@import url('https://fonts.googleapis.com/css2?family=Pretendard+Variable:wght@300;400;600;700&display=swap');

:root {
  --primary-color: #3b82f6;
  --secondary-color: #10b981;
  --accent-color: #f59e0b;
  --background-color: #f8fafc;
  --text-color: #1e293b;
  --card-bg: #ffffff;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --radius-lg: 1rem;
}

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

body {
  font-family: 'Pretendard Variable', -apple-system, BlinkMacSystemFont, system-ui, Roboto, sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  line-height: 1.6;
}

/* Header */
header {
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 1000;
  border-bottom: 1px solid rgba(0, 0, 0, 0.05);
  padding: 1rem 0;
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
  text-decoration: none;
}

.nav-links {
  display: flex;
  gap: 2rem;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-color);
  font-weight: 500;
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--primary-color);
}

/* Hero Section */
.hero {
  background: radial-gradient(circle at top right, #e0f2fe 0%, #ffffff 50%);
  padding: 6rem 1.5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  border-radius: 50%;
  opacity: 0.1;
  top: -100px;
  left: -100px;
  filter: blur(80px);
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  background: linear-gradient(to right, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 1.5rem;
  line-height: 1.2;
}

.hero p {
  font-size: 1.25rem;
  color: #64748b;
  margin-bottom: 2.5rem;
}

.cta-button {
  display: inline-block;
  background: var(--primary-color);
  color: white;
  padding: 1rem 2rem;
  border-radius: 2rem;
  text-decoration: none;
  font-weight: 600;
  transition: transform 0.2s, box-shadow 0.2s;
  box-shadow: var(--shadow-md);
}

.cta-button:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
  background: #2563eb;
}

/* Features Grid */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 4rem 1.5rem;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.section-title h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

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

.card {
  background: var(--card-bg);
  padding: 2rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  transition: transform 0.3s, box-shadow 0.3s;
  border: 1px solid rgba(0, 0, 0, 0.05);
}

.card:hover {
  transform: translateY(-5px);
  box-shadow: var(--shadow-lg);
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  display: inline-block;
  padding: 1rem;
  background: #eff6ff;
  border-radius: 1rem;
  color: var(--primary-color);
}

.card h3 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.card p {
  color: #64748b;
}

/* Info Section */
.info-section {
  background: #f1f5f9;
  padding: 4rem 1.5rem;
}

.info-content {
  max-width: 800px;
  margin: 0 auto;
  background: white;
  padding: 3rem;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.info-content h2 {
  font-size: 2rem;
  margin-bottom: 1.5rem;
  color: var(--text-color);
}

.info-content p {
  margin-bottom: 1.5rem;
  color: #475569;
}

/* Footer */
footer {
  background: white;
  padding: 4rem 1.5rem;
  border-top: 1px solid #e2e8f0;
  text-align: center;
  color: #64748b;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.5rem;
  }

  .nav-links {
    display: none;
  }
}

/* Causes Section Toggle */
.causes-wrapper {
  text-align: center;
  margin-top: 3rem;
  padding: 0 1rem;
}

#causesContent {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.6s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.6s ease;
  margin-top: 1.5rem;
  opacity: 0;
}

#causesContent:not(.hidden) {
  opacity: 1;
}

.causes-detail {
  background: white;
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  box-shadow: var(--shadow-md);
  margin: 0 auto;
  max-width: 900px;
  text-align: center;
  border: 1px solid rgba(0, 0, 0, 0.05);
}

.causes-detail h3 {
  color: var(--primary-color);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.causes-detail ul {
  list-style: none;
}

.causes-detail li {
  margin-bottom: 1rem;
  padding-left: 1.5rem;
  position: relative;
}

.causes-detail li::before {
  content: "•";
  color: var(--secondary-color);
  font-weight: bold;
  position: absolute;
  left: 0;
}

.causes-intro {
  margin-bottom: 2rem;
  color: #475569;
  line-height: 1.7;
}

.causes-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.cause-card {
  background: #f8fafc;
  border-radius: 1rem;
  padding: 2rem 1.5rem;
  transition: transform 0.3s ease;
  border: 1px solid #e2e8f0;
}

.cause-card:hover {
  transform: translateY(-5px);
  background: #fff;
  box-shadow: var(--shadow-md);
}

.visual-icon-wrapper {
  height: 100px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.5rem;
}

.visual-icon {
  font-size: 4rem;
  color: var(--primary-color);
}

.cause-card h4 {
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
  color: var(--text-color);
}

.cause-card p {
  font-size: 0.95rem;
  color: #64748b;
  line-height: 1.5;
}

/* Animations */
@keyframes float {

  0%,
  100% {
    transform: translateY(0);
  }

  50% {
    transform: translateY(-10px);
  }
}

@keyframes pulse-scale {

  0%,
  100% {
    transform: scale(1);
    opacity: 1;
  }

  50% {
    transform: scale(1.1);
    opacity: 0.8;
  }
}

@keyframes wiggle {

  0%,
  100% {
    transform: rotate(-3deg);
  }

  50% {
    transform: rotate(3deg);
  }
}

.anim-float {
  animation: float 3s ease-in-out infinite;
}

.anim-pulse {
  animation: pulse-scale 2s ease-in-out infinite;
}

.anim-wiggle {
  animation: wiggle 2s ease-in-out infinite;
}

/* Specific colors for visual distinction */
.icon-autoimmune {
  color: #ef4444;
}

.icon-genetic {
  color: #8b5cf6;
}

.icon-environment {
  color: #10b981;
}