:root {
  --primary-bg: #f9f9f9;
  --card-bg: #ffffff;
  --text-color: #333;
  --accent-color: #ff6b9e;
  --border-color: #e0e0e0;
  --shadow-color: rgba(0, 0, 0, 0.1);
  --active-gradient: linear-gradient(135deg, #ff9a9e 0%, #fad0c4 100%);
  
  /* Dark mode variables */
  --dark-bg: #1a1a1a;
  --dark-card: #2d2d2d;
  --dark-text: #f0f0f0;
  --dark-border: #444;
  --dark-shadow: rgba(0, 0, 0, 0.3);
}

/* Base styles */
body {
  margin: 0;
  padding: 0;
  background-color: var(--primary-bg);
  color: var(--text-color);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  transition: background-color 0.3s, color 0.3s;
}

/* Dark mode preference */
@media (prefers-color-scheme: dark) {
  body {
    --primary-bg: var(--dark-bg);
    --card-bg: var(--dark-card);
    --text-color: var(--dark-text);
    --border-color: var(--dark-border);
    --shadow-color: var(--dark-shadow);
  }
}

/* Header styles */
header {
  text-align: center;
  padding: 2rem 1rem 1rem;
  max-width: 800px;
  margin: 0 auto;
}

h1 {
  font-size: clamp(2rem, 5vw, 2.5rem);
  margin: 0 0 0.5rem;
  background: linear-gradient(90deg, #ff6b9e, #8a2be2);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.subtitle {
  font-size: 1.1rem;
  color: #666;
  margin: 0;
}

@media (prefers-color-scheme: dark) {
  .subtitle {
    color: #aaa;
  }
}

/* Grid container */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.5rem;
  width: 100%;
  max-width: 1200px;
  padding: 1rem;
  box-sizing: border-box;
  margin: 1rem auto 3rem;
}

/* Project card styles */
.project-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  text-align: center;
  padding: 1.5rem 1rem;
  text-decoration: none;
  color: var(--text-color);
  font-size: 1.1rem;
  box-shadow: 0 4px 12px var(--shadow-color);
  transition: transform 0.2s ease-out, box-shadow 0.2s ease-out;
  display: flex;
  flex-direction: column;
  align-items: center;
  will-change: transform;
  position: relative;
  overflow: hidden;
}

.project-card::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(255,255,255,0.1);
  opacity: 0;
  transition: opacity 0.2s;
}

.project-card:hover::after {
  opacity: 1;
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: 0.8rem;
  transition: transform 0.3s ease;
}

.card-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
  font-size: 1.2rem;
}

.card-desc {
  font-size: 0.9rem;
  color: #666;
  font-weight: 400;
  margin: 0;
}

@media (prefers-color-scheme: dark) {
  .card-desc {
    color: #aaa;
  }
}

/* Hover and active states */
.project-card:hover {
  transform: translateY(-5px) scale(1.02);
  box-shadow: 0 8px 24px var(--shadow-color);
}

.project-card:hover .card-icon {
  transform: scale(1.1);
}

.project-card:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
  transform: translateY(-3px);
}

.project-card:active {
  transform: translateY(0) scale(0.98);
}

/* Active card highlight */
.project-card.active {
  background: var(--active-gradient);
  color: #333;
  border-color: #ff9a9e;
}

.project-card.active .card-desc {
  color: #555;
}

/* Footer */
footer {
  margin-top: auto;
  padding: 1.5rem;
  text-align: center;
  color: #666;
  font-size: 0.9rem;
}

@media (prefers-color-scheme: dark) {
  footer {
    color: #888;
  }
}

/* Responsive adjustments */
@media (max-width: 768px) {
  .projects-grid {
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
  }
  
  .card-icon {
    font-size: 2rem;
  }
}

@media (max-width: 480px) {
  .projects-grid {
    grid-template-columns: 1fr;
  }
  
  header {
    padding: 1.5rem 1rem 0.5rem;
  }
  
  .subtitle {
    font-size: 1rem;
  }
}