/* CS310/5102 Course Website Styles */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
  --bg: #0d1117;
  --panel: #161b22;
  --panel-2: #1c2128;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #58a6ff;
  --accent-2: #bc8cff;
  --accent-3: #56d364;
  --danger: #f85149;
  --warning: #e3b341;
  --border: #30363d;
  --badge-bg: #21262d;
  --header-bg: rgba(13, 17, 23, 0.92);
  --header-height: 64px;
  --radius: 10px;
  --transition: 0.18s ease;
}

:root[data-theme="light"] {
  --bg: #f6f8fa;
  --panel: #ffffff;
  --panel-2: #f6f8fa;
  --text: #1f2328;
  --muted: #57606a;
  --accent: #0969da;
  --accent-2: #8250df;
  --accent-3: #1a7f37;
  --danger: #cf222e;
  --warning: #9a6700;
  --border: #d0d7de;
  --badge-bg: #eaeef2;
  --header-bg: rgba(246, 248, 250, 0.92);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  font-size: 15px;
}
html { scroll-behavior: smooth; }
a { color: var(--accent); text-decoration: none; transition: opacity var(--transition); }
a:hover { text-decoration: underline; opacity: 0.85; }

/* ── LAYOUT ── */
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }

/* ── HEADER ── */
.header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: var(--header-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  height: var(--header-height);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--header-height);
  gap: 1rem;
}
.brand {
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: -0.01em;
  color: var(--text);
  white-space: nowrap;
  flex-shrink: 0;
}
.brand em {
  font-style: normal;
  color: var(--accent);
}
.nav ul {
  list-style: none;
  display: flex;
  gap: 0.15rem;
  padding: 0;
  margin: 0;
}
.nav li a {
  color: var(--muted);
  padding: 0.38rem 0.65rem;
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 500;
  transition: color var(--transition), background var(--transition);
}
.nav li a:hover {
  color: var(--text);
  background: var(--badge-bg);
  text-decoration: none;
  opacity: 1;
}
.nav li a.active {
  color: var(--accent);
  background: rgba(88, 166, 255, 0.1);
}
:root[data-theme="light"] .nav li a.active {
  background: rgba(9, 105, 218, 0.08);
}
.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}
.theme-toggle {
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--border);
  padding: 0.32rem 0.65rem;
  border-radius: 6px;
  font-size: 0.82rem;
  font-family: inherit;
  cursor: pointer;
  transition: color var(--transition), background var(--transition), border-color var(--transition);
}
.theme-toggle:hover {
  color: var(--text);
  background: var(--badge-bg);
  border-color: var(--muted);
}

/* ── HERO ── */
.hero {
  margin-top: var(--header-height);
  padding: 1.0rem 0 0.5rem;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 60% 80% at 10% 50%, rgba(88, 166, 255, 0.07) 0%, transparent 60%),
    radial-gradient(ellipse 50% 60% at 90% 20%, rgba(188, 140, 255, 0.05) 0%, transparent 60%);
  pointer-events: none;
}
.hero-content { position: relative; z-index: 1; }
.hero-eyebrow {
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent);
  margin-bottom: 0.6rem;
}
.hero h1 {
  font-size: 2.8rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.1;
  color: var(--text);
  margin-bottom: 1.0rem;
}
.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.hero-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.3rem 0.75rem;
  background: var(--badge-bg);
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 0.825rem;
  color: var(--muted);
  line-height: 1.4;
}
.hero-chip strong { color: var(--text); font-weight: 600; }
.hero-chip a { color: var(--accent); }

/* ── MAIN ── */
.main { padding: 1.5rem 0 3rem; }
section.view + section.view { margin-top: 3rem; border-top: 1px solid var(--border); padding-top: 3rem; }

/* ── SECTION TITLE ── */
.section-title {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  margin: 0 0 1rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding-left: 0.75rem;
  border-left: 3px solid var(--accent);
}
h2.section-title + h2.section-title { margin-top: 1rem; }
.subtitle { color: var(--muted); margin-bottom: 0.75rem; font-size: 0.875rem; }

/* ── LECTURE MATERIALS GRID ── */
#lecture-materials {
  grid-template-columns: repeat(4, 1fr);
}
@media (max-width: 1000px) { #lecture-materials { grid-template-columns: repeat(3, 1fr); } }
@media (max-width: 700px)  { #lecture-materials { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 480px)  { #lecture-materials { grid-template-columns: 1fr; } }

/* ── CARDS ── */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 0.875rem;
}
.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.1rem 1.25rem;
  transition: border-color var(--transition), box-shadow var(--transition), transform var(--transition);
}
.card:hover {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent)22, 0 8px 24px rgba(0,0,0,0.25);
  transform: translateY(-2px);
}
:root[data-theme="light"] .card:hover {
  box-shadow: 0 0 0 1px var(--accent)33, 0 4px 16px rgba(0,0,0,0.08);
}
.card h3 {
  font-size: 0.975rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin-bottom: 0.5rem;
  color: var(--text);
}
.card h4 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--muted);
  margin: 0.75rem 0 0.4rem;
}

/* ── ANNOUNCEMENTS ── */
.ann-list {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  overflow: hidden;
}
.ann-item {
  display: grid;
  grid-template-columns: 6.5rem 1fr;
  grid-template-rows: auto auto;
  column-gap: 1rem;
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.875rem;
  align-items: baseline;
}
.ann-item:last-child { border-bottom: none; }
.ann-item:hover { background: var(--panel-2); }
.ann-date {
  font-size: 0.73rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--accent-2);
  text-transform: uppercase;
  grid-row: 1;
  grid-column: 1;
  padding-top: 0.1rem;
}
.ann-title {
  font-weight: 600;
  color: var(--text);
  grid-row: 1;
  grid-column: 2;
}
.ann-body {
  color: var(--muted);
  font-size: 0.825rem;
  grid-row: 2;
  grid-column: 2;
  line-height: 1.5;
}

/* ── KICKER ── */
.kicker {
  font-size: 0.73rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  color: var(--accent-2);
  text-transform: uppercase;
  margin-bottom: 0.3rem;
  display: block;
}

/* ── RESOURCE CHIPS ── */
.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin-top: 0.65rem;
}
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0.22rem 0.55rem;
  border-radius: 5px;
  font-size: 0.76rem;
  font-weight: 500;
  transition: opacity var(--transition), transform var(--transition);
  text-decoration: none !important;
  line-height: 1.4;
}
.chip:hover { opacity: 0.75; transform: translateY(-1px); text-decoration: none; }
.chip-notes   { background: rgba(88, 166, 255, 0.15);  color: #58a6ff; border: 1px solid rgba(88, 166, 255, 0.3); }
.chip-slides  { background: rgba(188, 140, 255, 0.15); color: #bc8cff; border: 1px solid rgba(188, 140, 255, 0.3); }
.chip-ws      { background: rgba(86, 211, 100, 0.15);  color: #56d364; border: 1px solid rgba(86, 211, 100, 0.3); }
.chip-rec     { background: rgba(248, 81, 73, 0.15);   color: #ff7b72; border: 1px solid rgba(248, 81, 73, 0.3); }
.chip-misc    { background: rgba(227, 179, 65, 0.15);  color: #e3b341; border: 1px solid rgba(227, 179, 65, 0.3); }

:root[data-theme="light"] .chip-notes  { background: rgba(9, 105, 218, 0.08);  color: #0969da; border-color: rgba(9, 105, 218, 0.25); }
:root[data-theme="light"] .chip-slides { background: rgba(130, 80, 223, 0.08); color: #8250df; border-color: rgba(130, 80, 223, 0.25); }
:root[data-theme="light"] .chip-ws     { background: rgba(26, 127, 55, 0.08);  color: #1a7f37; border-color: rgba(26, 127, 55, 0.25); }
:root[data-theme="light"] .chip-rec    { background: rgba(207, 34, 46, 0.08);  color: #cf222e; border-color: rgba(207, 34, 46, 0.25); }
:root[data-theme="light"] .chip-misc   { background: rgba(154, 103, 0, 0.08);  color: #9a6700; border-color: rgba(154, 103, 0, 0.25); }

/* ── TABLES ── */
.table-wrap {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--panel);
  margin-bottom: 1rem;
}
.table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  background: var(--panel);
}
.table th {
  font-weight: 600;
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--muted);
  background: var(--panel-2);
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border);
  text-align: left;
}
.table td {
  padding: 0.6rem 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}
.table tr:last-child td { border-bottom: none; }
.table tbody tr:hover td { background: var(--panel-2); }

/* Standalone table (not in .table-wrap) gets its own border */
.card > .table { border-radius: 6px; overflow: hidden; margin-top: 0.5rem; }
.card > .table th { background: var(--badge-bg); }

/* ── BADGES ── */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.15rem 0.5rem;
  border-radius: 20px;
  background: var(--badge-bg);
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 500;
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
}
.badge[style*="danger"] {
  background: rgba(248, 81, 73, 0.15);
  border-color: rgba(248, 81, 73, 0.3);
  color: var(--danger);
}

/* ── NOTICE ── */
.notice {
  background: var(--panel);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  padding: 0.9rem 1.1rem;
  border-radius: var(--radius);
}

/* ── LIST ── */
.list { padding-left: 1.25rem; margin: 0.4rem 0 0.6rem; }
.list li { margin: 0.3rem 0; font-size: 0.9rem; }

/* ── SMALL ── */
.small { font-size: 0.875rem; color: var(--muted); }
p.small { margin: 0.35rem 0; }

/* ── GRID-2 ── */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0.875rem; }
@media (max-width: 800px) { .grid-2 { grid-template-columns: 1fr; } }

/* ── VIEW ── */
.view { display: block; scroll-margin-top: calc(var(--header-height) + 1rem); }

/* ── BLOCKQUOTE ── */
blockquote.sample {
  border-left: 3px solid var(--border);
  margin: 0;
  padding: 0.75rem 1rem;
  color: var(--muted);
  font-size: 0.85rem;
  background: var(--panel-2);
  border-radius: 0 var(--radius) var(--radius) 0;
  line-height: 1.75;
}

/* ── FOOTER ── */
.footer {
  padding: 2rem 1.5rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
  text-align: center;
  margin-top: 2rem;
}

/* ── MOBILE NAV ── */
.header .toggle { display: none; }
@media (max-width: 900px) {
  .header { height: auto; }
  .header .toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    color: var(--text);
    background: transparent;
    border: 1px solid var(--border);
    padding: 0.32rem 0.6rem;
    border-radius: 6px;
    font-size: 0.85rem;
    font-family: inherit;
    cursor: pointer;
  }
  .nav { flex-wrap: wrap; height: auto; padding: 0.75rem 0; align-items: center; }
  /* brand + nav-actions on same row, ul collapses below */
  .nav ul { display: none; width: 100%; order: 99; }
  .nav.open ul { display: flex; flex-direction: column; gap: 0.2rem; margin-top: 0.5rem; padding-bottom: 0.5rem; }
  .nav-actions { margin-left: auto; }
  .hero h1 { font-size: 2rem; }
  .hero { padding: 2.5rem 0 2rem; }
}