.td-header-fixed {
  position: relative;
  z-index: 9999;
}

.td-header-fixed::before {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0; bottom: 0;
  background-color: rgba(255, 255, 255, 0.9); /* почти непрозрачный белый */
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: -1;
}

.td-header-fixed a,
.td-header-fixed .t-menu__link,
.td-header-fixed .t-menu__link-item {
  color: #000 !important; /* чёрный текст */
}