.learn { padding-bottom: 60px; }
.learn h1 { font-size: clamp(38px, 5.4vw, 66px); max-width: 19ch; }
.learn h2 { font-size: 30px; line-height: 1.2; }
.learn h3 { font-size: 24px; }
.learn section { padding: 28px 0; }
.breadcrumb { margin: 28px 0 0; color: var(--muted); font-size: 15px; }
.lesson-hero { padding: 48px 0; }
.lesson-hero .lede { max-width: 48ch; }
.lesson-actions { display: flex; flex-wrap: wrap; gap: 12px; margin: 26px 0 12px; }
.subtle, .lesson-screen figcaption { color: var(--muted); font-size: 15px; }
.lesson-layout { display: grid; grid-template-columns: minmax(0, 1fr) 320px; gap: 48px; align-items: start; }
.lesson-layout article { min-width: 0; }
.lesson-screen { margin: 0 0 24px; }
.lesson-screen img { border: 1px solid var(--line-strong); border-radius: 14px; width: 100%; height: auto; }
.lesson-screen figcaption { padding-top: 10px; }
.lesson-card { border: 1px solid var(--line-strong); border-radius: var(--radius); padding: 24px; margin-bottom: 22px; background: var(--bg-card); }
.lesson-card h2 { font-size: 24px; }
.lesson-card ol, .lesson-card ul { padding-left: 22px; }
.lesson-card li { margin-block: 12px; overflow-wrap: anywhere; }
.lesson-steps { padding-left: 30px; }
.lesson-steps > li { padding-left: 8px; margin: 32px 0; }
.lesson-steps > li::marker { color: var(--gold); font-weight: 700; }
.learn details { border-top: 1px solid var(--line-strong); padding: 14px 0; }
.learn summary { cursor: pointer; min-height: 28px; }
.learn label { display: block; cursor: pointer; padding: 10px 0; }
.learn [hidden] { display: none; }
.learn input[type=checkbox] { width: 20px; height: 20px; margin-right: 8px; vertical-align: middle; accent-color: var(--gold); }
.learn-footer { padding-block: 24px 50px; border-top: 1px solid var(--line-strong); color: var(--muted); }
@media (max-width: 850px) { .lesson-layout { grid-template-columns: 1fr; gap: 16px; } .lesson-aside { display: grid; grid-template-columns: 1fr; } .learn .lesson-hero { padding-top: 32px; } }
@media (max-width: 420px) { .nav .wrap { gap: 14px; } .nav .btn { font-size: 12px; padding: 10px; } .lesson-actions .btn { width: 100%; } }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } .btn { transition: none; } }

/* Optional Windows-interest form (task 12.21) */
.windows-interest { margin-top: 18px; padding: 18px; border: 1px solid var(--line); border-radius: var(--radius, 14px); background: var(--bg-card); display: grid; gap: 10px; max-width: 640px; }
.windows-interest h3 { margin: 0; font-size: 17px; }
.windows-interest p { margin: 0; }
.windows-interest label { display: grid; gap: 6px; }
.windows-interest input[type=email] { font: inherit; padding: 10px 12px; border-radius: 10px; border: 1px solid var(--line); background: var(--bg); color: inherit; min-width: 0; }
.windows-interest .consent { display: flex; gap: 10px; align-items: flex-start; }
.windows-interest .consent input { margin-top: 4px; flex: none; }
.windows-interest .windows-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.windows-interest .hp { position: absolute; left: -9999px; width: 1px; height: 1px; overflow: hidden; }
.windows-interest .windows-status:empty { display: none; }
/* Small print sits on the card, where --faint falls below 4.5:1. */
.windows-interest .fine { color: var(--muted); }

/* Lesson video (self-hosted, captions and chapters). */
#video video { width: 100%; height: auto; border-radius: 12px; background: #000; }
.video-chapters { list-style: none; padding: 0; margin: 12px 0; display: flex; flex-wrap: wrap; gap: 8px; }
.video-chapters button { font: inherit; font-size: 14px; color: var(--text); background: var(--bg-card); border: 1px solid var(--line-strong); border-radius: 999px; padding: 6px 12px; cursor: pointer; }
.video-chapters button:hover { border-color: var(--gold); }