:root {
  --color-bg: #f5f7fa;
  --color-surface: #ffffff;
  --color-text: #2d3748;
  --color-text-secondary: #718096;
  --color-accent: #4299e1;
  --color-accent-hover: #2b6cb0;
  --color-border: #e2e8f0;
  --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.08), 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-card-hover: 0 10px 25px rgba(0, 0, 0, 0.1), 0 4px 10px rgba(0, 0, 0, 0.06);
  --radius: 12px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background-color: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* Header */
header {
  text-align: center;
  padding: 80px 1.5rem 40px;
}

header h1 {
  font-size: 2.8rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  background: linear-gradient(135deg, var(--color-accent), #667eea);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 0.5rem;
}

header p {
  font-size: 1.1rem;
  color: var(--color-text-secondary);
  max-width: 480px;
  margin: 0 auto;
}

/* Main / Projects Grid */
.projects {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
  gap: 2rem;
  max-width: 880px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Card */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-card);
  padding: 2rem;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
  will-change: transform;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-card-hover);
  border-color: rgba(66, 153, 225, 0.4);
}

/* Card Icon */
.card-icon {
  width: 64px;
  height: 64px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  margin-bottom: 1.25rem;
  transition: transform var(--transition);
}

.card:hover .card-icon {
  transform: scale(1.05);
}

.card-icon.gis {
  background: linear-gradient(135deg, #ebf8ff, #bee3f8);
}

.card-icon.task {
  background: linear-gradient(135deg, #f0fff4, #c6f6d5);
}

.card-icon.portfolio {
  background: linear-gradient(135deg, #fff7ed, #fed7aa);
}

/* Card Content */
.card h2 {
  font-size: 1.35rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.card p {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: 1rem;
  line-height: 1.7;
}

/* Tags */
.card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.5rem;
}

.card-tags span {
  display: inline-block;
  font-size: 0.75rem;
  background: #edf2f7;
  color: var(--color-text-secondary);
  border-radius: 9999px;
  padding: 0.2rem 0.75rem;
  font-weight: 500;
}

/* Card Link */
.card-link {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.95rem;
  text-decoration: none;
  transition: color var(--transition), gap var(--transition);
}

.card-link:hover {
  color: var(--color-accent-hover);
  gap: 0.6rem;
}

.card-link .arrow {
  transition: transform var(--transition);
}

.card-link:hover .arrow {
  transform: translateX(2px);
}

/* Footer */
footer {
  text-align: center;
  margin-top: 4rem;
  padding: 2rem 1.5rem 3rem;
  color: var(--color-text-secondary);
  font-size: 0.85rem;
}

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

footer a:hover {
  text-decoration: underline;
}

/* Animations */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hidden {
  opacity: 0;
}

.animate-in {
  animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

.animate-in:nth-child(2) {
  animation-delay: 0.15s;
}

header.animate-in {
  animation-delay: 0s;
  animation-duration: 0.5s;
}

/* Responsive */
@media (max-width: 768px) {
  header {
    padding: 50px 1.5rem 30px;
  }

  header h1 {
    font-size: 2rem;
  }

  header p {
    font-size: 1rem;
  }

  .projects {
    grid-template-columns: 1fr;
    gap: 1.5rem;
  }

  footer {
    margin-top: 3rem;
  }
}

@media (max-width: 480px) {
  header {
    padding: 40px 1rem 20px;
  }

  header h1 {
    font-size: 1.75rem;
  }

  .projects {
    padding: 0 1rem;
  }

  .card {
    padding: 1.5rem;
  }
}