.rc-md-editor {
  .tool-bar {
    position: absolute;
    z-index: 1;
    right: 8px;
    top: 8px;
    .button {
      min-width: 24px;
      height: 28px;
      margin-right: 5px;
      display: inline-block;
      cursor: pointer; 
      font-size: 14px;        
      line-height: 28px;
      text-align: center;
      color: #999;
      &:hover {
        color: #333;
      }
    }
  }
}