Hi homeproav,
There are many ways to accomplish this, and this falls outside of the scope of support, but I'll point you in the right direction. If you are having issues with this, we won’t be able to help as we can only troubleshoot if there are errors with the code generated. The simplest way would be to use CSS, so that you can define the styles once for the entire page. There are many free resources available online which can help you with the CSS.
If you take a look at the HTML source generated by Method, you can see how the page is organized into the different tags. You will have to identify which tags to apply formatting to, and which properties to modify. Then, you can add the CSS in between the page's <head> ... </head> tags. For example, this CSS seems to accomplish what you are trying to achieve:
<style type="text/css">
form
{
font-family: Arial, Helvetica, sans-serif;
}
h2, h3, h4, table
{
color: white;
}
</style>
Please keep in mind that CSS is a very broad area so this might take some tweaking, especially if you are embedding the Leads form into an existing page on your website. Good luck!
-Russell