semi-design/packages/semi-foundation/button/splitButtonGroup.scss

$dropdown: #{$prefix}-dropdown;
$module: #{$prefix}-button;
$component: #{$module}-split;
$content: #{$module};
$icon: #{$module}-with-icon;

.#{$component} {
    display: inline-block;

    .#{$module} {
        border-radius: 0;
        margin-right: 1px;

        &-first {
            border-top-left-radius: $radius-button_splitButtonGroup_first_topLeft;
            border-bottom-left-radius: $radius-button_splitButtonGroup_first_bottomLeft;
        }

        &-last {
            border-top-right-radius: $radius-button_splitButtonGroup_last_topRight;
            border-bottom-right-radius: $radius-button_splitButtonGroup_last_bottomRight;
            margin-right: unset;
        }
    }


    &:hover {
        // 因为上面那条规则，导致原来的active被覆盖
        .#{$module}-borderless:active {
            background-color: $color-button_borderless-bg-active;
        }
    }
}