// 将px转换为rpx
@function px2rpx($px) {
    @return $px * 2rpx;
}

// 将rpx转换为px
@function rpx2px($rpx) {
    @return $rpx / 2px;
}

// 计算rem
@function rem($px) {
    @return $px / 16px * 1rem;
}

// 颜色变亮
@function tint($color, $percentage) {
    @return mix(white, $color, $percentage);
}

// 颜色变暗
@function shade($color, $percentage) {
    @return mix(black, $color, $percentage);
}