Those are just some variables I’m storing values in. This example is showing you how to change the CSS attributes of your HTML template using Python only
Here’s a hint: lets say the element that you’re trying to change is called .anvil-root-container. Colour and transparency are two separate attributes in CSS, I’ve already shown you show to change the colour with document.getElementById('anvil-root-container').style.background, which needs to be a hex colour code, formatted as a str, you can try using print(dir(document.getElementById('anvil-root-container').style)) to help you try and find the attribute related to transparency