/* Reading pages share the site's colors and typography. */
.learn-index{max-width:1160px;margin:64px auto 80px;padding:0 24px}.learn-index h1{font-size:clamp(32px,4vw,48px);line-height:1.55;letter-spacing:-.04em}.learn-intro{font-size:17px;line-height:2;margin:20px 0 34px}.lesson-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}.lesson-card{display:flex;flex-direction:column;background:white;border:1px solid #dce4f2;border-radius:14px;padding:26px;text-decoration:none;transition:transform .15s,border-color .15s;color:#23334c}.lesson-card:hover{transform:translateY(-3px);border-color:#7c9be3}.lesson-label{font-size:11px;font-weight:600;color:#5d7194;letter-spacing:.06em;display:block}.lesson-card .lesson-label{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap}.lesson-symbol{font-size:32px;font-weight:700;color:#355dd1;letter-spacing:-.04em;margin:32px 0 24px}.lesson-card h2{font-size:20px}.lesson-card p{font-size:14px;margin-bottom:28px}.card-bottom{margin-top:auto;padding-top:18px;border-top:1px solid #e6ebf4;color:#335fc4;font-size:14px;display:flex;gap:8px;flex-wrap:wrap;justify-content:space-between}.card-bottom small{color:#63728a}.learn-note{margin:28px 0;padding:24px;background:#edf2fc;border-radius:12px}.learn-note p{margin-bottom:0}.lesson-layout{display:grid;grid-template-columns:230px minmax(0,800px);gap:42px;max-width:1160px;margin:40px auto 64px;padding:0 24px}.lesson-toc{position:sticky;top:28px;align-self:start}.lesson-toc>a{font-size:14px}.lesson-toc nav{margin-top:28px;display:grid;gap:8px}.lesson-toc nav a{font-size:13px;padding:7px 0;text-decoration:none;color:#536888}.lesson-toc nav a:hover{color:#355dd1;text-decoration:underline}.lesson-heading>p:not(.info-eyebrow):not(.info-updated){font-size:16px;line-height:2}.lesson-heading{margin-bottom:28px}.lesson-article{padding:34px 38px}.lesson-article section{scroll-margin-top:24px}.lesson-article h2{font-size:21px;margin-top:8px}.lesson-article p,.lesson-article li{line-height:2}.lesson-article strong{color:#253b5b}.lesson-article code{font-size:.95em;color:#294c98;background:#f0f4fb;border-radius:4px;padding:2px 5px;overflow-wrap:anywhere}.table-scroll{overflow-x:auto;margin:20px 0;border:1px solid #dce4f2;border-radius:8px}.table-scroll:focus-visible{outline:3px solid #365fd8;outline-offset:3px}table{border-collapse:collapse;width:100%;font-size:14px}caption{text-align:left;padding:12px 14px;font-size:12px;color:#64748b;background:#f7f9fd}th,td{text-align:left;padding:12px 14px;border-bottom:1px solid #e3e9f3;vertical-align:top}thead th{background:#edf2fc;color:#2e4a78}tbody th{white-space:nowrap}tbody tr:last-child>*{border-bottom:0}.bit-strip{display:flex;margin:20px 0;border-radius:9px;overflow:hidden;font-size:12px;text-align:center;line-height:1.6}.bit-strip span:first-child{background:#355dd1;color:white;flex:27;padding:22px 8px}.bit-strip span:last-child{background:#dce6ff;color:#2c4b84;flex:5;min-width:72px;padding:12px 6px}.lesson-steps li{padding:6px 0 12px}.range-strip{display:flex;border:1px solid #dbe4f3;border-radius:8px;text-align:center;font-size:14px;margin:22px 0;overflow:hidden}.range-strip>span{padding:14px 8px;flex:1;background:#f0f3f9}.range-strip>strong{padding:14px 8px;flex:2;background:#e7efff}.range-strip small{display:block;font-size:10px;font-weight:400}.worked-example{background:#f3f6fc;border-radius:10px;padding:22px;margin:20px 0}.sequence-line{display:flex;align-items:center;justify-content:space-between;gap:8px;font-size:12px;padding:12px 0}.sequence-line strong{color:#355dd1}.formula{text-align:center;font-size:20px!important;padding:20px 10px;background:#edf2fc;border-radius:8px}.dns-flow{padding:0;list-style:none}.dns-flow li{display:flex;gap:16px;padding:16px;background:#f5f7fc;border-radius:9px;margin:12px 0}.dns-flow li>span{flex-shrink:0;font-size:13px;color:#355dd1;font-weight:700;padding-top:1px}.dns-flow p{font-size:14px;margin:4px 0 0}.practice-box .info-back{margin:8px 0 18px}.practice-box details{font-size:13px}.practice-box summary{cursor:pointer;padding:10px 0;color:#536888}.practice-box li,.lesson-refs li{font-size:13px}.lesson-next{display:flex;gap:16px;flex-wrap:wrap;margin:24px 0}.lesson-next a{font-size:14px;background:white;border:1px solid #dce4f2;border-radius:8px;padding:12px 16px;text-decoration:none}.lesson-refs p{font-size:13px}.lesson-article .info-notice{margin-top:18px}
@media(max-width:900px){.lesson-grid{grid-template-columns:1fr}.lesson-symbol{margin:20px 0}.lesson-card{padding:24px}.lesson-layout{grid-template-columns:1fr;gap:28px;max-width:800px}.lesson-toc{position:static}.lesson-toc nav{margin-top:18px;padding:18px;background:#edf2fc;border-radius:10px;gap:0}.lesson-toc nav a{padding:8px 0}.lesson-layout{margin-top:24px}}
@media(max-width:600px){.learn-index{margin:34px auto 50px;padding:0 20px}.learn-index h1{font-size:32px}.learn-intro{font-size:15px}.lesson-layout{padding:0 16px}.lesson-article{padding:24px 18px}.lesson-heading h1{font-size:28px}.lesson-article h2{font-size:19px}.lesson-article p,.lesson-article li{font-size:14px}th,td{padding:10px;font-size:12px}.worked-example{padding:16px}.sequence-line{font-size:10px}.lesson-next{flex-direction:column}.range-strip>span,.range-strip>strong{padding:12px 4px}.range-strip small{font-size:9px}.learn-note{padding:20px}}
@media(prefers-reduced-motion:reduce){.lesson-card{transition:none}.lesson-card:hover{transform:none}}