/* Original, strictly page-138 scoped Video Chapters. No theme/global overrides. */
.tutin-a25-chapters,.tutin-a25-chapters *{box-sizing:border-box}
.tutin-a25-chapters{max-width:1100px;margin:30px auto;padding:clamp(16px,3vw,28px);background:#f5fafb;border:1px solid #cbdde0;border-radius:16px;color:#1b3947;overflow-wrap:anywhere}
.tutin-a25-chapters h2{font-size:clamp(22px,3vw,30px);line-height:1.3;margin:10px 0}
.tutin-a25-chapters p{line-height:1.65}
.tac25-kicker{font-size:12px;letter-spacing:.08em;color:#096673;font-weight:800}
.tac25-chapter-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(210px,100%),1fr));gap:12px}
.tac25-chapter-grid button{cursor:pointer;text-align:left;border:1px solid #90b3ba;background:#fff;color:#183a44;border-radius:11px;padding:13px;min-width:0;line-height:1.3;font:inherit}
.tac25-chapter-grid button:hover:not(:disabled){border-color:#076a78;background:#eef8f9}
.tac25-chapter-grid button:disabled{cursor:not-allowed;opacity:.62}
.tac25-chapter-grid button:focus-visible,.tutin-a25-chapters a:focus-visible{outline:3px solid #bc6505;outline-offset:3px}
.tac25-chapter-grid button span,.tac25-chapter-grid button small{display:block;margin:5px 0}
.tac25-chapter-grid .tac25-time{font-size:13px;font-variant-numeric:tabular-nums;font-weight:800;color:#086f7b}
.tac25-chapter-grid .tac25-name{font-size:17px;font-weight:750}
.tac25-chapter-grid button small{color:#516774;font-size:13px}
.tac25-status{padding:12px 14px;background:#fff;border-left:4px solid #077383;border-radius:8px;margin:17px 0}
.tutin-a25-chapters a{color:#066a7b;font-weight:700}
@media(max-width:425px){.tac25-chapter-grid{grid-template-columns:1fr}.tutin-a25-chapters{margin:18px auto}}
@media(prefers-reduced-motion:reduce){.tutin-a25-chapters *{scroll-behavior:auto!important;transition:none!important}}