/* Reset and base styles */
* {
  margin: 0;
  padding: 0;
}

:root {
  /* Base color definitions */
  --color-dark: #1f1f1f;
  --color-light: #ffffff;
  --color-accent: #467265;
  --color-gray-dark: #666666;
  --color-gray-bright: #999999;
  --color-border-dark: #333333;
  --color-border-bright: #e5e5e5;

  /* Theme-dependent colors - Default is now light */
  --bg-primary: var(--color-light);
  --text-primary: var(--color-dark);
  --text-secondary: var(--color-gray-dark);
  --border-color: var(--color-border-bright);
  --card-bg: #f5f5f5;
  --section-alt-bg: linear-gradient(to bottom, #f8f9fa 0%, #e8e9ea 100%);
  --section-alt2-bg: linear-gradient(to bottom, #f0f0f0 0%, #e0e0e0 100%);
}

/* Dark theme */
body.dark-theme {
  --bg-primary: var(--color-dark);
  --text-primary: var(--color-light);
  --text-secondary: var(--color-gray-bright);
  --border-color: var(--color-border-dark);
  --card-bg: var(--color-dark);
  --section-alt-bg: linear-gradient(to bottom, #1a1a1a 0%, #0f0f0f 100%);
  --section-alt2-bg: linear-gradient(to bottom, #151515 0%, #0a0a0a 100%);
}

:root {
  --font-family: "Helvetica Neue", Helvetica, Arial, -apple-system,
    BlinkMacSystemFont, sans-serif;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-4xl: 2.5rem;

  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;

  --border-radius: 0.5rem;
  --border-radius-lg: 1rem;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

  --transition: all 0.3s ease;
  --logo-cutout-radius: 50%;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

/* Header */
.header {
  background-color: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  padding: 15px 0;
  position: sticky;
  top: 0;
  z-index: 1001;
  transition: background-color 0.3s ease;
}

.nav {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav-left {
  justify-self: start;
}

.nav-center {
  justify-self: center;
}

.nav-right {
  justify-self: end;
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav-logo-img {
  height: 20px;
}

.logo-light {
  display: flex;
}

.logo-dark {
  display: none;
}

body.dark-theme .logo-light {
  display: none;
}

body.dark-theme .logo-dark {
  display: flex;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav-link {
  color: var(--text-primary);
  text-decoration: none;
  font-weight: 400;
  font-size: 0.9rem;
  letter-spacing: 0.5px;
  transition: var(--transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-accent);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  cursor: pointer;
}

/* Theme toggle switch - inspired by day-night.png */
.theme-toggle-switch {
  cursor: pointer;
  transition: var(--transition);
}

.theme-toggle-track {
  width: 30px;
  height: 20px;
  background: linear-gradient(135deg, #e8e8e8 0%, #d0d0d0 100%);
  border-radius: 20px;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 8px;
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.1);
  transition: var(--transition);
}

body.dark-theme .theme-toggle-track {
  background: linear-gradient(135deg, #a2a2a0 0%, #1e1e1e 100%);
  box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.3);
}

.theme-toggle-slider {
  width: 20px;
  height: 20px;
  background: linear-gradient(135deg, #ffffff 0%, #f0f0f0 100%);
  border-radius: 50%;
  position: absolute;
  top: 0px;
  left: 0px;
  transition: all 0.3s cubic-bezier(0.8, 0, 0.2, 1);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
  z-index: 2;
}

body.dark-theme .theme-toggle-slider {
  left: 30px;
  background: linear-gradient(135deg, #f8f8f8 0%, #e0e0e0 100%);
}

.theme-icon {
  font-size: 1rem;
  transition: all 0.3s ease;
  z-index: 1;
  user-select: none;
}

.sun-icon {
  opacity: 1;
  color: #fbbf24;
  text-shadow: 0 0 3px rgba(251, 191, 36, 0.5);
}

.moon-icon {
  opacity: 0.3;
  color: #9ca3af;
}

/* Dark theme toggle state */
body.dark-theme .sun-icon {
  opacity: 0.3;
  color: #fbbf24;
}

body.dark-theme .moon-icon {
  opacity: 1;
  color: #ddd6fe;
  text-shadow: 0 0 3px rgba(221, 214, 254, 0.5);
}

.nav-toggle span {
  width: 25px;
  height: 3px;
  background-color: var(--text-primary);
  margin: 3px 0;
  transition: var(--transition);
}

/* Main content */
main {
  min-height: calc(100vh - 200px);
}

/* Hero section */
.hero {
  text-align: center;
  position: relative;
  overflow: hidden;
}

/* Hero background image with B&W + green tint matching #467265 */
.hero::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: inherit;
  background-size: cover;
  background-position: center;
  filter: grayscale(100%) sepia(40%) hue-rotate(110deg) saturate(1.2)
    brightness(0.9);
  opacity: 0.5;
  z-index: 0;
}

.hero > * {
  position: relative;
  z-index: 1;
}

.hero-content-wrapper {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-sm);
}

.hero-content {
  text-align: left;
  max-width: 600px;
  margin-left: -4rem;
  padding-left: 4rem;
}

.hero-title {
  font-size: var(--font-size-4xl);
  font-weight: 700;
  margin-bottom: var(--spacing-md);
  color: var(--color-light);
}

.hero-subtitle {
  font-size: var(--font-size-xl);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: inline-block;
  background-color: transparent;
  color: var(--color-light);
  padding: 0.75rem 1.5rem;
  font-size: 0.9rem;
  border: 2px solid var(--color-light);
  border-radius: var(--border-radius);
  text-decoration: none;
  font-weight: 600;
  transition: var(--transition);
}

.hero-cta:hover {
  background-color: var(--color-light);
  color: var(--color-dark);
}

/* Grid layouts */
.grid {
  display: grid;
  gap: var(--spacing-lg);
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

/* Past talks grid - always maintain 3-column width */
.grid-past-talks {
  display: grid;
  gap: var(--spacing-lg);
  grid-template-columns: repeat(3, minmax(0, 1fr));
  max-width: 100%;
}

/* Cards */
.card {
  background-color: var(--card-bg);
  color: var(--text-primary);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  transition: var(--transition);
  border: 1px solid var(--border-color);
  cursor: pointer;
}

.card.non-clickable {
  cursor: default;
  transition: none;
}

.card.non-clickable:hover {
  transform: none;
  box-shadow: none;
  border-color: var(--border-color);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-accent);
}

/* Past event cards with reduced opacity */
.card.past-event {
  opacity: 0.5;
}

.card.past-event:hover {
  opacity: 0.7 !important;
  transform: translateY(-6px);
}

/* Greyscale filter for past event images */
.card.past-event .card-image {
  filter: grayscale(100%);
}

.card.past-event:hover .card-image {
  filter: grayscale(70%);
}

.card-title {
  font-size: var(--font-size-xl);
  font-weight: 600;
  color: var(--text-primary);
}

.card-title a {
  color: inherit;
  text-decoration: none;
  transition: var(--transition);
}

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

.card-meta {
  color: var(--color-gray-bright);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-sm);
}

.card-summary {
  color: var(--color-gray-bright);
  margin-bottom: var(--spacing-sm);
}

.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
}

.tag {
  background-color: var(--color-accent);
  color: white;
  padding: 0.25rem 0.5rem;
  border-radius: var(--border-radius);
  font-size: 0.8rem;
  text-decoration: none;
  transition: var(--transition);
}

.tag:hover {
  background-color: #a0c7c4;
}

/* Override green link color for tags */
.content .tag {
  color: white;
}

.content .tag:hover {
  color: white;
  text-decoration: none;
}

/* Sections */
.section {
  padding-bottom: var(--spacing-2xl);
}

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

.section-alt2 {
  background: var(--section-alt2-bg);
}

.section-title {
  font-size: var(--font-size-3xl);
  font-weight: 700;
  text-align: center;
  padding-top: var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
  color: var(--text-primary);
}

.section-title-about {
  padding-top: 0;
}

.section-subtitle {
  font-size: var(--font-size-lg);
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-lg);
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

/* Content pages */
.content {
  max-width: 800px;
  margin: 0 auto;
  padding: var(--spacing-xl) var(--spacing-sm);
}

.content h1,
.content h2,
.content h3,
.content h4,
.content h5,
.content h6 {
  color: var(--text-primary);
  margin-top: 0;
  margin-bottom: var(--spacing-md);
}

.content h3 {
  margin-bottom: var(--spacing-xs);
}

.content h1 {
  font-size: var(--font-size-3xl);
}

.content h2 {
  font-size: var(--font-size-2xl);
  margin-top: var(--spacing-2xl);
}

.content.about-page h2 {
  margin-top: 0;
}

.content p {
  margin-bottom: var(--spacing-md);
}

.content ul,
.content ol {
  padding-left: 1.5rem;
  margin-bottom: var(--spacing-md);
}

.content li {
  margin-bottom: var(--spacing-xs);
}

.content a {
  color: var(--color-accent);
  text-decoration: none;
}

.content a:hover {
  text-decoration: underline;
}

.content pre {
  background-color: #2a2a2a;
  padding: var(--spacing-md);
  border-radius: var(--border-radius);
  overflow-x: auto;
  margin-bottom: var(--spacing-md);
}

.content code {
  background-color: #2a2a2a;
  padding: 0.2rem 0.4rem;
  border-radius: 0.25rem;
  font-size: 0.9em;
}

.content pre code {
  background-color: transparent;
  padding: 0;
}

/* Footer */
.footer {
  background-color: #f0f0f0;
  border-top: 1px solid var(--border-color);
  padding: var(--spacing-lg) 0 var(--spacing-xs);
  transition: background-color 0.3s ease;
}

body.dark-theme .footer {
  background-color: #1a1a1a;
}

/* Copyright section */
.copyright {
  text-align: center;
  padding: var(--spacing-xs) 0;
  background-color: #1a1a1a;
  border-top: 1px solid var(--color-border-dark);
}

body.dark-theme .copyright {
  background-color: #ffffff;
  border-top: 1px solid var(--color-border-bright);
}

.copyright p {
  font-size: 0.8rem;
  color: var(--color-gray-bright);
  margin: 0;
}

body.dark-theme .copyright p {
  color: var(--color-gray-dark);
}

.footer-content {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-sm);
}

@media (max-width: 768px) {
  .footer-content {
    grid-template-columns: 1fr 1fr;
  }

  .footer-section:first-child {
    grid-column: 1 / -1;
  }
}

.footer-section p {
  color: var(--color-gray-bright);
}

.footer-section h3,
.footer-section h4 {
  color: var(--text-primary);
}

.footer-section ul {
  list-style: none;
  font-size: 14px;
}

.footer-section ul li a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition);
}

.footer-section ul li a:hover {
  color: var(--color-accent);
}

.social-links {
  display: flex;
  gap: var(--spacing-md);
}

.social-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: var(--transition);
}

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

.footer-bottom {
  text-align: center;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
}

/* Card hover effects */
.card {
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.card:hover {
  transform: translateY(-6px);
  box-shadow: 0 10px 20px -3px rgba(0, 0, 0, 0.15);
}

/* Enhanced hover effects for blog and event cards */
.post-card:hover,
.talk-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 12px 24px -4px rgba(0, 0, 0, 0.2);
}

.post-card:hover .card-title,
.talk-card:hover .card-title {
  color: var(--color-accent);
}

.card-image {
  width: 100%;
  height: 200px;
  object-fit: contain;
  border-radius: var(--border-radius);
  margin: var(--spacing-md) 0;
  background-color: var(--card-bg);
}

/* Navigation animations */
.nav-link {
  position: relative;
  transition: var(--transition);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 0;
  height: 2px;
  background-color: var(--color-accent);
  transition: width 0.3s ease;
}

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

.nav-toggle span {
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.nav-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(6px, 6.5px);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(6px, -6.5px);
}

/* Enhanced button hover effects */
.tag {
  transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.tag:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(70, 114, 101, 0.3);
}

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

/* Focus states for accessibility */
.nav-link:focus,
.hero-cta:focus,
.tag:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* Enhanced form animations */
input:focus,
select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(70, 114, 101, 0.2);
  transform: scale(1.02);
}

/* Loading states */
.loading {
  opacity: 0.6;
}

/* Form elements */
.search-input,
.filter-select {
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--card-bg);
  color: var(--text-primary);
  border-radius: 0.25rem;
  transition: var(--transition);
}

.search-input {
  min-width: 300px;
}

.search-input:focus,
.filter-select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 2px rgba(70, 114, 101, 0.2);
}

/* Dark boxes that need to be theme-dependent */
.theme-box {
  background-color: #e8e8e8;
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  max-width: 40rem;
  margin: 0 auto;
}

body.dark-theme .theme-box {
  background-color: #d0d0d0;
  color: var(--color-dark);
  border: 1px solid #b0b0b0;
}

body.dark-theme .theme-box h3 {
  color: var(--color-dark) !important;
}

body.dark-theme .theme-box p {
  color: #333333 !important;
}

/* Keep button colors consistent in theme-box across light/dark modes */
body.dark-theme .theme-box .hero-cta {
  color: #666666;
  border-color: #666666;
}

body.dark-theme .theme-box .hero-cta:hover {
  background-color: #666666;
  color: #d0d0d0;
}

/* Responsive design */
@media (max-width: 768px) {
  .hero-content {
    margin-left: -2rem;
    padding-left: 2rem;
  }
  .nav-menu {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    flex-direction: column;
    padding: var(--spacing-lg) 0;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border-top: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
  }

  .nav-menu.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-toggle {
    display: flex;
  }

  .hero-title {
    font-size: var(--font-size-3xl);
  }

  .hero-subtitle {
    font-size: var(--font-size-lg);
  }

  .section-title {
    font-size: var(--font-size-2xl);
  }

  .grid-3 {
    grid-template-columns: 1fr;
  }

  .grid-past-talks {
    grid-template-columns: 1fr;
  }

  .social-links {
    justify-content: center;
  }

  .card:hover {
    transform: translateY(-4px) scale(1.01);
  }

  /* Add spacing for bullet points on mobile */
  .content ul,
  .content ol {
    padding-left: var(--spacing-xl);
    margin-bottom: var(--spacing-md);
  }

  .content li {
    margin-bottom: var(--spacing-xs);
    padding-left: var(--spacing-xs);
  }
}

@media (max-width: 480px) {
  .hero-content {
    margin-left: -1rem;
    padding-left: 1rem;
  }

  .hero-title {
    font-size: var(--font-size-2xl);
  }

  .hero-subtitle {
    font-size: var(--font-size-base);
  }

  .card {
    padding: var(--spacing-md);
  }

  .grid-2 {
    grid-template-columns: 1fr;
  }
}

/* Team member cards */
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(114px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
  max-width: 1000px;
  margin-left: auto;
  margin-right: auto;
}

.team-card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  padding: var(--spacing-sm);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  aspect-ratio: 3/4;
}

.team-photo-container {
  margin-bottom: var(--spacing-xs);
}

.team-photo {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--color-accent);
}

.team-name {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 0.25rem;
}

.team-description {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.3;
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }

  html {
    scroll-behavior: auto;
  }
}