Before you get too far down the design path on this site, I'd recommend doing some reading up on Responsive Design techniques. I realise that the site is at an early stage, but it already fails Google's
Mobile Friendly Test. This means it'll get downranked for searches made from mobile devices.
With Responsive Design you build 'mobile first' so that the site displays nicely on mobile devices and scales up for desktop, with images and layout adapting depending on the device or screen resolution. There's lots and lots of guides out there on responsive design, have a Google.
You also don't have to build from scratch, there's a wide range of free responsive design frameworks available to get you started and which take some of the headache out of it. However, some of the more popular ones such as Bootstrap and Foundation can get a bit bloated unless you download a custom version with the bits you don't need stripped out. There's plenty of alternative lightweight frameworks too. There's a list
here which whilst not exhaustive lists the main ones.