:root {
  --color-bg: #fafaf9;
  --color-text: #1a1a1a;
  --color-muted: #6b7280;
  --color-accent: #2563eb;
  --color-accent-dark: #1e40af;
  --color-card: #ffffff;
  --color-border: #e5e7eb;
  --max-width: 1100px;
  --radius: 8px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
}

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

img { max-width: 100%; height: auto; }

/* Navigation */
.site-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  background: var(--color-card);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-nav .logo {
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--color-text);
}

.site-nav .nav-links {
  list-style: none;
  display: flex;
  gap: 1.5rem;
  margin: 0;
  padding: 0;
}

.site-nav .nav-links a {
  color: var(--color-text);
  font-weight: 500;
  font-size: 0.95rem;
}

.site-nav .nav-links a:hover {
  color: var(--color-accent);
  text-decoration: none;
}

/* Main content area */
.site-main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 2rem;
}

/* Footer */
.site-footer {
  text-align: center;
  padding: 2rem;
  color: var(--color-muted);
  font-size: 0.9rem;
  border-top: 1px solid var(--color-border);
  margin-top: 4rem;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius);
  font-weight: 500;
  border: 1px solid var(--color-border);
  background: var(--color-card);
  color: var(--color-text);
  cursor: pointer;
  transition: all 0.15s;
}
.btn:hover { background: var(--color-bg); text-decoration: none; }
.btn-primary { background: var(--color-accent); color: white; border-color: var(--color-accent); }
.btn-primary:hover { background: var(--color-accent-dark); border-color: var(--color-accent-dark); color: white; }

/* Mobile responsive */
@media (max-width: 700px) {
  .site-nav { flex-direction: column; gap: 0.75rem; padding: 1rem; }
  .site-nav .nav-links { flex-wrap: wrap; justify-content: center; gap: 1rem; }
  .site-main { padding: 1.5rem 1rem; }
}