:root {
  color-scheme: light;
  --ink: #14213d;
  --muted: #5a6478;
  --line: #d8dfeb;
  --paper: #ffffff;
  --page: #f3f6fb;
  --blue: #1756a9;
  --blue-dark: #123f7d;
  --blue-soft: #eaf2ff;
  --coral: #d8694b;
  --code: #111827;
  --code-text: #e5edf8;
  --content: 72rem;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", sans-serif;
  font-synthesis: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { min-height: 100vh; margin: 0; color: var(--ink); background: var(--page); line-height: 1.65; }
a { color: var(--blue); text-underline-offset: .18em; }
a:hover { color: var(--blue-dark); }
a:focus-visible, button:focus-visible, select:focus-visible { outline: 3px solid #f5b82e; outline-offset: 3px; }

.skip-link { position: fixed; top: .75rem; left: .75rem; z-index: 20; padding: .7rem 1rem; border-radius: .35rem; color: #fff; background: var(--ink); transform: translateY(-180%); }
.skip-link:focus { transform: translateY(0); }
.site-header { border-bottom: 1px solid var(--line); background: rgb(255 255 255 / .96); box-shadow: 0 .25rem .75rem rgb(20 33 61 / .06); backdrop-filter: blur(10px); }
.nav-shell, .hero, .page-shell, .footer-shell { width: min(var(--content), calc(100% - 2rem)); margin-inline: auto; }
.nav-shell { display: flex; align-items: center; justify-content: space-between; gap: 1rem; min-height: 4.5rem; }
.brand { display: inline-flex; align-items: center; gap: .7rem; color: var(--ink); font-weight: 800; text-decoration: none; }
.brand-mark { display: grid; width: 2.25rem; height: 2.25rem; place-items: center; border-radius: .35rem; color: #fff; background: var(--blue); font-family: Georgia, serif; font-size: 1.15rem; }
.nav-note { color: var(--muted); font-size: .92rem; }
main { width: 100%; }
.course-intro { padding: clamp(4rem, 9vw, 7.5rem) 0 3.5rem; }
.hero { padding: clamp(3.5rem, 8vw, 6rem) 0 3rem; }
.hero.compact { padding-block: 3rem 2.25rem; }
.eyebrow { display: inline-flex; align-items: center; gap: .55rem; margin: 0 0 .9rem; color: var(--blue); font-size: .82rem; font-weight: 850; letter-spacing: .12em; text-transform: uppercase; }
.eyebrow::before { content: ""; width: 1.8rem; height: .2rem; border-radius: 99px; background: var(--coral); }
.breadcrumb { display: flex; flex-wrap: wrap; gap: .55rem; margin: 0 0 1rem; color: var(--muted); font-size: .92rem; }
.breadcrumb a { color: inherit; }
h1, h2, h3, h4 { line-height: 1.12; text-wrap: balance; }
h1 { max-width: 16ch; margin: 0; color: var(--ink); font-size: clamp(2.65rem, 7vw, 5.4rem); font-weight: 800; letter-spacing: -.055em; }
.compact h1 { max-width: 22ch; font-size: clamp(2.35rem, 5.5vw, 4.4rem); }
.compact h1 code { overflow-wrap: anywhere; }
.lead { max-width: 52rem; margin: 1.4rem 0 0; color: var(--muted); font-size: clamp(1.08rem, 2.3vw, 1.35rem); }

.callout { margin: 1.6rem 0; padding: 1.1rem 1.3rem; border-left: 4px solid var(--blue); background: var(--paper); }
.callout.success { border-color: #24704e; background: #e9f2ec; }
.callout strong { display: block; margin-bottom: .2rem; }
.callout p { margin: 0; }
details.callout > summary { color: var(--ink); font-weight: 800; cursor: pointer; }
details.callout > summary::marker { color: var(--blue); }
details.callout.success > summary::marker { color: #24704e; }
details.callout > summary:focus-visible { outline: 3px solid #f5b82e; outline-offset: 3px; }
details.callout[open] > summary { margin-bottom: .4rem; }
details.callout p strong { display: inline; margin-bottom: 0; }
.course-reference { margin: 1.7rem 0 0; font-weight: 800; }
.days { padding: 2rem 0 3rem; }
.section-heading { max-width: 52rem; margin-bottom: 2rem; }
.section-heading h2, .article h2 { margin: 0 0 .75rem; font-size: clamp(1.9rem, 4vw, 2.8rem); font-weight: 800; letter-spacing: -.035em; }
.section-heading p { color: var(--muted); }

/* Day entries remain one full-width, easy-to-scan vertical list. */
.day-card-grid { display: grid; grid-template-columns: 1fr; gap: 1rem; margin-bottom: 3rem; }
.day-card { min-height: 13rem; display: flex; flex-direction: column; padding: 1.35rem; border: 1px solid var(--line); border-radius: .8rem; color: inherit; background: var(--paper); box-shadow: 0 10px 30px rgb(20 33 61 / .04); text-decoration: none; transition: border-color 150ms ease, box-shadow 150ms ease, translate 150ms ease; }
a.day-card:hover { border-color: #91add5; box-shadow: 0 16px 36px rgb(20 33 61 / .09); translate: 0 -2px; }
.day-card span { color: var(--muted); font-size: .9rem; }
.day-card strong { margin: .2rem 0 2rem; color: var(--blue); font-size: clamp(3rem, 8vw, 5rem); line-height: .8; }
.day-card b { max-width: 40rem; font-size: 1.35rem; line-height: 1.2; }
.day-card small { margin-top: auto; padding-top: 1rem; border-top: 1px solid var(--line); color: var(--muted); font-size: .92rem; line-height: 1.45; }
.day-card-ready { border-top: .35rem solid var(--coral); }
.day-card-pending { background: linear-gradient(135deg, var(--paper), var(--blue-soft)); }
.day-card-pending strong { color: #7890ab; }
.day-card-locked { border-style: dashed; background: #edf1f7; box-shadow: none; }
.day-card-locked strong, .day-card-locked b { color: #64748b; }
.day-card-locked small { display: flex; flex-wrap: wrap; align-items: center; gap: .55rem; }
.day-card-locked .day-card-status { display: inline-flex; align-items: center; gap: .35rem; padding: .18rem .55rem; border: 1px solid #8796aa; border-radius: 999px; color: #3f4d61; background: #fff; font-size: .78rem; font-weight: 850; letter-spacing: .04em; text-transform: uppercase; }
.day-card-locked .day-card-status::before { content: ""; width: .55rem; height: .42rem; border: 2px solid currentColor; border-radius: .12rem; box-shadow: 0 -.35rem 0 -.18rem #edf1f7, 0 -.35rem 0 -.06rem currentColor; }
.course-map { display: grid; gap: 1rem; }
.program-card { min-height: 0; padding: 1.4rem; border: 1px solid var(--line); border-radius: .8rem; background: var(--paper); box-shadow: 0 10px 30px rgb(20 33 61 / .04); }
.reference-card { border-left: 4px solid var(--coral); }
.section-number, .step-no { color: var(--coral); font-size: .78rem; font-weight: 850; letter-spacing: .12em; text-transform: uppercase; }
.program-card h3 { margin: .7rem 0; font-size: 1.45rem; }
.program-card p { margin: 0; color: var(--muted); }
.card-link { display: inline-block; margin-top: 1.2rem; font-weight: 800; }

.section { padding: 1.5rem 0 5rem; }
.article { min-width: 0; max-width: 790px; padding: clamp(1.4rem, 5vw, 3rem); overflow: hidden; border: 1px solid var(--line); background: var(--paper); box-shadow: 0 1rem 3rem rgb(20 33 61 / .06); }
.section.page-shell > .article { max-width: none; }
.article h2 { margin-top: 3rem; }
.article h2:first-child { margin-top: 0; }
.article h3 { margin: 2rem 0 .6rem; font-size: 1.25rem; }
.article p, .article li { color: #34445c; }
.article li + li { margin-top: .45rem; }
.article code:not(pre code) { padding: .12em .35em; border-radius: .3em; color: #174779; background: var(--blue-soft); }
.table-scroll { width: 100%; max-width: 100%; margin: 1.2rem 0 1.7rem; overflow-x: auto; }
.table-scroll table { width: 100%; min-width: 40rem; border-collapse: collapse; }
.table-scroll th, .table-scroll td { padding: .7rem .8rem; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.table-scroll th { color: var(--ink); background: var(--blue-soft); }
.inline-capture { margin: 1.6rem 0 2rem; }
.inline-capture a { display: block; border-radius: .5rem; }
.inline-capture img { display: block; width: 100%; height: auto; border: 1px solid var(--line); border-radius: .5rem; background: var(--page); }
.inline-capture figcaption { margin-top: .6rem; color: var(--muted); font-size: .92rem; }
.deployment-flow { display: flex; flex-wrap: wrap; align-items: center; justify-content: center; gap: .7rem; margin: 1.6rem 0 2rem; padding: 1.2rem; border: 1px solid var(--line); border-radius: .6rem; background: var(--blue-soft); text-align: center; }
.deployment-flow .flow-node { min-width: 8.5rem; padding: .8rem; border: 1px solid #9db9df; border-radius: .45rem; color: var(--ink); background: var(--paper); font-weight: 800; line-height: 1.3; }
.deployment-flow small { color: var(--muted); font-weight: 500; }
.deployment-flow .flow-arrow { color: var(--blue); font-size: .86rem; font-weight: 800; }
.deployment-flow figcaption { flex-basis: 100%; margin-top: .4rem; color: var(--muted); font-size: .9rem; }
.lesson-layout { display: grid; grid-template-columns: 250px minmax(0, 1fr); gap: clamp(1.5rem, 5vw, 4rem); align-items: start; }
.lesson-nav { position: sticky; top: 1rem; padding: 1rem; border: 1px solid var(--line); border-radius: .5rem; background: var(--paper); }
.lesson-nav strong { display: block; margin: .15rem .55rem .7rem; }
.lesson-nav ol { margin: 0; padding: 0; list-style: none; counter-reset: lesson; }
.lesson-nav li { counter-increment: lesson; }
.lesson-nav a { display: grid; grid-template-columns: 1.5rem 1fr; gap: .45rem; padding: .48rem .55rem; border-radius: .35rem; color: var(--muted); font-size: .9rem; text-decoration: none; }
.lesson-nav a::before { content: counter(lesson, decimal-leading-zero); color: var(--blue); font-weight: 850; }
.lesson-nav a:hover, .lesson-nav a[aria-current="page"] { color: var(--blue); background: var(--blue-soft); }
.lesson-nav .section-links { margin-top: 1rem; padding-top: .8rem; border-top: 1px solid var(--line); }
.lesson-nav .section-links strong { margin-bottom: .4rem; }
.lesson-nav .section-links a { display: block; padding: .4rem .55rem; }
.lesson-nav .section-links a::before { content: none; }

.lesson-section { scroll-margin-top: 5rem; padding: clamp(1.4rem, 5vw, 3rem); border: 1px solid var(--line); background: var(--paper); box-shadow: 0 1rem 3rem rgb(20 33 61 / .06); }
.section-heading-number { color: var(--blue); font-size: .72em; font-weight: 900; }
.section-heading-number::after { content: "."; }
.lesson-section h2 { margin: 0 0 1rem; font-size: clamp(1.8rem, 4vw, 2.7rem); }
.lesson-section h3 { margin: 2rem 0 .55rem; font-size: 1.15rem; }
.lesson-section p { margin: 0 0 1rem; }
.lesson-section ul, .lesson-section ol { margin: 0 0 1.25rem; padding-left: 1.4rem; }
.lesson-section li + li { margin-top: .35rem; }
.checklist { padding: 0; list-style: none; }
.checklist li { position: relative; padding-left: 1.8rem; }
.checklist li::before { content: "✓"; position: absolute; left: 0; color: #24704e; font-weight: 900; }

.code-block { position: relative; min-width: 0; max-width: 100%; margin: 1.2rem 0 1.7rem; overflow: hidden; }
.code-path { display: block; padding: .55rem .85rem; border-radius: .5rem .5rem 0 0; color: #cbd5e1; background: #26354d; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: .78rem; }
pre { max-width: 100%; margin: 0; padding: 1.15rem; overflow-x: auto; border-radius: 0 0 .5rem .5rem; color: var(--code-text); background: var(--code); font: .9rem/1.55 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; tab-size: 4; }
pre code { color: inherit; font: inherit; }
.copy-button { position: absolute; top: .35rem; right: .45rem; padding: .28rem .55rem; border: 1px solid #64748b; border-radius: .35rem; color: #fff; background: #35445c; font: inherit; font-size: .75rem; cursor: pointer; }

.step-grid { display: grid; grid-template-columns: 1fr; gap: 0; }
.step-card { padding: 1.2rem 0; border-top: 1px solid var(--line); background: transparent; }
.step-card:last-child { border-bottom: 1px solid var(--line); }
.step-card h3 { margin: .45rem 0 .5rem; }
.step-card p { margin: 0; font-size: .94rem; }
.step-card ol { margin-bottom: 0; }
.pager { display: flex; justify-content: space-between; gap: 1rem; margin-top: 3rem; padding-top: 1.4rem; border-top: 1px solid var(--line); }
.pager a { max-width: 48%; font-weight: 800; text-decoration: none; }
.pager a:last-child { margin-left: auto; text-align: right; }
.site-footer { margin-top: 4rem; border-top: 1px solid var(--line); }
.footer-shell { display: flex; justify-content: space-between; gap: 1rem; padding-block: 1.5rem 2rem; color: var(--muted); font-size: .82rem; }

@media (max-width: 820px) {
  .lesson-layout { grid-template-columns: 1fr; }
  .lesson-nav { position: static; }
  .lesson-nav ol { display: grid; grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .nav-shell { align-items: flex-start; flex-direction: column; padding-block: .85rem; }
  .nav-note { display: none; }
  .day-card { min-height: 11rem; }
  .lesson-nav ol { grid-template-columns: 1fr; }
  .pager, .footer-shell { flex-direction: column; }
  .pager a, .pager a:last-child { max-width: 100%; margin: 0; text-align: left; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .day-card { transition: none; } }
@media print {
  @page { size: A4; margin: 14mm; }
  body { background: #fff; }
  .site-header, .site-footer { display: none; }
  .page-shell, .hero, .footer-shell { width: 100%; }
  .article, .lesson-section { box-shadow: none; }
  details.callout > :not(summary) { display: block !important; }
  details.callout > summary { margin-bottom: .4rem; list-style: none; }
  details.callout > summary::marker { content: ""; }
}