AdminLTE/build/scss/mixins/_navbar.scss

//
// Mixins: Navbar
//

// Navbar Variant
@mixin navbar-variant($name, $color) {
  .navbar-#{$name} {
    background-color: $color;
    color: color-yiq($color);

    &.navbar-light {
      .form-control-navbar {
        &::placeholder {
          color: rgba($gray-800, .8);
        }
        &,
        + .input-group-append > .btn-navbar {
          background-color: darken($color, 4%);
          border-color: darken($color, 9%);
          color: rgba($gray-800, .8);
        }

        &:focus {
          &::placeholder {
            color: $gray-800;
          }
          &,
          + .input-group-append .btn-navbar {
            background-color: darken($color, 5%);
            border-color: darken($color, 9%) !important;
            color: $gray-800;
          }
        }
      }
    }
    &.navbar-dark {
      .form-control-navbar {
        &::placeholder {
          color: rgba($white, .8);
        }
        &,
        + .input-group-append > .btn-navbar {
          background-color: lighten($color, 4%);
          border-color: lighten($color, 9%);
          color: rgba($white, .8);
        }

        &:focus {
          &::placeholder {
            color: $white;
          }
          &,
          + .input-group-append .btn-navbar {
            background-color: lighten($color, 5%);
            border-color: lighten($color, 9%) !important;
            color: $white;
          }
        }
      }
    }
  }
}