/* ─────────────────────────────────────────────────────────────
   Design tokens
   ───────────────────────────────────────────────────────────── */
:root {
  --navy:       #1E293B;
  --navy-light: #334155;
  --blue:       #2563EB;
  --blue-dim:   #DBEAFE;
  --slate-600:  #475569;
  --slate-400:  #94A3B8;
  --slate-200:  #E2E8F0;
  --slate-100:  #F1F5F9;
  --slate-50:   #F8FAFC;
  --white:      #FFFFFF;
  --amber-bg:   #FEF3C7;
  --amber-fg:   #92400E;
  --red-bg:     #FEE2E2;
  --red-fg:     #991B1B;
  --green-bg:   #D1FAE5;
  --green-fg:   #065F46;
  --text:       #1E293B;
  --text-muted: #64748B;

  --font:       'Inter', system-ui, -apple-system, sans-serif;
  --mono:       'JetBrains Mono', 'Fira Code', monospace;

  --nav-h:      56px;
  --content-w:  800px;
  --radius:     5px;
  --shadow:     0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
}

/* ─────────────────────────────────────────────────────────────
   Reset
   ───────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { font-family: var(--font); color: var(--text); background: var(--white); line-height: 1.6; }
img  { max-width: 100%; display: block; }
a    { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol { padding-left: 1.4rem; }

/* ─────────────────────────────────────────────────────────────
   Navbar
   ───────────────────────────────────────────────────────────── */
.navbar {
  background: var(--navy);
  position: sticky;
  top: 0;
  z-index: 200;
  box-shadow: 0 1px 0 rgba(255,255,255,.08);
}

.navbar-inner {
  max-width: calc(var(--content-w) + 4rem);
  margin: 0 auto;
  padding: 0 1.5rem;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  gap: 2rem;
}

/* Brand */
.navbar-brand {
  display: flex;
  align-items: baseline;
  gap: 0.55rem;
  text-decoration: none;
  flex-shrink: 0;
}
.navbar-brand:hover { text-decoration: none; }

.brand-code {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.04em;
  white-space: nowrap;
}

.brand-name {
  font-size: 0.8rem;
  font-weight: 400;
  color: var(--slate-400);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* Desktop nav links */
.navbar-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  margin-left: auto;
}

.nav-link {
  font-size: 0.825rem;
  font-weight: 500;
  color: var(--slate-400);
  padding: 0.35rem 0.7rem;
  border-radius: var(--radius);
  transition: color 0.12s, background 0.12s;
  white-space: nowrap;
}
.nav-link:hover { color: var(--white); background: var(--navy-light); text-decoration: none; }
.nav-link.active { color: var(--white); background: var(--navy-light); }
.nav-external { opacity: 0.7; }
.nav-external:hover { opacity: 1; }

/* Hamburger button */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px;
  height: 36px;
  padding: 6px;
  background: none;
  border: none;
  cursor: pointer;
  margin-left: auto;
  flex-shrink: 0;
}
.hamburger span {
  display: block;
  height: 2px;
  background: var(--slate-400);
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.2s;
  transform-origin: center;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* Mobile dropdown */
.mobile-menu {
  display: none;
  flex-direction: column;
  background: var(--navy-light);
  border-top: 1px solid rgba(255,255,255,.06);
  padding: 0.5rem 0;
}
.mobile-menu.open { display: flex; }

.mobile-link {
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--slate-400);
  padding: 0.65rem 1.5rem;
  transition: color 0.1s, background 0.1s;
}
.mobile-link:hover  { color: var(--white); background: rgba(255,255,255,.05); text-decoration: none; }
.mobile-link.active { color: var(--white); }

/* ─────────────────────────────────────────────────────────────
   Main content
   ───────────────────────────────────────────────────────────── */
.main-content {
  min-height: calc(100vh - var(--nav-h) - 56px);
  padding: 2.5rem 1.5rem;
}

.content-inner {
  max-width: var(--content-w);
  margin: 0 auto;
}

/* ─────────────────────────────────────────────────────────────
   Footer
   ───────────────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--slate-200);
  padding: 1rem 1.5rem;
  background: var(--slate-50);
}

.footer-inner {
  max-width: calc(var(--content-w) + 4rem);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ─────────────────────────────────────────────────────────────
   Page header
   ───────────────────────────────────────────────────────────── */
.page-header {
  margin-bottom: 2rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--slate-200);
}

.page-header h1 {
  font-size: 1.65rem;
  font-weight: 700;
  color: var(--navy);
  line-height: 1.2;
  margin-bottom: 0.3rem;
}

.page-subtitle {
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* ─────────────────────────────────────────────────────────────
   Typography
   ───────────────────────────────────────────────────────────── */
h2 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--navy);
  margin-top: 2.25rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--slate-100);
}

h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--navy-light);
  margin-top: 1.5rem;
  margin-bottom: 0.4rem;
}

p {
  font-size: 0.9rem;
  color: var(--slate-600);
  margin-bottom: 0.9rem;
  line-height: 1.7;
}

li {
  font-size: 0.9rem;
  color: var(--slate-600);
  line-height: 1.7;
  margin-bottom: 0.2rem;
}

code {
  font-family: var(--mono);
  font-size: 0.82rem;
  background: var(--slate-100);
  padding: 0.1em 0.35em;
  border-radius: 3px;
  color: var(--navy);
}

strong { color: var(--navy); }

/* ─────────────────────────────────────────────────────────────
   Callout
   ───────────────────────────────────────────────────────────── */
.callout {
  border-left: 3px solid var(--blue);
  background: var(--blue-dim);
  padding: 0.75rem 1rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.25rem 0;
  font-size: 0.875rem;
  color: var(--slate-600);
  line-height: 1.6;
}
.callout.warning { border-left-color: var(--amber-fg); background: var(--amber-bg); }
.callout.note    { border-left-color: var(--slate-400); background: var(--slate-100); }

/* ─────────────────────────────────────────────────────────────
   Objectives box
   ───────────────────────────────────────────────────────────── */
.objectives-box {
  border: 1px solid var(--slate-200);
  border-radius: var(--radius);
  background: var(--slate-50);
  padding: 1rem 1.25rem;
  margin: 1rem 0;
}
.objectives-box p:first-child { margin-top: 0; }
.objectives-box ul { margin-bottom: 0; }

/* ─────────────────────────────────────────────────────────────
   Announcements
   ───────────────────────────────────────────────────────────── */
.announcements { margin-bottom: 2rem; }

.announcement {
  display: flex;
  gap: 1.25rem;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--slate-100);
  font-size: 0.875rem;
  align-items: baseline;
}
.announcement:last-child { border-bottom: none; }

.ann-date {
  color: var(--text-muted);
  white-space: nowrap;
  min-width: 48px;
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
}
.ann-text { color: var(--slate-600); line-height: 1.55; }

/* ─────────────────────────────────────────────────────────────
   Upcoming deadlines
   ───────────────────────────────────────────────────────────── */
.deadline-list { margin-bottom: 2rem; }

.deadline-item {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--slate-100);
  font-size: 0.875rem;
  align-items: baseline;
}
.deadline-item:last-child { border-bottom: none; }

.deadline-date {
  color: var(--text-muted);
  white-space: nowrap;
  min-width: 88px;
  font-size: 0.78rem;
  font-variant-numeric: tabular-nums;
  flex-shrink: 0;
}
.deadline-title { font-weight: 600; }
.deadline-due { color: var(--text-muted); font-size: 0.8rem; }
.deadline-empty { color: var(--text-muted); font-size: 0.875rem; }

/* ─────────────────────────────────────────────────────────────
   Course info bar (home page)
   ───────────────────────────────────────────────────────────── */
.course-info-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 2rem;
  padding: 0.85rem 1rem;
  background: var(--slate-50);
  border: 1px solid var(--slate-200);
  border-radius: var(--radius);
  margin-bottom: 2rem;
  font-size: 0.82rem;
  color: var(--text-muted);
}
.info-item strong { color: var(--navy); }

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 0.75rem;
  margin-bottom: 2rem;
}
.person-card {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
  padding: 0.75rem 0.9rem;
  background: var(--slate-50);
  border: 1px solid var(--slate-200);
  border-radius: var(--radius);
  font-size: 0.82rem;
}
.person-role {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--blue);
}
.person-name { font-weight: 600; color: var(--navy); }
.person-detail { color: var(--text-muted); }

/* ─────────────────────────────────────────────────────────────
   Schedule table
   ───────────────────────────────────────────────────────────── */
.table-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 0 -1.5rem;
  padding: 0 1.5rem;
}

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.825rem;
  min-width: 640px;
}

.schedule-table thead th {
  text-align: left;
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 0.5rem 0.75rem;
  border-bottom: 2px solid var(--slate-200);
  white-space: nowrap;
}

.schedule-table tbody tr { border-bottom: 1px solid var(--slate-100); }
.schedule-table tbody tr:last-child { border-bottom: none; }
.schedule-table tbody tr:hover { background: var(--slate-50); }

.schedule-table td {
  padding: 0.6rem 0.75rem;
  vertical-align: top;
  color: var(--slate-600);
  line-height: 1.45;
}

.col-wk   { color: var(--text-muted); font-size: 0.78rem; white-space: nowrap; }
.col-date { white-space: nowrap; color: var(--text-muted); font-size: 0.78rem; }
.col-due  { font-weight: 500; color: var(--navy); }

/* Status row colours */
.row-holiday { background: var(--red-bg) !important; }
.row-async   { background: var(--amber-bg) !important; }
.row-online  { background: var(--blue-dim) !important; }

/* Status badge */
.badge {
  display: inline-block;
  font-size: 0.6rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.15em 0.5em;
  border-radius: 3px;
  margin-left: 0.4rem;
  vertical-align: middle;
  line-height: 1.5;
  text-transform: uppercase;
}
.badge-holiday { background: var(--red-bg);   color: var(--red-fg); }
.badge-async   { background: var(--amber-bg); color: var(--amber-fg); }
.badge-online  { background: var(--blue-dim); color: var(--blue); }

/* ─────────────────────────────────────────────────────────────
   Generic data table (syllabus grading, project phases)
   ───────────────────────────────────────────────────────────── */
.grading-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
  margin: 0.75rem 0 1.5rem;
}
.grading-table thead th {
  text-align: left;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-muted);
  padding: 0.7rem 1rem;
  border-bottom: 2px solid var(--slate-200);
}
.grading-table tbody td {
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--slate-100);
  color: var(--slate-600);
  vertical-align: top;
  line-height: 1.6;
}
.grading-table tbody tr:last-child td { border-bottom: none; }
.grading-table tbody tr:hover { background: var(--slate-50); }
.grading-table tfoot td {
  padding: 0.85rem 1rem;
  border-top: 2px solid var(--slate-200);
  font-weight: 600;
  color: var(--navy);
}

/* ─────────────────────────────────────────────────────────────
   Assignment list
   ───────────────────────────────────────────────────────────── */
.assignment-list { display: flex; flex-direction: column; margin-top: 1rem; }

.assignment-item {
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--slate-100);
}
.assignment-item:last-child { border-bottom: none; }

.assignment-item-title {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.15rem;
}
.assignment-item-title a { color: var(--blue); }

.assignment-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 0.4rem;
}
.assignment-desc {
  font-size: 0.855rem;
  color: var(--slate-600);
  line-height: 1.6;
}

/* ─────────────────────────────────────────────────────────────
   Checkpoint list
   ───────────────────────────────────────────────────────────── */
.checkpoint-list {
  margin: 1rem 0 0;
  padding-left: 1.25rem;
}
.checkpoint-list li {
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  color: var(--slate-600);
}
.checkpoint-list a { font-weight: 600; color: var(--blue); }

/* ─────────────────────────────────────────────────────────────
   Resource list
   ───────────────────────────────────────────────────────────── */
.resource-group { margin-bottom: 1.75rem; }

.resource-list { list-style: none; padding: 0; margin: 0; }
.resource-list li {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding: 0.45rem 0;
  border-bottom: 1px solid var(--slate-100);
  font-size: 0.875rem;
}
.resource-list li:last-child { border-bottom: none; }
.resource-note { font-size: 0.78rem; color: var(--text-muted); }

/* ─────────────────────────────────────────────────────────────
   Responsive
   ───────────────────────────────────────────────────────────── */
@media (max-width: 680px) {
  .navbar-links { display: none; }
  .hamburger    { display: flex; }
  .brand-name   { display: none; }      /* hide long name on small screens */

  .main-content { padding: 1.5rem 1rem; }
  .table-scroll { margin: 0 -1rem; padding: 0 1rem; }

  .page-header h1 { font-size: 1.35rem; }

  .footer-inner { flex-direction: column; gap: 0.25rem; }

  .grading-table { font-size: 0.82rem; }
  .acard-top  { flex-direction: column; align-items: flex-start; gap: 0.1rem; }
}

@media (max-width: 420px) {
  .course-info-bar { flex-direction: column; gap: 0.35rem; }
}

/* ─────────────────────────────────────────────────────────────
   Accessibility
   ───────────────────────────────────────────────────────────── */
:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; }
}