.lesson-intro{margin:0 0 64px}.lesson-banner{display:flex;align-items:end;justify-content:space-between;gap:28px;margin-bottom:20px}.lesson-banner h2,.prep-heading h2{font-size:2.25rem;line-height:1.05;letter-spacing:-.04em;margin:0}.lesson-banner>p{max-width:480px;color:var(--muted);margin:0}.lesson-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px}.lesson-card{position:relative;background:#fff;border:1px solid var(--line);border-radius:24px;padding:28px;overflow:hidden;box-shadow:var(--shadow)}.lesson-card:before{content:"";position:absolute;left:0;right:0;top:0;height:7px}.area-card:before{background:linear-gradient(90deg,var(--blue),#6d8fff)}.volume-card:before{background:linear-gradient(90deg,#13a8a5,var(--cyan))}.lesson-number{position:absolute;right:22px;top:17px;font-size:2.6rem;line-height:1;font-weight:950;color:#e8eef7}.lesson-card h3{font-size:1.5rem;letter-spacing:-.025em;margin:0 0 10px}.lesson-card>p{color:var(--muted)}.lesson-card h4{margin:20px 0 5px}.concept-box{display:grid;grid-template-columns:1fr auto;gap:8px 18px;background:var(--navy);color:#fff;padding:16px 18px;border-radius:15px;margin:19px 0}.concept-box span{color:#c6d6ee}.concept-box strong{font-size:1.08rem}.unit-chain{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:9px;background:#edf4ff;border-radius:13px;padding:13px;color:var(--navy)}.unit-chain span{font-weight:850}.unit-chain b{color:var(--blue)}.worked-example{margin-top:18px;padding:16px;border:1px solid var(--line);border-radius:14px;background:#fbfcfe}.worked-example>span{font-size:.72rem;letter-spacing:.11em;color:var(--blue);font-weight:900}.worked-example p{margin:5px 0;color:var(--muted)}.worked-example strong{display:block;color:var(--navy)}.learn-more{margin-top:14px;border-top:1px solid var(--line);padding-top:14px}.learn-more summary{cursor:pointer;font-weight:800;color:var(--blue)}.learn-more p{color:var(--muted);margin-bottom:0}.lesson-check{display:flex;justify-content:space-between;align-items:center;gap:24px;background:var(--navy);color:#fff;border-radius:19px;padding:19px 22px;margin-top:18px}.lesson-check>div{display:flex;align-items:center;gap:14px}.lesson-check p{margin:0;color:#d3def0}.lesson-check strong{color:#fff}.check-icon{display:grid;place-items:center;width:38px;height:38px;border-radius:50%;background:var(--cyan);color:var(--navy);font-weight:950;flex:0 0 auto}.prep-link{text-decoration:none;white-space:nowrap}.prep-heading{padding-top:8px;margin-bottom:18px}@media(max-width:760px){.lesson-banner{display:block}.lesson-banner>p{margin-top:10px}.lesson-grid{grid-template-columns:1fr}.lesson-card{padding:23px}.lesson-check{display:block}.lesson-check .primary{display:block;width:100%;margin-top:16px;text-align:center}}