/* ============================================================
   Course detail page (textbook-chapter reader)
   ============================================================ */

.course-body { background: #0B0B0E; }

/* ---------- Hero ---------- */
.course-hero { position: relative; min-height: 56vh; padding: 200px 24px 80px; overflow: hidden; }
.course-hero-bg { position: absolute; inset: 0; background-size: cover; background-position: center; opacity: 0.55; filter: saturate(0.85); transform: scale(1.06); animation: hero-breathe 28s ease-in-out infinite alternate; }
.course-hero-grad { position: absolute; inset: 0; background: linear-gradient(180deg, rgba(11,11,14,0.55) 0%, rgba(11,11,14,0.92) 65%, #0B0B0E 100%); }
.course-hero-inner { position: relative; max-width: 980px; margin: 0 auto; }
.course-crumbs { display: inline-flex; gap: 10px; align-items: center; font-size: 12px; color: var(--ink-3); letter-spacing: 0.04em; margin-bottom: 26px; }
.course-crumbs a { color: var(--ink-2); }
.course-crumbs a:hover { color: var(--ink-1); }
.course-crumbs-sep { color: var(--ink-4); }
.course-h { font-size: clamp(2.5rem, 6vw, 4.5rem); font-weight: 600; letter-spacing: -0.04em; line-height: 1; color: var(--ink-1); margin: 0 0 22px; text-wrap: balance; }
.course-sub { font-size: clamp(1.05rem, 1.6vw, 1.25rem); line-height: 1.55; color: var(--ink-2); max-width: 640px; margin: 0 0 32px; }
.course-meta { display: inline-flex; gap: 14px; align-items: baseline; flex-wrap: wrap; padding: 16px 0; border-top: 1px solid var(--line-1); border-bottom: 1px solid var(--line-1); font-size: 13px; color: var(--ink-3); }
.course-meta strong { color: var(--ink-1); font-weight: 500; font-variant-numeric: tabular-nums; }
.course-meta-sep { color: var(--ink-4); }

@keyframes hero-breathe {
  0%   { transform: scale(1.04); }
  100% { transform: scale(1.10); }
}

/* ---------- Layout shell ---------- */
.course-shell { max-width: 1180px; margin: 0 auto; padding: 60px 24px 80px; display: grid; grid-template-columns: 240px 1fr; gap: 60px; align-items: start; }

/* ---------- TOC sidebar ---------- */
.course-toc { position: sticky; top: 100px; align-self: start; max-height: calc(100vh - 120px); overflow-y: auto; padding-right: 8px; }
.course-toc::-webkit-scrollbar { width: 4px; }
.course-toc::-webkit-scrollbar-thumb { background: var(--line-1); border-radius: 2px; }
.course-toc-eyebrow { font-size: 10px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-3); font-weight: 600; margin-bottom: 18px; padding-bottom: 14px; border-bottom: 1px solid var(--line-1); }
.course-toc-list { list-style: none; padding: 0; margin: 0; }
.course-toc-list li { margin-bottom: 2px; }
.course-toc-list a { display: grid; grid-template-columns: 28px 1fr; gap: 10px; padding: 10px 8px; border-radius: 6px; font-size: 13px; color: var(--ink-3); text-decoration: none; line-height: 1.4; transition: background 200ms ease, color 200ms ease; }
.course-toc-list a:hover { color: var(--ink-1); background: rgba(255,255,255,0.025); opacity: 1; }
.course-toc-list a.is-on { color: #4DA3FF; background: rgba(77,163,255,0.06); }
.course-toc-num { color: var(--ink-4); font-variant-numeric: tabular-nums; font-weight: 600; }
.course-toc-title em { font-style: italic; color: var(--ink-4); font-weight: 400; }
.course-toc-soon { color: var(--ink-3); font-size: 13px; padding: 12px; line-height: 1.5; }

.course-toc-cta { margin-top: 32px; padding: 18px; border: 1px solid var(--line-1); border-radius: 12px; background: linear-gradient(180deg, rgba(77,163,255,0.04), transparent); }
.course-toc-cta-link { display: block; text-decoration: none; color: var(--ink-1); }
.course-toc-cta-link:hover { opacity: 1; }
.course-toc-cta-link strong { display: block; font-size: 14px; font-weight: 600; color: var(--ink-1); margin-bottom: 4px; }
.course-toc-cta-link:hover strong { color: #4DA3FF; }
.course-toc-cta-link span { display: block; font-size: 12px; color: var(--ink-3); line-height: 1.5; }

/* ---------- Lessons ---------- */
.course-main { max-width: 720px; }

.day { margin: 0 0 80px; padding: 0 0 64px; border-bottom: 1px solid var(--line-1); }
.day:last-of-type { border-bottom: 0; }
.day-head { margin-bottom: 32px; }
.day-eyebrow { display: inline-flex; gap: 8px; align-items: center; font-size: 11px; letter-spacing: 0.16em; text-transform: uppercase; color: var(--ink-3); font-weight: 600; margin-bottom: 14px; }
.day-eyebrow-sep { color: var(--ink-4); }
.day-eyebrow-tag { padding: 3px 8px; background: rgba(245,158,11,0.10); color: #F59E0B; border-radius: 4px; letter-spacing: 0.12em; font-size: 9px; }
.day-h { font-size: clamp(1.75rem, 3.4vw, 2.4rem); font-weight: 600; letter-spacing: -0.025em; line-height: 1.15; color: var(--ink-1); margin: 0; text-wrap: balance; }
.day.is-reflection .day-h { font-style: italic; font-family: var(--font-serif); font-weight: 400; }

.day-body p { font-size: 1.0625rem; line-height: 1.75; color: #DFDFDF; margin: 0 0 22px; text-wrap: pretty; }
.day-body p strong { color: #FFFFFF; font-weight: 600; }

.day-foot { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 32px; }
.day-card { padding: 20px 22px; border-radius: 14px; }
.day-card-takeaway { background: rgba(77,163,255,0.05); border: 1px solid rgba(77,163,255,0.18); }
.day-card-micro { background: rgba(74,222,128,0.04); border: 1px solid rgba(74,222,128,0.18); }
.day-card-eyebrow { font-size: 10px; letter-spacing: 0.16em; text-transform: uppercase; color: var(--ink-2); font-weight: 600; margin-bottom: 8px; }
.day-card-takeaway .day-card-eyebrow { color: #4DA3FF; }
.day-card-micro .day-card-eyebrow { color: #4ADE80; }
.day-card p { margin: 0; color: #EDEDED; font-size: 0.95rem; line-height: 1.55; }

.day.day-soon .day-h { color: var(--ink-2); }

@media (max-width: 900px) {
  .course-shell { grid-template-columns: 1fr; gap: 40px; padding-top: 40px; }
  .course-toc { position: static; max-height: none; padding: 16px; border: 1px solid var(--line-1); border-radius: 12px; }
  .course-toc-list { display: grid; grid-template-columns: 1fr 1fr; gap: 0; }
  .day-foot { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .course-toc-list { grid-template-columns: 1fr; }
  .course-hero { padding: 160px 24px 60px; min-height: 0; }
}

/* ---------- Final CTA ---------- */
.course-cta { padding: 80px 0 0; text-align: center; }
.course-cta-rule { width: 32px; height: 1px; background: var(--ink-4); margin: 0 auto 32px; }
.course-cta-eyebrow { font-size: 11px; letter-spacing: 0.18em; text-transform: uppercase; color: var(--ink-3); font-weight: 600; margin-bottom: 18px; }
.course-cta-h { font-size: clamp(2rem, 4vw, 2.8rem); font-weight: 500; letter-spacing: -0.025em; line-height: 1.1; margin: 0 0 22px; }
.course-cta-h em { font-family: var(--font-serif); font-style: italic; font-weight: 400; color: var(--ink-2); }
.course-cta-sub { color: var(--ink-2); font-size: 1rem; line-height: 1.6; max-width: 540px; margin: 0 auto 28px; }