/* ===== Reset & Base ===== */
*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --oxford-blue: #002147;
  --oxford-dark: #001229;
  --accent: #1a73a7;
  --accent-light: #2a8fc7;
  --bg-primary: #fafbfc;
  --bg-alt: #f0f2f5;
  --text-primary: #1a1d23;
  --text-secondary: #4a5060;
  --text-muted: #6b7280;
  --border: #e2e5ea;
  --card-bg: #ffffff;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow-sm: 0 1px 3px rgba(0, 33, 71, 0.06);
  --shadow-md: 0 4px 16px rgba(0, 33, 71, 0.08);
  --shadow-lg: 0 8px 32px rgba(0, 33, 71, 0.1);
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family:
    "Inter",
    -apple-system,
    BlinkMacSystemFont,
    sans-serif;
  color: var(--text-primary);
  background: var(--bg-primary);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 920px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(
    135deg,
    var(--oxford-blue) 0%,
    #003366 40%,
    var(--accent) 100%
  );
  color: #fff;
  padding: 5rem 2rem 4rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(
    ellipse at 30% 20%,
    rgba(255, 255, 255, 0.05) 0%,
    transparent 70%
  );
  pointer-events: none;
}

.hero-badge {
  display: inline-block;
  background: rgba(255, 255, 255, 0.12);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  padding: 0.35rem 1rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  letter-spacing: -0.02em;
}

.hero h1 .amp {
  font-style: italic;
  opacity: 0.7;
}

.hero-subtitle {
  font-size: 1.15rem;
  opacity: 0.85;
  max-width: 600px;
  margin: 0 auto 2rem;
  font-weight: 400;
}

.hero-lecturers {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
}

.lecturer-name {
  font-weight: 600;
  font-size: 1rem;
}

.lecturer-sep {
  opacity: 0.4;
  font-size: 1.2rem;
}

/* ===== Sections ===== */
.section {
  padding: 4rem 0;
}

.section-alt {
  background: var(--bg-alt);
}

h2 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--oxford-blue);
  margin-bottom: 1.25rem;
  letter-spacing: -0.01em;
}

.section p {
  color: var(--text-secondary);
  font-size: 1.02rem;
  max-width: 720px;
  line-height: 1.7;
}

/* ===== Info Cards ===== */
.info-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.info-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--transition),
    box-shadow var(--transition);
}

.info-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
}

.info-card-icon {
  font-size: 1.8rem;
  margin-bottom: 0.5rem;
}

.info-card-title {
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  margin-bottom: 0.25rem;
}

.info-card-text {
  font-size: 0.95rem;
  color: var(--text-secondary);
}

/* ===== Schedule ===== */
.schedule-grid {
  display: grid;
  gap: 1rem;
  margin-top: 1.5rem;
}

.week-card {
  display: flex;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  transition:
    transform var(--transition),
    box-shadow var(--transition);
}

.week-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.week-number {
  display: flex;
  align-items: center;
  justify-content: center;
  min-width: 64px;
  background: linear-gradient(180deg, var(--oxford-blue), var(--accent));
  color: #fff;
  font-size: 1.3rem;
  font-weight: 700;
  font-family: "JetBrains Mono", monospace;
}

.week-content {
  padding: 1.25rem 1.5rem;
  flex: 1;
}

.week-content h3 {
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--oxford-blue);
  margin-bottom: 0.35rem;
}

.week-content p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  margin-bottom: 0.5rem;
}

.slides-link {
  font-size: 0.82rem;
  font-weight: 500;
  color: var(--accent);
  text-decoration: none;
  transition: color var(--transition);
}

.slides-link:hover {
  color: var(--accent-light);
  text-decoration: underline;
}

/* ===== Assignment ===== */
.assignment-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  box-shadow: var(--shadow-sm);
  margin-top: 1rem;
}

.assignment-card p {
  margin-bottom: 1.25rem;
}

.assignment-details {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem 2rem;
  margin-bottom: 1.5rem;
  font-size: 0.92rem;
  color: var(--text-secondary);
}

.btn {
  display: inline-block;
  background: var(--oxford-blue);
  color: #fff;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition:
    background var(--transition),
    transform var(--transition);
}

.btn:hover {
  background: var(--accent);
  transform: translateY(-1px);
}

/* ===== Readings ===== */
.readings-list {
  list-style: none;
  margin-top: 1rem;
}

.readings-list li {
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.readings-list li:last-child {
  border-bottom: none;
}

.readings-list em {
  color: var(--text-primary);
}

.readings-list a {
  color: var(--accent);
  text-decoration: none;
  font-weight: 500;
}

.readings-list a:hover {
  text-decoration: underline;
}

/* ===== Footer ===== */
.footer {
  background: var(--oxford-dark);
  color: rgba(255, 255, 255, 0.6);
  text-align: center;
  padding: 2rem;
  font-size: 0.85rem;
}

/* ===== Responsive ===== */
@media (max-width: 640px) {
  .hero {
    padding: 3.5rem 1.5rem 3rem;
  }

  .info-cards {
    grid-template-columns: repeat(2, 1fr);
  }

  .week-card {
    flex-direction: column;
  }

  .week-number {
    min-width: unset;
    min-height: 40px;
  }

  .assignment-details {
    flex-direction: column;
    gap: 0.5rem;
  }
}