atom/static/config.less

#config-view {
  height: 100%;
  width: 100%;
  background: white;
  display: -webkit-flex;

  #panel-menu {
    background: #f3f3f3;

    li {
      width: 100px;
      padding: 10px;
      background: #ddd;
      box-sizing: border-box;
      cursor: pointer;

      &.active {
        background: #aaa;
      }
    }
  }

  #panels {
    -webkit-flex: 1;
    > div {
      padding: 10px;
    }

    label {
      display: inline-block;
      width: 180px;
      text-align: right;
      margin-right: 5px;
    }
  }
}