Freeze a block use loader/loading animation.

loading.less

.loading {
  &:before {
    background: rgba(255, 255, 255, 0.8);
    content: '';
    height: 100%;
    left: 0;
    position: absolute;
    top: 0;
    width: 100%;
    z-index: 1;
  }

  &:after {
    background: url('data:image/gif;base64,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');
    content: '';
    height: 16px;
    left: 50%;
    margin: -8px 0 0 -8px;
    position: absolute;
    top: 50%;
    width: 16px;
    z-index: 2;
  }
}