How do you add the css?
In the manifest or with inherit? Whats the process to add CSS to Odoo frontend

@Sven sailor Salazar, It really depends on the version you are using. In later versions you have to put your CSS file in folder structure static/src/css/custom_css.css and you need to add it in manifest file like: 'assets': {
'web.assets_backend': ['my_module/static/src/css/custom_css.css']
},
But in older versions it is linked in an xml file and the xml file is added in manifest like views and other xml files are added:
<?xml version="1.0" encoding="UTF-8" ?>
<odoo>

<template id="assets_backend" name="open_academy assets" inherit_id="web.assets_backend">
<xpath expr="." position="inside">
<link rel="stylesheet" type="text/css" href="/ol_custom_with/static/src/css/style.css"/>
</xpath>
</template>

</odoo>