:root {
  --bg: #f6f7f8;
  --surface: #ffffff;
  --text: #1b1f23;
  --muted: #5d6772;
  --border: #d9dee3;
  --accent: #0057b8;
  --header: #0f1720;
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

body {
  background: linear-gradient(180deg, #eef2f6 0%, var(--bg) 180px, var(--bg) 100%);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  /* App-shell: header/footer pinned, panes scroll. Reverted to normal
     document flow on mobile (see the max-width: 720px block). */
  overflow: hidden;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover,
a:focus-visible {
  text-decoration: underline;
}

.page {
  width: min(960px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1rem 0 0;
  height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Two-column layout: filter sidebar + course list, each scrolls on its own */
.layout {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 2rem;
  flex: 1;
  min-height: 0;
}

.sidebar {
  overflow-y: auto;
  min-height: 0;
  padding-right: 0.5rem;
  font-size: 0.85rem;
}

main {
  overflow-y: auto;
  min-height: 0;
  padding-right: 0.5rem;
}

.sidebar-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.sidebar-title {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.filter-clear {
  background: none;
  border: none;
  color: var(--accent);
  font-size: 0.78rem;
  cursor: pointer;
  padding: 0;
}

.facet {
  margin-bottom: 1.25rem;
}

.facet-title {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--header);
  margin-bottom: 0.35rem;
}

.facet-opt {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.12rem 0;
  cursor: pointer;
  color: var(--text);
}

.facet-opt input {
  margin: 0;
  flex: none;
}

.facet-opt span:nth-of-type(1) {
  flex: 1;
}

.facet-count {
  color: var(--muted);
  font-size: 0.72rem;
  font-variant-numeric: tabular-nums;
}

/* Filters toggle (mobile only) */
.filter-toggle {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text);
  font-size: 0.8rem;
  padding: 0.3rem 0.7rem;
  cursor: pointer;
}

.no-results {
  color: var(--muted);
  font-style: italic;
  padding: 1.5rem 0;
}

.site-header {
  flex: none;
  padding: 0.5rem 0 1.25rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.title-row {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
}

.site-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--header);
  letter-spacing: -0.01em;
}

.site-subtitle {
  font-size: 0.85rem;
  color: var(--muted);
  margin-top: 0.15rem;
}

/* Course list */
.course-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.course {
  border-bottom: 1px solid var(--border);
}

.course:first-child .course-header {
  padding-top: 0;
}

/* Clickable header */
.course-header {
  padding: 1rem 0;
  cursor: pointer;
  user-select: none;
  display: grid;
  grid-template-areas:
    "title   icon"
    "summary icon";
  grid-template-columns: 1fr auto;
  column-gap: 0.75rem;
  row-gap: 0.2rem;
}

.course-title {
  grid-area: title;
  line-height: 1.4;
}

/* Institution + course number: muted, recede behind the name */
.course-code {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--muted);
}

/* The course name itself: the prominent element */
.course-name {
  font-size: 1.08rem;
  font-weight: 700;
  color: var(--header);
  transition: color 0.1s;
}

.course-header:hover .course-name {
  color: var(--accent);
}

.course-term {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--muted);
}

.new-badge {
  display: inline-block;
  background: #d63b3b;
  color: #fff;
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  padding: 0.05rem 0.35rem;
  border-radius: 3px;
  vertical-align: 0.12em;
  margin-right: 0.35rem;
}

.course-summary {
  grid-area: summary;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.4rem 0.6rem;
  font-size: 0.8rem;
  color: var(--muted);
}

.sum-instructor {
  color: var(--muted);
}

/* High-level tags — uniform color and shape */
.sum-tags {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.3rem;
}

.tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  line-height: 1.3;
  padding: 0.08rem 0.5rem;
  border-radius: 4px;
  white-space: nowrap;
  background: #eef1f4;
  color: var(--muted);
  border: 1px solid var(--border);
}

/* Expand chevron */
.expand-icon {
  grid-area: icon;
  align-self: start;
  margin-top: 0.3rem;
  font-size: 0.6rem;
  color: var(--muted);
  transition: transform 0.15s;
}

.course.open .expand-icon {
  transform: rotate(180deg);
}

/* Collapsed body */
.course-body {
  display: none;
  padding-bottom: 1rem;
}

.course.open .course-body {
  display: block;
}

/* Detail fields */
.course-fields {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.18rem 1.1rem;
  margin: 0;
}

.course-fields dt {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding-top: 0.05rem;
  white-space: nowrap;
}

.course-fields dd {
  font-size: 0.875rem;
  color: var(--text);
  margin: 0;
  overflow-wrap: break-word;
  min-width: 0;
}

.course.empty {
  color: var(--muted);
  font-style: italic;
  padding: 1rem 0;
}

/* Collapse the sidebar into a toggle on narrow screens, and drop the
   app-shell back to normal page scrolling. */
@media (max-width: 720px) {
  body {
    overflow: visible;
  }
  .page {
    height: auto;
    display: block;
    padding-bottom: 2rem;
  }
  .layout {
    display: block;
    min-height: 0;
  }
  main {
    overflow: visible;
    padding-right: 0;
  }
  .filter-toggle {
    display: inline-block;
  }
  .sidebar {
    overflow: visible;
    display: none;
    margin-bottom: 1.5rem;
    padding: 1rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 8px;
  }
  .sidebar.open {
    display: block;
  }
  .site-footer {
    border-top: none;
  }
}

@media (max-width: 480px) {
  .course-fields {
    grid-template-columns: 1fr;
    gap: 0;
  }
  .course-fields dt {
    margin-top: 0.5rem;
  }
  .course-fields dd {
    margin-bottom: 0.1rem;
  }
}

.site-footer {
  flex: none;
  padding: 0.75rem 0;
  border-top: 1px solid var(--border);
  font-size: 0.78rem;
  color: var(--muted);
  text-align: center;
}