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

:root {
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-primary-light: #dbeafe;
  --color-text: #1f2937;
  --color-text-light: #6b7280;
  --color-background: #f9fafb;
  --color-surface: #ffffff;
  --color-border: #e5e7eb;
  --color-focus: #2563eb;
  --font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --border-radius: 0.5rem;
  --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);
  --transition: 0.2s ease;
  --container-max: 1200px;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  font-family: var(--font-family);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-background);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 50%;
  transform: translateX(-50%);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-primary);
  color: white;
  text-decoration: none;
  border-radius: var(--border-radius);
  z-index: 1000;
  font-weight: 600;
}

.skip-link:focus {
  top: var(--spacing-md);
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: var(--spacing-md);
  padding-bottom: var(--spacing-md);
}

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

.site-nav ul {
  display: flex;
  list-style: none;
  gap: var(--spacing-lg);
}

.site-nav a {
  color: var(--color-text);
  text-decoration: none;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--border-radius);
  transition: color var(--transition), background var(--transition);
}

.site-nav a:hover,
.site-nav a:focus {
  color: var(--color-primary);
  background: var(--color-primary-light);
  outline: none;
}

.site-nav a:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

main {
  flex: 1;
  padding: var(--spacing-2xl) 0;
}

h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
}

.portfolio-info {
  display: grid;
  grid-template-columns: 1fr auto auto;
  gap: var(--spacing-lg);
  align-items: start;
  padding: var(--spacing-lg);
  background: var(--color-surface);
  border-radius: var(--border-radius);
  border: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
}

.portfolio-meta {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.portfolio-meta dt {
  font-weight: 600;
  color: var(--color-text-light);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--spacing-lg);
}

.project-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition);
  display: flex;
  flex-direction: column;
}

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

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

.project-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: var(--spacing-sm);
  color: var(--color-text);
}

.project-card p {
  color: var(--color-text-light);
  margin-bottom: var(--spacing-md);
  flex: 1;
}

.project-technologies {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-xs);
  margin-bottom: var(--spacing-md);
}

.tech-tag {
  background: var(--color-primary-light);
  color: var(--color-primary);
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 500;
}

.project-links {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: auto;
}

.project-link {
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-xs);
  padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-primary);
  color: white;
  text-decoration: none;
  border-radius: var(--border-radius);
  font-size: 0.875rem;
  font-weight: 500;
  transition: background var(--transition);
}

.project-link:hover,
.project-link:focus {
  background: var(--color-primary-hover);
  color: white;
  outline: none;
}

.project-link:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

.project-link.secondary {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}

.project-link.secondary:hover,
.project-link.secondary:focus {
  background: var(--color-primary-light);
}

.loading {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--spacing-2xl);
  color: var(--color-text-light);
}

.about-section p {
  max-width: 700px;
  margin-bottom: var(--spacing-md);
  color: var(--color-text-light);
}

.site-footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-lg) 0;
  margin-top: auto;
}

.site-footer p {
  text-align: center;
  color: var(--color-text-light);
  font-size: 0.875rem;
}

@media (max-width: 768px) {
  .site-header .container {
    flex-direction: column;
    gap: var(--spacing-md);
  }

  .site-nav ul {
    gap: var(--spacing-md);
  }

  .portfolio-info {
    grid-template-columns: 1fr;
  }

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

  h2 {
    font-size: 1.5rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--spacing-sm);
  }

  .site-title {
    font-size: 1.25rem;
  }

  .project-card {
    padding: var(--spacing-md);
  }
}