.section-title { margin: 0 0 10px; }
    .quiz-item { display: grid; grid-template-columns: 1fr 120px; gap: 14px; align-items: center; border: 1px solid #d6e3f3; border-radius: 14px; padding: 14px; background: #fff; }
    .quiz-item + .quiz-item { margin-top: 12px; }
    .quiz-item h3 { margin: 0 0 8px; font-size: 1rem; }
    .quiz-options { display: grid; gap: 6px; margin-bottom: 8px; }
    .quiz-actions { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
    .quiz-feedback { font-weight: 700; font-size: .92rem; }
    .quiz-feedback.ok { color: var(--ok); }
    .quiz-feedback.bad { color: var(--warn); }
    .bulb-icon { width: 92px; height: 92px; justify-self: center; }
    .bulb-icon .glow, .bulb-icon .crack { opacity: 0; transition: opacity .2s ease; }
    .bulb-icon.correct .glow { opacity: 1; }
    .bulb-icon.correct .glass { fill: #ffe38b; stroke: #b8860b; }
    .bulb-icon.wrong .filament { opacity: 0; }
    .bulb-icon.wrong .glass { fill: #c8ccd1; stroke: #6b7280; }
    .bulb-icon.wrong .crack { opacity: 1; }
    .motor-wrap { margin-top: 16px; padding: 14px; border-radius: 16px; border: 1px solid #b8d3f1; background: #eef6ff; display: none; }
    .motor-wrap.active { display: block; }
    .motor-svg { width: 100%; max-width: 540px; display: block; margin: 0 auto; background: #f8fcff; border-radius: 12px; border: 1px solid #c8def5; }

    .crossword-wrap { margin-top: 16px; }
    .crossword-layout { display: grid; grid-template-columns: auto 1fr; gap: 16px; align-items: start; }
    .crossword-board { display: grid; grid-template-columns: repeat(13, 32px); grid-template-rows: repeat(13, 32px); gap: 2px; background: #d7e6f8; padding: 8px; border-radius: 12px; width: fit-content; }
    .cw-cell { position: relative; width: 32px; height: 32px; background: #0f1f35; border-radius: 4px; }
    .cw-cell.play { background: #fff; border: 1px solid #aac7e8; }
    .cw-cell input { width: 100%; height: 100%; border: none; text-transform: uppercase; text-align: center; font-weight: 800; font-size: 1rem; background: transparent; color: #143150; outline: none; }
    .cw-num { position: absolute; top: 1px; left: 2px; font-size: .55rem; color: #4a6a8f; font-weight: 700; }
    .crossword-clues { background: #fff; border: 1px solid #d5e3f3; border-radius: 12px; padding: 10px; }
    .crossword-clues h3 { margin: 0 0 8px; font-size: 1rem; }
    .crossword-clues ol { margin: 0; padding-left: 18px; display: grid; gap: 6px; }
    .crossword-actions { margin-top: 10px; display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
    .cw-feedback { font-weight: 700; }
    .crossword-wrap.show-solution .cw-cell.play input { background: #ffd9d9 !important; color: #7f1d1d; }
    .crossword-wrap.complete .crossword-board,
    .crossword-wrap.complete .crossword-clues { box-shadow: 0 0 0 2px #ffd54a, 0 0 20px rgba(255, 213, 74, .8); animation: cwGlow 1s ease-in-out infinite alternate; }
    .exercise-page .lesson-header { margin-bottom: 28px; }
    .exercise-category { margin: 0 0 14px; border: 1px solid #d9dfe2; border-radius: 12px; overflow: hidden; background: #fff; color: #25343a; }
    .exercise-category > summary { display: grid; grid-template-columns: 105px minmax(0, 1fr) auto 18px; align-items: center; gap: 16px; min-height: 88px; padding: 18px 22px; background: #3d444c; color: #fff; cursor: pointer; list-style: none; }
    .exercise-category > summary::-webkit-details-marker { display: none; }
    .exercise-category > summary::after { content: '⌄'; font-size: 25px; line-height: 1; color: #b6c3cc; transform: rotate(0); transition: transform .2s ease; }
    .exercise-category[open] > summary::after { transform: rotate(180deg); }
    .exercise-category > summary:hover { background: #343c43; }
    .exercise-category > summary:focus-visible { outline: 3px solid #149982; outline-offset: -5px; }
    .exercise-category-number { color: #b6c3cc; font-size: .69rem; font-weight: 800; letter-spacing: .09em; }
    .exercise-category-name { font-size: 1.2rem; font-weight: 700; }
    .exercise-category-count { font-size: .78rem; font-weight: 700; color: #c6d3d8; white-space: nowrap; }
    .exercise-category-body { padding: 22px; border-top: 1px solid #d9dfe2; }
    .exercise-category-body > p:first-child { margin-top: 0; color: #5a6972; }
    .exercise-category-body button { border-radius: 5px; }
    .exercise-page .lesson-next { margin-top: 32px; }
    .exercise-page .quiz-item { border-color: #dae1e5; border-radius: 10px; }
    .exercise-page .crossword-board { background: #d9e7e2; }
    .exercise-page .cw-cell { background: #25343a; }
    .exercise-page .cw-cell.play { border-color: #b6d4ca; }
    .exercise-page .crossword-clues { border-color: #dae1e5; }
    .activity-intro { max-width: 75ch; }
    .activity-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; margin-top: 16px; }
    .activity-card { border: 1px solid #dae1e5; border-radius: 10px; padding: 18px; background: #fff; }
    .activity-card h3 { margin: 0 0 10px; font-size: 1.08rem; }
    .activity-card p { margin: 8px 0; }
    .activity-card ol { margin: 10px 0; padding-left: 22px; }
    .activity-card li + li { margin-top: 6px; }
    .activity-tag { display: inline-block; margin-bottom: 10px; color: #148570; font-size: .8rem; font-weight: 800; letter-spacing: .04em; text-transform: uppercase; }
    .activity-card details { margin-top: 14px; border-top: 1px solid #deebf3; padding-top: 12px; }
    .activity-card summary { color: #137860; cursor: pointer; font-weight: 700; }
    .activity-card details p { margin-bottom: 0; }
    .activity-safety { margin: 16px 0 0; border-left: 4px solid #dc8b25; border-radius: 8px; padding: 12px 15px; background: #fff8ed; }
    .activity-sources { margin: 14px 0 0; font-size: .85rem; }
    @media (max-width: 760px) { .activity-grid { grid-template-columns: 1fr; } .exercise-category > summary { grid-template-columns: minmax(0, 1fr) auto 18px; gap: 4px 12px; } .exercise-category-number { grid-column: 1 / -1; } .exercise-category-name { font-size: 1.06rem; } .exercise-category-body { padding: 16px; } }
    @media print { .exercise-category > summary { background: #fff; color: #25343a; min-height: 0; padding: 12px 0; } .exercise-category-number, .exercise-category-count { color: #53636c; } .exercise-category > summary::after, .quiz-actions, .crossword-actions { display: none; } .exercise-category:not([open]) > .exercise-category-body { display: block; } .activity-card { break-inside: avoid; } }
    @keyframes cwGlow { from { filter: brightness(1); } to { filter: brightness(1.12); } }
    @media (max-width: 980px) { .crossword-layout { grid-template-columns: 1fr; } }
    @media (max-width: 760px) { .quiz-item { grid-template-columns: 1fr; } }
  
.crossword-layout { overflow-x:auto; padding-bottom:8px; }

.electric-activity-list { display:grid; gap:14px; }
.electric-activity-link { display:grid; grid-template-columns:48px 1fr 24px; gap:18px; align-items:center; padding:24px; border:1px solid #d9dfe2; border-radius:12px; background:#fff; color:#25343a; text-decoration:none; transition:border-color .2s,background .2s; }
.electric-activity-link:hover { border-color:#137860; background:#f2f8f5; }
.electric-activity-link:focus-visible { outline:3px solid #149982; outline-offset:3px; }
.electric-activity-link h2 { font-size:1.2rem; margin:0 0 6px; }
.electric-activity-link p { margin:0; color:#5a6972; }
.electric-activity-number { color:#137860; font-weight:800; }
@media(max-width:600px) { .electric-activity-link { padding:18px; gap:10px; grid-template-columns:28px 1fr 18px; } }