The theme sets the fonts and button style for a whole landing page, so every section looks like your brand without styling each one.
Change the theme

- Go to Landing pages → All landing pages and open a page.
- On the Design tab, click Theme in the top bar.
- Under Typography, pick fonts for Titles, Body and Buttons.
- Under Button style, set the Fill and Text colors and the corner Radius. The Preview shows the result.
- Switch between the desktop and phone icons to check both layouts.
Changes save automatically. Sections with their own styling keep it.