:root{font-family:system-ui,-apple-system,"PingFang SC","Microsoft YaHei",sans-serif;color:#204835;background:#f0f5eb;--ink:#204835;--muted:#5c735c;--line:#d0dec9;--paper:#fffef8}*{box-sizing:border-box}body{margin:0}a{color:inherit;text-decoration:none}button{font:inherit;cursor:pointer}a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid #9552bb;outline-offset:4px}.hub-header{max-width:1220px;margin:auto;padding:28px 36px;display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);gap:18px}.hub-brand{font-size:33px;display:flex;align-items:center;gap:12px}.hub-brand span{font-size:22px;font-weight:750;letter-spacing:2px}nav{display:flex;align-items:center;gap:25px;font-size:15px}nav a{padding:10px 0}.test-entry{font-size:13px;color:var(--muted);border:1px solid var(--line);padding:8px 14px;border-radius:7px}main{max-width:1148px;margin:auto;padding:0 32px 40px}.eyebrow{color:var(--muted);font-size:13px;letter-spacing:2px;margin-bottom:18px}.hero{padding:70px 0 66px;position:relative;max-width:900px}.hero h1{font-size:clamp(38px,5vw,64px);line-height:1.2;letter-spacing:2px;margin:0 0 25px}.hero>p:not(.eyebrow){font-size:18px;color:var(--muted);line-height:1.9}.primary{display:inline-block;border:1px solid var(--ink);background:var(--ink);color:#fffdf4;font-size:15px;line-height:1.5;border-radius:10px;padding:13px 23px;min-height:48px}.primary:hover{background:#326a4f}.hero .primary{margin-top:15px}.hero-note{display:block;font-size:13px;color:#76846d;margin-top:17px}h2{font-size:27px;line-height:1.45;margin:12px 0 22px}h3{font-size:22px;line-height:1.55;margin:17px 0 14px}.section-head{display:flex;justify-content:space-between;align-items:center}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.guide-card{display:flex;flex-direction:column;background:var(--paper);padding:30px 27px;border:1px solid var(--line);border-radius:19px;transition:transform .2s,border-color .2s}.guide-card:hover{transform:translateY(-3px);border-color:#6d966c}.tag{font-size:13px;color:#6b7c61}.guide-card p{font-size:16px;line-height:1.9;color:var(--muted);margin:0 0 20px}.read-link{margin-top:auto;font-size:14px;text-decoration:underline;text-underline-offset:4px}.reading{display:grid;grid-template-columns:1fr 1fr;gap:55px;margin:65px 0}.reading p:not(.eyebrow){color:var(--muted);font-size:16px;line-height:1.9}.reading-list a{display:grid;gap:11px;padding:21px 0;border-bottom:1px solid var(--line)}.reading-list span,.reading-list small{color:#6b7c61;font-size:13px}.reading-list strong{font-size:18px;line-height:1.6}.status-card{padding:30px 34px;background:#e2edd9;border:1px solid #cddfc2;border-radius:17px}.status-card>span{font-size:13px;color:#637e57}.status-card p{color:#526e4d;font-size:16px;line-height:1.9;max-width:770px}.status-card a{font-size:15px;text-decoration:underline;text-underline-offset:4px}.page-title{padding:52px 0 28px}.page-title h1{font-size:45px;letter-spacing:2px;margin:15px 0}.page-title>p:not(.eyebrow){color:var(--muted);font-size:17px;line-height:1.8}.article{max-width:790px;margin:auto;padding-top:48px}.back-link{font-size:14px;color:var(--muted);display:inline-block;margin-bottom:30px}.article h1{font-size:38px;line-height:1.4;margin:0 0 20px}.lead{font-size:19px;line-height:1.9;color:var(--muted)}.byline{font-size:13px;color:#7a8571;border-bottom:1px solid var(--line);padding:5px 0 27px;margin-bottom:35px}.article-body{font-size:17px;line-height:1.95;color:#36523c}.article-body h2{font-size:24px;line-height:1.5;margin:38px 0 12px;color:var(--ink)}.article-body p{margin:15px 0}.article-body li{padding:5px 0}.article-body ol,.article-body ul{padding-left:25px}.article-body details{background:#e7eee1;border-radius:10px;padding:16px 20px;margin:14px 0;font-size:16px}.article-body summary{cursor:pointer;color:var(--ink);font-weight:550}.article-actions{display:flex;align-items:center;gap:27px;margin-top:35px}.article-actions a{text-decoration:underline;font-size:15px}.article-note{padding:23px 27px;background:#e7eee1;border-radius:13px;margin:35px 0;font-size:15px;line-height:1.9}.article-note p{margin:9px 0 0}.article-note a{text-decoration:underline}.related{display:flex;flex-direction:column;gap:15px;font-size:16px}.related a{text-decoration:underline;text-underline-offset:4px}.examples{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:17px;margin:25px 0}.example{margin:0;min-width:0}.example-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:5px;background:#dbe7d0;padding:10px;border-radius:13px}.number{aspect-ratio:1;min-width:0;line-height:1.2;display:grid;place-items:center;background:#fffdef;border-radius:5px;font-size:22px;font-weight:650}.number.empty{background:#dbe7d0;color:#768b68;font-size:13px}.example figcaption{font-size:13px;line-height:1.7;color:var(--muted);margin-top:10px}footer{max-width:1220px;border-top:1px solid var(--line);margin:0 auto;padding:30px 36px;color:#6b7c61;font-size:13px;line-height:1.8}footer>div{display:flex;gap:15px 25px;align-items:center;flex-wrap:wrap}footer>div>span{margin-right:auto}footer p{font-size:12px;margin-top:22px}footer a:hover{text-decoration:underline}.link-button{border:0;background:none;padding:5px 0;color:inherit;font-size:13px}.consent{position:fixed;bottom:18px;right:20px;max-width:430px;margin-left:20px;padding:20px 23px;background:#fffef7;border:1px solid #a8c295;border-radius:16px;box-shadow:0 10px 40px #21482d22;z-index:20}.consent p{font-size:15px;line-height:1.6;margin:0 0 14px}.consent small{font-size:13px;color:var(--muted)}.consent>div{display:flex;gap:8px;align-items:center;flex-wrap:wrap}.consent button{background:#e1ecd8;border:1px solid #c8dabb;border-radius:7px;padding:9px 12px;font-size:14px;color:var(--ink)}.consent a{font-size:13px;color:var(--muted);margin-left:3px}.toast{position:fixed;bottom:30px;left:50%;transform:translateX(-50%);background:var(--ink);color:#fff;padding:13px 23px;border-radius:11px;z-index:30;max-width:90vw;font-size:15px}[hidden]{display:none!important}@media(max-width:760px){.hub-header{padding:19px 20px;align-items:flex-start}.hub-brand{gap:7px;font-size:28px}.hub-brand span{font-size:19px;white-space:nowrap}nav{gap:14px;font-size:13px;justify-content:flex-end;flex-wrap:wrap}.test-entry{display:none}main{padding:0 20px 32px}.hero{padding:42px 0}.hero h1{font-size:39px;letter-spacing:1px}.hero>p:not(.eyebrow){font-size:16px}.cards{grid-template-columns:1fr}.guide-card{padding:24px}.reading{grid-template-columns:1fr;gap:8px;margin:43px 0}h2{font-size:24px}.status-card{padding:24px}.page-title{padding:30px 0 18px}.page-title h1{font-size:35px}.article{padding-top:28px}.article h1{font-size:29px}.lead{font-size:17px}.article-body{font-size:16px}.article-body h2{font-size:22px}.examples{gap:8px}.example-grid{padding:7px;gap:4px}.number{font-size:18px}.example figcaption{font-size:12px}.article-actions{gap:20px}.consent{bottom:12px;left:12px;right:12px;max-width:none;margin:0}footer{padding:25px 20px}footer>div{gap:14px}footer>div>span{flex-basis:100%}}@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}

/* Worked examples stay readable on a phone and on paper. */
.article-summary{padding:20px 23px;background:#e2edd9;border-radius:12px}.article-jumps{display:flex;flex-wrap:wrap;gap:10px 20px;margin:22px 0}.article-jumps a,.source-note a{font-size:14px;text-decoration:underline;text-underline-offset:4px}.article-body h2[id]{scroll-margin-top:20px}.walkthrough-steps{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:24px 20px;margin:25px 0}.walkthrough-steps .example{break-inside:avoid}.number.moved{background:#28513f;color:#fffef8;box-shadow:inset 0 0 0 2px #173c29}.parity-example{display:grid;grid-template-columns:190px minmax(0,1fr);gap:26px;align-items:start;margin:24px 0}.parity-example p:first-child{margin-top:0}.source-note{font-size:14px;color:var(--muted);border-top:1px solid var(--line);padding-top:20px}.article-body a{text-decoration:underline;text-underline-offset:3px}@media(max-width:600px){.walkthrough-steps{grid-template-columns:repeat(2,minmax(0,1fr));gap:22px 16px}.parity-example{grid-template-columns:1fr}.parity-example .example{max-width:200px;margin:auto}.article-jumps{justify-content:flex-start;font-size:13px}.article-summary{padding:17px}}@media print{body{background:white;color:#111}.hub-header,footer,.consent,.toast,.back-link,.article-actions,.related,.article-jumps{display:none!important}main{max-width:none;padding:0}.article{max-width:none;padding:0}.article h1{font-size:26px}.article-body{font-size:11pt;color:#111;line-height:1.65}.walkthrough-steps{grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;break-inside:avoid}.example-grid{background:#eee}.number{border:1px solid #777;background:white;color:#111}.number.moved{border:3px solid #111;background:white;color:#111;box-shadow:none}.number.empty{background:#eee;color:#666}.article-body h2{break-after:avoid}.article-note{background:none;border:1px solid #bbb}.source-note{font-size:9pt}a{color:#111}}