/* ==========================================================================
   upsense — Course Detail Page
   Editorial long-form reading experience
   ========================================================================== */

.course-article {
  padding-bottom: var(--space-3xl);
}

/* -- Header --------------------------------------------------------------- */

.course-header {
  padding-top: calc(var(--nav-h) + var(--space-3xl));
  padding-bottom: var(--space-2xl);
  border-bottom: 1px solid var(--border-light);
  margin-bottom: var(--space-xl);
}

.course-header-meta {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  margin-bottom: var(--space-lg);
}

.course-header-cat {
  font-family: var(--font-ui);
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.course-header-dot {
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: var(--text-muted);
}

.course-header-stage,
.course-header-time {
  font-family: var(--font-ui);
  font-size: 0.7rem;
  color: var(--text-muted);
}

.course-header-title {
  font-family: 'Pretendard Variable', 'Pretendard', sans-serif;
  font-weight: 800;
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  letter-spacing: -0.02em;
  line-height: 1.3;
  color: var(--text);
  margin-bottom: var(--space-md);
}

.course-header-desc {
  font-size: 1rem;
  font-weight: 300;
  color: var(--text-secondary);
  line-height: 1.75;
  max-width: 560px;
}

.course-header-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  margin-top: var(--space-lg);
}

.course-header-tag {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 400;
}

/* -- Table of Contents ---------------------------------------------------- */

.course-toc {
  padding: var(--space-xl) 0;
  margin-bottom: var(--space-xl);
  border-bottom: 1px solid var(--border-light);
}

.course-toc-label {
  font-family: var(--font-ui);
  font-size: 0.6rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--text-muted);
  margin-bottom: var(--space-md);
}

.course-toc-list {
  list-style: none;
  counter-reset: toc;
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.course-toc-list li {
  counter-increment: toc;
}

.course-toc-list a {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-decoration: none;
  padding: var(--space-xs) 0;
  transition: color 0.2s;
}

.course-toc-list a::before {
  content: counter(toc, decimal-leading-zero);
  font-family: var(--font-ui);
  font-size: 0.7rem;
  font-weight: 600;
  color: var(--text-muted);
  min-width: 24px;
}

.course-toc-list a:hover {
  color: var(--text);
}

/* -- Section -------------------------------------------------------------- */

.course-section {
  padding: var(--space-2xl) 0;
  border-bottom: 1px solid var(--border-light);
}

.course-section:last-of-type {
  border-bottom: none;
}

.course-section-num {
  font-family: var(--font-ui);
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--text-muted);
  letter-spacing: 0.1em;
  margin-bottom: var(--space-sm);
}

.course-section-title {
  font-family: 'Pretendard Variable', 'Pretendard', sans-serif;
  font-weight: 700;
  font-size: 1.3rem;
  color: var(--text);
  letter-spacing: -0.01em;
  line-height: 1.35;
  margin-bottom: var(--space-lg);
}

.course-section-body {
  font-family: 'Pretendard Variable', 'Pretendard', sans-serif;
  font-size: 0.95rem;
  line-height: 1.85;
  color: var(--text-secondary);
}

.course-section-body p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
  line-height: 1.85;
}

.course-section-body p:last-child {
  margin-bottom: 0;
}

.course-section-body strong {
  font-weight: 700;
  color: var(--text);
}

/* -- Tip ------------------------------------------------------------------ */

.course-tip {
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  background: #FAFAFA;
  border-left: 3px solid var(--accent);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.course-tip-label {
  font-family: var(--font-ui);
  font-size: 0.6rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: var(--space-xs);
}

.course-tip-text {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

/* -- Checklist ------------------------------------------------------------ */

.course-checklist {
  list-style: none;
  margin-top: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.course-checklist li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

.course-check-box {
  width: 18px;
  height: 18px;
  border: 2px solid var(--border);
  border-radius: 4px;
  flex-shrink: 0;
  margin-top: 0.2em;
}

/* -- Takeaways ------------------------------------------------------------ */

.course-takeaways {
  background: #FAFAFA;
  border-radius: var(--radius-md);
  padding: var(--space-xl) !important;
  border: 1px solid var(--border-light);
  margin-top: var(--space-lg);
}

.course-takeaway-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.course-takeaway-list li {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

.course-takeaway-list li::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
  margin-top: 0.55em;
}

/* -- Action Items --------------------------------------------------------- */

.course-actions {
  margin-top: var(--space-lg);
}

.course-action-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.course-action-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-sm);
}

.course-action-num {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--accent);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-ui);
  font-size: 0.7rem;
  font-weight: 700;
  flex-shrink: 0;
}

.course-action-text {
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--text-secondary);
  padding-top: 0.15rem;
}

/* -- Bottom Nav ----------------------------------------------------------- */

.course-bottom-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-2xl) 0;
  border-top: 1px solid var(--border);
  margin-top: var(--space-2xl);
  gap: var(--space-md);
}

.course-nav-btn {
  font-family: var(--font-body);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 0.6rem 1.2rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  transition: all var(--ease);
}

.course-nav-btn:hover {
  border-color: var(--accent);
  color: var(--text);
}

.course-nav-all {
  font-weight: 600;
  color: var(--text);
}

/* -- Responsive ----------------------------------------------------------- */

@media (max-width: 639px) {
  .course-header {
    padding-top: calc(var(--nav-h) + var(--space-2xl));
  }

  .course-header-title {
    font-size: clamp(1.4rem, 5vw, 1.8rem);
  }

  .course-section {
    padding: var(--space-xl) 0;
  }

  .course-bottom-nav {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .course-nav-btn {
    width: 100%;
    text-align: center;
  }
}

@media (min-width: 768px) {
  .course-header {
    padding-top: calc(var(--nav-h) + var(--space-4xl));
    padding-bottom: var(--space-3xl);
  }
}

@media print {
  .nav, .footer, .course-bottom-nav { display: none !important; }
  .course-header { padding-top: 0; }
  .course-section { page-break-inside: avoid; }
  .reveal { opacity: 1 !important; transform: none !important; }
}