vaadin-framework/themes/src/main/resources/VAADIN/themes/base/common/reconnect-dialog.scss

@mixin base-reconnect-dialog {
  .v-reconnect-dialog {
    color: white;
    top: 12px;
    right: 12px;
    max-width: 100%;
    border-radius: 0;
    @include box-shadow(0 0 20px 0 rgba(0,0,0,0.25));
    padding: 10px;

    background-color: #444;
    text-align: center;

    .text {
        display: inline-block;
        padding-left: 10px;
    }

    .spinner {
        background-image: url(img/reconnect-spinner.gif);
        width: 31px;
        height: 31px;
        display: none;
        vertical-align: middle;
    }

    &.active .spinner {
        display: inline-block;
    }
  }
}