siyuan/app/src/assets/scss/_toolbar.scss

.protyle {
  &-toolbar {
    background-color: var(--b3-theme-background);
    z-index: 3;
    position: fixed;
    box-shadow: var(--b3-point-shadow);
    border-radius: 4px;
    display: flex;
    transition: top .15s cubic-bezier(0, 0, .2, 1) 0ms;

    &__item {
      color: var(--b3-theme-on-surface);
      border: 0;
      background-color: transparent;
      height: 29px;
      box-sizing: border-box;
      font-size: 0;
      padding: 0 6px;

      &:focus {
        outline: none;
      }

      svg {
        fill: currentColor;
        display: inline-block;
        stroke-width: 0;
        stroke: currentColor;
        width: 14px;
        height: 14px;
      }

      &--current {
        color: var(--b3-theme-primary);
      }

      &:hover {
        background-color: var(--b3-border-color);
      }
    }

    &__divider {
      border-left: 1px solid var(--b3-border-color);
      margin: 6px 4px;
    }
  }

  &-util {
    @extend .b3-menu;
    z-index: 200;
  }

  &-font {
    font-size: 12px;
    padding: 4px 8px;

    &__style {
      background-color: transparent;
      margin-right: 4px;
      transition: var(--b3-transition);
      padding: 0 4px;
      border-radius: 2px;
      border: 1px solid transparent;
      color: var(--b3-theme-on-background);
      white-space: nowrap;

      &:hover {
        border-color: var(--b3-border-color);
      }
    }
  }
}