I was also running into this issue as well and I've tried a lot of things people recommended yet nothing worked. However I finally found a way to fix it!
Under the asset you'll see a "add new asset" you want to click on that then chose "create a blank file" then there should be a drop down menu box that allows you to chose ".scss.liquid" after that in the box to the right type in "theme" (don't include the quotation marks) and then click "add asset." After that it should be blank, now you want to copy and paste the raw code for the "theme.scss.liquid" that I found. The link to the code is raw.githubusercontent.com/Shopify/shopify-css-important/master/assets/theme.scss.liquid
Once you copy and paste everything save it on shopify and you should be good.Hopefully this helps!
Fair enough, but what I wanted to know or at least understand is why I do not have<theme.css.liquid> in my Assets folder. Clearly, other people using the latest version of the Debut theme can find this file. Am I experiencing a bug? I am sure others, who don't have any experience in CSS might have the same issue and would benefit from having a clear explanation. Anyway, thanks again @Alett_Lewis.
Starting recently new versions of shopify theme will not have SASS based css files.
Even if you download a new version from the theme store if the liquid, or sass, version of theme.css still doesn't exist then most likely that theme has been converted to no longer use the .scss.liquid version as part of Shopify's depreciation of the SASS language in favor of a modern CSS standard workflow.
Which means alot of posts dealing with those files types are now badly outdated.
What is the solution to adjust the background and menu heading colours on the main header banner in the new version of Debut using the CSS version? I created my store on 26-Dec-2020 and I don't have the SCSS asset files so I am most likely on the newer platform. Any help would be appreciated.
I liked your idea and created a new file theme.css.Liquid and trying to get the code through the link you have provided, but can not access it.
Please give me access to the code or share code with me.
This may not be 100% correct, but I think the .css format is overall faster than the .scss.liquid format. I'm guessing the "theme.css" is a more compressed version of "theme.scss.liquid". I had this same issue of not being able to find the "theme.scss.liquid", but did some experimenting and found this out.
Hope this helped,