/* Lecture design: the Lecture 1 page styles, shared by every lecture. */

/* Lecture 1 page: hand-built layout. Shares the design tokens in theme.css. */
.l1-hero {
  position: relative;
  overflow: hidden;
  isolation: isolate;
  border: 1px solid var(--border);
  border-radius: 22px;
  padding: 28px 28px 24px;
  background:
    radial-gradient(640px 320px at 0% 0%, rgba(124, 92, 255, 0.30), transparent 65%),
    radial-gradient(520px 300px at 100% 100%, rgba(34, 211, 238, 0.20), transparent 60%),
    var(--surface);
  box-shadow: var(--shadow-lift);
  margin-bottom: 16px;
}
.l1-hero .kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--accent);
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  border: 1px solid color-mix(in srgb, var(--accent) 25%, transparent);
}
.l1-hero h1 {
  margin: 12px 0 10px;
  font-size: clamp(26px, 3.8vw, 40px);
  line-height: 1.12;
  letter-spacing: -0.03em;
  max-width: 42ch;
  background: linear-gradient(90deg, var(--text), var(--accent));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.l1-hero .summary { font-size: 17px; color: var(--muted); max-width: 72ch; margin: 0 0 14px; line-height: 1.6; }
.l1-meta { display: flex; flex-wrap: wrap; gap: 8px; }

/* core learning path (Lecture 1) */
.roadmap-card--path {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  grid-template-rows: auto auto auto;
  gap: 0 20px;
  padding: 20px 22px 18px;
  background:
    radial-gradient(ellipse 80% 60% at 100% 0%, rgba(98, 84, 232, 0.1), transparent 55%),
    linear-gradient(165deg, var(--surface) 0%, var(--surface-2) 100%);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lift);
  margin: 0 0 16px;
  position: relative;
  overflow: hidden;
}
.roadmap-card__head {
  grid-column: 1;
  grid-row: 1;
  min-width: 0;
}
.roadmap-card__badge {
  display: inline-block;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent-text);
  background: var(--brand-gradient);
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 8px;
  box-shadow: 0 6px 16px -8px rgba(79, 70, 229, 0.65);
}
.roadmap-card--path h3 {
  margin: 0 0 6px;
  font-size: 20px;
  letter-spacing: -0.02em;
  color: var(--heading);
}
.roadmap-card--path .caption {
  margin: 0;
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.55;
  max-width: 62ch;
}
.roadmap-card__visual {
  grid-column: 2;
  grid-row: 1 / 3;
  align-self: start;
  opacity: 0.92;
}
.roadmap-card__hero-art {
  display: block;
  width: 112px;
  height: auto;
  filter: drop-shadow(0 12px 28px rgba(37, 36, 80, 0.12));
}
.roadmap-phases {
  grid-column: 1 / -1;
  grid-row: 2;
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-top: 18px;
}
.roadmap-phase {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
  padding: 14px 0 6px;
}
.roadmap-phase__connector {
  height: 28px;
  margin: 4px 0 0 27px;
  border-left: 2px dashed var(--border-strong);
}
.roadmap-phase__head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
}
.roadmap-phase__art {
  flex: 0 0 auto;
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 6px;
  box-shadow: var(--shadow);
}
.roadmap-phase__meta { min-width: 0; }
.roadmap-phase__kicker {
  display: block;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--accent);
}
.roadmap-phase__title {
  margin: 2px 0 4px;
  font-size: 16px;
  font-weight: 800;
  color: var(--heading);
}
.roadmap-phase__blurb {
  margin: 0;
  font-size: 13px;
  line-height: 1.45;
  color: var(--muted);
}
.roadmap-phase__steps {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-left: 66px;
}
.roadmap-step {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 12px 8px 8px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
  box-shadow: var(--shadow);
  transition: border-color 0.15s ease, transform 0.15s ease, box-shadow 0.15s ease;
  max-width: 100%;
}
.roadmap-step:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lift);
}
.roadmap-step__num {
  flex: 0 0 auto;
  width: 32px;
  height: 32px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-size: 12px;
  font-weight: 800;
  color: var(--accent-text);
  background: var(--brand-gradient);
}
.roadmap-step__copy {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}
.roadmap-step__copy strong {
  font-size: 13px;
  font-weight: 700;
  line-height: 1.3;
}
.roadmap-step__sub {
  font-size: 11px;
  font-weight: 600;
  color: var(--muted);
}
.roadmap-card__foot {
  grid-column: 1 / -1;
  grid-row: 3;
  margin: 12px 0 0;
  padding-top: 12px;
  border-top: 1px solid var(--border);
  font-size: 12.5px;
  color: var(--muted);
  line-height: 1.5;
}
.visual-canvas .diagram--path { min-height: 320px; }
@media (max-width: 720px) {
  .roadmap-card--path {
    grid-template-columns: 1fr;
  }
  .roadmap-card__visual {
    grid-column: 1;
    grid-row: 2;
    justify-self: start;
    margin-top: 8px;
  }
  .roadmap-phases { grid-row: 3; }
  .roadmap-card__foot { grid-row: 4; }
  .roadmap-phase__steps { padding-left: 0; }
  .roadmap-phase__connector { margin-left: 25px; }
}

/* section headers */
.l1-section { margin-top: 32px; }
.l1-section > header { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.l1-section > header .num {
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: var(--brand-gradient);
  color: #ffffff;
  font-weight: 800;
  box-shadow: 0 8px 18px -8px rgba(79, 70, 229, 0.7);
}
.l1-section > header h2 { margin: 0; font-size: 24px; letter-spacing: -0.015em; }

.prose p { font-size: 16.5px; line-height: 1.75; color: var(--text); margin: 0 0 14px; }
.prose p.muted { color: var(--muted); }

/* cards */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 14px; margin: 18px 0; }
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px 22px;
  box-shadow: var(--shadow);
  transition: transform 200ms ease, box-shadow 200ms ease;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lift); }
.card .tag { font-size: 12px; font-weight: 800; letter-spacing: 0.07em; text-transform: uppercase; color: var(--accent); }
.card h3 { margin: 6px 0 8px; font-size: 17px; }
.card p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.6; }

/* objectives */
.objectives { list-style: none; margin: 0; padding: 0; display: grid; gap: 10px; counter-reset: obj; }
.objectives li {
  counter-increment: obj;
  position: relative;
  padding: 14px 18px 14px 58px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  font-size: 16px;
  line-height: 1.6;
}
.objectives li::before {
  content: counter(obj);
  position: absolute;
  left: 16px;
  top: 14px;
  width: 28px;
  height: 28px;
  border-radius: 9px;
  display: grid;
  place-items: center;
  background: var(--brand-gradient);
  color: #ffffff;
  font-weight: 800;
  font-size: 13px;
}

/* concept blocks */
.concept {
  border-left: 3px solid var(--accent);
  padding: 4px 0 4px 18px;
  margin: 26px 0 0;
}
.concept h3 { margin: 0 0 8px; font-size: 19px; }
.concept p { font-size: 16px; line-height: 1.72; color: var(--text); margin: 0 0 12px; }
.concept .lbl {
  display: inline-block;
  font-size: 11.5px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-right: 6px;
}

/* path timeline */
.path { list-style: none; margin: 14px 0 0; padding: 0; position: relative; }
.path li {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 14px;
  padding: 12px 0;
  position: relative;
}
.path li::before {
  content: "";
  position: absolute;
  left: 21px;
  top: 48px;
  bottom: -12px;
  width: 2px;
  background: var(--border);
}
.path li:last-child::before { display: none; }
.path .dot {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: var(--brand-soft);
  color: var(--accent);
  font-weight: 800;
  position: relative;
  z-index: 1;
}
.path h3 { margin: 4px 0 4px; font-size: 16.5px; }
.path p { margin: 0; color: var(--muted); font-size: 15px; line-height: 1.6; }

/* steps */
.steps { display: grid; gap: 14px; margin-top: 16px; }
.step {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 16px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 18px 20px;
  box-shadow: var(--shadow);
}
.step .badge {
  width: 40px;
  height: 40px;
  border-radius: 14px;
  display: grid;
  place-items: center;
  background: var(--brand-gradient);
  color: #ffffff;
  font-weight: 800;
}
.step h3 { margin: 2px 0 6px; font-size: 17px; }
.step p { margin: 0; font-size: 15.5px; line-height: 1.65; color: var(--text); }

.pace {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 10px;
}
.pace div {
  background: var(--surface-2);
  border-radius: 14px;
  padding: 12px 14px;
  font-size: 14.5px;
  color: var(--text);
  border: 1px solid var(--border);
}
.pace b { display: block; font-size: 12px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--accent); margin-bottom: 2px; }

/* artifacts */
.table-card table td:first-child, .table-card table th:first-child { white-space: nowrap; }

/* mistakes */
.mistake {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 4px solid var(--bad);
  border-radius: var(--radius-lg);
  padding: 18px 22px;
  margin: 14px 0;
  box-shadow: var(--shadow);
}
.mistake h3 { margin: 0 0 10px; font-size: 17px; }
.mistake .k { display: block; font-size: 15px; line-height: 1.65; color: var(--text); margin: 6px 0; }
.mistake .k b { font-size: 11.5px; letter-spacing: 0.07em; text-transform: uppercase; color: var(--muted); display: inline-block; min-width: 100px; }

.practices { display: grid; gap: 10px; margin: 16px 0 0; padding: 0; list-style: none; counter-reset: bp; }
.practices li {
  counter-increment: bp;
  display: grid;
  grid-template-columns: 34px 1fr;
  gap: 12px;
  align-items: start;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text);
}
.practices li::before {
  content: counter(bp);
  width: 30px;
  height: 30px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  background: var(--brand-soft);
  color: var(--accent);
  font-weight: 800;
  font-size: 13px;
}

/* takeaways */
.takeaways { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 12px; margin-top: 16px; }
.takeaway {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 14px 16px;
  font-size: 15.5px;
  line-height: 1.6;
}
.takeaway .tick {
  flex: 0 0 auto;
  width: 26px;
  height: 26px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: var(--ok-bg);
  color: var(--ok);
  font-weight: 800;
  font-size: 13px;
}

/* knowledge check */
.kc { display: grid; gap: 12px; }
.kc .q {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 18px 22px;
  box-shadow: var(--shadow);
}
.kc .q .n { font-size: 12px; font-weight: 800; letter-spacing: 0.07em; text-transform: uppercase; color: var(--accent); }
.kc .q p { margin: 6px 0 0; font-size: 16px; font-weight: 600; line-height: 1.6; }
details.key {
  margin-top: 18px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 12px 18px;
}
details.key summary { cursor: pointer; font-weight: 800; padding: 6px 0; }
details.key ol { padding-left: 20px; margin: 10px 0 4px; }
details.key li { margin: 10px 0; line-height: 1.65; font-size: 15.5px; }

/* quiz */
.quiz-shell {
  margin-top: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 22px 24px;
  box-shadow: var(--shadow);
}
.quiz-shell h3 { margin: 0 0 4px; font-size: 19px; }
.quiz-shell .lead { margin: 0 0 14px; color: var(--muted); font-size: 15px; }
.quiz-head { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; justify-content: space-between; margin-bottom: 6px; }
.quiz-head .meta { color: var(--muted); font-size: 13.5px; }
.quiz-actions { display: flex; gap: 8px; }
.quiz .q { padding: 14px 0; border-bottom: 1px solid var(--border); }
.quiz .q:last-child { border-bottom: 0; }
.quiz .q > p { margin: 0 0 8px; font-weight: 700; }
.quiz .q label { display: flex; gap: 10px; align-items: flex-start; padding: 8px 10px; border-radius: 10px; cursor: pointer; }
.quiz .q label:hover { background: var(--surface-2); }
.quiz .q label.right { background: var(--ok-bg); color: var(--ok); }
.quiz .q label.wrong { background: var(--bad-bg); color: var(--bad); }
.quiz .verdict { font-size: 13.5px; color: var(--muted); margin-top: 4px; }
.score { margin: 10px 0; padding: 12px 16px; border-radius: 12px; background: var(--surface-2); font-weight: 800; }
.score[hidden] { display: none; }

/* lesson footer */
.lesson-nav { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 46px; }
.lesson-nav a {
  display: block;
  padding: 16px 18px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  text-decoration: none;
  color: var(--text);
  font-weight: 800;
  box-shadow: var(--shadow);
}
.lesson-nav a span { display: block; font-size: 12px; text-transform: uppercase; letter-spacing: 0.07em; color: var(--muted); margin-bottom: 2px; }
.lesson-nav a.next { text-align: right; }
.lesson-nav a:hover { border-color: var(--accent); }

.page-wrap { max-width: 1040px; margin: 0 auto; padding: 32px 24px 56px; }
article.lecture { max-width: none; font-size: 16px; }
.topbar { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 20px; }
.crumbs { font-size: 14px; color: var(--muted); }
.crumbs a { color: var(--muted); }

@media (max-width: 860px) {
  .l1-hero { padding: 30px 22px 28px; border-radius: 22px; }
  .l1-hero .summary { font-size: 16.5px; }
  .page-wrap { padding: 22px 16px 44px; }
  .lesson-nav { grid-template-columns: 1fr; }
  .lesson-nav a.next { text-align: left; }
  .l1-section > header h2 { font-size: 21px; }
}
@media (prefers-reduced-motion: reduce) {
  .card { transition: none; }
  .card:hover { transform: none; }
}

/* lesson layout shared by every lecture */
.l1-section > p { font-size: 16.5px; line-height: 1.75; color: var(--text); margin: 0 0 14px; }
.l1-section > p.caption { font-size: 13px; font-weight: 800; color: var(--muted); margin: 18px 0 8px; }
.l1-section > .table-card { margin: 12px 0 22px; }
.l1-title { font-size: clamp(30px, 4.6vw, 46px); line-height: 1.1; letter-spacing: -0.03em; max-width: 20ch; background: linear-gradient(90deg, var(--text), var(--accent)); -webkit-background-clip: text; background-clip: text; color: transparent; margin: 18px 0 14px; }
.l1-hero .summary { font-size: 17px; color: var(--muted); max-width: 72ch; margin: 0 0 14px; line-height: 1.6; }
.l1-meta .chip { background: var(--surface-2); }
.takeaways { list-style: none; padding: 0; margin: 14px 0 18px; display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 12px; counter-reset: tk; }
.takeaways li { counter-increment: tk; position: relative; margin: 0; padding: 14px 16px 14px 56px; background: var(--surface); border: 1px solid var(--border); border-radius: 16px; box-shadow: var(--shadow); font-size: 15.5px; line-height: 1.6; color: var(--text); }
.takeaways li::before { content: counter(tk); position: absolute; left: 14px; top: 14px; width: 26px; height: 26px; border-radius: 999px; display: grid; place-items: center; background: var(--ok-bg); color: var(--ok); font-weight: 800; font-size: 13px; }
.practice-title { margin: 28px 0 4px; font-size: 18px; }
.l1-section .kc + .kc { margin-top: 12px; }
.l1-section .objectives { list-style: none; margin: 0 0 6px; padding: 0; }
.l1-section details.key ol li { font-size: 15.5px; }
.lesson-nav a.prev { text-align: left; }
.quiz-shell .quiz { margin-top: 6px; }

.topbar-actions { display: flex; gap: 8px; align-items: center; }

/* Centre the lecture content in the main column, as on the Lecture 1 page */
.layout > main { max-width: 1040px; margin: 0 auto; width: 100%; }
.lecture { max-width: none; }

/* ---------- course player layout (Udemy-style): dark top bar, content, course-content panel on the right ---------- */


.layout.player {
  grid-template-columns: minmax(0, 1fr) minmax(300px, 380px);
  background: var(--bg);
}
.layout.player:not(:has(> .outline)) {
  grid-template-columns: minmax(0, 1fr);
}
.layout.player.side-collapsed { grid-template-columns: minmax(0, 1fr); }
.layout.player > main {
  max-width: none;
  margin: 0;
  padding: 16px clamp(16px, 2vw, 28px) 44px;
  width: 100%;
  min-width: 0;
}
.layout.player > main.page-wrap,
.layout.player > main.lecture-page {
  max-width: none;
  margin: 0;
}
.layout.player .lecture-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(160px, 188px);
  gap: 16px 20px;
  align-items: start;
  width: 100%;
  max-width: none;
  margin: 0;
}
.layout.player .lecture-layout > .lecture,
.layout.player .lecture-block,
.layout.player article.lecture {
  max-width: none;
  margin: 0;
  width: 100%;
}
.layout.player .lecture-topbar,
.layout.player .topbar,
.layout.player .section-hero,
.layout.player .curriculum-panel {
  max-width: none;
  margin-left: 0;
  margin-right: 0;
  width: 100%;
}
.layout.player .topbar,
.layout.player .lecture-topbar {
  margin-bottom: 12px;
}
.lecture-toc {
  position: sticky;
  top: 12px;
  padding: 12px 12px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow);
}
.lecture-toc__title {
  margin: 0 0 12px;
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--muted);
}
.lecture-toc__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.lecture-toc__list a {
  display: block;
  padding: 5px 8px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 600;
  line-height: 1.35;
  color: var(--muted);
  text-decoration: none;
}
.lecture-toc__list a:hover {
  color: var(--text);
  background: var(--surface-2);
}
.lecture--welcome .l1-section,
.lecture--welcome .roadmap-card,
.lecture--welcome .quiz-shell {
  width: 100%;
}
.lecture--welcome .roadmap-card {
  margin-top: 0;
}
.lecture--welcome .l1-section {
  margin-top: 28px;
}
.lecture--welcome .l1-hero {
  margin-bottom: 12px;
}
.lecture-page .lecture-layout > .lecture {
  min-width: 0;
}
.layout.player.single-lecture .lecture-stage {
  width: 100%;
  max-width: none;
}
.layout.player.single-lecture .lecture-block[hidden] {
  display: none !important;
}
.layout.player.single-lecture .section-hero,
.layout.player.single-lecture .curriculum-panel,
.layout.player.single-lecture .item-card {
  display: none !important;
}
.layout.player.single-lecture .lecture-nav.section-nav {
  margin-top: 28px;
  max-width: none;
}
.layout.player.single-lecture .topbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 12px;
  max-width: none;
}
.layout.player.single-lecture .topbar .crumbs {
  flex: 1 1 auto;
  min-width: 0;
}
@media (min-width: 1081px) {
  .layout.player .lecture-layout {
    grid-template-columns: minmax(0, 1fr) 176px;
  }
  /* One navigation rail: use course outline on wide screens, not a second TOC column */
  .layout.player:not(.side-collapsed):has(> .outline) .lecture-toc {
    display: none;
  }
  .layout.player:not(.side-collapsed):has(> .outline) .lecture-layout {
    grid-template-columns: minmax(0, 1fr);
  }
}
.lecture-page .l1-section [id],
.lecture-page .roadmap-card [id] {
  scroll-margin-top: 24px;
}
@media (max-width: 1080px) {
  .layout.player .lecture-layout {
    grid-template-columns: minmax(0, 1fr);
  }
  .lecture-toc {
    display: none;
  }
}
@media (max-width: 860px) {
  .layout.player > main {
    padding: 18px 16px 44px;
  }
}

.layout.player > .outline.outline--player {
  position: sticky;
  top: 0;
  display: flex;
  flex-direction: column;
  height: calc(100vh - 66px);
  padding: 0;
  overflow: hidden;
  border-left: 1px solid color-mix(in srgb, var(--accent) 18%, var(--border));
  background:
    radial-gradient(520px 240px at 100% 0%, color-mix(in srgb, var(--accent) 14%, transparent), transparent 70%),
    radial-gradient(400px 200px at 0% 100%, color-mix(in srgb, #22d3ee 10%, transparent), transparent 65%),
    linear-gradient(180deg, var(--surface) 0%, color-mix(in srgb, var(--surface) 92%, var(--bg)) 100%);
  box-shadow: -12px 0 40px -24px rgba(15, 23, 42, 0.18);
}
.layout.player > .outline .outline-head {
  position: relative;
  z-index: 2;
  flex: 0 0 auto;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  padding: 18px 16px 14px;
  margin: 0;
  border-bottom: 1px solid color-mix(in srgb, var(--border) 80%, transparent);
  background: color-mix(in srgb, var(--surface) 88%, transparent);
  backdrop-filter: blur(10px);
}
.layout.player > .outline .outline-head__badge {
  display: inline-flex;
  padding: 4px 10px;
  margin-bottom: 8px;
  border-radius: 999px;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--accent) 22%, transparent);
}
.layout.player > .outline .outline-head h2 {
  margin: 0 0 4px;
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text);
}
.layout.player > .outline .outline-head__meta {
  margin: 0;
  font-size: 12px;
  color: var(--muted);
  font-weight: 600;
}
.layout.player > .outline .outline-collapse {
  flex: 0 0 auto;
  margin-top: 4px;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-size: 11px;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}
.layout.player > .outline .outline-collapse:hover {
  color: var(--text);
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
  background: var(--surface-2);
}
.layout.player > .outline .outline-scroll {
  flex: 1 1 auto;
  overflow-y: auto;
  overscroll-behavior: contain;
  padding: 8px 10px 16px;
  scrollbar-width: thin;
  scrollbar-color: color-mix(in srgb, var(--accent) 40%, var(--border)) transparent;
}
.layout.player .outline-sections { padding: 0; list-style: none; margin: 0; }
.layout.player .outline-section {
  margin: 0 0 8px;
  border-radius: 14px;
  border: 1px solid transparent;
  overflow: hidden;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.layout.player .outline-section.is-current-section {
  border-color: color-mix(in srgb, var(--accent) 28%, var(--border));
  box-shadow: 0 8px 24px -16px color-mix(in srgb, var(--accent) 45%, transparent);
  background: color-mix(in srgb, var(--accent) 4%, var(--surface));
}
.layout.player .outline-section.open .sec-row {
  background: color-mix(in srgb, var(--surface-2) 70%, transparent);
}
.layout.player .sec-row {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 8px 6px 10px;
  min-height: 52px;
}
.layout.player .sec-index {
  flex: 0 0 auto;
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  font-size: 11px;
  font-weight: 800;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 10%, var(--surface));
  border: 1px solid color-mix(in srgb, var(--accent) 18%, transparent);
}
.layout.player > .outline.outline--player a.sec {
  display: flex;
  align-items: center;
  flex: 1;
  min-width: 0;
  padding: 8px 8px 8px 0;
  font-size: 13.5px;
  font-weight: 800;
  line-height: 1.35;
  color: var(--text);
  text-decoration: none;
  border-radius: 8px;
  background: transparent !important;
}
.layout.player > .outline.outline--player a.sec .sec-title {
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
}
.layout.player > .outline.outline--player a.sec:hover {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 6%, transparent) !important;
}
.layout.player > .outline.outline--player a.sec.current {
  color: var(--accent);
  background: transparent !important;
  box-shadow: none;
}
.layout.player .outline-section.is-current-section > .sec-row a.sec.current .sec-title {
  color: var(--text);
}
.layout.player .sec-toggle {
  flex: 0 0 auto;
  width: 32px;
  height: 32px;
  margin: 0;
  border: 1px solid transparent;
  border-radius: 10px;
  background: transparent;
  color: var(--muted);
  cursor: pointer;
  display: grid;
  place-items: center;
  transition: background 0.15s ease, transform 0.15s ease, border-color 0.15s ease;
}
.layout.player .sec-toggle:hover {
  background: var(--surface);
  border-color: var(--border);
  color: var(--text);
}
.layout.player .outline-section.open > .sec-row .sec-toggle {
  background: color-mix(in srgb, var(--accent) 10%, var(--surface));
  border-color: color-mix(in srgb, var(--accent) 22%, transparent);
  color: var(--accent);
}
.layout.player .sec-toggle .chevron { font-size: 12px; transition: transform 0.2s ease; }
.layout.player .outline-section.open > .sec-row .chevron { transform: rotate(90deg); }
.layout.player .sec-items {
  list-style: none;
  padding: 4px 6px 10px;
  margin: 0;
}
.layout.player .sec-items li { margin: 0 0 4px; padding: 0; }
.layout.player .outline-link {
  display: grid;
  grid-template-columns: 36px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  padding: 10px 10px 10px 8px;
  border-radius: 12px;
  text-decoration: none;
  color: var(--text);
  border: 1px solid transparent;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}
.layout.player .outline-link:hover {
  background: color-mix(in srgb, var(--surface-2) 90%, var(--accent));
  border-color: color-mix(in srgb, var(--border) 90%, var(--accent));
  transform: translateX(2px);
}
.layout.player .outline-link__num {
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border-radius: 11px;
  font-size: 13px;
  font-weight: 800;
  color: #fff;
  background: var(--brand-gradient, linear-gradient(135deg, #6366f1, #8b5cf6));
  box-shadow: 0 6px 14px -8px color-mix(in srgb, var(--accent) 70%, transparent);
}
.layout.player .outline-link__num--alt {
  font-size: 18px;
  font-weight: 900;
  color: var(--muted);
  background: var(--surface-2);
  box-shadow: none;
  border: 1px dashed var(--border);
}
.layout.player .outline-link__body { min-width: 0; }
.layout.player .outline-link__kicker {
  display: block;
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 2px;
}
.layout.player .outline-link__title {
  display: block;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--text);
}
.layout.player > .outline.outline--player .sec-items li.item a {
  background: transparent;
}
.layout.player > .outline.outline--player .sec-items li.current .outline-link {
  background: linear-gradient(
    90deg,
    color-mix(in srgb, var(--accent) 16%, var(--surface)),
    color-mix(in srgb, var(--accent) 6%, transparent)
  ) !important;
  border-color: color-mix(in srgb, var(--accent) 35%, var(--border));
  box-shadow: inset 3px 0 0 var(--accent);
}
.layout.player .sec-items li.current .outline-link__title { color: var(--text); }
.layout.player .sec-items li.current .outline-link__kicker { color: var(--accent); }
.layout.player .sec-items li.item--q .outline-link__num--alt { color: #b45309; border-color: color-mix(in srgb, #f59e0b 40%, var(--border)); }
.layout.player .sec-items li.item--p .outline-link__num--alt { color: #0369a1; }

.layout.player .lesson-nav { margin-top: 36px; }
@media (max-width: 860px) {
  .layout.player { grid-template-columns: minmax(0, 1fr); }
  .layout.player > .outline { position: static; height: auto; border-left: 0; border-top: 1px solid var(--border); }
  .layout.player > main, .layout.player > main.page-wrap { padding: 20px 16px 44px; }
}

/* lecture table of contents nested under outline items */
.layout.player .outline ul.toc {
  list-style: none;
  margin: 4px 0 6px 46px;
  padding: 6px 0 6px 12px;
  border-left: 2px solid color-mix(in srgb, var(--accent) 25%, var(--border));
}
.layout.player .outline ul.toc[hidden] { display: none; }
.layout.player .outline ul.toc a {
  display: block;
  font-size: 11.5px;
  padding: 4px 8px;
  border-radius: 8px;
  color: var(--muted);
  font-weight: 600;
}
.layout.player .outline ul.toc a:hover {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 8%, transparent);
}
.layout.player .outline ul.toc li.current a {
  color: var(--accent);
  font-weight: 800;
}

/* Section knowledge-quiz hub (Bonus 5, etc.) */
.section-quiz-hub {
  margin: 0 0 32px;
  padding: 24px 22px 26px;
  border-radius: 20px;
  border: 1px solid var(--border);
  background: linear-gradient(
    165deg,
    color-mix(in srgb, var(--accent) 8%, var(--surface)),
    var(--surface)
  );
}
.section-quiz-hub__head {
  display: flex;
  gap: 16px;
  align-items: flex-start;
  margin-bottom: 20px;
}
.section-quiz-hub__head .lead { margin: 6px 0 0; max-width: 62ch; }
.section-quiz-hub__icon { flex-shrink: 0; }
.section-quiz-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}
.section-quiz-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 16px 16px 18px;
  border-radius: 16px;
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: 0 10px 28px -22px color-mix(in srgb, var(--text) 35%, transparent);
}
.section-quiz-card__badge {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
}
.section-quiz-card__title {
  margin: 0;
  font-size: 15px;
  line-height: 1.35;
}
.section-quiz-card__desc,
.section-quiz-card__meta {
  margin: 0;
  font-size: 13px;
  color: var(--muted);
  line-height: 1.45;
}
.section-quiz-card__cta { margin-top: auto; align-self: flex-start; }

.quiz-curriculum-lectures {
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 6px;
}
.quiz-curriculum-lectures a {
  font-weight: 600;
  font-size: 14px;
}
.quiz-discovery--curriculum .quiz-hero-panel--curriculum {
  margin-bottom: 20px;
}

/* Locked lecture: shown in place of a paid lecture body */
.lecture-locked {
  display: grid;
  gap: 12px;
  padding: 24px;
  margin: 24px 0;
  border-radius: 18px;
  border: 1px solid var(--border);
  background: var(--surface);
  box-shadow: var(--shadow-lift);
}
.lecture-locked .kicker { color: var(--accent); font-size: 12px; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; }
.lecture-locked__title { margin: 0; font-size: 22px; }
.lecture-locked .lead { margin: 0; color: var(--muted); }
.lecture-locked__preview {
  position: relative;
  max-height: 180px;
  overflow: hidden;
  padding: 14px 16px;
  border-radius: 12px;
  background: var(--brand-soft);
}
.lecture-locked__preview p { margin: 0; line-height: 1.6; }
.lecture-locked__preview::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 56px;
  background: linear-gradient(to bottom, transparent, var(--surface));
}
.lecture-locked__actions { display: flex; flex-wrap: wrap; gap: 10px; }

/* Content protection: lecture text is not selectable or draggable, and is hidden in print and while inactive */
.lecture-protected {
  position: relative;
  -webkit-user-select: none;
  user-select: none;
  -webkit-touch-callout: none;
}
.lecture-protected img { -webkit-user-drag: none; }
.lecture-watermark {
  position: absolute;
  inset: 0;
  z-index: 2;
  pointer-events: none;
  background-repeat: repeat;
  background-size: 360px 160px;
}
body.is-content-covered::after {
  content: "Lecture content is hidden while this window is inactive.";
  position: fixed;
  inset: 0;
  z-index: 999;
  display: grid;
  place-items: center;
  padding: 24px;
  background: var(--bg);
  color: var(--text);
  font-size: 18px;
  font-weight: 700;
  text-align: center;
}
body.is-print-blocked .lecture-protected { visibility: hidden; }
@media print {
  .lecture-protected { display: none !important; }
  body:has(.lecture-protected)::before {
    content: "Printing is not available for lecture content. Read the lecture on screen.";
    display: block;
    padding: 24px;
    font-size: 16px;
    border-bottom: 1px solid #999;
  }
}