We built it using Webflow (an amazing YC company!) and used the Timber template as the foundation: https://webflow.com/templates/html/timber-ui-kit-website-tem...
One thing we strived for during the design phase was to make it feel like a tool you would want to use. From the colors to the bold fonts and large screenshots. I personally was inspired by what Stripe and Slack did, take a traditionally "unsexy" space and aim to make it "sexy".