: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;
}

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;
}

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

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

.page {
  width: min(680px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 1rem 0 3rem;
}

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

.course-title {
  grid-area: title;
  font-size: 1rem;
  font-weight: 600;
  line-height: 1.4;
  transition: color 0.1s;
}

.course-summary {
  grid-area: summary;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.15rem 0;
  font-size: 0.8rem;
  color: var(--muted);
}

.sum-sep {
  margin: 0 0.35rem;
  color: var(--border);
}

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

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

.sum-mats {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0 0.3rem;
}

/* 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;
}

.instructor-notes {
  font-size: 0.8rem;
  color: var(--muted);
  margin-top: -0.05rem;
}

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

/* Material badges */
.mat-y,
.mat-n {
  font-size: 0.8rem;
  margin-right: 0.6rem;
}

.mat-lectures {
  font-weight: 600;
}

.mat-y::after {
  content: " \2713";
  color: #2a7d2a;
}

.mat-n {
  color: var(--muted);
}

.mat-n::after {
  content: " \2717";
}

/* Tighter badges in the summary line */
.sum-mats .mat-y,
.sum-mats .mat-n {
  margin-right: 0.35rem;
}

@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 {
  margin-top: 2.5rem;
  font-size: 0.78rem;
  color: var(--muted);
  text-align: center;
}