/* ==========================================================================
   COURSES.CSS — Courses page layout (sidebar + main catalog)
   ========================================================================== */

/* Page shell — sidebar + content sit side by side */
.courses-layout {
  display: grid;
  grid-template-columns: 260px minmax(0, 1fr);
  gap: var(--space-md);
  max-width: calc(var(--max-width) + 260px + var(--space-md));
  margin: 0 auto;
  padding: var(--space-md);
  padding-top: var(--space-md);
  align-items: start;
}

/* --------------------------------------------------------------------------
   SIDEBAR — sticky catalog navigation with grouped links
   -------------------------------------------------------------------------- */
.side-bar {
  position: sticky;
  top: calc(var(--nav-height) + var(--space-sm));
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  max-height: calc(100vh - var(--nav-height) - var(--space-md));
  padding: var(--space-md);
  background-color: var(--bg-dark);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--radius-lg);
  box-shadow: 0 8px 32px rgba(13, 13, 13, 0.18);
  overflow: hidden;
}

/* Header — title + path count pill */
.side-bar__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-xs);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.side-bar__title {
  font-size: 0.9375rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--bg-light);
  line-height: 1.2;
}

.side-bar__count {
  flex-shrink: 0;
  padding: 0.2rem 0.5rem;
  font-size: 0.625rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: #a8a8a8;
  background-color: rgba(247, 247, 245, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 999px;
}

/* Scrollable nav area */
.side-bar__nav {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  padding-right: 0.25rem;
  scrollbar-width: thin;
  scrollbar-color: rgba(255, 255, 255, 0.15) transparent;
}

.side-bar__nav::-webkit-scrollbar {
  width: 4px;
}

.side-bar__nav::-webkit-scrollbar-thumb {
  background-color: rgba(255, 255, 255, 0.15);
  border-radius: 999px;
}

/* Section label inside nav groups */
.side-bar__section {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.side-bar__label {
  padding: 0.25rem 0.75rem 0.125rem;
  font-size: 0.625rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #666666;
}

.side-bar__divider {
  height: 1px;
  margin: 0.125rem 0;
  background-color: rgba(255, 255, 255, 0.08);
}

.side-bar__group {
  display: flex;
  flex-direction: column;
  gap: 0.125rem;
}

/* Primary nav link */
.side-bar__link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: #a8a8a8;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  transition:
    color var(--transition),
    background-color var(--transition),
    border-color var(--transition);
}

.side-bar__link:hover {
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.07);
}

.side-bar__link-icon {
  flex-shrink: 0;
  width: 1rem;
  font-size: 0.625rem;
  text-align: center;
  color: #666666;
  transition: color var(--transition);
}

.side-bar__link:hover .side-bar__link-icon {
  color: #a8a8a8;
}

/* Count badge on overview links */
.side-bar__badge {
  margin-left: auto;
  padding: 0.125rem 0.4rem;
  font-size: 0.625rem;
  font-weight: 600;
  color: #888888;
  background-color: rgba(247, 247, 245, 0.06);
  border-radius: 999px;
}

.side-bar__badge--featured {
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.14);
}

/* Desktop vs mobile link labels */
.side-bar__link-text--short {
  display: none;
}

/* Featured Python link */
.side-bar__link--featured {
  border-color: rgba(255, 255, 255, 0.1);
  background-color: rgba(247, 247, 245, 0.05);
}

.side-bar__link--featured .side-bar__link-icon {
  color: var(--bg-light);
}

/* Nested course links — indented sub-nav */
.side-bar__sublink {
  display: block;
  padding: 0.375rem 0.75rem 0.375rem 1.75rem;
  font-size: 0.75rem;
  font-weight: 500;
  color: #777777;
  border-radius: var(--radius-sm);
  border-left: 2px solid transparent;
  transition:
    color var(--transition),
    background-color var(--transition),
    border-color var(--transition);
}

.side-bar__sublink:hover {
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.05);
  border-left-color: rgba(247, 247, 245, 0.25);
}

/* Footer — back link */
.side-bar__footer {
  padding-top: var(--space-sm);
  border-top: 1px solid rgba(255, 255, 255, 0.08);
}

.side-bar__footer-link {
  display: block;
  padding: 0.5rem 0.75rem;
  font-size: 0.8125rem;
  font-weight: 500;
  color: #888888;
  border-radius: var(--radius-sm);
  transition:
    color var(--transition),
    background-color var(--transition);
}

.side-bar__footer-link:hover {
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.07);
}

/* --------------------------------------------------------------------------
   ACTIVE STATES — CSS-only via :target (no JavaScript)
   Highlights the sidebar link matching the scrolled-to section.
   -------------------------------------------------------------------------- */

/* Default: All Courses active when no hash in URL */
body:not(:has(:target)) .side-bar__link[href="#courses"] {
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.1);
  border-color: rgba(255, 255, 255, 0.08);
}

body:not(:has(:target)) .side-bar__link[href="#courses"] .side-bar__link-icon {
  color: var(--bg-light);
}

/* Category overview links */
body:has(#courses:target) .side-bar__link[href="#courses"],
body:has(#web-foundations:target) .side-bar__link[href="#web-foundations"],
body:has(#programming:target) .side-bar__link[href="#programming"],
body:has(#tools:target) .side-bar__link[href="#tools"],
body:has(#course-python:target) .side-bar__link[href="#course-python"] {
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.1);
  border-color: rgba(255, 255, 255, 0.08);
}

body:has(#courses:target) .side-bar__link[href="#courses"] .side-bar__link-icon,
body:has(#web-foundations:target) .side-bar__link[href="#web-foundations"] .side-bar__link-icon,
body:has(#programming:target) .side-bar__link[href="#programming"] .side-bar__link-icon,
body:has(#tools:target) .side-bar__link[href="#tools"] .side-bar__link-icon,
body:has(#course-python:target) .side-bar__link[href="#course-python"] .side-bar__link-icon {
  color: var(--bg-light);
}

/* Individual course sublinks */
body:has(#course-html:target) .side-bar__sublink[href="#course-html"],
body:has(#course-css:target) .side-bar__sublink[href="#course-css"],
body:has(#course-javascript:target) .side-bar__sublink[href="#course-javascript"],
body:has(#course-dsa:target) .side-bar__sublink[href="#course-dsa"],
body:has(#course-problem-solving:target) .side-bar__sublink[href="#course-problem-solving"],
body:has(#course-git:target) .side-bar__sublink[href="#course-git"],
body:has(#course-webdev:target) .side-bar__sublink[href="#course-webdev"],
body:has(#course-ai:target) .side-bar__sublink[href="#course-ai"] {
  color: var(--bg-light);
  background-color: rgba(247, 247, 245, 0.07);
  border-left-color: var(--bg-light);
}

/* --------------------------------------------------------------------------
   MAIN CONTENT — scrollable course catalog panel
   -------------------------------------------------------------------------- */
.course-content {
  min-width: 0;
  padding: var(--space-lg);
  background-color: #ffffff;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  box-shadow: 0 4px 24px rgba(13, 13, 13, 0.06);
}

/* Page header */
.courses-page-header {
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border-color);
}

.courses-page-title {
  font-size: clamp(1.625rem, 2.5vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--text-primary);
  margin-bottom: 0.375rem;
}

.courses-page-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --------------------------------------------------------------------------
   RESPONSIVE
   -------------------------------------------------------------------------- */
@media (max-width: 992px) {
  .courses-layout {
    grid-template-columns: 1fr;
    padding: var(--space-sm);
    gap: var(--space-sm);
  }

  .side-bar {
    position: static;
    max-height: none;
    gap: var(--space-sm);
  }

  .side-bar__header {
    padding-bottom: var(--space-xs);
  }

  /* On tablet/mobile: hide nested links, show category pills only */
  .side-bar__sublink {
    display: none;
  }

  .side-bar__section .side-bar__label {
    display: none;
  }

  .side-bar__nav {
    flex-direction: row;
    flex-wrap: wrap;
    overflow: visible;
    gap: 0.375rem;
  }

  .side-bar__section {
    display: contents;
  }

  .side-bar__group {
    display: contents;
  }

  .side-bar__divider {
    display: none;
  }

  .side-bar__link {
    padding: 0.45rem 0.75rem;
    font-size: 0.8125rem;
    background-color: rgba(247, 247, 245, 0.06);
    border-color: rgba(255, 255, 255, 0.08);
  }

  .side-bar__link-icon {
    display: none;
  }

  .side-bar__link-text--long {
    display: none;
  }

  .side-bar__link-text--short {
    display: inline;
  }

  .side-bar__badge:not(.side-bar__badge--featured) {
    display: none;
  }

  .side-bar__footer {
    display: none;
  }
}

@media (max-width: 576px) {
  .course-content {
    padding: var(--space-md);
  }

  .side-bar {
    padding: var(--space-sm);
  }
}