/* Motion lesson pages: header, course sidebar, heading, player frame and pager.
   Builds on /mb.css; the mobile drawer mechanics live in academy-navigation.css. */
body[data-format="motion"] {
  --side: 312px;
  min-height: 100vh;
  background: radial-gradient(60% 40% at 70% 0%, rgba(120, 225, 213, 0.07), transparent 70%), var(--bg);
}

/* ---------- header ---------- */
.lesson-header {
  gap: 20px;
  background: rgba(5, 9, 15, 0.72);
  box-shadow: inset 0 -1px 0 var(--line);
  backdrop-filter: blur(18px) saturate(1.3);
}
.lesson-header.is-hidden {
  transform: none;
}
.crumbs {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  margin-left: calc(var(--side) - 240px);
  color: var(--muted);
  font-size: 14px;
  white-space: nowrap;
}
.crumbs a {
  color: var(--text-2);
  transition: color 0.3s;
}
.crumbs a:hover {
  color: var(--teal);
}
.crumbs span {
  color: var(--dim);
}
.crumbs strong {
  overflow: hidden;
  text-overflow: ellipsis;
  color: var(--text);
  font-weight: 800;
}
.header-map {
  margin-left: auto;
}

/* ---------- sidebar ---------- */
.lesson-sidebar {
  position: fixed;
  top: var(--header-h);
  bottom: 0;
  left: 0;
  width: var(--side);
  padding: 22px 18px 40px;
  overflow-y: auto;
  border-right: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(8, 14, 24, 0.92), rgba(5, 9, 15, 0.96));
  scrollbar-width: thin;
  scrollbar-color: #26394a transparent;
}
.lesson-sidebar .academy-home {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 10px 2px;
  font-size: 16px;
  font-weight: 900;
}
.lesson-sidebar .academy-home span {
  font-family: var(--f-mono);
  font-size: 10px;
  letter-spacing: 0.24em;
  color: var(--dim);
}
.sidebar-label {
  margin: 2px 10px 16px;
  color: var(--muted);
  font-size: 12px;
}
.course-group {
  margin: 22px 10px 8px;
  font-family: var(--f-mono);
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.24em;
  color: var(--dim);
}
.course-menu > a {
  display: grid;
  grid-template-columns: 30px 1fr;
  gap: 8px;
  align-items: start;
  padding: 10px 10px;
  border-radius: 12px;
  transition:
    background 0.3s,
    color 0.3s;
}
.course-menu > a:hover {
  background: rgba(237, 242, 237, 0.04);
}
.course-number {
  padding-top: 3px;
  font-family: var(--f-display);
  font-size: 17px;
  font-weight: 700;
  color: var(--dim);
}
.course-menu small {
  display: block;
  color: var(--dim);
  font-size: 11px;
  line-height: 1.4;
}
.course-menu strong {
  display: block;
  color: var(--text-2);
  font-size: 14px;
  font-weight: 700;
  line-height: 1.45;
}
.course-menu > a.course-current {
  background: linear-gradient(90deg, rgba(120, 225, 213, 0.14), rgba(120, 225, 213, 0.02));
  box-shadow: inset 2px 0 0 var(--teal);
}
.course-current .course-number,
.course-current strong {
  color: var(--teal);
}
.chapter-menu {
  display: grid;
  gap: 2px;
  margin: 6px 0 10px 38px;
  padding-left: 12px;
  border-left: 1px solid var(--line-2);
}
.chapter-menu button {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 7px 10px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--muted);
  font-size: 13px;
  text-align: left;
  transition:
    background 0.3s,
    color 0.3s;
}
.chapter-menu button i {
  flex: none;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--line-2);
  transition:
    background 0.3s,
    box-shadow 0.3s;
}
.chapter-menu button:hover {
  color: var(--text);
  background: rgba(237, 242, 237, 0.04);
}
.chapter-menu button[aria-current] {
  color: var(--text);
}
.chapter-menu button[aria-current] i {
  background: var(--teal);
  box-shadow: 0 0 10px var(--teal);
}
.lesson-prerequisite {
  display: grid;
  gap: 6px;
  margin: 24px 4px 0;
  padding: 16px;
  border-radius: 14px;
  background: rgba(232, 189, 125, 0.06);
  box-shadow: inset 0 0 0 1px rgba(232, 189, 125, 0.22);
}
.lesson-prerequisite > span {
  color: var(--gold);
  font-size: 12px;
  font-weight: 700;
}
.lesson-prerequisite a strong {
  color: var(--text-2);
  font-size: 14px;
  font-weight: 700;
}
.lesson-prerequisite a:hover strong {
  color: var(--teal);
}
.sidebar-note {
  display: grid;
  grid-template-columns: 32px 1fr;
  gap: 12px;
  margin: 18px 4px 0;
  padding: 16px;
  border-radius: 14px;
  box-shadow: inset 0 0 0 1px var(--line);
}
.note-orbit {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  box-shadow: inset 0 0 0 1px rgba(120, 225, 213, 0.5);
  color: var(--teal);
  font-size: 13px;
}
.sidebar-note p {
  color: var(--text-2);
  font-size: 13px;
  line-height: 1.7;
}

/* ---------- main ---------- */
#story {
  margin-left: var(--side);
  padding: calc(var(--header-h) + 28px) clamp(20px, 3.5vw, 56px) 32px;
}
.lesson-heading {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 20px;
  width: min(100%, calc((100vh - 210px) * 16 / 9));
  margin: 0 auto 18px;
}
.lesson-heading p {
  font-family: var(--f-mono);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: 0.2em;
  color: var(--teal);
}
.lesson-heading p span {
  color: var(--dim);
}
.lesson-heading h2 {
  margin-top: 8px;
  font-size: clamp(28px, 3vw, 44px);
  font-weight: 900;
  line-height: 1.2;
  letter-spacing: -0.02em;
}
.lesson-format {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex: none;
  padding: 8px 14px;
  border-radius: 999px;
  box-shadow: inset 0 0 0 1px var(--line-2);
  color: var(--text-2);
  font-size: 13px;
  font-weight: 700;
}
.lesson-format i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--teal);
  box-shadow: 0 0 10px var(--teal);
}
.lesson-format span {
  color: var(--muted);
  font-family: var(--f-mono);
  font-weight: 500;
}
body[data-format="motion"] .motion-stage {
  border: 0;
  border-radius: var(--r-l);
  box-shadow:
    inset 0 0 0 1px var(--line-2),
    0 40px 100px -40px rgba(0, 0, 0, 0.95),
    0 0 120px -60px rgba(120, 225, 213, 0.45);
}
body[data-format="motion"] .motion-note {
  width: min(100%, calc((100vh - 210px) * 16 / 9));
  margin: 18px auto 0;
  color: var(--dim);
  font-size: 12.5px;
  line-height: 1.8;
}
.lesson-pager {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  width: min(100%, calc((100vh - 210px) * 16 / 9));
  margin: 36px auto 0;
}
.lesson-pager a {
  position: relative;
  display: grid;
  gap: 4px;
  padding: 20px 22px;
  border-radius: var(--r-m);
  background: linear-gradient(180deg, rgba(20, 33, 45, 0.6), rgba(10, 17, 26, 0.7));
  box-shadow: inset 0 0 0 1px var(--line);
  transition:
    transform 0.5s var(--ease),
    box-shadow 0.4s;
}
.lesson-pager a:hover {
  transform: translateY(-3px);
  box-shadow:
    inset 0 0 0 1px rgba(120, 225, 213, 0.4),
    0 24px 60px -30px rgba(120, 225, 213, 0.5);
}
.lesson-pager .pager-next {
  text-align: right;
}
.lesson-pager small {
  font-family: var(--f-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--teal);
}
.lesson-pager strong {
  font-size: 19px;
  font-weight: 900;
}
.lesson-pager span {
  color: var(--muted);
  font-size: 13px;
}
.lesson-foot {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-left: var(--side);
  padding: 22px clamp(20px, 3.5vw, 56px) 32px;
  border-top: 1px solid var(--line);
  color: var(--dim);
  font-size: 12.5px;
}

/* ---------- tablet: collapse the sidebar under the player ---------- */
@media (max-width: 1100px) and (min-width: 651px) {
  body[data-format="motion"] {
    --side: 0px;
  }
  .crumbs {
    margin-left: 24px;
  }
  .lesson-sidebar {
    position: static;
    width: auto;
    margin: 0 clamp(20px, 3.5vw, 56px) 40px;
    border: 0;
    border-radius: var(--r-l);
    box-shadow: inset 0 0 0 1px var(--line);
    order: 2;
  }
  body[data-format="motion"] {
    display: flex;
    flex-direction: column;
  }
  #story {
    order: 1;
  }
  .lesson-foot {
    order: 3;
  }
}

/* ---------- phone: sidebar becomes the drawer (academy-navigation.css) ---------- */
@media (max-width: 650px), (max-width: 950px) and (max-height: 500px) {
  body[data-format="motion"] {
    --side: 0px;
  }
  .lesson-header {
    gap: 10px;
  }
  .lesson-header .mb-brand small,
  .header-map {
    display: none;
  }
  .academy-nav-toggle {
    margin-left: auto !important;
    border-radius: 999px !important;
    border-color: var(--line-2) !important;
    background: rgba(237, 242, 237, 0.05) !important;
    color: var(--text) !important;
  }
  body[data-format="motion"] .lesson-sidebar {
    top: 0;
    width: min(360px, calc(100vw - 36px));
    background: var(--bg-2);
    border-right: 1px solid var(--line-2);
  }
  body[data-format="motion"] .academy-nav-bar {
    background: var(--bg-2);
    border-bottom-color: var(--line);
  }
  #story {
    padding: calc(var(--header-h) + 16px) 14px 24px;
  }
  .lesson-heading {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }
  .lesson-pager {
    grid-template-columns: 1fr;
  }
  .lesson-pager .pager-next {
    text-align: left;
  }
  .lesson-foot {
    flex-direction: column;
    padding-inline: 14px;
  }
}