:root {
  --color-bg: #f7f9fc;
  --color-surface: #ffffff;
  --color-text: #1f2a37;
  --color-muted: #6b7280;
  --color-border: #e5e7eb;
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-secondary: #4b5563;
  --color-error: #dc2626;
  --shadow-soft: 0 12px 30px rgba(15, 23, 42, 0.08);
  --radius-lg: 18px;
  --radius-md: 12px;
  --radius-sm: 8px;
  --transition-base: 200ms ease;
  --max-width: 960px;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
}

.logo {
  font-weight: 700;
}

nav a {
  margin-left: 1rem;
  text-decoration: none;
  color: var(--color-muted);
  transition: color var(--transition-base);
}

nav a.active {
  border-bottom: 2px solid var(--color-primary);
  color: var(--color-primary);
}

main {
  max-width: var(--max-width);
  padding: 1.5rem;
  margin: 0 auto;
}

footer {
  border-top: 1px solid var(--color-border);
  padding: 1rem 1.5rem;
  text-align: center;
  font-size: 0.8rem;
  color: var(--color-muted);
  background: var(--color-surface);
}

.hero {
  padding: 2rem 0;
}

.hero-actions .btn {
  margin-right: 0.5rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.6rem 1.15rem;
  background: var(--color-primary);
  color: #fff;
  text-decoration: none;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-soft);
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base);
}

.btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 18px 35px rgba(37, 99, 235, 0.25);
}

.btn.secondary {
  background: var(--color-secondary);
}

.portfolio-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
}

.portfolio-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface);
  box-shadow: var(--shadow-soft);
  transition:
    transform var(--transition-base),
    box-shadow var(--transition-base);
}

.portfolio-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 20px 45px rgba(15, 23, 42, 0.15);
}

.portfolio-card img {
  width: 100%;
  height: 180px;
  object-fit: cover;
}

.portfolio-card h2 {
  margin: 0 0 0.25rem;
  font-size: 1.15rem;
}

.error-message {
  margin-top: 1rem;
  color: var(--color-error);
}

section {
  margin-bottom: 2rem;
  padding: 1.75rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
}

section h2 {
  margin-top: 0;
  margin-bottom: 0.75rem;
  color: var(--color-primary-dark);
}

.portfolio-card-content {
  padding: 1.25rem 1.5rem 1.5rem;
}

.portfolio-card .meta {
  font-size: 0.9rem;
  color: var(--color-muted);
  margin: 0 0 0.35rem;
}

.empty {
  padding: 1rem;
  text-align: center;
  color: var(--color-muted);
  border: 1px dashed var(--color-border);
  border-radius: var(--radius-md);
  background: rgba(37, 99, 235, 0.05);
}

@media (max-width: 600px) {
  header {
    flex-direction: column;
    align-items: flex-start;
  }
  nav {
    margin-top: 0.5rem;
  }
  main {
    padding: 1rem;
  }
  section {
    padding: 1.25rem;
  }
  .btn {
    width: 100%;
    justify-content: center;
  }
}