How to solve the problem of parent div being transparent and child div being transparent? _html/css_WEB-ITnose

It is said on the Internet that the position attribute of the child div is set to relation. This method is not effective for the parent div using position:relation. However, my parent div has already used position:relation. In this case, the setting in the child div will be will lose its effect. Are there any other solutions?

Reply to discussion (solution)

Use alpha transparency,
http://leegorous.net/tools/bg-alpha.html
Generate with this tool.

Add a layer inside the parent
This layer is transparent
so that the others will not be transparent
This layer only needs to have the same size background image as the parent

Use alpha transparency,
http://leegorous.net/tools/bg-alpha.html
Use this tool to generate.