:root {
  --primary: #4361ee;
  --dark: #111;
  --light: #fff;
  --radius: 6px;
  --transition: 150ms ease;
}

.sticky-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.6rem 1rem;
  background-color: var(--light);
  position: sticky;
  top: 0;
  width: 100%;
  z-index: 1000;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial;
  border-bottom: 1px solid #eee;
  gap: 0.5rem;
}

.sticky-header .logo {
  font-size: 1rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  cursor: pointer;
}

.hamburger-menu {
  display: none;
  background: none;
  border: none;
  color: var(--dark);
  font-size: 1.1rem;
  cursor: pointer;
  padding: 0.25rem;
}

.nav-links {
  display: flex;
  gap: 0.75rem;
  align-items: center;
}

.nav-links a {
  color: var(--dark);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 0.35rem 0.4rem;
  border-radius: 4px;
  transition: background var(--transition), color var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--primary);
  background: rgba(67,97,238,0.06);
}

/* Mobile */
@media (max-width: 768px) {
  .hamburger-menu { display: block; }
  .nav-links {
    position: absolute;
    top: 100%;
    right: 0.5rem;
    background: var(--light);
    flex-direction: column;
    gap: 0;
    padding: 0.25rem 0;
    min-width: 180px;
    border-radius: var(--radius);
    border: 1px solid #eee;
    box-shadow: none;
    transform-origin: top right;
    display: none;
  }
  .nav-links.show { display: flex; }
  .nav-links a {
    padding: 0.5rem 0.8rem;
    width: 100%;
  }
}