You can customize an embed form by selecting different colours for text and background and even changing the design of the button that matches your website's UI.
You can customise the following:
Button Design
Shape
Outline Colour
Fill Colour
Text Colour
Page Header
Background Colour
Page Background
Background Colour
Thank you page
Background Colour
Headline
Text Colour
Fields
Text Colour
Steps to Customise an embed form
Enable the Referral form for your organisation Turn on Referral Links
Click on My Apps and select Contact
Select the organisation on the Manage Contact page if you are part of multiple organisations.
Click on More Options and select Public forms(Referrals).
You arrive on the Manage Public Forms page, create a New Public form or if you already have a public Form select Look & Feel.
You arrive on Edit Look & Feel, make changes by selecting colours and designs for your embed form.
Once you are done scroll down and press Save
Now copy the link for the embed form.
Once you have added the embed code to your website, you will be able to view the customised form on your webpage.