:root {
  color-scheme: light;
  --ink: #203c3b;
  --muted: #526766;
  --paper: #f5f7f4;
  --line: #cbd5ce;
  --accent: #175c4b;
  font-family: "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  color: var(--ink);
  background: var(--paper);
  font-synthesis: none;
  scroll-behavior: smooth;
  scroll-padding-top: 28px;
  scrollbar-color: #6c837b var(--paper);
}
* { box-sizing: border-box; }
body { margin: 0; line-height: 1.75; }
a { color: inherit; text-underline-offset: 5px; }
button, input { font: inherit; accent-color: var(--accent); }
button, a, input { -webkit-tap-highlight-color: transparent; }
button { cursor: pointer; }
::selection { background: #c5ded3; color: #18372d; }
:focus-visible { outline: 3px solid #bd763d; outline-offset: 6px; }
h1, h2, h3, p { margin: 0; }
h1, h2 { text-wrap: balance; font-weight: 500; }
svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.5; flex-shrink: 0; }
.section-width { width: min(1280px, calc(100% - 112px)); margin-inline: auto; }
.skip-link { position: absolute; z-index: 10; top: 12px; left: 12px; padding: 12px 20px; background: white; transform: translateY(-160%); }
.skip-link:focus { transform: none; }
.site-header { position: absolute; z-index: 2; inset: 0 0 auto; display: flex; justify-content: space-between; align-items: center; padding: 26px 56px; color: white; background: linear-gradient(#102a3bb3, transparent); }
.wordmark { font-size: 23px; font-weight: 600; text-decoration: none; display: flex; align-items: center; gap: 20px; }
.wordmark span { font-size: 11px; letter-spacing: .13em; font-weight: 500; }
nav { display: flex; gap: 34px; }
nav a { padding-block: 8px; text-decoration: none; font-size: 14px; }
nav a:hover, .wordmark:hover { text-decoration: underline; }
.hero { min-height: 760px; height: min(920px, 100svh); position: relative; background: #193c49; color: #fff; display: flex; align-items: flex-end; }
.hero-image, .hero-shade { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero-image { object-fit: cover; object-position: center 52%; }
.hero-shade { background: linear-gradient(90deg, #102b3c78 0%, #102b3c08 80%), linear-gradient(0deg, #0a2938cc 0%, #0a293800 80%); }
.hero-copy { position: relative; width: 100%; padding: 210px 7.5% 142px; }
h1 { font-size: clamp(46px, 4.7vw, 76px); line-height: 1.28; letter-spacing: -.025em; }
.hero-copy p { margin-top: 26px; font-size: 16px; line-height: 1.9; color: #f0f4f3; }
.hero-link { display: inline-flex; gap: 32px; align-items: center; margin-top: 34px; padding-block: 8px; text-decoration: none; border-bottom: 1px solid #d7e6e0; }
.hero-link:hover { color: #d2eddd; border-color: #d2eddd; }
.hero-caption { position: absolute; bottom: 30px; inset-inline: 56px; display: flex; justify-content: space-between; gap: 20px; color: #e1ece9; font-size: 12px; }
.playground { padding-block: 110px 100px; }
.section-heading { display: flex; justify-content: space-between; align-items: flex-end; gap: 40px; margin-bottom: 48px; }
h2 { font-size: clamp(30px, 3vw, 44px); line-height: 1.45; letter-spacing: -.025em; }
.section-heading p { color: var(--muted); font-size: 15px; max-width: 32em; }
.experiment { display: grid; grid-template-columns: 300px minmax(0, 1fr); border: 1px solid var(--line); }
.experiment-controls { padding: 36px; }
h3 { font-weight: 600; font-size: 19px; }
fieldset { padding: 0; margin: 30px 0; border: 0; }
legend, .range-label { font-size: 14px; font-weight: 600; }
.radio-option { display: flex; align-items: center; gap: 10px; min-height: 44px; cursor: pointer; font-size: 15px; }
.radio-option:first-of-type { margin-top: 8px; }
input[type=radio] { margin: 0; width: 18px; height: 18px; }
.range-label { display: flex; justify-content: space-between; align-items: center; gap: 12px; }
output { font-weight: 400; font-variant-numeric: tabular-nums; }
input[type=range] { width: 100%; height: 44px; margin: 0; cursor: pointer; }
#reset { margin-top: 20px; min-height: 44px; padding: 8px 16px; border: 1px solid #8b9d93; background: transparent; color: var(--ink); border-radius: 4px; }
#reset:hover { background: #e1e9e1; }
.experiment-hint { margin-top: 24px; font-size: 12px; line-height: 1.8; color: var(--muted); }
.experiment-result { min-width: 0; background: #e7ece5; border-left: 1px solid var(--line); }
.preview-heading { display: flex; justify-content: space-between; gap: 20px; padding: 18px 28px; font-size: 12px; }
.preview-heading span:last-child { font-size: 10px; letter-spacing: .1em; }
.preview-stage { padding: 12px 28px 28px; }
.landscape-layout { display: flex; flex-direction: row; gap: 16px; height: 240px; }
.landscape-tile { flex: 1; min-width: 0; min-height: 0; position: relative; background-image: linear-gradient(0deg,#092b3eaa,transparent 90%),url("/learning-assets/landscape.webp"); background-size: auto 340px; overflow: hidden; }
.tile-sky { background-position: 15% 12%; }
.tile-mountain { background-position: 70% 55%; }
.tile-lake { background-position: 40% 95%; }
.landscape-tile span { position: absolute; left: 16px; bottom: 12px; color: white; font-size: 14px; }
pre { margin: 0; padding: 24px 28px; background: #173d3c; color: #e8eee7; overflow-x: auto; font: 13px/1.8 Consolas, monospace; }
.code-selector { color: #bed9c9; }
#code-direction, #code-gap { color: #f6cf9e; }
.notes { padding-bottom: 112px; }
.notes .section-heading { padding-bottom: 32px; border-bottom: 1px solid var(--line); margin-bottom: 0; }
.note { display: grid; grid-template-columns: 180px minmax(0,1fr) 235px; gap: 32px; align-items: start; padding: 34px 0; border-bottom: 1px solid var(--line); }
.note-language { font-size: 21px; line-height: 1.4; }
.note p { font-size: 14px; color: var(--muted); max-width: 44em; margin-top: 10px; }
.note a { display: flex; align-items: center; gap: 16px; justify-self: end; font-size: 13px; padding: 6px 0; text-decoration: none; }
.note a:hover { text-decoration: underline; color: var(--accent); }
.about { background: #dce7df; padding-block: 90px; }
.about-layout { display: grid; grid-template-columns: 1fr 1fr; gap: 100px; }
.about-layout p { color: #37554a; max-width: 40em; font-size: 15px; }
.about-layout p + p { margin-top: 20px; }
.about-link { display: inline-flex; gap: 30px; align-items: center; margin-top: 30px; padding-block: 8px; text-decoration: none; border-bottom: 1px solid #607c70; }
.about-link:hover { color: #08724d; }
.site-footer { padding-block: 34px 30px; }
.footer-top { display: flex; justify-content: space-between; gap: 20px; font-size: 13px; color: var(--muted); }
.footer-top a { display: inline-flex; align-items: center; gap: 14px; text-decoration: none; min-height: 44px; }
.footer-top > span { align-self: center; }
.footer-top a:hover { text-decoration: underline; }
.filing { margin-top: 36px; padding-inline: 20px; text-align: center; font-size: 12px; color: var(--muted); }
.filing a { display: inline-block; padding: 10px 6px; min-height: 44px; font-size: 14px; text-decoration: none; }
.filing a:hover { color: var(--accent); text-decoration: underline; }
.visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
@media (max-width: 1000px) {
  .section-width { width: calc(100% - 64px); }
  .site-header { padding-inline: 32px; }
  .wordmark span { display: none; }
  .hero-copy { padding-inline: 7%; }
  .hero-caption { inset-inline: 32px; }
  .section-heading { align-items: flex-start; }
  .experiment { grid-template-columns: 260px minmax(0,1fr); }
  .experiment-controls { padding: 28px; }
  .note { grid-template-columns: 140px minmax(0,1fr); }
  .note a { grid-column: 2; justify-self: start; }
  .about-layout { gap: 48px; }
}
@media (max-width: 650px) {
  :root { scroll-padding-top: 20px; }
  .section-width { width: calc(100% - 40px); }
  .site-header { padding: 20px; align-items: flex-start; gap: 20px; }
  .wordmark { font-size: 19px; white-space: nowrap; }
  nav { gap: 14px; flex-wrap: wrap; justify-content: flex-end; }
  nav a { font-size: 12px; padding-top: 2px; min-height: 32px; }
  .hero { height: 90svh; min-height: 660px; max-height: 850px; }
  .hero-image { object-position: 58% center; }
  .hero-shade { background: linear-gradient(0deg,#0a2938ee 0%,#0a293860 65%,#0a293830); }
  .hero-copy { padding: 180px 24px 128px; }
  h1 { font-size: clamp(36px, 8.6vw, 52px); }
  .hero-copy p { font-size: 14px; max-width: 28em; margin-top: 24px; }
  .hero-link { font-size: 14px; margin-top: 28px; gap: 24px; }
  .hero-caption { inset-inline: 24px; flex-direction: column; gap: 4px; bottom: 24px; font-size: 10px; }
  .playground { padding-block: 64px; }
  .section-heading { flex-direction: column; gap: 20px; margin-bottom: 30px; }
  .section-heading p { font-size: 14px; }
  .experiment { grid-template-columns: 1fr; }
  .experiment-controls { padding: 24px; }
  fieldset { margin: 20px 0; display: flex; gap: 20px; flex-wrap: wrap; }
  .radio-option:first-of-type { margin-top: 0; }
  .radio-option { margin-top: 0; }
  .experiment-hint { margin-top: 16px; }
  .experiment-result { border-left: 0; border-top: 1px solid var(--line); }
  .preview-heading { padding: 18px 20px; }
  .preview-stage { padding: 4px 20px 20px; }
  .landscape-layout { height: 210px; }
  .landscape-tile span { left: 8px; bottom: 8px; font-size: 12px; }
  pre { padding: 24px 20px; font-size: 12px; }
  .notes { padding-bottom: 64px; }
  .note { grid-template-columns: 1fr; gap: 16px; padding: 28px 0; }
  .note a { grid-column: 1; }
  .note-language { font-size: 17px; color: var(--accent); }
  .about { padding-block: 60px; }
  .about-layout { grid-template-columns: 1fr; gap: 28px; }
  .footer-top { font-size: 12px; }
  .filing { margin-top: 28px; }
}
@media (prefers-reduced-motion: reduce) { :root { scroll-behavior: auto; } }