/* Sticky header */
.header {
  background: #fff;
  z-index: 9999;
}
/* Keep #header out of document flow from the start so AJAX injection causes no CLS */
#header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 9999;
}
/* Pre-reserve space for fixed header. Values are slightly above the measured
   actual heights (~120px desktop, ~143px mobile) so JS only ever shrinks
   padding-top (less visually disruptive than growing it). */
body {
  padding-top: 130px;
}
@media (max-width: 768px) {
  body {
    padding-top: 160px;
  }
  .navbar-collapse {
    max-height: calc(100vh - 160px);
    overflow-y: auto;
  }
}