:root {
  color-scheme: light;
  font-family: "Segoe UI", system-ui, sans-serif;
  color: #172b36;
  background: #f7f7f2;
  font-synthesis: none;
  --ink: #172b36;
  --muted: #607078;
  --line: #dce0d9;
  --green: #d3ef88;
}
* { box-sizing: border-box; }
body { margin: 0; line-height: 1.5; }
a { color: inherit; text-underline-offset: 4px; }
a:focus-visible, pre:focus-visible { outline: 3px solid #327050; outline-offset: 5px; }
svg { width: 20px; height: 20px; flex-shrink: 0; }
.site-header, main, footer { width: min(1240px, calc(100% - 80px)); margin-inline: auto; }
.site-header { display: flex; justify-content: space-between; align-items: center; gap: 24px; padding-block: 25px; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; font-size: 27px; font-weight: 750; letter-spacing: -1.2px; text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 46px; height: 43px; margin-right: 11px; border: 2px solid var(--ink); border-radius: 10px; background: var(--ink); color: var(--green); font-size: 24px; letter-spacing: -1px; }
.brand-dot { color: #508266; }
.header-note { color: var(--muted); font-size: 11px; font-weight: 650; letter-spacing: 1.8px; }
.collection-heading { display: flex; align-items: center; justify-content: space-between; gap: 28px; padding-block: 45px 38px; }
.heading-main { display: flex; align-items: center; gap: 22px; }
.collection-number { display: grid; place-items: center; width: 86px; height: 91px; flex-shrink: 0; border: 1px solid #b8d174; border-radius: 18px 18px 18px 3px; background: var(--green); font-size: 51px; font-weight: 650; line-height: 1; letter-spacing: -4px; padding-right: 4px; }
.eyebrow { margin: 0 0 5px; color: var(--muted); font-size: 10px; font-weight: 700; letter-spacing: 2.1px; }
h1 { margin: 0; font-size: clamp(30px, 3.9vw, 50px); font-weight: 700; line-height: 1.15; letter-spacing: -2px; }
.title-dot { color: #6c9272; }
.lesson-count { display: flex; align-items: center; gap: 9px; font-size: 23px; font-variant-numeric: tabular-nums; font-weight: 650; }
.lesson-count span { font-size: 13px; font-weight: 400; color: var(--muted); }
.lessons { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 28px 25px; }
.lesson { min-width: 0; overflow: hidden; background: #fff; border: 1px solid #dce0d9; border-radius: 16px; scroll-margin-top: 24px; }
.cover { aspect-ratio: 8 / 5; overflow: hidden; border-bottom: 1px solid #172b3610; }
.cover img { display: block; width: 100%; height: 100%; object-fit: cover; }
.lesson-info { padding: 20px 22px 17px; }
.lesson-label { display: flex; justify-content: space-between; align-items: center; color: var(--muted); font-size: 10px; font-weight: 650; letter-spacing: 1.4px; }
.lesson-label > :last-child { font-size: 11px; letter-spacing: 0; }
h2 { min-height: 56px; margin: 7px 0 20px; font-size: 22px; font-weight: 650; line-height: 1.25; letter-spacing: -.55px; overflow-wrap: anywhere; }
.actions { display: grid; grid-template-columns: 1.1fr 1fr; gap: 9px; }
.button { display: inline-flex; justify-content: center; align-items: center; gap: 8px; min-height: 46px; padding: 10px 13px; border: 1px solid var(--ink); border-radius: 7px; font-size: 13px; line-height: 1.25; font-weight: 600; text-decoration: none; }
.button-primary { background: var(--ink); color: #fff; }
.button-primary:hover { background: #304d5e; border-color: #304d5e; }
.button-primary svg:first-child { width: 16px; height: 16px; }
.button-primary svg:last-child:not(:first-child) { width: 16px; margin-left: auto; }
.updated { display: flex; justify-content: space-between; gap: 10px; margin: 17px 0 0; padding-top: 12px; border-top: 1px solid #edf0eb; color: var(--muted); font-size: 11px; }
.updated time { white-space: nowrap; font-variant-numeric: tabular-nums; }
footer { display: flex; align-items: center; gap: 18px; margin-top: 48px; padding-block: 26px 32px; border-top: 1px solid var(--line); color: var(--muted); font-size: 12px; }
footer p { margin: 0; max-width: 650px; }
footer a { margin-left: auto; white-space: nowrap; }
.footer-mark { color: var(--ink); font-size: 20px; font-weight: 700; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }

/* Two module cards, using the C# workshop's catalogue design. */
body { min-height: 100vh; }
.brand-mark { width: 54px; font-size: 15px; letter-spacing: -.5px; }
.collection-number svg { width: 42px; height: 42px; }
.collection-heading { padding-bottom: 20px; }
.lead { max-width: 760px; margin: 0 0 32px; color: var(--muted); font-size: 17px; line-height: 1.7; }
.lessons { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.lesson { display: flex; flex-direction: column; transition: border-color .18s ease, box-shadow .18s ease; }
.lesson:hover { border-color: #a8b9a4; box-shadow: 0 8px 28px #172b360a; }
.cover { aspect-ratio: 2 / 1; }
.cover img { object-fit: contain; }
.cover-ikt { background: #e0ead4; }
.cover-word { background: #dbe6f3; }
.lesson-info { flex: 1; display: flex; flex-direction: column; padding: 24px 26px 20px; }
h2 { min-height: 0; margin: 10px 0; font-size: 28px; }
.description { color: var(--muted); margin: 0 0 18px; font-size: 15px; }
.tags { display: flex; flex-wrap: wrap; gap: 8px; list-style: none; padding: 0; margin: 0 0 24px; }
.tags li { border: 1px solid var(--line); border-radius: 5px; padding: 4px 9px; font-size: 12px; color: #425e69; }
.actions { grid-template-columns: 1fr; margin-top: auto; }
.button { min-height: 48px; justify-content: flex-start; font-size: 14px; }
.updated { margin-top: 20px; }
.help { margin-top: 40px; padding: 26px; border: 1px solid var(--line); border-radius: 16px; background: #eef1e8; }
.help h2 { margin: 0 0 22px; font-size: 22px; }
.help ol { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 28px; list-style: none; margin: 0; padding: 0; counter-reset: steps; }
.help li { counter-increment: steps; }
.help li::before { content: '0' counter(steps); display: block; margin-bottom: 10px; color: #508266; font-size: 12px; font-weight: 700; letter-spacing: 1px; }
.help h3 { margin: 0 0 7px; font-size: 15px; }
.help p { margin: 0; color: #52646b; font-size: 13px; line-height: 1.7; }
.skip-link { position: absolute; top: 12px; left: 16px; padding: 12px 18px; background: var(--ink); color: white; z-index: 1; transform: translateY(-180%); }
.skip-link:focus { transform: translateY(0); }
@media (max-width: 1050px) {
  .site-header, main, footer { width: calc(100% - 48px); }
  .lessons { gap: 24px; }
  .collection-number { width: 72px; height: 78px; }
  .lesson-count { flex-shrink: 0; }
}
@media (max-width: 700px) {
  .site-header, main, footer { width: calc(100% - 32px); }
  .site-header { padding-block: 18px; gap: 16px; }
  .brand { font-size: 24px; }
  .brand-mark { width: 46px; height: 38px; font-size: 13px; }
  .header-note { font-size: 9px; letter-spacing: .8px; max-width: 105px; text-align: right; }
  .collection-heading { padding-block: 29px 20px; }
  .heading-main { gap: 14px; }
  .collection-number { width: 55px; height: 63px; border-radius: 12px 12px 12px 2px; }
  .collection-number svg { width: 30px; height: 30px; }
  .lesson-count { display: none; }
  .eyebrow { font-size: 8px; letter-spacing: 1.5px; }
  h1 { font-size: clamp(26px, 6.4vw, 38px); letter-spacing: -1px; }
  .lead { font-size: 15px; margin-bottom: 26px; }
  .lessons { grid-template-columns: 1fr; gap: 24px; }
  h2 { font-size: 25px; }
  .lesson-info { padding: 20px; }
  .help { margin-top: 28px; padding: 22px; }
  .help ol { grid-template-columns: 1fr; gap: 22px; }
  footer { align-items: flex-start; flex-wrap: wrap; margin-top: 32px; gap: 12px; }
  footer p { flex: 1; }
  footer a { width: 100%; margin: 0; }
}
@media (prefers-reduced-motion: reduce) { .lesson { transition: none; } }