Building theme without LESS

I have a working html mockup of how I want a site to look complete with CSS etc.
Is there a way forward with just referenciing the 2 css files used in a new theme or does it absolutely have to be broken out into the relevant LESS files.

you can create a new custom css file. add into header file. then you can start your hml/css conversion.

Yes davemcl, you just need to add to your custom theme the reference to the css file in default_head_blocks.xml, there is no need to call them LESS.

Here are my notes from exactly how I did it on one of my Magento 2.4.1 websites. Assuming you have created a custom VENDOR/THEME already…

  1. Create app/design/frontend/VENDOR/THEME/Magento_Theme/layout/default_head_blocks.xml
    with this code…
<page xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:View/Layout/etc/page_configuration.xsd">
    <head>
        <css src="css/MYCUSTOMCSS.css" rel="stylesheet" type="text/css"  />
    </head>
</page>

2 Create /app/design/frontend/VENDOR/THEME/web/css/MYCUSTOMCSS.css

Magento reference is here…