/* Lab0 - Main Stylesheet */

:root {
  --background: #ffffff;
  --foreground: #0a0a0a;
  --muted: #f4f4f5;
  --muted-foreground: #71717a;
  --border: #e4e4e7;
  --primary: #0a0a0a;
  --primary-foreground: #fafafa;
  --radius: 0.5rem;
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--foreground);
  background: var(--background);
  line-height: 1.6;
}

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

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.container-narrow {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.header {
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  background: white;
  z-index: 100;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.25rem;
}

.logo-icon {
  font-size: 1.5rem;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.header-nav a {
  font-size: 0.9rem;
  color: var(--muted-foreground);
  transition: color 0.2s;
}

.header-nav a:hover {
  color: var(--foreground);
}

.nav-cta {
  background: var(--primary);
  color: var(--primary-foreground) !important;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
}

/* Footer */
.footer {
  background: #000;
  color: #aaa;
  padding: 4rem 2rem 2rem;
}

.footer-inner {
  max-width: 1200px;
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 3rem;
}

.footer .logo {
  color: white;
  margin-bottom: 1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
}

.footer-description {
  font-size: 0.9rem;
  line-height: 1.7;
}

.footer-section-title {
  color: white;
  font-weight: 600;
  font-size: 0.85rem;
  margin-bottom: 1rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.6rem;
}

.footer-links a {
  color: #aaa;
  text-decoration: none;
  font-size: 0.9rem;
}

.footer-links a:hover {
  color: white;
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid #222;
  font-size: 0.85rem;
}

.footer-bottom p {
  margin: 0.25rem 0;
}

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  transition: all 0.2s;
}

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

.btn-primary:hover {
  opacity: 0.9;
}

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

.btn-secondary:hover {
  background: #e4e4e7;
}

/* Typography */
h1, h2, h3, h4 {
  font-weight: 700;
  line-height: 1.3;
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 1.75rem;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.25rem;
}

/* Guide Cards */
.guide-card {
  background: white;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: all 0.2s;
}

.guide-card:hover {
  border-color: var(--foreground);
}

.guide-card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
}

/* Utility */
.text-muted {
  color: var(--muted-foreground);
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-4 { margin-top: 2rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-4 { margin-bottom: 2rem; }