.course-hero {
  padding: 5.5rem 0 3.5rem;
  border-bottom: 1px solid var(--border);
  background:
    radial-gradient(circle at 20% 10%, rgba(34, 197, 94, 0.16), transparent 32rem),
    radial-gradient(circle at 80% 0%, rgba(59, 130, 246, 0.14), transparent 28rem);
}

.course-hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 2rem;
  align-items: center;
}

.course-hero h1 {
  max-width: 900px;
  margin: 0.8rem 0 1.2rem;
  font-size: clamp(2.4rem, 5vw, 4.6rem);
  line-height: 1.02;
  letter-spacing: -0.06em;
}

.course-hero-text {
  max-width: 760px;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.75;
}

.course-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
  margin-top: 1.5rem;
}

.course-tags span {
  padding: 0.55rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.04);
  color: var(--muted);
  font-size: 0.9rem;
}

.progress-card,
.study-panel,
.module-card,
.course-sidebar {
  border: 1px solid var(--border);
  border-radius: 1.4rem;
  background: rgba(255, 255, 255, 0.035);
  box-shadow: var(--shadow);
}

.progress-card {
  padding: 1.4rem;
}

.progress-card strong {
  display: block;
  margin-top: 0.4rem;
  font-size: 2rem;
  letter-spacing: -0.04em;
}

.progress-card p {
  margin-top: 0.8rem;
  color: var(--muted);
}

.progress-bar {
  width: 100%;
  height: 0.65rem;
  margin-top: 1rem;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
}

.progress-bar span {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, #22c55e, #3b82f6);
}

.course-layout {
  display: grid;
  grid-template-columns: 340px minmax(0, 1fr);
  gap: 1.5rem;
  align-items: start;
}

.course-sidebar {
  position: sticky;
  top: 6rem;
  padding: 1.2rem;
}

.course-sidebar h2 {
  margin: 0 0 1rem;
  font-size: 1.1rem;
}

.course-checklist {
  display: grid;
  gap: 0.75rem;
}

.check-item {
  display: flex;
  gap: 0.8rem;
  align-items: center;
  padding: 0.9rem;
  border: 1px solid var(--border);
  border-radius: 1rem;
  background: rgba(0, 0, 0, 0.18);
  color: var(--text);
  text-decoration: none;
  transition: 0.2s ease;
}

.check-item:hover {
  transform: translateY(-2px);
  border-color: rgba(59, 130, 246, 0.6);
}

.check-item span {
  display: grid;
  width: 2.2rem;
  height: 2.2rem;
  place-items: center;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.06);
}

.check-item strong {
  display: block;
  font-size: 0.95rem;
}

.check-item small {
  display: block;
  margin-top: 0.2rem;
  color: var(--muted);
  font-size: 0.78rem;
}

.check-item.done {
  border-color: rgba(34, 197, 94, 0.45);
}

.check-item.active {
  border-color: rgba(59, 130, 246, 0.65);
  background: rgba(59, 130, 246, 0.08);
}

.course-content {
  display: grid;
  gap: 1.2rem;
}

.study-panel {
  padding: 1.4rem;
}

.study-panel h2 {
  margin: 0.3rem 0 1rem;
}

.focus-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 1rem;
}

.focus-grid article {
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 1rem;
  background: rgba(0, 0, 0, 0.16);
}

.focus-grid p {
  margin: 0.5rem 0 0;
  color: var(--muted);
  line-height: 1.6;
}

.module-card {
  padding: 1.4rem;
  scroll-margin-top: 7rem;
}

.module-card.is-active {
  border-color: rgba(59, 130, 246, 0.65);
  background: rgba(59, 130, 246, 0.06);
}

.module-header {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: flex-start;
  margin-bottom: 1rem;
}

.module-header h2 {
  margin: 0.25rem 0 0;
}

.status {
  flex: 0 0 auto;
  padding: 0.4rem 0.65rem;
  border-radius: 999px;
  font-size: 0.78rem;
}

.status.done {
  background: rgba(34, 197, 94, 0.12);
  color: #86efac;
}

.status.active {
  background: rgba(59, 130, 246, 0.12);
  color: #93c5fd;
}

.status.pending {
  background: rgba(255, 255, 255, 0.07);
  color: var(--muted);
}

.lesson-list {
  display: grid;
  gap: 0.55rem;
  margin: 1rem 0;
  padding: 0;
  list-style: none;
}

.lesson-list li {
  padding: 0.75rem 0.85rem;
  border: 1px solid var(--border);
  border-radius: 0.8rem;
  background: rgba(0, 0, 0, 0.16);
  color: var(--muted);
}

details {
  margin-top: 1rem;
}

summary {
  cursor: pointer;
  color: var(--text);
  font-weight: 700;
}

.note-box {
  margin-top: 0.8rem;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 1rem;
  background: rgba(0, 0, 0, 0.22);
}

.note-box p {
  margin: 0.4rem 0;
  color: var(--muted);
  line-height: 1.7;
}

code {
  padding: 0.1rem 0.35rem;
  border-radius: 0.35rem;
  background: rgba(255, 255, 255, 0.08);
  color: #93c5fd;
}

pre {
  overflow-x: auto;
  margin: 1rem 0 0;
  padding: 1rem;
  border-radius: 0.9rem;
  background: rgba(0, 0, 0, 0.45);
}

pre code {
  padding: 0;
  background: transparent;
}

.log-list {
  display: grid;
  gap: 0.8rem;
}

.log-entry {
  display: grid;
  gap: 0.4rem;
  padding: 1rem;
  border: 1px solid var(--border);
  border-radius: 1rem;
  background: rgba(0, 0, 0, 0.16);
}

.log-entry time {
  color: var(--muted);
  font-size: 0.85rem;
}

.log-entry p {
  margin: 0;
  color: var(--muted);
  line-height: 1.6;
}

.back-area {
  padding-bottom: 2rem;
}

.mini-label {
  color: var(--muted);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

@media (max-width: 960px) {
  .course-hero-grid,
  .course-layout,
  .focus-grid {
    grid-template-columns: 1fr;
  }

  .course-sidebar {
    position: static;
  }
}

@media (max-width: 640px) {
  .course-hero {
    padding-top: 4.5rem;
  }

  .module-header {
    flex-direction: column;
  }

  .check-item {
    align-items: flex-start;
  }
}