/* CSS Variables */
:root {
  --color-primary: #002D72;      /* JHU Blue */
  --color-primary-dark: #001a42;
  --color-accent: #CF4520;       /* JHU Spirit Orange */
  --color-accent-light: #e85a35;
  --color-text: #2d3748;
  --color-text-light: #718096;
  --color-bg: #ffffff;
  --color-bg-alt: #f7fafc;
  --color-border: #e2e8f0;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-serif: 'Source Serif 4', Georgia, serif;
  --max-width: 1200px;
  --header-height: 80px;
  --transition: 0.3s ease;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --radius: 8px;
}

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

/* Base */
html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography */
h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.3;
  color: var(--color-primary);
}

h1 { font-size: 2.5rem; margin-bottom: 1.5rem; }
h2 { font-size: 1.75rem; margin-bottom: 1rem; margin-top: 2.5rem; }
h3 { font-size: 1.25rem; margin-bottom: 0.75rem; margin-top: 2rem; }

p {
  margin-bottom: 1rem;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-accent);
}

/* Header */
.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  display: flex;
  align-items: center;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.site-brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}
.skip-link {
  position: absolute;
  left: -999px;
  top: -999px;
  background: var(--color-primary);
  color: white;
  padding: 0.5rem 0.75rem;
  border-radius: 4px;
  z-index: 9999;
}
.skip-link:focus {
  left: 16px;
  top: 16px;
}

.wse-logo {
  height: 40px;
  width: auto;
  display: block;
}

.jhu-shield {
  height: 60px;
  width: auto;
  display: block;
}

.site-title {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  line-height: 1.2;
}

.title-text {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-light);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.title-accent {
  font-family: var(--font-serif);
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-primary);
}

.site-title:hover .title-accent {
  color: var(--color-accent);
}

/* Navigation */
.site-nav {
  display: flex;
  align-items: center;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-links a {
  font-weight: 500;
  font-size: 0.9375rem;
  padding: 0.5rem 0;
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition);
}

.nav-links a:hover::after,
.nav-links a.active::after {
  width: 100%;
}

.nav-links a.active {
  color: var(--color-accent);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-primary);
  transition: var(--transition);
}

/* Main */
.site-main {
  flex: 1;
  padding: 3rem 0;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  color: white;
  padding: 4rem 3rem;
  border-radius: var(--radius);
  margin-bottom: 3rem;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  right: 0;
  width: 50%;
  height: 100%;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'%3E%3Ccircle cx='50' cy='50' r='40' fill='none' stroke='rgba(255,255,255,0.05)' stroke-width='1'/%3E%3Ccircle cx='50' cy='50' r='30' fill='none' stroke='rgba(255,255,255,0.05)' stroke-width='1'/%3E%3Ccircle cx='50' cy='50' r='20' fill='none' stroke='rgba(255,255,255,0.05)' stroke-width='1'/%3E%3C/svg%3E") center/contain no-repeat;
  opacity: 0.5;
}

.hero h1 {
  color: white;
  font-size: 2.75rem;
  margin-bottom: 1rem;
  position: relative;
}

.hero p {
  font-size: 1.125rem;
  opacity: 0.95;
  max-width: 700px;
  position: relative;
}

.hero a {
  color: #93c5fd;
}

.hero a:hover {
  color: white;
}

/* Research Areas */
.research-areas {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.research-tag {
  background: var(--color-bg-alt);
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  font-size: 0.9375rem;
  color: var(--color-text);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.research-tag::before {
  content: '→';
  color: var(--color-accent);
  font-weight: bold;
}

/* People Section */
.people-section {
  margin-bottom: 3rem;
}

.people-section h2 {
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--color-border);
  margin-top: 0;
}

.people-section h2:first-of-type {
  margin-top: 0;
}

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

.person-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 1.25rem;
  transition: var(--transition);
  display: flex;
  align-items: center;
  gap: 1rem;
}

.person-card:hover {
  box-shadow: var(--shadow);
  border-color: var(--color-primary);
}

.person-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-accent) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 600;
  font-size: 1.125rem;
  flex-shrink: 0;
}

.person-photo {
  background: none;
  padding: 0;
  overflow: hidden;
}

.person-photo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.person-info {
  flex: 1;
}

.person-name {
  font-weight: 600;
  color: var(--color-primary);
  font-size: 1rem;
  margin: 0;
}

.person-name a {
  color: inherit;
}

.person-name a:hover {
  color: var(--color-accent);
}

.person-role {
  font-size: 0.875rem;
  color: var(--color-text-light);
  margin: 0;
}

/* Simple list for alumni */
.people-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.5rem 2rem;
  margin-top: 1rem;
}

.people-list li {
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--color-border);
}

.people-list a {
  font-weight: 500;
}

/* Seminar Section */
.seminar-info {
  background: var(--color-bg-alt);
  border-left: 4px solid var(--color-accent);
  padding: 1.5rem 2rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin-bottom: 2rem;
}

.seminar-info p {
  margin: 0;
  font-size: 1.0625rem;
}

.seminar-info strong {
  color: var(--color-primary);
}

.mailing-list-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1rem;
  padding: 0.75rem 1.25rem;
  background: var(--color-primary);
  color: white;
  border-radius: var(--radius);
  font-weight: 500;
  transition: var(--transition);
}

.mailing-list-link:hover {
  background: var(--color-primary-dark);
  color: white;
}

/* Info Cards */
.info-card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 2rem;
  margin-bottom: 1.5rem;
}

.info-card h3 {
  margin-top: 0;
  color: var(--color-primary);
}

/* Footer */
.site-footer {
  background: var(--color-primary);
  color: rgba(255, 255, 255, 0.9);
  padding: 2rem 0;
  margin-top: auto;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1.5rem;
}

.footer-info p {
  margin: 0.25rem 0;
  font-size: 0.9375rem;
}

.footer-info a {
  color: rgba(255, 255, 255, 0.9);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.footer-info a:hover {
  color: white;
}

.footer-logo img {
  height: 50px;
  opacity: 0.9;
}

.jhu-shield-small {
  height: 56px;
  width: auto;
  opacity: 0.9;
  filter: brightness(0) invert(1);
}

.wse-logo-small {
  height: 36px;
  width: auto;
  opacity: 0.9;
}

/* Responsive */
@media (max-width: 768px) {
  :root {
    --header-height: 70px;
  }

  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }

  .nav-toggle {
    display: flex;
  }

  .nav-links {
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-bg);
    padding: 1rem 24px;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
    display: none;
    box-shadow: var(--shadow);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links li {
    border-bottom: 1px solid var(--color-border);
  }

  .nav-links a {
    display: block;
    padding: 1rem 0;
  }

  .hero {
    padding: 2.5rem 1.5rem;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .title-accent {
    font-size: 1.25rem;
  }

  .jhu-shield {
    height: 48px;
  }

  .wse-logo {
    height: 32px;
  }

  .people-grid {
    grid-template-columns: 1fr;
  }

  .footer-content {
    flex-direction: column;
    text-align: center;
  }
}

/* Print styles */
@media print {
  .site-header,
  .site-footer,
  .nav-toggle {
    display: none;
  }

  .site-main {
    padding: 0;
  }

  .hero {
    background: none;
    color: var(--color-text);
    padding: 1rem 0;
  }

  .hero h1 {
    color: var(--color-primary);
  }
}