This template comes with a custom integration of Just Validate plugin. See more about it at https://github.com/horprogs/Just-validate.
This plugin is a lightweight (~4,5kb gzip) form validation in Javascript Vanilla, without dependencies, with customizable rules (including remote validation), customizable messages and customizable submit form with ajax helper.
In this form, I check the following:
Stylesheet switching is done via JavaScript and can cause a blink while page loads. This will not happen in your production code.