This page has a collection of CSS tweaks for the WP Express Checkout plugin.
The CSS tweaks can be added to the following interface of your site (without modifying the plugin’s code).
Appearance -> Customize -> Additional CSS
Customize the Buy Now Button
This tutorial has some tips for customizing the Buy Now button of the WP Express Checkout plugin.
Customize the Apply Coupon/Discount Button
The example below illustrates how CSS modifications can be applied to personalize the apply coupon button’s appearance. You are free to use any color of your preference.

Add the following CSS code to customize the apply coupon button with a transparent background, black border color, black text, and a “grey background on hover” effect:
.wpec_coupon_apply_btn{ background-color: #FFF; background-image: none; border-color: #000; color: #000; } .wpec_coupon_apply_btn:hover{ background-color: #DDD; background-image: none; border-color: #000; color: #000; }
Add the following CSS code to set the button’s font size to 20px.
.wpec_coupon_apply_btn{ font-size: 20px; }
Template 1 Product Display
The following CSS tweaks are for the template 1 product display shortcode.
Template 1 – Bigger Thumbnail Image
Add the following CSS code to set the thumbnail image width to 100px and the height to auto adjust.
.wpec-product-item-thumbnail img { width: 100px; height: auto; }
Template 1 – Larger Font for the Product Name
Add the following CSS code to set the font-size of product name to 36px
.wpec-product-name a { font-size: 36px; }
Template 1 – Larger Font for the Product Description
Add the following CSS code to set the font-size of product description to 20px
.wpec-product-description{ font-size: 20px; }
Template 1 – Adding a Background Color
Add the following CSS code to use a lightgrey background color to the template 1 product display:
.wpec-product-item{ background-color: lightgrey; }