/* Shared reader components: every foreground and surface comes from the theme.
   Keep this file free of literal colors and per-page dark overrides. */
.ut-qa-card {border:0;border-bottom:1px dashed var(--site-line);border-radius:0;background:transparent;box-shadow:none;margin-bottom:2.25rem;padding-bottom:2rem;overflow:visible}
.ut-qa-card:last-child {border-bottom:0}
.ut-qa-card:hover {box-shadow:none;transform:none}
.ut-qa-header,.ut-qa-question-box {background:transparent;border:0;padding:0;position:relative;margin-bottom:.85rem}
.ut-qa-num-badge,.ut-qa-q-badge {display:inline-flex;align-items:center;gap:.35rem;background:var(--site-action);color:var(--site-on-action);font-size:14px;font-weight:700;padding:.3rem .7rem;border-radius:6px;margin-bottom:.6rem;line-height:1.4}
.ut-qa-question-text {font-size:1.15rem;font-weight:700;color:var(--site-ink)!important;line-height:1.85;margin:0;font-family:'Hind Siliguri','Segoe UI',system-ui,sans-serif}
.ut-qa-question-text .katex,.ut-qa-solution-text .katex {color:var(--site-ink);font-weight:inherit}
.ut-qa-solution-box {background:transparent;border:0;padding:0;margin-top:.5rem}
.ut-qa-solution-label {display:flex;align-items:center;gap:.75rem;margin-bottom:.4rem}
.ut-qa-sol-badge {display:inline-flex;align-items:center;gap:.35rem;background:transparent;color:var(--site-success);font-weight:800;font-size:1.05rem;padding:0;box-shadow:none;border-radius:0;line-height:1.6}
.ut-qa-solution-label>span:last-child {display:none}
.ut-qa-solution-text {color:var(--site-ink);font-size:1.08rem;line-height:2.1;background:transparent;border:0;border-radius:0;padding:0;margin-top:.25rem;box-shadow:none;font-family:'Hind Siliguri','Segoe UI',system-ui,sans-serif;white-space:normal!important;overflow-x:auto}
.ut-qa-solution-text strong {display:inline-block;color:var(--site-success)}
.ut-qa-solution-text strong:last-child {background:var(--site-success-bg);border:1px solid var(--site-success-line);border-left:4px solid var(--site-success);padding:.45rem .95rem;border-radius:6px;color:var(--site-success);font-weight:700;font-size:1.05rem;margin-top:.75rem;box-shadow:none}
.ut-qa-solution-text .katex-display,.blog-content-body .katex-display {margin:.35rem 0 .45rem!important;padding:0!important;background:transparent!important;border:0!important;box-shadow:none!important;text-align:left!important}
.ut-qa-solution-text .katex-display>.katex,.blog-content-body .katex-display>.katex {text-align:left!important;display:inline-block!important}
.ut-chapter-nav-card {background:var(--site-surface);border:1px solid var(--site-line);border-radius:14px;box-shadow:none;margin-bottom:1.5rem;overflow:hidden;color:var(--site-ink)}
.ut-pill-scroll-track {display:flex;align-items:center;gap:.5rem;overflow-x:auto;padding:.35rem .25rem .65rem;scrollbar-width:thin;scrollbar-color:var(--site-line) transparent;-webkit-overflow-scrolling:touch}
.ut-pill-scroll-track::-webkit-scrollbar {height:5px}
.ut-pill-scroll-track::-webkit-scrollbar-thumb {background:var(--site-line);border-radius:999px}
.ut-subchapter-pill {display:inline-flex;align-items:center;gap:.4rem;padding:.45rem .95rem;border-radius:999px;font-size:14px;font-weight:600;white-space:nowrap;text-decoration:none;flex-shrink:0;user-select:none}
.ut-subchapter-pill.is-active {background:var(--site-action);color:var(--site-on-action)}
.ut-subchapter-pill.is-inactive {background:var(--site-soft);color:var(--site-muted);border:1px solid var(--site-line)}
.ut-subchapter-pill.is-inactive:hover {background:var(--site-soft);color:var(--site-link);border-color:var(--site-link)}
.ut-mcq-item {background:var(--site-surface);border:1px solid var(--site-line);border-radius:12px;padding:1.25rem 1.5rem;margin-bottom:1.5rem;box-shadow:none;color:var(--site-ink)}
.ut-mcq-item:hover {border-color:var(--site-muted)}
.ut-mcq-q {font-size:1.15rem;font-weight:700;color:var(--site-ink);line-height:1.8;margin-bottom:1rem;font-family:'Hind Siliguri','Segoe UI',system-ui,sans-serif}
.ut-mcq-grid {display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:.75rem;margin-bottom:1rem}
.ut-mcq-opt {background:var(--site-soft);border:1px solid var(--site-line);border-radius:8px;padding:.65rem 1rem;font-size:1rem;color:var(--site-ink);font-weight:500;display:flex;align-items:center;gap:.5rem}
.ut-mcq-opt strong {color:var(--site-ink);background:var(--site-surface);border:1px solid var(--site-line);border-radius:4px;padding:.1rem .45rem;font-size:14px}
.ut-mcq-details {margin-top:.75rem;border-radius:8px;border:1px solid var(--site-success-line);overflow:hidden;background:var(--site-success-bg)}
.ut-mcq-summary {padding:.6rem 1rem;background:var(--site-success-bg);cursor:pointer;font-weight:700;font-size:1rem;color:var(--site-success);user-select:none;display:flex;align-items:center;justify-content:space-between}
.ut-mcq-summary:hover {background:var(--site-soft)}
.ut-mcq-explanation {padding:1rem 1.25rem;background:var(--site-surface);border-top:1px solid var(--site-success-line);color:var(--site-ink);font-size:1.02rem;line-height:1.85}
.ut-mcq-ans-badge {display:inline-block;background:var(--site-success-action);color:var(--site-on-action);font-weight:700;padding:.35rem .85rem;border-radius:6px;margin-bottom:.5rem;font-size:1rem}
.ut-exercise-nav {margin:24px 0;padding:18px 0;border-top:1px solid var(--site-line);border-bottom:1px solid var(--site-line);color:var(--site-ink)}
.ut-exercise-nav__header {display:flex;align-items:baseline;justify-content:space-between;gap:8px 20px;flex-wrap:wrap;margin-bottom:12px}
.ut-exercise-nav__header h2 {margin:0;font-size:16px;font-weight:700;line-height:1.5;color:var(--site-ink)}
.ut-exercise-nav__chapter {font-size:14px;line-height:1.5;color:var(--site-muted);min-width:0;overflow-wrap:anywhere}
.ut-exercise-nav__links {display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.ut-exercise-nav__link,.ut-exercise-nav__boundary {display:flex;flex-direction:column;justify-content:center;gap:5px;min-width:0;padding:12px 16px;border:1px solid var(--site-line);border-radius:12px;background:var(--site-surface);color:var(--site-ink);text-decoration:none;line-height:1.5}
.ut-exercise-nav__label {font-size:14px;font-weight:600;color:var(--site-link)}
.ut-exercise-nav__title {font-size:16px;font-weight:650;line-height:1.5;color:var(--site-ink);overflow-wrap:anywhere}
.ut-exercise-nav__link:hover {background:var(--site-soft);border-color:var(--site-link);color:var(--site-ink)}
.ut-exercise-nav__boundary {background:transparent;border-style:dashed}
.ut-exercise-nav__boundary .ut-exercise-nav__label {color:var(--site-muted)}
.ut-exercise-nav__boundary .ut-exercise-nav__title {font-size:14px;font-weight:400;color:var(--site-muted)}
:is(.ut-exercise-nav__link,.ut-subchapter-pill,.ut-mcq-summary):focus-visible {outline:3px solid var(--site-link);outline-offset:3px}
@media(max-width:575px) {
    .ut-exercise-nav__links {grid-template-columns:1fr;gap:8px}
    .ut-exercise-nav__header {align-items:flex-start;flex-direction:column;gap:4px}
    .ut-mcq-item {padding:18px 16px}
    .ut-mcq-grid {grid-template-columns:minmax(0,1fr)}
}