:root {
  --color-bg: #ffffff;
  --color-text: #0f172a;
  --color-primary: #0f172a; /* Navy */
  --color-secondary: #334155;
  --color-accent: #38bdf8; /* Electric Blue */
  --color-light-bg: #f8fafc;
  --color-card-bg: #ffffff;
  --color-border: #e2e8f0;
  
  --font-main: 'Pretendard', -apple-system, BlinkMacSystemFont, system-ui, sans-serif;
  
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 2rem;
  --spacing-xl: 4rem;
  
  --border-radius: 12px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
  --shadow-md: 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);
}

/* Dark Mode Variables */
[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-text: #f1f5f9;
  --color-primary: #f8fafc;
  --color-secondary: #94a3b8;
  --color-light-bg: #1e293b;
  --color-card-bg: #1e293b;
  --color-border: #334155;
}

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

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

a {
  text-decoration: none;
  color: inherit;
}

ul {
  list-style: none;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

/* Header */
header {
  position: sticky;
  top: 0;
  background-color: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--color-border);
  z-index: 1000;
}

[data-theme="dark"] header {
  background-color: rgba(15, 23, 42, 0.8);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 70px;
}

.logo {
  font-weight: 700;
  font-size: 1.5rem;
  color: var(--color-primary);
}

.logo span {
  color: var(--color-accent);
}

nav ul {
  display: flex;
  gap: var(--spacing-lg);
}

nav a {
  font-weight: 500;
  font-size: 0.95rem;
  transition: color 0.2s;
}

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

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.8rem 1.5rem;
  border-radius: var(--border-radius);
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-primary {
  background-color: var(--color-accent);
  color: #fff;
  border: none;
}

.btn-secondary {
  background-color: transparent;
  border: 2px solid var(--color-border);
  color: var(--color-text);
}

.btn-icon {
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  padding: var(--spacing-sm);
}

/* Hero Section */
.hero {
  padding: 6rem 0;
  overflow: hidden;
}

.hero-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-xl);
}

.hero-text {
  flex: 1;
}

.hero-text h1 {
  font-size: 3.5rem;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  letter-spacing: -0.02em;
}

.hero-text p {
  font-size: 1.125rem;
  color: var(--color-secondary);
  margin-bottom: var(--spacing-lg);
}

.badge {
  display: inline-block;
  background-color: var(--color-light-bg);
  color: var(--color-accent);
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--spacing-md);
}

.cta-group {
  display: flex;
  gap: var(--spacing-md);
}

.hero-visual {
  flex: 1;
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Simple visual animation */
.brain-pulse {
  position: relative;
  width: 200px;
  height: 200px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.brain-icon {
  font-size: 5rem;
  z-index: 2;
}

.pulse-circle {
  position: absolute;
  width: 100%;
  height: 100%;
  border-radius: 50%;
  background-color: var(--color-accent);
  opacity: 0.2;
  animation: pulse 3s infinite ease-out;
}

.pulse-circle:nth-child(2) {
  animation-delay: 1.5s;
}

@keyframes pulse {
  0% { transform: scale(0.8); opacity: 0.5; }
  100% { transform: scale(1.5); opacity: 0; }
}

/* Sections */
.section {
  padding: var(--spacing-xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.section-header h2 {
  font-size: 2.25rem;
  margin-bottom: var(--spacing-sm);
}

.section-header p {
  color: var(--color-secondary);
}

.bg-light {
  background-color: var(--color-light-bg);
}

/* Brain Map */
.brain-map-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-lg);
}

.brain-svg {
  width: 100%;
  max-width: 500px;
  background-color: var(--color-card-bg); /* Placeholder background */
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-lg);
  padding: var(--spacing-lg);
}

.brain-node {
  cursor: pointer;
  fill: var(--color-accent);
  transition: r 0.3s;
}

.brain-node:hover {
  r: 40;
}

.info-card {
  background-color: var(--color-card-bg);
  padding: var(--spacing-lg);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-md);
  max-width: 400px;
  text-align: center;
  border: 1px solid var(--color-border);
  opacity: 1;
  transform: translateY(0);
  transition: opacity 0.3s, transform 0.3s;
}

.info-card.hidden {
  opacity: 0;
  transform: translateY(20px);
  pointer-events: none;
}

/* Grid & Cards */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: var(--spacing-lg);
}

.card {
  background-color: var(--color-card-bg);
  border-radius: var(--border-radius);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  transition: transform 0.2s, box-shadow 0.2s;
}

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

.card-image {
  height: 200px;
  background-color: var(--color-secondary);
}

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

.tag {
  color: var(--color-accent);
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  margin-bottom: var(--spacing-sm);
  display: block;
}

.card h3 {
  font-size: 1.25rem;
  margin-bottom: var(--spacing-sm);
}

.card p {
  color: var(--color-secondary);
  font-size: 0.95rem;
  margin-bottom: var(--spacing-md);
}

.read-more {
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.9rem;
}

.split-layout {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
}

.text-content {
  flex: 1;
}

.test-card {
  flex: 1;
  padding: var(--spacing-xl);
  text-align: center;
}

.card-icon {
  font-size: 3rem;
  margin-bottom: var(--spacing-md);
}

.progress-bar {
  width: 100%;
  height: 8px;
  background-color: var(--color-border);
  border-radius: 4px;
  margin-top: var(--spacing-md);
  overflow: hidden;
}

.fill {
  height: 100%;
  background-color: var(--color-accent);
  transition: width 0.3s ease;
}

/* Footer */
footer {
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--color-border);
  margin-top: var(--spacing-xl);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  color: var(--color-secondary);
}

.social-links a {
  margin-left: var(--spacing-md);
}

/* Mobile Responsive */
@media (max-width: 768px) {
  .hero-content, .split-layout {
    flex-direction: column;
    text-align: center;
  }
  
  .hero-text h1 {
    font-size: 2.5rem;
  }
  
  .cta-group {
    justify-content: center;
  }
}

/* Test Container Styles */
.hidden {
  display: none !important;
}

#test-question-box {
  text-align: left;
}

.question-header {
  display: flex;
  justify-content: space-between;
  color: var(--color-secondary);
  font-size: 0.9rem;
  margin-bottom: var(--spacing-md);
}

.options-grid {
  display: grid;
  gap: var(--spacing-sm);
  margin-top: var(--spacing-lg);
}

.option-btn {
  padding: var(--spacing-md);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: all 0.2s;
  color: var(--color-text);
  font-family: var(--font-main);
  text-align: left;
}

.option-btn:hover {
  border-color: var(--color-accent);
  background-color: rgba(56, 189, 248, 0.1);
}

.score-display {
  font-size: 3rem;
  font-weight: 700;
  color: var(--color-accent);
  margin: var(--spacing-md) 0;
}

.score-display span:last-child {
  font-size: 1rem;
  color: var(--color-secondary);
}