/* Classroom-only stationery palette, keeping the site's editorial typography. */
body.classroom{--it-paper:#f4f6f3;--it-surface:#fffef9;--it-primary:#245d70;--it-primary-dark:#173e4c;--it-border:#bfcacb;margin:0;background:var(--it-paper);font-size:17px}
.classroom *{box-sizing:border-box}.classroom .wrap{width:min(1120px,calc(100% - 40px));margin:auto}.class-header{border-top:6px solid #245d70;border-bottom:1px solid var(--it-border);padding:20px 0}.class-brand{font-family:Georgia,serif;font-size:23px;color:var(--it-ink);text-decoration:none}.class-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap}.class-nav{display:flex;gap:20px;flex-wrap:wrap;font-size:15px}.classroom main{padding:36px 0 60px}.crumb{font-size:14px;margin-bottom:30px}.eyebrow{text-transform:uppercase;letter-spacing:.12em;font-size:12px;font-weight:bold;color:#245d70}.classroom h1{font-size:clamp(38px,6vw,64px);font-weight:400;max-width:900px;margin:12px 0 20px}.intro{font-size:21px;max-width:780px}.classroom h2{font-size:30px;font-weight:400;margin:0 0 18px}.classroom h3{font-size:23px;font-weight:400}.classroom section{margin-top:42px}.lesson-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:28px;margin-top:38px}.lesson-card{border-top:3px solid #245d70;padding-top:18px}.lesson-card h2{font-size:28px}.lesson-number{font-family:Georgia,serif;font-size:40px;color:#245d70}.lesson-layout{display:grid;grid-template-columns:300px minmax(0,1fr);gap:36px;align-items:start}.experiment{background:var(--it-surface);border:1px solid var(--it-border);padding:24px}.controls{display:grid;gap:16px}.classroom label{font-size:15px;font-weight:bold;display:block}.classroom input,.classroom select{font:inherit;background:white;color:#252823;border:1px solid #78898c;width:100%;padding:10px;margin-top:5px;border-radius:0;min-height:44px}.classroom button,.button-link{font:inherit;display:inline-block;background:#245d70;color:white;border:1px solid #245d70;padding:10px 16px;min-height:44px;cursor:pointer;text-decoration:none}.classroom button.secondary{background:transparent;color:#245d70}.classroom :focus-visible{outline:3px solid #9d4d17;outline-offset:3px}.actions{display:flex;gap:10px;flex-wrap:wrap;margin:18px 0}.hint,.meta{font-size:14px;color:#505b5d}.table-scroll{overflow-x:auto;max-width:100%;margin:18px 0}.classroom table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums;font-size:15px}.classroom th,.classroom td{text-align:right;border-bottom:1px solid #c9d2d2;padding:10px;white-space:nowrap}.classroom th:first-child,.classroom td:first-child{text-align:left}.classroom caption{text-align:left;font-weight:bold;margin:10px 0}.classroom details{border-top:1px solid var(--it-border);padding:16px 0}.classroom summary{cursor:pointer;font-weight:bold;min-height:35px}.note{border-left:3px solid #245d70;padding:14px 20px;background:#e8eff0}.error{color:#8b231c;font-weight:bold}.result-line{font-size:20px}.chart{width:100%;height:auto;display:block;background:white;border:1px solid #d9dfdf}.classroom footer{border-top:1px solid var(--it-border);padding:28px 0;font-size:14px}.footer-links{display:flex;gap:20px;flex-wrap:wrap}.classroom ol li,.classroom ul li{margin-bottom:12px}.classroom [hidden]{display:none!important}.teacher{max-width:850px}.classroom .skip-link{position:absolute;left:10px;top:-100px;background:white;padding:12px;z-index:10}.classroom .skip-link:focus{top:10px}
@media(max-width:760px){.lesson-grid,.lesson-layout{grid-template-columns:1fr}.classroom .wrap{width:calc(100% - 28px)}.classroom main{padding-top:24px}.experiment{padding:18px}.intro{font-size:19px}.class-nav{gap:14px}.classroom h1{font-size:39px}}
@media print{.class-header,.classroom footer,.actions,.controls,.prediction,.no-print{display:none!important}.classroom main{padding:0}.classroom .wrap{width:100%}.lesson-layout,.lesson-grid{display:block}.experiment{border:0;padding:0}.classroom details{break-inside:avoid}.classroom details>*{display:block!important}.classroom section{margin-top:24px}.chart{max-height:220px}.classroom a{color:#000}.classroom body{background:white}}