Overview
If you want to change the font size of specific text elements in your cart (such as upsell titles or variant options), you can do so using Upcart’s built-in Custom CSS editor.
Step 1: Inspect the element
Open your storefront and launch the Upcart drawer.
Right-click on the element whose font size you want to change.
Choose Inspect from your browser’s context menu to open the Developer Tools.
Locate the element’s class name in the HTML panel.
Example:upcart-item-option
Step 2: Access the custom CSS editor
Go to Shopify Admin > Apps > Upcart
Open the Cart Editor
Click on Settings
Find the Custom CSS section
Step 3: Write your custom CSS
In the CSS input field:
Start with a period (
.) followed by the class nameAdd
{ font-size: 14px !important; }(or your desired size)
Example:
.upcart-item-option { font-size: 14px !important; }Use !important to make sure your rule overrides Upcart’s default styles.
Step 4: Save and test
Click Save in the Cart Editor
Refresh your storefront page
Open the cart drawer and confirm the font size has updated
If the text hasn't changed, double-check the class name or use the browser’s Inspect tool again to confirm you’re targeting the correct element.