Yes, you can.
In the page editor, click the plus icon on the left to open the list of sections you can add. In that menu, you’ll find a Custom section.
Add the Custom section to your page, then click 'Add content'. 
Among the content options, choose Embed. This allows you to add:
Custom HTML and CSS
YouTube videos, Calendly calendars, and any other scripts or embed codes
If LandingRabbit doesn’t yet support a specific layout you need, the embed option is a quick way to add exactly what you want to your page.
If you’d like assistance creating something custom, feel free to reach out to us at [email protected]. We’re happy to help.