amis2/packages/amis-editor-core/scss/_leftPanel.scss

.editor-left-panel {
  position: relative;
  flex: 0 0 308px; // 48px + 260px
  // min-width: 308px;
  background: #fff;
  overflow: visible;
  box-shadow: 2px 0 20px 0 rgba(0, 0, 0, 0.1);
  z-index: 5;
  // 搞点动画？
  transition: width ease-in-out 0.2s;
  transform: translateZ(0);

  // 宽度可拖拽时不增加过渡，避免卡顿
  &.width-draggable {
    transition: none;
  }

  &.fixed-status {
    position: fixed;
    top: 0;
    left: 0;
    width: auto;
    height: 100%;
  }

  // 悬浮icon
  .editor-panel-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    height: 16px;
    width: 16px;
    z-index: 100;
    display: flex;
    justify-content: center;
    align-items: center;

    .panel-btn {
      width: 16px;
      height: 16px;
      fill: $default-icon-color;
      color: $default-icon-color;
      cursor: pointer;

      &:hover {
        fill: $Editor-theme;
        color: $Editor-theme;
      }
    }
  }

  // 折叠状态
  &.hidden-status {
    flex: 0 0 48px;
    min-width: 48px;
    width: 48px;

    > .editor-panel-btn {
      display: none;
    }
  }

  // 折叠收缩 icon
  .left-panel-arrow {
    position: absolute;
    width: 16px;
    height: 50px;
    top: 50%;
    right: -15px;
    transform: translateY(-50%);
    background-color: transparent;
    box-sizing: border-box;
    z-index: 10;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;

    &::before {
      content: '';
      position: absolute;
      border-radius: 0 10px 10px 0;
      box-sizing: border-box;
      // border: 1px solid rgba(0, 0, 0, 0.1);
      border-left: 0;
      // box-shadow: -2px 2px 2px #f0f1f2;
      top: 0;
      right: 0;
      bottom: 0;
      left: 0;
      background: #fff;
      z-index: -1;
      transform: perspective(50px) rotateY(30deg);
      transition: all 0.15s;
    }
    &::after {
      content: '';
      position: absolute;
      width: 6px;
      height: 8px;
      // right: 50%;
      top: 50%;
      -webkit-mask-image: url(../static/side_hide_left.svg);
      -webkit-mask-size: 100% 100%;
      mask-size: 100% 100%;
      -webkit-mask-repeat: no-repeat;
      mask-repeat: no-repeat;
      background-color: #a1a6b3;
      transform: translate(-50%, -50%) rotate(0deg);
      transition: all 0.15s;
    }

    &.hidden-status {
      &::after {
        transform: translate(-50%, -50%) rotate(180deg);
      }
    }
  }

  .editorPanel-tabs {
    position: relative;
    height: 100%;
    display: flex;

    > [class$='Tabs-linksWrapper'] {
      position: relative;
      flex: 0 0 48px;
      border: none;
      border-right: 1px solid #e6e6e8;
      height: 100%;
      box-sizing: border-box;
    }

    .editorPanel-tabs-header {
      padding-top: 20px;

      > li {
        margin: 0 0 12px 0 !important;
        padding: 0;
        overflow: visible; // 避免 tooltip被遮挡
        width: 48px;
        height: 48px;
        box-sizing: border-box;
        padding: 0 3px;
        display: flex !important;
        flex-direction: column;
        justify-content: flex-start;
        align-items: center;

        > a {
          position: relative;
          display: inline-block;
          width: 100%;
          height: 100%;
          margin: 0 !important;
          padding: 0 !important;
          border: none !important;
          overflow: visible; // 避免 tooltip被遮挡
          display: flex;
          justify-content: center;
          align-items: center;

          // 用于设置自定义tab面板中的icon样式
          .editor-tab-icon {
            position: relative;
            width: 100%;
            height: 100%;
            display: flex;
            justify-content: center;
            align-items: center;

            > svg {
              width: 48px;
              height: 48px;
              color: #151b26;
            }
          }
        }

        &.is-active,
        &:hover {
          background: #eef3fe;

          > a {
            background: #eef3fe;
          }

          .editor-tab-icon > svg {
            color: $editor-active-color !important;
          }
        }

        // 选中态左侧边框高亮
        &.is-active {
          padding: 0 3px 0 0;
          border-left: 3px solid $editor-active-color;
        }
      }
    }

    > .editorPanel-tabs-content {
      position: relative;
      flex: 1 1 auto;
      height: 100%;
      border: none;

      .editorPanel-tabs-pane {
        position: relative;
        height: 100%;
        padding: 0;
        width: $Editor-aside-width;
        box-sizing: border-box;
      }
    }
  }

  // 代码编辑面板
  .ae-Editor-codePane {
    position: relative;
    height: 100%;
    // transition: width ease-out 0.3s;
    max-width: 800px;

    // monaco-editor 里面的，会把内容撑开。
    .overflowingContentWidgets {
      margin-top: -99999px;
    }
  }
}

// 左侧面板悬浮模式时的占位，避免折叠状态遮挡内容区
.editor-left-panel-fixed-placeholder {
  position: relative;
  flex: 0 0 48px;
  background: #fff;
}