Currently trying to change the top menu background color, tried to change it from the css files, found out through firebug that the file pub/static/frontend/Venustheme/beat/en_US/css/styles-l.css is the one responsible for this,
And even tried to change it on firebug to confirm, turns out it actually is.
Checked the URL in core_config_data turned out to be correct, can anyone help with this? and is there a way to change the css files through the admin interface?
Also what is the difference between beat and beat_child?
and does the less file affect that in anyway?
You shouldn't modify the CSS from the pub folder directly, you should modify the source CSS file and then deploy the changes using the command-line tool.
As you can see in this diagram, there is a fallback system implemented in Magento 2 for CSS:
I recommend you to read the following article from Inchoo: