.course-page { min-height: 100vh; background: var(--paper); }
.course-layout { min-height: calc(100vh - var(--site-header-height)); display: grid; grid-template-columns: 360px minmax(0, 1fr); overflow: visible; }
.course-sidebar { --ink: var(--nav-ink); --muted: var(--nav-muted); --surface: var(--nav-surface); --subtle: var(--nav-surface); --hover: var(--nav-hover); --line: var(--nav-line); position: sticky; top: var(--site-header-height); height: calc(100vh - var(--site-header-height)); padding: 30px 20px 40px; align-self: start; overflow-y: auto; border-right: 1px solid var(--line); background: var(--nav-bg); color: var(--ink); scrollbar-width: thin; scrollbar-color: var(--line) transparent; }
.course-disclosure > summary { display: none; }
.sidebar-head { padding: 0 8px; }
.back-link { display: inline-block; margin-bottom: 29px; color: var(--muted); font-size: 13px; text-decoration: none; }
.course-sidebar h1 { margin: 0; font: 600 20px/1.35 "Manrope", sans-serif; letter-spacing: -.025em; }
.sidebar-groups { margin-top: 16px; color: var(--muted); font-size: 12px; line-height: 1.6; }
.course-search { height: 40px; margin: 28px 0 25px; padding: 0 11px; display: flex; align-items: center; gap: 8px; border: 1px solid var(--line); border-radius: 9px; background: var(--subtle); }
.course-search svg { width: 16px; flex: 0 0 auto; fill: none; stroke: var(--muted); stroke-width: 1.8; }
.course-search input { width: 100%; border: 0; outline: 0; background: transparent; color: var(--ink); font-size: 15px; }
.course-search input::placeholder { color: var(--muted); }
.course-search-feedback { margin: -14px 8px 18px; color: var(--muted); font-size: 12px; line-height: 1.5; }
.course-search-feedback p { margin: 0; }
.course-search-feedback button { margin-top: 8px; min-height: 44px; padding: 8px 12px; border: 1px solid var(--line-strong); border-radius: 6px; background: var(--surface); color: var(--ink); font: inherit; cursor: pointer; }
.nav-search-excerpt { font-size: 12px; line-height: 1.6; overflow-wrap: anywhere; }
.nav-section a mark, .markdown-body mark[data-course-search] { border-radius: 2px; background: var(--sand); color: var(--accent-ink); }
.markdown-body mark[data-course-search] { scroll-margin-block: calc(var(--site-header-height) + 24px); }
.nav-section { margin-bottom: 10px; }
.nav-section > summary { min-height: 44px; padding: 10px 8px; display: grid; grid-template-columns: 30px minmax(0, 1fr) auto; align-items: center; gap: 12px; cursor: pointer; color: var(--ink); font-size: 14px; font-weight: 500; line-height: 1.45; letter-spacing: normal; text-transform: none; }
.nav-category-icon { width: 30px; height: 30px; display: grid; place-items: center; border-radius: 50%; color: #fff; background: #687b96; }
.nav-category-icon svg { width: 17px; height: 17px; }
.nav-icon-intro { background: #7d6bc3; }
.nav-icon-html { background: #dc7954; }
.nav-icon-git { background: #d65f70; }
.nav-icon-js { background: #a67a19; }
.nav-icon-web { background: #4182a3; }
.nav-icon-practice { background: #418d81; }
.nav-icon-check { background: #6877bd; }
.nav-icon-final { background: #ad7956; }
.nav-icon-resources { background: #7c8292; }
.nav-section a { margin-left: 42px; padding: 10px 12px; display: grid; gap: 4px; border: 1px solid transparent; border-radius: 8px; color: var(--muted); text-decoration: none; transition: background .18s, border-color .18s; }
.nav-section a:hover { background: var(--hover); }
.nav-section a.active { background: var(--hover); color: var(--ink); transition: none; }
.nav-item-title { overflow: hidden; font-size: 14px; font-weight: 400; line-height: 1.5; overflow-wrap: anywhere; }
.nav-item-kind { display: block; margin-bottom: 3px; color: var(--muted); font-size: 11px; line-height: 1.5; }
.nav-semesters { display: flex; gap: 4px; padding: 4px; border: 1px solid var(--line); border-radius: 9px; }
.nav-semesters button { flex: 1; min-height: 44px; padding: 8px; border: 0; border-radius: 6px; background: transparent; color: var(--muted); font: inherit; font-size: 13px; cursor: pointer; }
.nav-semesters button:hover { background: var(--hover); }
.nav-semesters button[aria-pressed="true"] { background: var(--surface); color: var(--ink); }
.nav-semester-note { margin: 10px 8px 18px; color: var(--muted); font-size: 12px; line-height: 1.5; }
.nav-empty { color: var(--muted); font-size: 12px; text-align: center; }

.course-main { min-width: 0; }
.course-overview, .reader { max-width: 1160px; margin: 0 auto; padding: 74px clamp(28px, 6vw, 86px) 110px; }
.course-hero { min-height: 440px; display: flex; flex-direction: column; justify-content: center; border-bottom: 1px solid var(--line); }
.course-eyebrow { margin: 0 0 18px; color: var(--muted); font-size: 10px; font-weight: 700; letter-spacing: normal; text-transform: none; }
.course-hero h2 { max-width: 920px; margin: 0; font: 500 clamp(30px, 3.6vw, 48px)/1.2 "Unbounded", "Manrope", sans-serif; letter-spacing: -.04em; }
.course-intro { max-width: 720px; margin: 28px 0 0; color: var(--muted); font-size: 18px; line-height: 1.6; }
.overview-actions { margin-top: 36px; display: flex; align-items: center; gap: 18px; }
.button-course { background: var(--course-accent); color: var(--accent-ink); }
.coming-badge { padding: 12px 16px; border: 1px solid var(--ink); border-radius: 6px; font-size: 12px; font-weight: 700; }
.outcomes { padding: 80px 0; border-bottom: 1px solid var(--line); }
.outcomes h3, .curriculum h3 { margin: 0; font: 700 clamp(26px, 2.7vw, 36px)/1.25 "Manrope", sans-serif; letter-spacing: -.04em; }
.outcomes-grid { margin: 28px 0 0; padding: 0; display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; list-style: none; line-height: 1.6; }
.outcomes-grid li { min-width: 0; padding: 22px; border: 1px solid var(--course-edge); border-radius: 16px; background: var(--course-tint); font-size: 14px; }
.curriculum { padding-top: 85px; }
.curriculum-head { margin-bottom: 32px; display: flex; align-items: baseline; justify-content: space-between; flex-wrap: wrap; gap: 8px 16px; }
.curriculum-head > span { color: var(--muted); font-size: 12px; }
.curriculum-term { margin: 32px 0 16px; color: var(--muted); font-size: 13px; line-height: 1.5; }
.curriculum-section { border-top: 1px solid var(--ink); }
.curriculum-section-head { min-height: 120px; display: grid; grid-template-columns: 45px 1fr auto; align-items: center; gap: 24px; }
.curriculum-section-head > span { color: var(--muted); font: 500 10px "Manrope", sans-serif; }
.curriculum-section-head h4 { margin: 0 0 8px; font: 500 19px "Manrope", sans-serif; letter-spacing: -.025em; }
.curriculum-section-head p { margin: 0; color: var(--muted); font-size: 12px; }
.curriculum-items { padding: 0 0 32px 69px; }
.curriculum-items a { min-height: 64px; padding: 10px 0; display: grid; grid-template-columns: 36px 1fr 24px; align-items: center; gap: 10px; border-top: 1px solid var(--line); text-decoration: none; }
.curriculum-items a:hover strong { color: var(--link); }
.curriculum-items a > span:nth-child(2) { display: grid; gap: 3px; }
.curriculum-items small { color: var(--muted); font-size: 10px; font-weight: 700; letter-spacing: normal; text-transform: none; }
.curriculum-items strong { font-size: 15px; line-height: 1.45; transition: color .18s; }
.item-number { color: var(--muted); font-size: 10px; }
.item-arrow { font-size: 17px; }
.course-empty { padding: 55px; display: grid; gap: 20px; border: 1px solid var(--line); border-radius: 18px; background: var(--surface); color: var(--muted); }
.course-empty a { font-weight: 700; }

.reader { max-width: 1020px; }
.reader-head { margin-bottom: 28px; display: grid; grid-template-columns: minmax(0, 1fr); gap: 24px; }
.reader-head > div { min-width: 0; }
.reader-back { display: inline-block; margin-bottom: 40px; color: var(--muted); font-size: 11px; text-decoration: none; }
.reader-kind { margin: 0 0 13px; color: var(--muted); font-size: 13px; font-weight: 700; letter-spacing: normal; text-transform: none; }
#reader-title { max-width: 780px; margin: 0; font: 700 clamp(28px, 3.5vw, 46px)/1.2 "Manrope", sans-serif; letter-spacing: -.025em; }
.reader-actions { display: flex; flex-wrap: wrap; gap: 8px; }
.reader-actions button, .download-button { min-height: 44px; padding: 0 12px; display: inline-flex; align-items: center; border: 1px solid var(--line); border-radius: 9px; background: transparent; color: var(--ink); cursor: pointer; font-size: 12px; font-weight: 600; text-decoration: none; }
.download-button[hidden] { display: none; }
.download-button { background: var(--course-accent); border-color: transparent; color: var(--accent-ink); }
.markdown-body { color: var(--ink); font-size: 17px; line-height: 1.78; }
.markdown-body > :first-child { margin-top: 0; }
.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4 { scroll-margin-top: 95px; color: var(--ink); font-family: "Manrope", sans-serif; font-weight: 500; letter-spacing: -.035em; line-height: 1.25; }
.markdown-body h1 { margin: 0 0 38px; font-size: clamp(31px, 4vw, 48px); }
.markdown-body h2 { margin: 64px 0 20px; padding-top: 6px; font-size: clamp(24px, 2.7vw, 34px); }
.markdown-body h3 { margin: 40px 0 16px; font-size: 20px; }
.markdown-body h4 { margin: 28px 0 12px; font-size: 16px; }
.markdown-body p, .markdown-body ul, .markdown-body ol { margin: 0 0 20px; }
.markdown-body li { margin: 7px 0; }
.markdown-body a { color: var(--link); overflow-wrap: anywhere; text-decoration-thickness: 1px; text-underline-offset: 3px; }
.markdown-body blockquote { margin: 28px 0; padding: 20px 24px; border-left: 3px solid var(--course-edge); border-radius: 0 12px 12px 0; background: var(--course-tint); color: var(--ink); }
.markdown-body code { padding: .15em .35em; border: 1px solid var(--code-border); border-radius: 5px; background: var(--code-bg); font: 13px/1.5 "JetBrains Mono", monospace; }
.markdown-body :not(pre) > code { overflow-wrap: anywhere; box-decoration-break: clone; -webkit-box-decoration-break: clone; }
.markdown-body pre { margin: 28px 0; padding: 22px; overflow-x: auto; border: 1px solid var(--code-border); border-radius: 14px; background: var(--code-bg); color: var(--ink); }
.markdown-body pre code { padding: 0; border: 0; border-radius: 0; background: transparent; color: inherit; font-size: 13px; }
.markdown-body pre .token.comment, .markdown-body pre .token.prolog, .markdown-body pre .token.doctype, .markdown-body pre .token.cdata { color: var(--syntax-comment); }
.markdown-body pre .token.comment { font-style: italic; }
.markdown-body pre .token.punctuation, .markdown-body pre .token.operator { color: var(--syntax-punctuation); }
.markdown-body pre .token.tag, .markdown-body pre .token.keyword, .markdown-body pre .token.atrule { color: var(--syntax-keyword); }
.markdown-body pre .token.attr-name, .markdown-body pre .token.property, .markdown-body pre .token.variable { color: var(--syntax-property); }
.markdown-body pre .token.attr-value, .markdown-body pre .token.string, .markdown-body pre .token.char, .markdown-body pre .token.url, .markdown-body pre .token.regex { color: var(--syntax-string); }
.markdown-body pre .token.number, .markdown-body pre .token.boolean, .markdown-body pre .token.constant, .markdown-body pre .token.symbol, .markdown-body pre .token.builtin { color: var(--syntax-number); }
.markdown-body pre .token.function, .markdown-body pre .token.class-name { color: var(--syntax-function); }
.markdown-body pre .token.selector, .markdown-body pre .token.important { color: var(--syntax-selector); }
.markdown-body table { width: 100%; margin: 28px 0; border-collapse: collapse; font-size: 14px; }
.markdown-body th, .markdown-body td { padding: 11px 13px; border: 1px solid var(--line); text-align: left; }
.markdown-body th { background: var(--subtle); }
.markdown-body hr { margin: 54px 0; border: 0; border-top: 1px solid var(--line); }
.markdown-body img { max-width: 100%; border-radius: 12px; }

/* Exercise answers are native disclosures: usable with a keyboard and without JS. */
.markdown-body .practice-solution { margin: 24px 0 8px; border: 1px solid var(--course-edge); border-radius: 14px; background: var(--surface); }
.practice-solution > summary { min-height: 56px; padding: 12px 16px 12px 20px; display: flex; align-items: center; justify-content: space-between; gap: 16px; list-style: none; border-radius: 13px; color: var(--ink); font: 600 15px/1.45 "Manrope", sans-serif; cursor: pointer; }
.practice-solution > summary::-webkit-details-marker { display: none; }
.practice-solution > summary::after { content: "+"; width: 32px; height: 32px; flex: 0 0 32px; display: grid; place-items: center; border: 1px solid var(--course-edge); border-radius: 9px; background: var(--course-tint); font: 500 22px/1 "Manrope", sans-serif; }
.practice-solution > summary:hover { background: var(--hover); }
.practice-solution > summary:focus-visible { outline: 2px solid var(--focus); outline-offset: -4px; }
.practice-solution__hide, .practice-solution[open] .practice-solution__show { display: none; }
.practice-solution[open] .practice-solution__hide { display: inline; }
.practice-solution[open] > summary::after { content: "−"; }
.markdown-body .practice-solution > :not(summary) { margin-left: clamp(14px, 3vw, 20px); margin-right: clamp(14px, 3vw, 20px); }
.markdown-body .practice-solution > pre { margin-top: 14px; margin-bottom: 18px; }
.markdown-body .practice-solution > :last-child { margin-bottom: 20px; }

/* In-article diagrams use selectable, translated text and adapt to narrow screens. */
.web-visual { margin: 32px 0 40px; padding: clamp(18px, 3vw, 28px); border: 1px solid var(--course-edge); border-radius: 18px; background: var(--course-tint); color: var(--ink); }
.web-visual figcaption { display: flex; flex-direction: column; gap: 4px; margin-bottom: 18px; line-height: 1.3; }
.web-visual figcaption strong { font-size: clamp(19px, 2.3vw, 25px); letter-spacing: -.025em; }
.web-visual__eyebrow { color: var(--muted); font-size: 12px; font-weight: 800; letter-spacing: .08em; text-transform: uppercase; }
.web-visual__grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 10px; }
.web-visual__card { min-width: 0; display: grid; grid-template-columns: 38px minmax(0, 1fr); gap: 11px; align-items: start; padding: 15px 13px; border: 1px solid var(--line); border-radius: 12px; background: var(--surface); }
.web-visual__card > div { min-width: 0; }
.web-visual__number { display: grid; place-items: center; width: 38px; height: 38px; border-radius: 50%; background: var(--course-tint); color: var(--ink); font-size: 13px; font-weight: 800; line-height: 1; }
.web-visual__card strong, .web-visual__card div > span { display: block; overflow-wrap: anywhere; }
.web-visual__card strong { margin-bottom: 5px; font-size: 15px; line-height: 1.35; }
.web-visual__card div > span { color: var(--muted); font-size: 14px; line-height: 1.5; }
.web-visual__note { margin-top: 16px; color: var(--ink); font-size: 14px; line-height: 1.55; }
.web-visual--flow .web-visual__grid { grid-template-columns: minmax(0, 1fr); gap: 20px; }
.web-visual--flow .web-visual__card { position: relative; }
.web-visual--flow .web-visual__card:not(:last-child)::after { content: "↓"; position: absolute; left: 23px; bottom: -20px; z-index: 1; color: var(--ink); font-size: 17px; font-weight: 700; line-height: 20px; }

@media (max-width: 620px) { .web-visual__grid { grid-template-columns: minmax(0, 1fr); } }
.lesson-screenshot { margin: 30px 0; }
.lesson-screenshot > a { display: block; border-radius: 12px; }
.lesson-screenshot img { display: block; width: 100%; height: auto; border: 1px solid var(--line); cursor: zoom-in; }
.lesson-screenshot figcaption { margin-top: 12px; color: var(--muted); font-size: 14px; line-height: 1.6; }
.lesson-screenshot > a:focus-visible { outline: 3px solid var(--link); outline-offset: 5px; }
.checkpoint-action { margin: 0 0 45px; padding: 20px; display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 18px; border: 1px solid var(--course-edge); border-radius: 16px; background: var(--course-tint); }
.checkpoint-action > span { font-size: 9px; font-weight: 800; letter-spacing: normal; text-transform: none; writing-mode: vertical-rl; }
.checkpoint-action strong { display: block; margin-bottom: 5px; font-size: 15px; }
.checkpoint-action p { margin: 0; font-size: 12px; line-height: 1.5; }
.checkpoint-action a { padding: 11px 14px; border-radius: 9px; background: var(--ink); color:var(--on-primary); font-size: 11px; font-weight: 700; text-decoration: none; white-space: nowrap; }
.reader-pagination { margin-top: 85px; padding-top: 26px; display: grid; grid-template-columns: 1fr 1fr; gap: 12px; border-top: 1px solid var(--line); }
.reader-pagination a { min-height: 95px; padding: 18px; display: flex; flex-direction: column; justify-content: space-between; border: 1px solid var(--line); border-radius: 13px; background: var(--surface); text-decoration: none; }
.reader-pagination a:last-child { text-align: right; }
.reader-pagination span { color: var(--muted); font-size: 9px; font-weight: 700; letter-spacing: normal; text-transform: none; }
.reader-pagination strong { font-size: 12px; }
.reader-pagination a:hover { border-color: var(--course-edge); background: var(--course-tint); }
.document-preview { min-height: 420px; display: grid; place-content: center; justify-items: center; text-align: center; }
.document-preview .document-icon { width: 80px; height: 98px; display: grid; place-items: center; border: 1px solid var(--ink); border-radius: 9px; background: var(--surface);  font: 600 11px "Manrope", sans-serif; }
.document-preview h3 { margin-top: 34px; }
.document-preview p { max-width: 540px; color: var(--muted); }
.reader-skeleton { display: grid; gap: 15px; }
.reader-skeleton span { height: 16px; border-radius: 8px; background: linear-gradient(90deg, var(--hover), var(--hover), var(--hover)); background-size: 200% 100%; animation: shimmer 1.2s infinite; }
.reader-skeleton span:nth-child(1) { height: 44px; width: 72%; }
.reader-skeleton span:nth-child(3) { width: 88%; }
.reader-error { padding: 40px; border: 1px solid var(--line); border-radius: 16px; text-align: center; }
@keyframes shimmer { to { background-position: -200% 0; } }

@media (max-width: 900px) {
  .course-layout { grid-template-columns: 290px minmax(0, 1fr); }
  .course-sidebar h1 { font-size: 19px; }
  .course-overview, .reader { padding-inline: 34px; }
  .outcomes-grid { grid-template-columns: 1fr; }
}
@media (max-width: 700px) {
  .course-page { overflow-x: hidden; }
  .course-layout { display: block; }
  .course-sidebar { position: relative; top: auto; height: auto; max-height: none; padding: 0 20px; border: 0; border-bottom: 1px solid var(--line); }
  .course-disclosure > summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 48px; list-style: none; cursor: pointer; font-size: 14px; font-weight: 600; }
  .course-disclosure > summary::-webkit-details-marker { display: none; }
  .course-disclosure > summary::after { content: ""; width: 7px; height: 7px; margin-right: 4px; border-right: 1.5px solid; border-bottom: 1.5px solid; transform: rotate(45deg); }
  .course-disclosure[open] > summary::after { transform: rotate(225deg); }
  .sidebar-head { display: grid; grid-template-columns: auto 1fr; align-items: center; gap: 12px; padding: 12px 0 0; border-top: 1px solid var(--line); }
  .back-link { grid-column: 1 / -1; margin-bottom: 6px; }
  .course-sidebar h1 { font-size: 16px; }
  .sidebar-groups { grid-column: 1 / -1; margin: 0; }
  .course-search { margin: 18px 0 12px; }
  .course-search-feedback { margin: 0 8px 12px; }
  .material-nav { max-height: 480px; overflow-y: auto; }
  .course-overview, .reader { padding: 28px 20px 64px; }
  .course-hero { min-height: 0; padding-bottom: 32px; }
  .course-hero h2 { max-width: 100%; font-size: clamp(28px, 7.5vw, 38px); line-height: 1.12; }
  .course-intro { font-size: 16px; }
  .overview-actions { margin-top: 24px; }
  .outcomes { padding-block: 36px; }
  .curriculum { padding-top: 36px; }
  .curriculum-section-head { grid-template-columns: 32px 1fr auto; gap: 10px; }
  .curriculum-section-head p { display: none; }
  .curriculum-items { padding-left: 42px; }
  .reader-head { align-items: stretch; flex-direction: column; }
  .reader-back { margin-bottom: 24px; }
  .reader-actions { flex-wrap: wrap; }
  .markdown-body { font-size: 16px; }
  .markdown-table-scroll { width: 100%; margin: 28px 0; overflow-x: auto; -webkit-overflow-scrolling: touch; }
  .markdown-table-scroll .markdown-table { width: max-content; min-width: 100%; margin: 0; }
  .markdown-body pre { margin-inline: -8px; padding: 17px; }
  .checkpoint-action { grid-template-columns: 1fr; }
  .checkpoint-action > span { writing-mode: initial; }
  .reader-pagination { grid-template-columns: 1fr; }
}

/* Native disclosures keep course maps compact and work with keyboard input. */
.nav-section > summary, .curriculum-section-head { list-style: none; }
.nav-section > summary::-webkit-details-marker, .curriculum-section-head::-webkit-details-marker { display: none; }
.curriculum-section-head::after { content: "›"; font-size: 22px; transition: transform .15s; }
.curriculum-section[open] > summary::after { transform: rotate(90deg); }
.section-count { color: var(--muted); font-size: 12px; font-weight: 500; font-variant-numeric: tabular-nums; }
.curriculum-section-head { cursor: pointer; grid-template-columns: 45px minmax(0, 1fr) auto 18px; }
.nav-section > summary:hover, .nav-section[open] > summary { background: var(--hover); border-radius: 8px; }
.nav-section > summary:focus-visible, .curriculum-section-head:focus-visible { outline: 2px solid var(--focus); outline-offset: 3px; }
@media (max-width: 700px) {
  .curriculum-section-head { grid-template-columns: 24px minmax(0, 1fr) auto 16px; gap: 10px; min-height: 88px; }
}