For example, select thebackgroundid in CSS and use thebackgroundproperty to set the color and the background image. Set the color asrgba(0, 0, 0, 0.7)and use a place holder image in theurl()function. Use the different background properties as in the first method to set the image co...
新的规范引入了“相对颜色语法”，您可以在其中执行以下操作