:root {
  --paper: #f5f4ed;
  --ink: #273d34;
  --body: #47534b;
  --muted: #626b61;
  --line: #d4d7ca;
  --wash: #e9ecdf;
  --accent: #315e45;
  --selection: #d0dfc6;
  --sans: "PingFang SC", "Microsoft YaHei", sans-serif;
  --serif: "Site Serif", "Songti SC", "SimSun", serif;
}
@font-face {
  font-family: "Site Serif";
  src: url("/fonts/noto-serif-sc-headings.ttf") format("truetype");
  font-style: normal;
  font-weight: 500;
  font-display: swap;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 30px; overflow-x: clip; }
body { margin: 0; background: var(--paper); color: var(--body); font-family: var(--sans); font-size: 16px; line-height: 1.8; overflow-x: clip; }
::selection { background: var(--selection); color: var(--ink); }
a { color: inherit; text-decoration-thickness: 1px; text-underline-offset: 6px; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 7px; }
a:hover { color: var(--accent); }
.page { width: min(1120px, calc(100% - 112px)); margin-inline: auto; }
.site-header { min-height: 112px; display: flex; align-items: center; justify-content: space-between; gap: 30px; border-bottom: 1px solid var(--line); }
.wordmark { color: var(--ink); font-size: 24px; font-weight: 650; letter-spacing: -.5px; text-decoration: none; }
.wordmark span { font-size: 15px; font-weight: 400; letter-spacing: 0; margin-left: 12px; }
nav { display: flex; gap: 32px; font-size: 14px; }
nav a { text-decoration: none; }
.intro { display: grid; grid-template-columns: 1.3fr 1fr; align-items: center; gap: 60px; padding: 96px 0 100px; }
h1, h2, p { margin: 0; }
h1 { color: var(--ink); font-family: var(--serif); font-size: clamp(48px, 5.4vw, 74px); line-height: 1.45; font-weight: 500; letter-spacing: -.035em; text-wrap: balance; overflow-wrap: break-word; min-width: 0; }
.intro-copy { font-size: 17px; line-height: 2; padding-top: 8px; }
.intro-copy p + p { margin-top: 12px; }
.text-link { display: inline-block; color: var(--accent); margin-top: 24px; font-size: 15px; }
.learning { padding-bottom: 60px; }
.section-heading { display: flex; align-items: baseline; justify-content: space-between; gap: 20px; padding-bottom: 20px; }
h2 { font-weight: 500; color: var(--ink); font-size: 24px; }
.section-heading p { color: var(--muted); font-size: 14px; }
.topics { margin: 0; border-top: 1px solid var(--line); }
.topics > div { display: grid; grid-template-columns: 1fr 2fr; gap: 30px; align-items: baseline; padding: 24px 0; border-bottom: 1px solid var(--line); }
dt { color: var(--ink); font-size: 18px; }
dd { margin: 0; color: var(--muted); font-size: 15px; }
.about { padding: 35px 40px; background: var(--wash); }
.about h2 { font-family: var(--serif); font-size: 27px; margin-bottom: 12px; }
.about p { font-size: 15px; line-height: 1.9; }
.site-footer { padding: 40px 0 28px; display: flex; flex-direction: column; align-items: center; gap: 5px; color: var(--muted); font-size: 13px; text-align: center; }
.site-footer a { text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.skip-link { position: fixed; z-index: 10; left: 16px; top: 12px; padding: 8px 16px; background: var(--ink); color: var(--paper); transform: translateY(-200%); }
.skip-link:focus { transform: translateY(0); }
.skip-link:hover { color: var(--paper); }
@media (min-width: 1500px) { .intro { padding-top: 112px; padding-bottom: 112px; } }
@media (max-width: 760px) {
  .page { width: calc(100% - 44px); }
  .site-header { min-height: 90px; gap: 16px; }
  .wordmark { font-size: 22px; }
  .wordmark span { display: block; margin-left: 0; font-size: 12px; }
  nav { gap: 20px; font-size: 13px; }
  .intro { grid-template-columns: minmax(0, 1fr); gap: 28px; padding: 54px 0 58px; }
  h1 { font-size: clamp(42px, 10vw, 62px); line-height: 1.4; }
  .intro-copy { padding: 0; font-size: 16px; }
  .intro-copy p + p { margin-top: 10px; }
  .text-link { margin-top: 18px; }
  .desktop-break { display: none; }
  .section-heading { display: block; padding-bottom: 16px; }
  .section-heading p { margin-top: 6px; font-size: 13px; }
  h2 { font-size: 22px; }
  .topics > div { grid-template-columns: minmax(0, 1fr); gap: 7px; padding: 20px 0; }
  .learning { padding-bottom: 38px; }
  dd { font-size: 14px; }
  .about { padding: 26px 24px; }
  .about h2 { font-size: 23px; }
  .about p { font-size: 14px; }
  .site-footer { font-size: 12px; padding: 32px 0 24px; }
}
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }