Hello,
The first idea, is to check that your css command is well built and with a good priority, I detail my idea :
1. First the minimum necessary to work properly :
Check that your selector is well written, good class (or Id) html and no mistake or typo
If your command is visible in your browser inspector tool, but is overridden (css command crossed out), then his priority isn't strong enough.
2. Now, some css priority system explanation :
From less to the highest priority :
.html_class_element {command: value}
.html_class_module .html_class_element {command: value}
.html_class_page .html_class_module .html_class_element {command: value}
.html_class_page .html_class_module .html_class_element {command: value !important;}
Note, that if
2 css commands have strictly the
same selector, then the
last written in the css file will be the one used.
For get an transparent background, you can use this kind of css command :
.your_required_container_class {
background-color: rgba(0,0,0,0.5);
}
Learn more about, background-color, rgba commands,
here
.
Hope this will help you to achieve what you need.
Or in order to be more specific in our help we will need to access your website, later when it will be on internet.
Regards