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48px}.back{font-size:13px}.lesson-heading{margin-bottom:24px}h1{font-size:32px;letter-spacing:-.5px;line-height:1.3;margin:12px 0 8px}.lesson-heading p{margin:0;color:var(--muted)}.lesson-layout{display:grid;grid-template-columns:290px minmax(0,1fr);gap:24px;align-items:start}.list-caption{font-size:12px;color:var(--muted);margin-bottom:10px}.lesson-list{display:grid;gap:8px}.lesson-choice{display:flex;align-items:center;gap:12px;padding:15px 12px;border:1px solid var(--line);border-radius:12px;background:white;color:var(--ink);min-width:0}.lesson-choice strong{font-size:15px;display:block}.lesson-choice small{font-size:12px;color:var(--muted);display:block}.lesson-id{font-weight:700;font-size:14px;color:var(--accent);background:#edf3fc;border-radius:8px;padding:6px}.choice-arrow{margin-left:auto;color:var(--muted)}.lesson-choice[aria-current=true]{border-color:var(--accent);background:#edf3fc;box-shadow:0 3px 12px #30588d0a}.lesson-detail{background:white;border:1px solid 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img{display:block;width:1200px;max-width:none;height:auto}.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip-path:inset(50%)}[hidden]{display:none!important}@media(hover:hover){.lesson-choice:hover{background:#edf3fc;box-shadow:0 4px 14px #233d5910}a:hover{text-decoration:underline}button:hover:not(:disabled){background:#e9f0fa}}@media(max-width:750px){.nav{padding:10px 16px;flex-wrap:wrap;gap:10px}nav{font-size:12px;gap:16px}.brand .partner-logo{max-height:32px}main{padding:18px 14px 32px}.lesson-heading{margin-bottom:16px}h1{font-size:25px}.lesson-heading p{font-size:14px}.lesson-layout{grid-template-columns:minmax(0,1fr);gap:16px}.lesson-list{grid-template-columns:repeat(2,minmax(0,1fr));gap:7px}.lesson-choice{padding:10px 8px;gap:8px;border-radius:9px}.lesson-choice strong{font-size:13px;line-height:1.4}.lesson-choice small{font-size:10px;line-height:1.5}.lesson-id{font-size:12px;padding:4px}.choice-arrow{display:none}.detail-heading{padding:16px 14px 10px}h2{font-size:21px}.detail-heading p{font-size:13px}.lesson-tabs{padding:0 14px}.reader-toolbar{padding:10px;gap:8px}.reader-links{width:100%;justify-content:space-between}.page-frame{padding:8px}.page-frame img{max-height:60dvh}.code-frame{padding:6px}#codePanel{padding:14px}footer{padding:18px 16px}.zoom-content img{width:1000px}.lesson-notes{margin:14px}.list-caption{margin-bottom:6px}}
/* Preview-first workspace: topic context stays beside the document. */
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