@font-face{font-family:'EK Barlow';src:url('../fonts/BarlowCondensed-ExtraBold.ttf') format('truetype');font-weight:800;font-display:swap}
:root{--bg:#101214;--surface:#191f24;--ink:#f2f4f4;--muted:#a5b5bf;--accent:#00bfd3;--line:#35464e}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.6 'Segoe UI',sans-serif}a{color:inherit}h1,h2,h3,p,figure{margin:0}h1,h2{font:800 36px/1.05 'EK Barlow',sans-serif}h1{font-size:46px;max-width:18ch;margin-bottom:12px}h2{margin-bottom:16px;max-width:24ch}h3{font-size:16px;font-weight:700;line-height:1.35}p{color:var(--muted)}a:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:4px}.header{display:flex;justify-content:space-between;align-items:center;gap:12px;max-width:1120px;margin:auto;padding:12px 16px;border-bottom:1px solid var(--line)}.header>a:first-child{display:flex;align-items:center;min-height:44px}.header img{display:block;width:142px;height:auto}.button{display:inline-flex;gap:8px;align-items:center;justify-content:center;min-height:44px;padding:10px 12px;border:1px solid var(--accent);border-radius:3px;font-size:13px;font-weight:600;text-decoration:none;transition:transform .2s,background .2s}.button:hover{transform:translateY(-2px);background:var(--accent);color:var(--bg)}main{max-width:1120px;margin:auto;padding:24px 16px 40px}section{scroll-margin-top:20px}.intro{margin-bottom:28px}.intro>p{max-width:48ch}.eyebrow{display:block;color:var(--accent);font-size:12px;font-weight:700;letter-spacing:.07em;text-transform:uppercase;margin-bottom:12px}.intro nav{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}.intro nav a{display:inline-flex;align-items:center;min-height:44px;padding:8px 12px;border:1px solid var(--line);border-radius:3px;text-decoration:none;font-size:13px;transition:border-color .2s,background .2s}.intro nav a:hover{border-color:var(--accent);background:var(--surface)}.lesson{padding:28px 0;margin-bottom:24px}.lesson>p{max-width:75ch;margin-bottom:20px}.lesson.light,.lesson.surface,.lesson.closing{padding:28px 16px;border-radius:3px}.light{background:var(--ink);color:var(--bg)}.light p{color:var(--line)}.light .eyebrow{color:var(--line)}.surface{background:var(--surface);border:1px solid var(--line)}.diagram{margin:24px 0}.diagram>figcaption{font-size:14px;font-weight:600;line-height:1.5;margin-bottom:16px}.examples{display:grid;gap:16px}.example{overflow:hidden;border:1px solid var(--line);background:var(--bg);color:var(--ink);border-radius:3px}.example>h3{padding:16px 16px 0;min-height:56px}.example img{display:block;width:100%;height:auto}.example>p,.light .example>p{padding:0 16px 16px;color:var(--muted);font-size:14px;line-height:1.5}.caption,.light .caption{font-size:12px;line-height:1.5;margin-top:14px;max-width:100ch;color:var(--muted)}.light .caption{color:var(--line)}.takeaway{border-left:3px solid var(--accent);padding:4px 0 4px 12px;margin:20px 0 0!important}.light .takeaway{border-left-color:var(--bg)}.checks{display:grid;gap:20px;margin:24px 0}.checks h3{margin-bottom:8px;color:var(--ink)}.checks p{font-size:14px;line-height:1.6}details{border-top:1px solid var(--line)}details:last-child{border-bottom:1px solid var(--line)}.light details{border-color:var(--muted)}summary{cursor:pointer;padding:16px 0;min-height:52px;font-weight:600;line-height:1.5}details p{padding-bottom:20px}details[open] summary{color:var(--accent)}.light details[open] summary{color:var(--bg)}.closing{display:grid;gap:20px;background:var(--accent);color:var(--bg)}.closing .eyebrow,.closing p{color:var(--bg)}.closing h2{max-width:22ch}.dark{background:var(--bg);color:var(--ink);border-color:var(--bg);justify-self:start}.dark:hover{background:var(--ink);color:var(--bg)}.closing a:focus-visible{outline-color:var(--bg)}footer{padding-top:20px;font-size:12px;line-height:1.6}footer .sources-title{font-weight:700;color:var(--ink);margin-bottom:8px}footer>p{max-width:90ch}.sources{display:flex;flex-wrap:wrap;gap:0 24px;margin-top:8px}.sources a{display:inline-flex;align-items:center;min-height:44px;padding-block:10px;color:var(--muted);text-underline-offset:3px}.back{display:inline-flex;gap:8px;align-items:center;min-height:44px;margin-top:12px;font-size:14px;color:var(--ink)}.skip{position:absolute;top:-100px;display:inline-flex;align-items:center;min-width:44px;min-height:44px}.skip:focus{top:8px;left:8px;z-index:10;background:var(--accent);color:var(--bg);padding:12px}
@media(min-width:700px){body{font-size:16px}.header{padding:16px 32px}.header img{width:190px}.button{font-size:14px;padding:12px 16px}main{padding:40px 32px 56px}h1{font-size:64px;max-width:22ch}h2{font-size:42px}.intro{margin-bottom:40px}.lesson{padding:40px 0;margin-bottom:32px}.lesson.light,.lesson.surface,.lesson.closing{padding:40px 32px}.examples.three{grid-template-columns:repeat(3,minmax(0,1fr))}.examples.two,.checks{grid-template-columns:repeat(2,minmax(0,1fr))}.example>h3{font-size:16px;min-height:68px}.example>p{font-size:14px}.closing{grid-template-columns:1.7fr 1fr;align-items:center;gap:32px}.closing .button{justify-self:end}.sources{gap:0 24px}}