@media (min-width: 901px) {
  .site-header {
    position: fixed;
    width: 100%;
    max-width: none;
    padding-left: max(2rem, calc((100vw - var(--max)) / 2 + 2rem));
    padding-right: max(2rem, calc((100vw - var(--max)) / 2 + 2rem));
    transition: background-color .25s ease, border-color .25s ease, box-shadow .25s ease;
  }

  .site-header.is-scrolled {
    background: #07090af7;
    border-color: #2a2e30;
    box-shadow: 0 10px 30px #0005;
  }
}

@media (max-width: 900px) {
  .site-header {
    position: absolute;
    width: auto;
    max-width: var(--max);
    background: transparent;
    box-shadow: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-header { transition: none; }
}