css实现正片叠底

mix-blend-mode: normal; //正常
mix-blend-mode: multiply; //正片叠底
mix-blend-mode: screen; //滤色
mix-blend-mode: overlay; //叠加
mix-blend-mode: darken; //变暗
mix-blend-mode: lighten; //变亮
mix-blend-mode: color-dodge; //颜色减淡
mix-blend-mode: color-burn; //颜色加深
mix-blend-mode: hard-light; //强光
mix-blend-mode: soft-light; //柔光
mix-blend-mode: difference; //差值
mix-blend-mode: exclusion; //排除
mix-blend-mode: hue; //色相
mix-blend-mode: saturation; //饱和度
mix-blend-mode: color; //颜色
mix-blend-mode: luminosity; //亮度
mix-blend-mode: initial; //初始
mix-blend-mode: inherit; //继承
mix-blend-mode: unset; //复原

这里就是div自己的背景图片和自己的背景颜色混合了，实现了正片叠低。注意只有一个元素div，这个div有背景图片和背景颜色。

background-blend-mode: multiply;是div属性，mix-blend-mode: multiply; 是img的属性，两个东西有差别