Hey there, @Alex155
Bo here from Shopify Support!
This tutorial is specific to an unedited version of the Venture theme, (VERSION 9.7.4). We cannot guarantee results for themes that have been modified with custom coding and/or apps. We suggest hiring a Shopify Expert if you are not comfortable proceeding with the following tutorial, or wish to make any variations to this tutorial.
NB When editing the CSS of your theme it is always a good idea to duplicate your theme first and making the changes on the duplicate. This will prevent any errors from occurring on your live site. We also recommend adding CSS to the bottom of the file as opposed to altering the preexisting code. The new code will overwrite the previous code.
If this is something you are not comfortable with doing, you do have some design time with our themes team with a paid plan. You can reach out to our support team directly about this.
Let me know how this goes and if there is anything else I can assist you with, I'm happy to help!
All the Best,