/* ===== CSS Variables ===== */
:root {
  --primary: #4B2E84;
  --primary-light: #6B4FA4;
  --primary-dark: #3A2268;
  --accent: #E8B931;
  --accent-soft: #f6e8b1;
  --teal: #2c7a7b;
  --teal-light: #38b2ac;
  --text: #2d3748;
  --text-light: #718096;
  --bg: #ffffff;
  --bg-alt: #f7fafc;
  --bg-warm: #faf5ff;
  --border: #e2e8f0;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(75,46,132,0.08);
  --shadow-lg: 0 8px 24px rgba(75,46,132,0.1);
  --max-width: 1100px;
  --nav-height: 64px;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== Reset ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

/* ===== Typography ===== */
a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.25s var(--ease);
  background-image: linear-gradient(var(--primary-light), var(--primary-light));
  background-size: 0% 1px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  transition: background-size 0.3s var(--ease), color 0.25s var(--ease);
}
a:hover {
  color: var(--primary-light);
  background-size: 100% 1px;
}

img { max-width: 100%; height: auto; display: block; }

h1, h2, h3, h4 { line-height: 1.3; color: var(--primary-dark); }
h1 { font-size: 2rem; margin-bottom: 0.75rem; letter-spacing: -0.02em; }
h2 {
  font-size: 1.45rem;
  margin: 2.5rem 0 0.75rem;
  padding-left: 0.75rem;
  border-left: 3px solid var(--accent);
  letter-spacing: -0.01em;
}
h3 { font-size: 1.15rem; margin: 1.5rem 0 0.5rem; }
p { margin-bottom: 1rem; }
ul, ol { margin: 0 0 1rem 1.5rem; }
li { margin-bottom: 0.4rem; }
li::marker { color: var(--primary-light); }
hr { border: none; border-top: 1px solid var(--border); margin: 2.5rem 0; }
strong { color: var(--primary-dark); }
blockquote {
  border-left: 3px solid var(--primary-light);
  margin: 1.5rem 0;
  padding: 0.75rem 1.25rem;
  background: var(--bg-warm);
  border-radius: 0 var(--radius) var(--radius) 0;
  font-style: italic;
  color: var(--text-light);
}
blockquote p:last-child { margin-bottom: 0; }

/* ===== Navigation ===== */
.site-header {
  background: var(--primary);
  color: white;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 12px rgba(58,34,104,0.25);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  height: var(--nav-height);
  gap: 2rem;
}

.site-brand {
  font-size: 1.3rem;
  font-weight: 700;
  color: white;
  white-space: nowrap;
  letter-spacing: -0.02em;
  background: none;
}
.site-brand:hover { color: var(--accent); background: none; }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: white;
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 0.25rem;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}

.nav-item { position: relative; }

.nav-expand {
  display: none;  /* hidden on desktop, shown on mobile */
}

.nav-link {
  color: rgba(255,255,255,0.85);
  padding: 0.4rem 0.7rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  font-weight: 500;
  transition: all 0.25s var(--ease);
  display: block;
  white-space: nowrap;
  background: none;
}
.nav-link:hover, .nav-link.active {
  color: white;
  background: rgba(255,255,255,0.15);
}

/* Dropdown */
.nav-dropdown {
  display: none;
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  background: white;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  min-width: 230px;
  padding: 0.5rem 0;
  z-index: 200;
  list-style: none;
  margin: 0;
  border: 1px solid var(--border);
}
.nav-item:hover .nav-dropdown { display: block; }

.nav-dropdown a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--text);
  font-size: 0.875rem;
  transition: all 0.2s var(--ease);
  background: none;
}
.nav-dropdown a:hover {
  background: var(--bg-alt);
  color: var(--primary);
  padding-left: 1.25rem;
}

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 50%, #2a1a4e 100%);
  color: white;
  padding: 5rem 1.5rem 4.5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -25%;
  width: 150%;
  height: 200%;
  background: radial-gradient(ellipse at 30% 50%, rgba(107,79,164,0.3) 0%, transparent 60%);
  pointer-events: none;
}
.hero h1 {
  color: white;
  font-size: 2.75rem;
  margin-bottom: 1rem;
  position: relative;
  font-weight: 800;
  letter-spacing: -0.03em;
}
.hero p {
  color: rgba(255,255,255,0.8);
  font-size: 1.15rem;
  max-width: 700px;
  margin: 0 auto;
  position: relative;
  line-height: 1.6;
}

/* ===== Main Content ===== */
.page-wrapper {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 3rem;
}

.page-title {
  border-bottom: none;
  padding-bottom: 0.5rem;
  margin-bottom: 1.5rem;
  position: relative;
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}
.page-title::after {
  content: '';
  display: block;
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  border-radius: 2px;
  margin-top: 0.5rem;
}

/* ===== Cards ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.5rem;
  margin: 1.5rem 0;
}

.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  transition: all 0.3s var(--ease);
  box-shadow: var(--shadow);
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--primary-light));
  opacity: 0;
  transition: opacity 0.3s var(--ease);
}
.card:hover {
  box-shadow: var(--shadow-lg);
  border-color: transparent;
  transform: translateY(-3px);
}
.card:hover::before { opacity: 1; }
.card h3 { margin-top: 0; font-size: 1.1rem; }
.card h3 a { background: none; }
.card h3 a:hover { background: none; }
.card p { font-size: 0.925rem; color: var(--text-light); margin-bottom: 0; }

/* ===== Team ===== */
.team-member {
  background: var(--bg-alt);
  border-radius: var(--radius-lg);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1rem;
  border-left: 4px solid var(--primary);
  transition: all 0.2s var(--ease);
}
.team-member:hover {
  border-left-color: var(--accent);
  background: var(--bg-warm);
}
.team-member h3 { margin-top: 0; }
.team-member p { margin-bottom: 0.25rem; }

/* ===== Publications ===== */
.pub-list { list-style: none; padding: 0; margin: 0; }
.pub-list li {
  padding: 0.85rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.925rem;
  transition: all 0.2s var(--ease);
}
.pub-list li:hover {
  padding-left: 0.5rem;
  border-bottom-color: var(--primary-light);
}
.pub-list li:last-child { border-bottom: none; }
.pub-list a { font-weight: 500; }

/* ===== News ===== */
.news-item {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border);
  transition: all 0.2s var(--ease);
}
.news-item:first-child { padding-top: 0; }
.news-item:last-child { border-bottom: none; }
.news-item:hover { padding-left: 0.5rem; }
.news-item h3 { margin-top: 0; }
.news-date {
  display: inline-block;
  font-size: 0.75rem;
  color: var(--primary-light);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  margin-bottom: 0.25rem;
}

/* ===== Links Section ===== */
.link-section { margin-bottom: 2rem; }
.link-section h3 {
  font-size: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--primary);
  border-bottom: 2px solid var(--border);
  padding-bottom: 0.4rem;
}
.link-list { columns: 2; column-gap: 2rem; }
.link-list li { break-inside: avoid; }

/* ===== Stat Cards (for ROI/Impact pages) ===== */
.stat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
}
.stat-card {
  background: linear-gradient(135deg, var(--bg-alt), var(--bg-warm));
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  text-align: center;
  border: 1px solid var(--border);
  transition: all 0.3s var(--ease);
}
.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}
.stat-number {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 0.4rem;
}
.stat-label {
  font-size: 0.85rem;
  color: var(--text-light);
  line-height: 1.4;
}

/* ===== Feature Cards (for Brain Health etc.) ===== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1.25rem;
  margin: 1.5rem 0;
}
.feature-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: all 0.3s var(--ease);
}
.feature-card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--primary-light);
}
.feature-card h3 {
  margin-top: 0;
  font-size: 1.05rem;
  color: var(--primary);
}

/* ===== Sidebar Layout ===== */
.with-sidebar {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 2.5rem;
}

.sidebar {
  position: sticky;
  top: calc(var(--nav-height) + 1.5rem);
  align-self: start;
}

.sidebar-nav { list-style: none; padding: 0; margin: 0; }
.sidebar-nav li { margin-bottom: 0.25rem; }
.sidebar-nav a {
  display: block;
  padding: 0.4rem 0.75rem;
  border-radius: var(--radius);
  font-size: 0.875rem;
  color: var(--text-light);
  transition: all 0.2s var(--ease);
  background: none;
}
.sidebar-nav a:hover, .sidebar-nav a.active {
  background: var(--bg-alt);
  color: var(--primary);
}
.sidebar-nav .section-title {
  font-weight: 600;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-light);
  padding: 0.75rem 0.75rem 0.25rem;
}

/* ===== Footer ===== */
.site-footer {
  background: linear-gradient(135deg, var(--primary-dark) 0%, #1a1040 100%);
  color: rgba(255,255,255,0.7);
  padding: 2.5rem 1.5rem;
  margin-top: 4rem;
  text-align: center;
  font-size: 0.875rem;
  position: relative;
}
.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--primary), var(--accent), var(--primary));
}
.site-footer a {
  color: var(--accent);
  background: none;
  font-weight: 500;
}
.site-footer a:hover { color: var(--accent-soft); background: none; }
.site-footer p + p { margin-top: 0.5rem; }

/* ===== Smooth page entrance ===== */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}
.page-wrapper { animation: fadeUp 0.4s var(--ease); }

/* ===== Selection ===== */
::selection {
  background: var(--primary);
  color: white;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-menu {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--primary);
    flex-direction: column;
    padding: 1rem;
    box-shadow: var(--shadow-md);
  }
  .nav-menu.open { display: flex; }
  .nav-dropdown {
    position: static;
    box-shadow: none;
    background: rgba(255,255,255,0.05);
    border-radius: var(--radius);
    margin-top: 0.25rem;
    border: none;
  }
  .nav-item { display: flex; flex-wrap: wrap; align-items: center; }
  .nav-link { flex: 1; }
  .nav-expand {
    display: block;
    background: none;
    border: none;
    color: rgba(255,255,255,0.7);
    font-size: 1.1rem;
    padding: 0.4rem 0.75rem;
    cursor: pointer;
    transition: transform 0.2s var(--ease);
  }
  .nav-item.open > .nav-expand { transform: rotate(180deg); }
  .nav-dropdown { width: 100%; }
  .nav-dropdown a { color: rgba(255,255,255,0.8); background: none; }
  .nav-dropdown a:hover { background: rgba(255,255,255,0.1); color: white; }
  .nav-item:hover .nav-dropdown { display: none; }
  .nav-item.open .nav-dropdown { display: block; }

  .with-sidebar { grid-template-columns: 1fr; }
  .sidebar { display: none; }
  .hero { padding: 3.5rem 1.5rem 3rem; }
  .hero h1 { font-size: 2rem; }
  .page-title { font-size: 1.75rem; }
  h2 { font-size: 1.3rem; }
  .card-grid { grid-template-columns: 1fr; }
  .stat-grid { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: 1fr; }
  .link-list { columns: 1; }
}