/* Sticky header + nav + toggle styles */

.post-header {
    position: sticky;
    top: 0;
    z-index: 999;
    background-color: var(--bg-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--hr-color);
  }
  
.post-header::after {
    content: "";
    position: absolute;
    bottom: -1px;
    left: 0;
    right: 0;
    height: 1px;
    background: var(--hr-color);
    opacity: 0.6;
  }
  
.post-header .brand a {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-color);
    text-decoration: none;
    padding-left: 0.5rem;
  }
  
.post-nav {
    display: flex;
    gap: 1rem;
    align-items: center;
  }
  
.post-nav a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--link-color);
    text-decoration: none;
    padding-right: 0.5rem;
  }
  
.post-nav a:hover {
    text-decoration: underline;
  }