/**
 * Stackforge Academy — Course detail page.
 *
 * Two-column from 1024px with a sticky enrollment card; single column
 * below, where the enrollment card moves to the top so the price and
 * CTA are the first thing a visitor sees rather than the last.
 */

/* ---------- Hero ---------- */

.course-hero {
  background: var(--sf-ink);
  color: var(--sf-on-ink);
  padding-block: var(--sf-space-12);
  position: relative;
  overflow: hidden;
}

.course-hero::before {
  content: "";
  position: absolute;
  top: -30%;
  right: -10%;
  width: 420px;
  height: 420px;
  background: radial-gradient(circle, rgba(68, 56, 202, 0.35), transparent 70%);
  pointer-events: none;
}

.course-hero__inner { position: relative; max-width: 760px; }

.course-hero h1 {
  color: var(--sf-on-ink);
  margin-bottom: var(--sf-space-4);
}

.course-hero__lead {
  font-size: var(--sf-text-lg);
  color: var(--sf-on-ink-muted);
  margin-bottom: var(--sf-space-6);
}

.course-hero__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sf-space-5);
  font-family: var(--sf-font-mono);
  font-size: var(--sf-text-xs);
  color: var(--sf-on-ink-muted);
}

.course-hero__instructors {
  display: flex;
  align-items: center;
  gap: var(--sf-space-2);
}

.course-hero__instructors img {
  width: 28px;
  height: 28px;
  border-radius: var(--sf-radius-full);
  border: 2px solid var(--sf-ink);
}

.course-hero__instructors img + img { margin-left: calc(var(--sf-space-3) * -1); }

/* ---------- Layout ---------- */

.course-detail {
  padding-block: var(--sf-space-10) var(--sf-space-16);
}

.course-detail__layout {
  display: grid;
  gap: var(--sf-space-8);
  grid-template-columns: 1fr;
  align-items: start;
}

@media (min-width: 1024px) {
  .course-detail__layout {
    grid-template-columns: minmax(0, 1fr) 340px;
    gap: var(--sf-space-10);
  }

  /* Sidebar first in the DOM (so it leads on mobile) but visually on
     the right at desktop widths. */
  .course-detail__sidebar { order: 2; }
  .course-detail__main { order: 1; }
}

.course-section + .course-section {
  margin-top: var(--sf-space-12);
  padding-top: var(--sf-space-12);
  border-top: 1px solid var(--sf-border);
}

.course-section__title {
  font-size: var(--sf-text-2xl);
  margin-bottom: var(--sf-space-5);
}

/* ---------- Enrollment card ---------- */

.enroll-card {
  background: var(--sf-surface);
  border: 1px solid var(--sf-border);
  border-radius: var(--sf-radius-lg);
  box-shadow: var(--sf-shadow-md);
  overflow: hidden;
}

@media (min-width: 1024px) {
  .enroll-card {
    position: sticky;
    top: calc(var(--sf-header-height) + var(--sf-space-6));
  }
}

.enroll-card__media {
  aspect-ratio: 16 / 9;
  background: var(--sf-indigo-50);
  position: relative;
}
.enroll-card__media img { width: 100%; height: 100%; object-fit: cover; }

.enroll-card__play {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(var(--sf-shadow-rgb), 0.45);
  border: none;
  color: var(--sf-on-ink);
  cursor: pointer;
  font-size: var(--sf-text-sm);
  gap: var(--sf-space-2);
  transition: background var(--sf-duration-fast) var(--sf-ease);
}
.enroll-card__play:hover { background: rgba(var(--sf-shadow-rgb), 0.6); }

.enroll-card__body { padding: var(--sf-space-6); }

.enroll-card__price {
  font-family: var(--sf-font-mono);
  font-size: var(--sf-text-3xl);
  font-weight: var(--sf-weight-semibold);
  color: var(--sf-ink);
  margin-bottom: var(--sf-space-1);
}

.enroll-card__price-was {
  font-size: var(--sf-text-lg);
  color: var(--sf-slate-400);
  text-decoration: line-through;
  margin-right: var(--sf-space-2);
}

.enroll-card__facts {
  list-style: none;
  margin: var(--sf-space-5) 0 0;
  padding: var(--sf-space-5) 0 0;
  border-top: 1px solid var(--sf-border);
}

.enroll-card__facts li {
  display: flex;
  justify-content: space-between;
  gap: var(--sf-space-3);
  padding: var(--sf-space-2) 0;
  font-size: var(--sf-text-sm);
  color: var(--sf-slate-600);
}

.enroll-card__facts strong {
  color: var(--sf-slate-900);
  font-weight: var(--sf-weight-medium);
}

/* ---------- Outcome / requirement lists ---------- */

.course-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: var(--sf-space-3);
}

@media (min-width: 768px) {
  .course-list--two { grid-template-columns: repeat(2, 1fr); }
}

.course-list li {
  display: flex;
  align-items: flex-start;
  gap: var(--sf-space-3);
  font-size: var(--sf-text-sm);
  color: var(--sf-slate-600);
}

.course-list li::before {
  content: "";
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  margin-top: 2px;
  border-radius: 50%;
  background: var(--sf-green-100) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%231e9e6c' stroke-width='3'%3E%3Cpath d='M5 12l4 4 10-10'/%3E%3C/svg%3E") no-repeat center / 11px;
}

.course-list--neutral li::before {
  background: var(--sf-indigo-50) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%234438ca' stroke-width='3'%3E%3Cpath d='M5 12h14'/%3E%3C/svg%3E") no-repeat center / 11px;
}

/* ---------- Curriculum ---------- */

.curriculum-topic {
  border: 1px solid var(--sf-border);
  border-radius: var(--sf-radius-md);
  background: var(--sf-surface);
}

.curriculum-topic + .curriculum-topic { margin-top: var(--sf-space-3); }

.curriculum-topic__toggle {
  display: flex;
  width: 100%;
  align-items: center;
  gap: var(--sf-space-3);
  min-height: 56px;
  padding: var(--sf-space-4) var(--sf-space-5);
  background: none;
  border: none;
  text-align: left;
  cursor: pointer;
  font-size: var(--sf-text-base);
  font-weight: var(--sf-weight-semibold);
  color: var(--sf-slate-900);
}

.curriculum-topic__toggle:hover { color: var(--sf-indigo); }

.curriculum-topic__count {
  margin-left: auto;
  font-family: var(--sf-font-mono);
  font-size: var(--sf-text-xs);
  color: var(--sf-slate-400);
  font-weight: var(--sf-weight-regular);
}

.curriculum-topic__chevron {
  transition: transform var(--sf-duration-base) var(--sf-ease);
  color: var(--sf-slate-400);
}
.curriculum-topic__toggle[aria-expanded="true"] .curriculum-topic__chevron { transform: rotate(180deg); }

.curriculum-topic__body {
  padding: 0 var(--sf-space-3) var(--sf-space-3);
}
.curriculum-topic__body[hidden] { display: none; }

.curriculum-item {
  display: flex;
  align-items: center;
  gap: var(--sf-space-3);
  min-height: 44px;
  padding: var(--sf-space-3) var(--sf-space-4);
  border-radius: var(--sf-radius-sm);
  font-size: var(--sf-text-sm);
  color: var(--sf-slate-600);
  text-decoration: none;
}

a.curriculum-item:hover { background: var(--sf-indigo-50); color: var(--sf-indigo); }

.curriculum-item--locked { color: var(--sf-slate-400); }
.curriculum-item__title { flex: 1; min-width: 0; }
.curriculum-item__duration { font-family: var(--sf-font-mono); font-size: var(--sf-text-xs); color: var(--sf-slate-400); }

/* ---------- Instructor block ---------- */

.instructor-block {
  display: flex;
  gap: var(--sf-space-5);
  align-items: flex-start;
}

.instructor-block__avatar {
  width: 72px;
  height: 72px;
  border-radius: var(--sf-radius-full);
  flex-shrink: 0;
}

@media (max-width: 559px) {
  .instructor-block { flex-direction: column; }
}

/* ---------- Prerequisites ---------- */

.course-prerequisites__note {
  font-size: var(--sf-text-sm);
  color: var(--sf-slate-600);
  margin-bottom: var(--sf-space-4);
}

.course-prerequisites__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: var(--sf-space-2);
}

.course-prerequisite {
  display: flex;
  align-items: center;
  gap: var(--sf-space-3);
  padding: var(--sf-space-3) var(--sf-space-4);
  border: 1px solid var(--sf-border);
  border-radius: var(--sf-radius-md);
  background: var(--sf-surface);
}

.course-prerequisite.is-complete { border-color: var(--sf-green); }

.course-prerequisite__state {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: var(--sf-radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--sf-text-xs);
  background: var(--sf-border);
  color: var(--sf-slate-600);
}

.course-prerequisite.is-complete .course-prerequisite__state {
  background: var(--sf-green-100);
  color: var(--sf-green);
}

.course-prerequisite__body { display: flex; flex-direction: column; gap: 2px; min-width: 0; }

.course-prerequisite__title {
  font-weight: var(--sf-weight-medium);
  color: var(--sf-slate-900);
  text-decoration: none;
}
.course-prerequisite__title:hover { color: var(--sf-indigo); }

.course-prerequisite__status {
  font-family: var(--sf-font-mono);
  font-size: var(--sf-text-xs);
  color: var(--sf-slate-400);
}