Following are the ways in which you can customize your poll, quiz, survey or form.
Color Theme & Font
You can customize the color theme and font of your item from the look & feel settings section.
In case you do not find a color theme or font that fits your need from the list, you can set your own color theme and font using the css override feature detailed below.
You can set to add your brand logo to all the items created in your account.
See this article for more details.
You can set to remove the "Powered by Opinion Stage" logo from your items by setting the "Remove Opinion Stage branding" checkbox in the look & feel settings.
You can configure almost every design aspect of your item including colors, font, sizes, margins and more using the css override feature. See this article for the full detail.