; }
.code-directive { color: var(--cyan); }
.code-keyword { color: var(--violet); }
.code-string { color: var(--amber); }
.course-visual-output { display: flex; align-items: center; gap: 17px; padding: 15px 20px; border-top: 1px solid var(--line); background: rgba(120, 223, 215, .055); }
.course-visual-output span { color: var(--cyan); font: 10px ui-monospace, Consolas, monospace; letter-spacing: .14em; }
.course-visual-output strong { font: 12px ui-monospace, Consolas, monospace; }
.course-chapter-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
.course-chapter { display: block; min-height: 196px; padding: 24px; border: 1px solid var(--line); border-radius: 15px; background: var(--panel); text-decoration: none; }
.course-chapter-open { border-color: rgba(201, 183, 255, .4); background: linear-gradient(130deg, rgba(67, 53, 111, .53), rgba(16, 31, 44, .88)); }
.course-chapter-open:hover { border-color: var(--violet); transform: translateY(-2px); }
.course-chapter-top { display: flex; justify-content: space-between; align-items: center; color: var(--soft); font: 11px ui-monospace, Consolas, monospace; letter-spacing: .08em; }
.course-chapter-open .course-chapter-top { color: var(--cyan); }
.course-chapter-arrow { color: var(--violet); font-size: 20px; }
.course-chapter h3 { margin: 17px 0 10px; font-size: 21px; letter-spacing: -.03em; }
.course-chapter p { margin: 0; color: var(--muted); font-size: 13px; line-height: 1.75; }
.course-chapter code { color: var(--cyan); font-family: ui-monospace, Consolas, monospace; }
.course-chapter-outcome { display: block; margin-top: 17px; color: var(--violet); font-size: 11px; line-height: 1.7; }
.course-method-section { background: linear-gradient(180deg, rgba(30, 41, 66, .3), transparent); }
.course-method-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
.course-method-grid article { padding: 24px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); }
.course-method-grid span { color: var(--cyan); font: 11px ui-monospace, Consolas, monospace; }
.course-method-grid h3 { margin: 15px 0 8px; font-size: 18px; }
.course-method-grid p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.8; }
.course-next-step { display: flex; justify-content: space-between; align-items: center; gap: 25px; margin-top: 25px; padding: 28px 30px; border: 1px solid rgba(201, 183, 255, .26); border-radius: 15px; background: rgba(201, 183, 255, .07); }
.course-next-step .eyebrow { margin-bottom: 10px; }
.course-next-step h3 { margin: 0 0 8px; font-size: 23px; }
.course-next-step p { max-width: 40em; margin: 0; color: var(--muted); font-size: 12px; line-height: 1.8; }
.course-next-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 10px; }

/* Long-form C lesson */
.lesson-breadcrumbs { display: flex; flex-wrap: wrap; align-items: center; gap: 9px; padding-top: 43px; color: var(--soft); font-size: 12px; }
.lesson-breadcrumbs a { color: var(--muted); text-decoration: none; }
.lesson-breadcrumbs a:hover { color: var(--violet); }
.lesson-breadcrumbs span:last-child { color: var(--text); }
.lesson-hero { max-width: 850px; padding: 65px 0 72px; }
.lesson-hero h1 { margin: 0; font-size: clamp(42px, 5.2vw, 67px); line-height: 1.18; letter-spacing: -.052em; }
.lesson-hero h1 em { color: var(--violet); font-style: normal; }
.lesson-lede { max-width: 45em; margin: 24px 0 0; color: var(--muted); font-size: 16px; line-height: 1.95; }
.lesson-meta { display: flex; flex-wrap: wrap; gap: 9px; margin-top: 24px; }
.lesson-meta span { padding: 7px 10px; border: 1px solid var(--line); border-radius: 99px; color: var(--soft); font-size: 11px; }
.lesson-hero-actions { display: flex; flex-wrap: wrap; gap: 11px; margin-top: 32px; }
.lesson-layout { display: grid; grid-template-columns: 224px minmax(0, 1fr); align-items: start; gap: clamp(28px, 4vw, 62px); border-top: 1px solid var(--line); }
.lesson-toc { position: sticky; top: 106px; margin-top: 34px; padding: 17px 15px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); }
.lesson-toc > p { margin: 0 0 12px; padding: 0 7px; color: var(--cyan); font-size: 11px; font-weight: 800; letter-spacing: .12em; }
.lesson-toc nav { display: grid; gap: 2px; }
.lesson-toc a { padding: 8px 7px; border-radius: 6px; color: var(--muted); font-size: 11px; line-height: 1.5; text-decoration: none; }
.lesson-toc a:hover, .lesson-toc a:focus-visible { color: var(--text); background: rgba(201, 183, 255, .09); }
.lesson-body { min-width: 0; padding-bottom: 30px; }
.lesson-section { padding: 52px 0 58px; border-bottom: 1px solid var(--line); scroll-margin-top: 94px; }
.lesson-section-head { margin-bottom: 17px; }
.lesson-kicker { display: block; margin-bottom: 10px; color: var(--cyan); font: 11px ui-monospace, Consolas, monospace; letter-spacing: .1em; }
.lesson-section h2 { margin: 0; font-size: clamp(27px, 3vw, 36px); line-height: 1.26; letter-spacing: -.04em; }
.lesson-section h3 { font-size: 17px; line-height: 1.4; }
.lesson-section p, .lesson-section li, .lesson-section dd { color: var(--muted); font-size: 14px; line-height: 1.9; }
.lesson-section p { margin: 15px 0; }
.lesson-section strong { color: var(--text); }
.lesson-section p code, .lesson-section li code, .lesson-section dd code, .lesson-section dt code, .lesson-section summary code, .lesson-lede code { padding: 2px 5px; border-radius: 5px; background: rgba(201, 183, 255, .1); color: #ded4ff; font: .9em ui-monospace, Consolas, monospace; }
.lesson-checklist { display: grid; gap: 10px; margin: 20px 0; padding-left: 25px; }
.lesson-checklist li::marker { color: var(--cyan); }
.lesson-callout { margin-top: 23px; padding: 19px 21px; border: 1px solid rgba(120, 223, 215, .27); border-radius: 12px; background: rgba(120, 223, 215, .06); }
.lesson-callout > strong { color: var(--cyan); font-size: 13px; }
.lesson-callout p { margin: 7px 0 0; font-size: 13px; }
.lesson-note { margin-top: 20px; padding: 16px 19px; border-left: 3px solid var(--amber); border-radius: 0 9px 9px 0; background: rgba(242, 195, 132, .065); color: var(--muted); font-size: 13px; line-height: 1.85; }
.lesson-note strong { color: var(--amber); }
.lesson-platform-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 13px; margin-top: 22px; }
.lesson-platform { min-width: 0; padding: 19px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); }
.lesson-platform-tag { color: var(--cyan); font: 11px ui-monospace, Consolas, monospace; letter-spacing: .08em; }
.lesson-platform h3 { margin: 10px 0; font-size: 17px; }
.lesson-platform p, .lesson-platform li { font-size: 12px; line-height: 1.8; }
.lesson-platform a, .lesson-links a { color: var(--violet); text-underline-offset: 3px; }
.lesson-steps { margin: 10px 0; padding-left: 20px; }
.lesson-steps li + li { margin-top: 6px; }
.lesson-code-label { display: flex; justify-content: space-between; gap: 15px; margin-top: 23px; padding: 10px 15px; border: 1px solid var(--line); border-bottom: 0; border-radius: 10px 10px 0 0; background: #172136; color: var(--soft); font: 11px ui-monospace, Consolas, monospace; }
.lesson-code-label span:first-child { color: var(--cyan); }
.lesson-code { max-width: 100%; overflow-x: auto; margin: 16px 0; padding: 17px 19px; border: 1px solid var(--line); border-radius: 10px; background: #0b1221; color: #e7edff; font: 12px/1.85 ui-monospace, Consolas, "Courier New", monospace; tab-size: 4; }
.lesson-code-label + .lesson-code { margin-top: 0; border-radius: 0 0 10px 10px; }
.lesson-code code { font: inherit; }
.lesson-output { border-color: rgba(120, 223, 215, .25); color: var(--cyan); }
.lesson-line-list { display: grid; gap: 11px; margin: 22px 0 0; }
.lesson-line-list > div { padding: 18px 20px; border: 1px solid var(--line); border-radius: 11px; background: var(--panel); }
.lesson-line-list dt { margin-bottom: 8px; font-size: 13px; font-weight: 700; }
.lesson-line-list dd { margin: 0; font-size: 13px; }
.lesson-flow { display: grid; gap: 9px; margin: 23px 0; padding: 0; list-style: none; }
.lesson-flow li { display: flex; gap: 16px; padding: 15px 17px; border: 1px solid var(--line); border-radius: 10px; background: var(--panel); }
.lesson-flow li > span { flex: 0 0 auto; color: var(--cyan); font: 11px ui-monospace, Consolas, monospace; }
.lesson-flow li p { margin: 4px 0 0; font-size: 12px; }
.lesson-answer { margin-top: 17px; border: 1px solid var(--line); border-radius: 10px; background: rgba(201, 183, 255, .045); }
.lesson-answer[open] { border-color: rgba(201, 183, 255, .35); }
.lesson-answer summary { padding: 13px 16px; color: var(--violet); font-size: 13px; font-weight: 700; line-height: 1.6; cursor: pointer; }
.lesson-answer > div { padding: 0 16px 16px; }
.lesson-answer p { margin: 7px 0; font-size: 12px; }
.lesson-answer .lesson-code { margin-block: 12px; }
.lesson-table-wrap { max-width: 100%; overflow-x: auto; margin-top: 20px; border: 1px solid var(--line); border-radius: 10px; }
.lesson-table { width: 100%; min-width: 620px; border-collapse: collapse; background: var(--panel); text-align: left; }
.lesson-table th, .lesson-table td { padding: 13px 15px; border-bottom: 1px solid var(--line); vertical-align: top; }
.lesson-table th { color: var(--cyan); font-size: 11px; }
.lesson-table td { color: var(--muted); font-size: 12px; line-height: 1.75; }
.lesson-table tbody tr:last-child td { border-bottom: 0; }
.lesson-table code { color: var(--violet); font: .94em ui-monospace, Consolas, monospace; }
.lesson-exercise { margin-top: 17px; padding: 20px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); }
.lesson-exercise-head span { color: var(--amber); font: 11px ui-monospace, Consolas, monospace; letter-spacing: .06em; }
.lesson-exercise h3 { margin: 8px 0; font-size: 19px; }
.lesson-exercise p { margin: 9px 0; font-size: 13px; }
.lesson-links { display: grid; gap: 11px; margin: 20px 0 0; padding: 0; list-style: none; }
.lesson-links li { display: flex; flex-wrap: wrap; gap: 7px 15px; padding: 12px 15px; border: 1px solid var(--line); border-radius: 9px; background: var(--panel); font-size: 12px; }
.lesson-links li span { color: var(--soft); font-size: 11px; }
.lesson-source-note { color: var(--soft) !important; font-size: 12px !important; }
.lesson-bottom-nav { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; padding-top: 28px; }

.site-footer { margin-top: 90px; border-top: 1px solid var(--line); }
.footer-inner { display: flex; align-items: start; justify-content: space-between; gap: 20px; padding-top: 28px; padding-bottom: 36px; }
.footer-inner strong { font-size: 11px; letter-spacing: .15em; }
.footer-inner p { margin: 8px 0 0; color: var(--soft); font-size: 11px; line-height: 1.7; }
.footer-links { display: flex; gap: 16px; flex-wrap: wrap; }
.footer-links a { color: var(--muted); font-size: 11px; text-decoration: none; }
.footer-links a:hover { color: var(--text); }

@media (max-width: 930px) {
  .hero { grid-template-columns: 1fr; gap: 44px; padding-top: 80px; }
  .hero-visual { max-width: 580px; width: 100%; }
  .hardware-grid, .task-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .course-hero-grid { grid-template-columns: 1fr; gap: 38px; }
  .course-visual { max-width: 590px; }
  .course-next-step { align-items: flex-start; flex-direction: column; }
  .course-next-actions { justify-content: flex-start; }
  .lesson-layout { grid-template-columns: 1fr; gap: 0; }
  .lesson-toc { position: static; margin-top: 0; }
  .lesson-toc nav { grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 2px 8px; }
  .lesson-section:first-child { padding-top: 43px; }
}
@media (max-width: 660px) {
  .container { width: min(100% - 32px, 520px); }
  .header-inner { min-height: auto; flex-wrap: wrap; gap: 12px; padding-block: 14px; }
  .brand-label { font-size: 10px; }
  .site-nav { width: 100%; justify-content: flex-start; gap: 18px; overflow-x: auto; padding-bottom: 4px; }
  .site-nav a { font-size: 11px; }
  .site-nav .nav-cta { padding: 5px 8px; }
  .hero { padding-top: 70px; padding-bottom: 75px; }
  .hero h1 { font-size: clamp(40px, 10.2vw, 56px); }
  .hero-copy { font-size: 15px; }
  .section { padding-top: 65px; padding-bottom: 70px; }
  .section-head, .component-section-head { display: block; }
  .section-intro, .component-section-head p { margin-top: 14px; }
  .route-strip, .phase-grid, .component-grid { grid-template-columns: 1fr; }
  .route-stop:not(:last-child)::after { content: "↓"; top: auto; right: 17px; bottom: -20px; }
  .route-stop { min-height: 104px; }
  .phase-card { padding: 23px; }
  .phase-card > p, .topic-list { min-height: 0; }
  .hardware-grid, .task-grid { grid-template-columns: 1fr 1fr; }
  .hardware-card { padding: 18px; }
  .hardware-card h3 { min-height: 0; }
  .feature-card { grid-template-columns: 1fr; padding: 25px; }
  .page-hero { padding-top: 65px; }
  .reading-guide { grid-template-columns: 1fr 1fr; gap: 19px; }
  .reading-guide div { padding: 0; }
  .reading-guide div + div { border-left: 0; }
  .component-section { padding-top: 64px; }
  .footer-inner { flex-direction: column; }
  .course-hero { padding-top: 28px; padding-bottom: 65px; }
  .course-hero-grid { padding-top: 48px; }
  .course-hero h1 { font-size: clamp(40px, 10.2vw, 55px); }
  .course-lead { font-size: 15px; }
  .course-chapter-grid, .course-method-grid { grid-template-columns: 1fr; }
  .course-chapter { min-height: 0; }
  .course-next-step { padding: 23px; }
  .lesson-breadcrumbs { padding-top: 27px; }
  .lesson-hero { padding: 54px 0 60px; }
  .lesson-hero h1 { font-size: clamp(40px, 10vw, 54px); }
  .lesson-lede { font-size: 15px; }
  .lesson-toc nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .lesson-platform-grid { grid-template-columns: 1fr; }
  .lesson-section { padding-block: 43px; }
  .lesson-line-list > div { padding: 16px; }
  .lesson-bottom-nav { justify-content: flex-start; }
}
@media (max-width: 410px) {
  .hardware-grid, .task-grid, .reading-guide { grid-template-columns: 1fr; }
  .component-body { padding-left: 19px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }