:root{--ink:#182024;--muted:#5d696c;--paper:#f2f0e8;--panel:#fbfaf5;--yellow:#ffd84c;--orange:#f26b38;--teal:#167f78;--line:#cfd2c8;--shadow:0 24px 70px rgba(31,37,38,.12)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;line-height:1.62}a{color:inherit}.skip{position:absolute;left:-999px}.skip:focus{left:12px;top:12px;background:white;padding:10px;z-index:10}.site-header{position:sticky;top:0;z-index:5;background:rgba(242,240,232,.94);border-bottom:1px solid var(--line);backdrop-filter:blur(12px)}.nav,main,.footer-inner{width:min(1150px,calc(100% - 40px));margin:auto}.nav{min-height:72px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:flex;align-items:center;text-decoration:none;font-weight:900;letter-spacing:-.03em}.brand i{display:grid;place-items:center;width:36px;height:36px;background:var(--yellow);border:2px solid var(--ink);font-style:normal;margin-right:10px;transform:rotate(-4deg)}.nav-links{display:flex;gap:24px;align-items:center}.nav a{text-decoration:none;font-weight:750}.button{display:inline-flex;justify-content:center;align-items:center;background:var(--ink);color:#fff;border:2px solid var(--ink);padding:12px 19px;text-decoration:none;font-weight:850;box-shadow:5px 5px 0 var(--orange)}.button.small{padding:8px 14px}.hero{display:grid;grid-template-columns:1.08fr .92fr;gap:72px;align-items:center;min-height:690px;padding:92px 0}.eyebrow{color:var(--teal);font-size:.77rem;font-weight:950;text-transform:uppercase;letter-spacing:.17em}h1,h2,h3{margin:0;line-height:1.04;letter-spacing:-.045em}h1{font-size:clamp(3.6rem,7vw,6.8rem)}h2{font-size:clamp(2.2rem,4vw,4rem)}h3{font-size:1.2rem}.lead{font-size:1.2rem;color:var(--muted);max-width:700px;margin:28px 0}.diagram{min-height:480px;position:relative;background:var(--panel);border:2px solid var(--ink);box-shadow:12px 12px 0 var(--yellow);overflow:hidden}.diagram:before{content:"";position:absolute;inset:0;background-image:radial-gradient(var(--line) 1px,transparent 1px);background-size:24px 24px}.node{position:absolute;z-index:1;display:grid;place-items:center;width:145px;height:145px;border-radius:50%;background:var(--panel);border:2px solid var(--ink);text-align:center;font-weight:900}.node.center{top:50%;left:50%;transform:translate(-50%,-50%);background:var(--yellow);font-size:1.2rem}.node.observe{top:10%;left:8%}.node.test{top:12%;right:7%;background:#d6f1ed}.node.learn{bottom:8%;left:16%;background:#ffe0d3}.arrow{position:absolute;z-index:0;border:2px dashed var(--teal);border-radius:50%;inset:58px;transform:rotate(11deg)}.section{padding:90px 0;border-top:1px solid var(--line)}.section-head{display:grid;grid-template-columns:.88fr 1.12fr;gap:80px;margin-bottom:44px}.section p,.cards p,.article p,.article li{font-size:1.08rem;color:var(--muted)}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}.cards article{background:var(--panel);border:2px solid var(--ink);padding:30px;box-shadow:7px 7px 0 var(--line)}.cards span{font-weight:900;color:var(--teal);font-size:.8rem}.cards h3{margin:18px 0 9px}.callout{margin-bottom:90px;background:var(--teal);color:white;padding:58px;display:grid;grid-template-columns:1fr auto;gap:40px;align-items:center;border:2px solid var(--ink);box-shadow:10px 10px 0 var(--yellow)}.callout p{color:#d9f1ed;max-width:730px}.callout .eyebrow{color:var(--yellow)}.callout .button{background:white;color:var(--ink)}.article{max-width:850px;padding:86px 0 120px}.article h1{font-size:clamp(3.2rem,6vw,5.6rem)}.article h2{font-size:2.1rem;margin-top:56px}.principle{display:grid;grid-template-columns:70px 1fr;gap:20px;margin:28px 0;padding:25px;background:var(--panel);border:1px solid var(--line)}.principle b{font-size:1.6rem;color:var(--orange)}.note{padding:24px;border-left:5px solid var(--yellow);background:var(--panel)}.site-footer{border-top:1px solid var(--line)}.footer-inner{padding:30px 0 46px;display:flex;justify-content:space-between;gap:20px;color:var(--muted);font-size:.9rem}.footer-inner nav{display:flex;gap:18px}.footer-inner a{text-decoration:none;font-weight:700}@media(max-width:850px){.hero,.section-head{grid-template-columns:1fr}.hero{padding:64px 0}.cards{grid-template-columns:1fr 1fr}.callout{grid-template-columns:1fr}.nav-links>a:first-child{display:none}}@media(max-width:560px){.nav,main,.footer-inner{width:min(100% - 28px,1150px)}.brand{font-size:.86rem}.button.small{font-size:.76rem}.cards{grid-template-columns:1fr}.diagram{min-height:360px}.node{width:105px;height:105px;font-size:.75rem}.callout{padding:32px}.footer-inner{flex-direction:column}.principle{grid-template-columns:1fr}}