.colors1 {
  --cassiopeia-color-primary: #000000;
  --cassiopeia-color-link: #000000;
  --link-color: #000000;
  --link-color-rgb: 48, 99, 141;
  --cassiopeia-color-hover: #000000;
}
.container-header .mod-menu {
justify-content: center;
color: #ffffff;
padding: 0;
}
@media (max-width: 768px) {.container-header .mod-menu
  .main-menu, 
  #main-menu, 
  .your-menu-class { 
    text-align: center;
  }

  .main-menu li, 
  #main-menu li, 
  .your-menu-class li {
    display: inline-block;
    float: none;
  }
}