:root{--bg:#f6faff;--surface:#ffffff;--ink:#152238;--muted:#4a5872;--accent:#1360d2;--accent-ink:#ffffff;--accent2:#17924c;--line:#d4e1f3;--hero-ink:#ffffff;--r:14px;--maxw:1200px;--measure:66ch;--hf:'Grandstander', 'Comic Neue', 'Trebuchet MS', sans-serif;--bf:'Open Sans', system-ui, sans-serif}
*,*::before,*::after{box-sizing:border-box}
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body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.65 var(--bf)}
img{max-width:100%;height:auto;display:block}
a{color:var(--accent);text-underline-offset:.18em}
h1,h2,h3,h4{font-family:var(--hf);line-height:1.18;margin:1.6em 0 .5em;font-weight:700;letter-spacing:0}
h1{font-size:clamp(2rem,5vw,3.4rem);margin-top:0}
h2{font-size:clamp(1.4rem,3vw,2rem)}h3{font-size:1.2rem}
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@media(min-width:1800px){body article.prose>:is(p,ul,ol,h2,h3,h4,blockquote,dl,details,.callout,.disclosure,.table-wrap){max-width:52rem}}
.skip{position:absolute;left:-999px}.skip:focus{left:10px;top:10px;background:var(--surface);padding:8px;z-index:9}
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nav.main a{color:var(--ink);text-decoration:none;font-size:.95rem;padding:4px 0;border-bottom:2px solid transparent}
nav.main a[aria-current]{border-color:var(--accent)}
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.hero{position:relative;overflow:hidden}
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.hero .lead{font-size:1.18rem;color:var(--muted);max-width:60ch}
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.hero.plain{background:var(--surface);border-bottom:1px solid var(--line)}
@media(max-width:760px){.hero.split .wrap{grid-template-columns:1fr}.hero.full{min-height:340px}.hero .wrap{padding-top:36px;padding-bottom:36px}}
.page{display:grid;gap:48px;padding-top:40px;padding-bottom:64px}
.page.toc-layout{grid-template-columns:220px minmax(0,1fr)}
.page.toc-layout .toc{position:sticky;top:20px;align-self:start;font-size:.92rem;border-left:3px solid var(--accent);padding-left:14px}
.page.toc-layout .toc ul{list-style:none;padding:0;margin:0}.page.toc-layout .toc li{margin:.35em 0}
.page.toc-layout .toc a{color:var(--muted);text-decoration:none}
@media(max-width:860px){.page.toc-layout{grid-template-columns:1fr}.page.toc-layout .toc{position:static}}
/* Content uses the full container width (cards, grids, tables); only running text keeps a readable measure. */
article.prose{max-width:none;min-width:0}
article.prose>:is(p,ul,ol,h2,h3,h4,blockquote,dl,details,.callout,.disclosure,.table-wrap){max-width:47.5rem;margin-left:auto;margin-right:auto}
.page.toc-layout article.prose>*{margin-left:0;margin-right:0}
/* A heading that introduces a full-width block (cards, grid, table) lines up with that block, not the text column. */
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.page.wide article.prose>*{max-width:none}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:18px;margin:0 0 1.4em}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--r);padding:20px}
.card h3{margin-top:0}.card p:last-child{margin-bottom:0}
a.card{display:block;color:var(--ink);text-decoration:none}a.card:hover{border-color:var(--accent)}
.callout{border-left:4px solid var(--accent2);background:var(--surface);padding:14px 18px;border-radius:0 var(--r) var(--r) 0;margin:0 0 1.2em}
.table-wrap{overflow-x:auto;margin:0 0 1.2em}
table{border-collapse:collapse;width:100%;font-size:.95rem}
th,td{border-bottom:1px solid var(--line);padding:9px 10px;text-align:left;vertical-align:top}
th{font-family:var(--hf);background:var(--surface)}
details{border:1px solid var(--line);border-radius:var(--r);padding:10px 16px;background:var(--surface)}
summary{cursor:pointer;font-weight:600}
.steps{counter-reset:s;list-style:none;padding:0}.steps li{counter-increment:s;position:relative;padding-left:44px;margin-bottom:1em}
.steps li::before{content:counter(s);position:absolute;left:0;top:0;width:30px;height:30px;border-radius:50%;background:var(--accent);color:var(--accent-ink);display:grid;place-items:center;font-weight:700;font-size:.9rem}
.btn{display:inline-block;background:var(--accent);color:var(--accent-ink);padding:10px 18px;border-radius:var(--r);text-decoration:none;font-weight:600;border:0;font:inherit;cursor:pointer}
.aff{border:1px dashed var(--accent);border-radius:var(--r);padding:16px 18px;margin:0 0 1.2em;background:var(--surface)}
.aff .tag{font-size:.75rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted)}
.disclosure{font-size:.88rem;color:var(--muted);border:1px solid var(--line);border-radius:var(--r);padding:10px 14px;margin:0 0 1.6em}
.meta{font-size:.88rem;color:var(--muted)}
dl dt{font-family:var(--hf);font-weight:700;margin-top:1em}dl dd{margin:.2em 0 0 0;color:var(--ink)}
footer.site{border-top:1px solid var(--line);background:var(--surface);font-size:.92rem;color:var(--muted)}
footer.site .wrap{padding-top:32px;padding-bottom:32px;display:grid;gap:18px}
footer.site ul{list-style:none;padding:0;margin:0;display:flex;flex-wrap:wrap;gap:6px 18px}
footer.site a{color:var(--muted)}
.hs header.site{background:#1360d2;border-bottom:0;box-shadow:inset 0 -6px 0 #ffc61a}
.hs header.site .wrap{padding-top:14px;padding-bottom:20px}
.hs .brand{color:#fff;font-weight:800;font-size:1.4rem}
.hs nav.main a{color:#e6efff;font-weight:600;font-size:.94rem;border-bottom:3px solid transparent}
.hs nav.main a:hover{color:#fff;border-color:rgba(255,198,26,.6)}
.hs nav.main a[aria-current]{color:#fff;border-color:#ffc61a}
.hs .menu-btn{color:#fff;border:2px solid rgba(255,255,255,.6);font-weight:600}
.hs .hero{background-color:#f6faff;background-image:linear-gradient(rgba(19,96,210,.08) 1px,transparent 1px),linear-gradient(90deg,rgba(19,96,210,.08) 1px,transparent 1px);background-size:24px 24px;border-bottom:3px solid #d4e1f3}
.hs .hero .kicker{display:inline-block;font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.1em;color:#0f5a2f;background:#ddf3e6;border:2px solid #17924c;border-radius:6px;padding:3px 10px;margin:0 0 1em}
.hs .hero h1{color:#0e3f8c;max-width:22ch}
.hs .hero .lead{color:#33415a}
.hs .hero.plain{background-color:#f6faff}
.hs .hero.plain .wrap:has(.art){display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,.85fr);grid-template-rows:1fr auto auto auto 1fr;column-gap:56px}
.hs .hero.plain .wrap:has(.art)>:not(.art){grid-column:1}
.hs .hero.plain .wrap:has(.art)>.kicker{grid-row:2;justify-self:start}.hs .hero.plain .wrap:has(.art)>h1{grid-row:3}.hs .hero.plain .wrap:has(.art)>.lead{grid-row:4}
.hs .hero .art{grid-column:2;grid-row:1/6;align-self:center;width:100%;max-width:560px;justify-self:center;background:#fff;border:3px solid #152238;border-radius:18px;padding:22px 18px 14px;box-shadow:10px 10px 0 #ffc61a}
.hs .hero.banner img{border:3px solid #152238;border-radius:18px;box-shadow:10px 10px 0 #ffc61a;max-height:420px}
@media(max-width:860px){.hs .hero.plain .wrap:has(.art){display:block}.hs .hero.plain .wrap:has(.art)>*{grid-column:1;grid-row:auto}.hs .hero .art{grid-row:auto;margin-top:26px;max-width:420px}}
.hs .prose h2{color:#0e3f8c;display:flex;align-items:center;gap:.5em}
.hs .prose h2::before{content:"";flex:none;width:.7em;height:.7em;border-radius:3px;background:#ffc61a;box-shadow:.22em .22em 0 #17924c}
.hs .prose h3{color:#152238}
.hs .card{border:2px solid #d4e1f3;border-radius:14px;border-top:8px solid #1360d2}
.hs .cards>.card:nth-child(3n+2){border-top-color:#17924c}.hs .cards>.card:nth-child(3n){border-top-color:#ffc61a}
.hs a.card:hover{border-color:#1360d2;transform:translateY(-2px);box-shadow:0 8px 0 #e3edfc}
.hs a.card{transition:transform .15s,box-shadow .15s}
.hs .callout{position:relative;border:2px solid #152238;border-radius:12px;background:#fffbea;padding:30px 20px 16px;overflow:hidden}
.hs .callout::before{content:"";position:absolute;left:0;right:0;top:0;height:12px;background:repeating-linear-gradient(-45deg,#ffc61a 0 12px,#152238 12px 24px)}
.hs .steps li::before{background:#17924c;border-radius:8px;font-family:var(--hf)}
.hs th{background:#1360d2;color:#fff;font-family:var(--bf);font-weight:700;font-size:.9rem}
.hs .table-wrap{border:2px solid #d4e1f3;border-radius:12px;background:#fff}
.hs tbody tr:nth-child(even) td{background:#f1f6fe}
.hs details{border:2px solid #d4e1f3;border-radius:12px}
.hs summary{color:#0e3f8c}
.hs .ph{margin:0 auto 1.6em;max-width:60rem}.hs .ph img{border-radius:16px;border:3px solid #152238;width:100%;aspect-ratio:16/8;object-fit:cover}
.hs .ph figcaption{font-size:.88rem;color:var(--muted);margin-top:.5em}
.hs footer.site{background:#0f2445;color:#c9d6ea;border-top:6px solid #17924c}
.hs footer.site a{color:#ffd659}
/* Periodic table of experiments */
.hs .pt-wrap{margin:0 0 2.2em}
.hs .pt-key{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 14px}
.hs .pt-key button{font:600 .9rem var(--bf);color:#152238;background:var(--b);border:2px solid var(--c);border-radius:999px;padding:6px 14px;cursor:pointer}
.hs .pt-key button[aria-pressed="true"]{background:var(--c);color:#fff}
.hs .pt{display:grid;grid-template-columns:repeat(auto-fill,minmax(124px,1fr));gap:8px}
.hs .el{position:relative;display:grid;grid-template-rows:auto 1fr auto auto;aspect-ratio:1/1.08;padding:8px 10px;background:var(--b);border:2px solid var(--c);border-radius:6px;color:#152238;text-decoration:none;transition:transform .15s,box-shadow .15s,opacity .2s}
.hs a.el:hover,.hs a.el:focus-visible{transform:translateY(-3px);box-shadow:0 6px 0 var(--c)}
.hs a.el:focus-visible{outline:3px solid #ffc61a;outline-offset:2px}
.hs .el .no{font-weight:700;font-size:.85rem;color:var(--c)}
.hs .el .tm{position:absolute;top:8px;right:10px;font-size:.68rem;font-weight:600;color:#33415a;max-width:60%;text-align:right;line-height:1.2}
.hs .el .sym{align-self:center;font-family:var(--hf);font-weight:800;font-size:2.3rem;line-height:1;color:var(--c)}
.hs .el.nature .sym{color:#7a5800}
.hs .el .nm{font-size:.8rem;font-weight:600;line-height:1.2}
.hs .el .ft{display:flex;justify-content:space-between;align-items:center;margin-top:5px;font-size:.72rem;font-weight:700}
.hs .lv{display:inline-flex;gap:3px;vertical-align:middle}
.hs .lv i{width:8px;height:8px;border-radius:50%;border:1.5px solid #152238;background:#fff}
.hs .lv i.on{background:#152238}
.hs .keytile{--c:#152238;--b:#fff;border-style:dashed;grid-column:span 2;grid-row:span 2;aspect-ratio:auto;padding:14px 16px}
.hs .keytile .sym{font-size:4.6rem}.hs .keytile .nm{font-size:1rem}.hs .keytile .no{font-size:1rem}.hs .keytile .tm{font-size:.85rem;top:14px;right:16px}.hs .keytile .ft{font-size:.9rem}
.hs .pt[data-show="chem"] .el:not(.chem,.keytile),.hs .pt[data-show="phys"] .el:not(.phys,.keytile),.hs .pt[data-show="nature"] .el:not(.nature,.keytile),.hs .pt[data-show="sky"] .el:not(.sky,.keytile){opacity:.18}
.hs .pt-legend{display:flex;flex-wrap:wrap;gap:6px 22px;font-size:.88rem;color:var(--muted);margin:14px 0 0}
.hs .pt.mini{grid-template-columns:repeat(auto-fill,minmax(108px,1fr));gap:6px;margin:0 0 1.6em}
.hs .pt.mini .el .sym{font-size:1.9rem}
/* Experiment cards */
.hs .xps{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,520px),1fr));gap:22px;margin:0 0 2em}
.hs .xp{display:grid;grid-template-columns:118px minmax(0,1fr);gap:18px;align-items:start;background:#fff;border:2px solid #d4e1f3;border-left:8px solid var(--c);border-radius:14px;padding:18px;scroll-margin-top:16px}
.hs .xp>.el{position:sticky;top:12px}
.hs .xp h3{margin:0;font-size:1.35rem}
.hs .xp-m{margin:.2em 0 .8em;font-size:.88rem;font-weight:600;color:var(--muted)}
.hs .xp-cols{display:grid;grid-template-columns:minmax(0,.85fr) minmax(0,1.15fr);gap:16px}
.hs .xp h4{margin:0 0 .3em;font-family:var(--bf);font-size:.78rem;text-transform:uppercase;letter-spacing:.08em;color:var(--c)}
.hs .xp ul,.hs .xp ol{padding-left:1.2em;margin:0 0 .9em;font-size:.95rem}
.hs .xp p{margin:0 0 .6em;font-size:.95rem}
.hs .xp-s{background:#fffbea;border-radius:8px;padding:6px 10px}
.hs .xp-g{background:#eef9f2;border-radius:8px;padding:6px 10px}
/* Age ladder */
.hs .ladder{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,340px),1fr));gap:20px;margin:0 0 2em}
.hs .rung{background:#fff;border:2px solid #d4e1f3;border-radius:14px;padding:16px 18px 4px}
.hs .rung h3{margin:0 0 .3em;color:#0e3f8c}.hs .rung p{font-size:.95rem}
@media(max-width:700px){.hs .xp{grid-template-columns:1fr}.hs .xp>.el{position:static;width:118px}.hs .xp-cols{grid-template-columns:1fr;gap:0}.hs .pt{grid-template-columns:repeat(auto-fill,minmax(100px,1fr))}.hs .el .sym{font-size:1.9rem}.hs .keytile .sym{font-size:3.4rem}}
@media(min-width:1800px){.hs{font-size:18.5px}.hs .pt{grid-template-columns:repeat(auto-fill,minmax(140px,1fr))}.hs .el .sym{font-size:2.7rem}.hs .el .nm{font-size:.88rem}.hs .keytile .sym{font-size:5.4rem}.hs .keytile .nm{font-size:1.05rem}}
@media(min-width:2300px){.hs .pt{grid-template-columns:repeat(auto-fill,minmax(156px,1fr))}}