AdminLte/build/scss/_site-search.scss

.site-search-block {
  display: none;
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1100;
  box-shadow: 0 5px 5px rgba(0, 0, 0, .2);
  background: $input-bg;

  .site-search-backdrop {
    content: ' ';
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.2);
    z-index: -1;
  }

  .form-control {
    border: 0;
    border-radius: 0;
    padding-left: 60px;
    padding-right: 60px;
  }

  &,
  .form-control,
  .site-search-close {
    height: $main-header-height;
  }

  .site-search-close,
  .site-search-submit {
    position: absolute;
    top: 0;
    display: block;
    color: #444;
    width: 50px;
    text-align: center;
    line-height: $main-header-height;
    cursor: pointer;
    &:hover {
      color: #999;
      text-decoration: none;
    }
  }

  .site-search-close {
    left: 0;
  }

  .site-search-submit {
    right: 0;
    background: $white;
    border: 0;
    padding: 0;
  }
}