.lesson-nav{display:flex;flex-wrap:wrap;gap:12px;align-items:center;justify-content:space-between;margin:24px 0;padding:16px;border:1px solid currentColor;border-radius:12px}.lesson-nav a{display:inline-flex;align-items:center;min-height:44px;padding:8px 12px;text-decoration:underline}.lesson-title{font-size:clamp(1.7rem,4vw,2.5rem);line-height:1.2;margin:28px 0}.course-resume{display:block;padding:16px;border:1px solid currentColor;border-radius:10px;margin-block:16px;font-weight:700}.unit{content-visibility:auto;contain-intrinsic-size:auto 1200px}@media print{.unit{content-visibility:visible}.lesson-nav,.course-resume{display:none}}