The set of files that defines how a WordPress, PrestaShop or other CMS site looks: layout, colours, fonts, pages.
What it is
The theme is the site's outfit. Content and features live in the CMS, while the theme decides how they look. It used to be called a template.
Ready-made or custom?
A ready-made theme is quick and cheap, but it brings limits and often extra code that slows the site down. A custom theme is designed for the specific business and its needs.
What we watch for
Speed, mobile layout, accessibility and the ability to update it without losing changes.