.lesson-learning { max-width: 940px; padding: 0; overflow: hidden; }
.lesson-heading { padding: 38px 42px 30px; border-bottom: 1px solid var(--line); background: linear-gradient(135deg, #fff, #f7f5ff); }
.lesson-heading h1 { margin: 8px 0 0; }
.learning-section { padding: 36px 42px; border-bottom: 1px solid var(--line); }
.section-heading { display: flex; align-items: center; gap: 16px; margin-bottom: 24px; }
.section-heading h2 { font-size: 27px; line-height: 1.1; margin: 2px 0; }
.section-heading .eyebrow { margin: 0; }
.section-number { display: grid; place-items: center; width: 46px; height: 46px; border-radius: 14px; background: #eeeafd; color: var(--primary); font-weight: 900; }
.lesson-theory { margin: 0; font-size: 17px; line-height: 1.72; }
.lesson-theory p { margin: 0 0 16px; }
.lesson-theory h3 { margin: 34px 0 14px; padding-bottom: 10px; border-bottom: 1px solid var(--line); font-size: 22px; line-height: 1.3; }
.lesson-theory h3:first-child { margin-top: 0; }
.lesson-theory ul { margin: 0 0 22px; padding: 18px 22px 18px 42px; border-radius: 14px; background: #f7f8fc; }
.lesson-theory li { margin: 7px 0; padding-left: 4px; }
.theory-stat { display: inline-flex; margin: 6px 8px 16px 0; padding: 12px 16px; border-radius: 12px; background: #eeeafd; color: var(--primary); font-size: 24px; }
.embedded-materials { display: grid; gap: 24px; }
.embedded-card { border: 1px solid var(--line); border-radius: 18px; overflow: hidden; background: #fafbfe; }
.embedded-card__head { display: flex; justify-content: space-between; align-items: flex-start; gap: 20px; padding: 18px 20px; background: #fff; border-bottom: 1px solid var(--line); }
.embedded-card__head h3 { margin: 6px 0 0; font-size: 19px; }
.embedded-card__head > a { white-space: nowrap; color: var(--primary); font-weight: 700; text-decoration: none; }
.material-badge { display: inline-flex; padding: 4px 8px; border-radius: 999px; background: #eeeafd; color: var(--primary); font-size: 11px; font-weight: 800; text-transform: uppercase; letter-spacing: .08em; }
.material-badge.video { background: #e7f7f1; color: #19805d; }
.material-password { margin: 10px 0 0; color: #555d6d; font-size: 14px; }
.material-password strong { display: inline-block; margin-left: 4px; padding: 3px 8px; border-radius: 7px; background: #f1eefc; color: var(--primary); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.embed-frame-wrap { position: relative; aspect-ratio: 16 / 10; background: #eef0f6; }
.embed-frame-wrap iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.embedded-card video { display: block; width: 100%; max-height: 560px; background: #111; }
.practice-section { background: #fbfaff; }
.practice-task { padding: 20px 22px; border: 1px solid #dcd6ff; border-left: 5px solid var(--primary); border-radius: 14px; background: #fff; font-size: 17px; }
.practice-task p { margin: 0; }
.practice-link { background: #fff; }
.practice-link small { color: var(--primary); font-weight: 700; text-transform: uppercase; letter-spacing: .06em; }
.references-section h2 { margin-top: 0; }
.workbook-source { margin: 28px 42px; border: 1px solid var(--line); border-radius: 14px; background: #fafbfe; }
.workbook-source summary { cursor: pointer; padding: 16px 18px; font-weight: 800; }
.workbook-grid { padding: 0 18px 18px; display: grid; gap: 18px; }
.workbook-grid .workbook-page { margin: 0; }
.lesson-actions { padding: 0 42px 38px; }
.lesson-actions form { margin: 0; }

@media (max-width: 800px) {
  .lesson-learning { padding: 0; }
  .lesson-heading, .learning-section { padding: 26px 22px; }
  .lesson-heading h1 { font-size: 29px; }
  .section-heading h2 { font-size: 23px; }
  .embedded-card__head { display: block; }
  .embedded-card__head > a { display: inline-block; margin-top: 12px; }
  .embed-frame-wrap { aspect-ratio: 4 / 5; }
  .workbook-source { margin: 22px; }
  .lesson-actions { padding: 0 22px 28px; }
}