/* === Base === */
:root {
  --green: #6a9c45;
  --green-dark: #4e7a2e;
  --green-light: #e8f0e0;
  --gray-dark: #2d2d2d;
  --gray-mid: #555;
  --gray-light: #f5f5f5;
  --white: #fff;
  --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-width: 900px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: var(--font-sans);
  color: var(--gray-dark);
  line-height: 1.6;
  background: var(--white);
}

a { color: var(--green-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

/* === Navigation === */
nav {
  background: var(--gray-dark);
  padding: 0.75rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav .nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}

nav .nav-brand {
  color: var(--white);
  font-weight: 700;
  font-size: 1rem;
}

nav .nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

nav .nav-links a {
  color: #ccc;
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

nav .nav-links a:hover,
nav .nav-links a.active {
  color: var(--white);
  text-decoration: none;
}

/* === Main Content === */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
}

/* === Landing Page / Flyer === */
.hero {
  text-align: center;
  padding: 2.5rem 0 2rem;
  border-bottom: 3px solid var(--green);
}

.hero .psu-label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--green-dark);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.25rem;
}

.hero h1 {
  font-size: 2.4rem;
  font-weight: 800;
  color: var(--gray-dark);
  margin-bottom: 0.25rem;
}

.hero .course-code {
  font-size: 1.1rem;
  color: var(--gray-mid);
  font-weight: 500;
}

.details-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin: 2rem 0;
}

.detail-card {
  background: var(--gray-light);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  border-left: 4px solid var(--green);
}

.detail-card .label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--green-dark);
  margin-bottom: 0.25rem;
}

.detail-card .value {
  font-size: 0.95rem;
  color: var(--gray-dark);
}

.detail-card .value a {
  word-break: break-all;
}

.section { margin-top: 2rem; }
.section h2 {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--gray-dark);
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 2px solid var(--green-light);
}

.section p,
.section li {
  font-size: 0.95rem;
  color: var(--gray-mid);
}

.section ul {
  padding-left: 1.25rem;
  margin-top: 0.5rem;
}

.section li { margin-bottom: 0.35rem; }

.topics-list {
  list-style: none;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.4rem 1.5rem;
}

.topics-list li {
  font-size: 0.9rem;
  padding: 0.3rem 0;
  padding-left: 1.25rem;
  position: relative;
}

.topics-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.65rem;
  width: 8px;
  height: 8px;
  background: var(--green);
  border-radius: 50%;
}

.cta-bar {
  margin-top: 2rem;
  padding: 1.5rem;
  background: var(--green-light);
  border-radius: 8px;
  text-align: center;
}

.cta-bar p {
  font-size: 0.95rem;
  color: var(--gray-dark);
}

.cta-bar .cta-links {
  margin-top: 0.5rem;
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  flex-wrap: wrap;
}

.cta-bar .cta-links a {
  display: inline-block;
  padding: 0.5rem 1.25rem;
  background: var(--green);
  color: var(--white);
  border-radius: 6px;
  font-weight: 600;
  font-size: 0.9rem;
  transition: background 0.2s;
}

.cta-bar .cta-links a:hover {
  background: var(--green-dark);
  text-decoration: none;
}

/* === Syllabus & Resources Pages === */
.page-header {
  padding: 1.5rem 0 1rem;
  border-bottom: 3px solid var(--green);
  margin-bottom: 2rem;
}

.page-header h1 {
  font-size: 1.8rem;
  font-weight: 800;
}

.page-header .subtitle {
  color: var(--gray-mid);
  font-size: 1rem;
}

.content h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
  padding-bottom: 0.35rem;
  border-bottom: 2px solid var(--green-light);
}

.content h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

.content p {
  margin-bottom: 0.75rem;
  font-size: 0.95rem;
  color: var(--gray-mid);
}

.content ul, .content ol {
  padding-left: 1.25rem;
  margin-bottom: 0.75rem;
}

.content li {
  font-size: 0.95rem;
  color: var(--gray-mid);
  margin-bottom: 0.35rem;
}

.content strong { color: var(--gray-dark); }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.9rem;
}

th {
  background: var(--gray-dark);
  color: var(--white);
  text-align: left;
  padding: 0.6rem 0.75rem;
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

td {
  padding: 0.55rem 0.75rem;
  border-bottom: 1px solid #e0e0e0;
  vertical-align: top;
}

tr:hover td { background: var(--gray-light); }

code {
  font-family: var(--font-mono);
  font-size: 0.85em;
  background: var(--green-light);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

/* === Footer === */
footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem;
  text-align: center;
  font-size: 0.8rem;
  color: #999;
  border-top: 1px solid #e0e0e0;
}

/* === Print Styles (Flyer Mode) === */
@media print {
  @page {
    size: letter;
    margin: 0.4in 0.5in;
  }

  nav, footer, .cta-links { display: none !important; }

  body { font-size: 10pt; line-height: 1.35; }

  main { padding: 0; }

  .hero { padding: 0.25rem 0 0.5rem; border-bottom-width: 2px; }
  .hero .psu-label { font-size: 7.5pt; margin-bottom: 0.1rem; }
  .hero h1 { font-size: 20pt; margin-bottom: 0.1rem; }
  .hero .course-code { font-size: 9.5pt; }

  .details-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 0.35rem;
    margin: 0.5rem 0;
  }

  .detail-card {
    padding: 0.3rem 0.6rem;
    border-left-width: 3px;
    border-radius: 4px;
    -webkit-print-color-adjust: exact;
    print-color-adjust: exact;
  }

  .detail-card .label { font-size: 6pt; margin-bottom: 0.1rem; }
  .detail-card .value { font-size: 8.5pt; }

  .section { margin-top: 0.4rem; }
  .section h2 {
    font-size: 11pt;
    margin-bottom: 0.25rem;
    padding-bottom: 0.2rem;
  }

  .section p, .section li { font-size: 8.5pt; }
  .section p { margin-bottom: 0.2rem; }

  .topics-list { gap: 0.1rem 1rem; }
  .topics-list li { font-size: 8pt; padding: 0.1rem 0 0.1rem 0.9rem; }
  .topics-list li::before { width: 5px; height: 5px; top: 0.45rem; }

  table { margin: 0.3rem 0; font-size: 8pt; }
  th { padding: 0.3rem 0.5rem; font-size: 7pt; }
  td { padding: 0.25rem 0.5rem; }

  .cta-bar {
    margin-top: 0.4rem;
    padding: 0.5rem;
    border-radius: 6px;
    -webkit-print-color-adjust: exact;
    print-color-adjust: exact;
  }

  .cta-bar p { font-size: 8.5pt; }
  .cta-url { display: block !important; font-size: 8pt; margin-top: 0.15rem; color: var(--green-dark); }

  a { color: var(--green-dark) !important; }
}

/* Hide print-only elements on screen */
.cta-url { display: none; }

/* === Responsive === */
@media (max-width: 600px) {
  .hero h1 { font-size: 1.8rem; }
  .details-grid { grid-template-columns: 1fr; }
  .topics-list { grid-template-columns: 1fr; }
  nav .nav-inner { flex-direction: column; align-items: flex-start; }
}