I also have Raspberry Pi, but i can't log in on Chromium v65.0.3325.181 on, because of an unknown error.
Items required: Raspberry Pi, HDMI monitor, USB mouse, USB keyboard, micro USB charger
Steps to reproduce:
Connect monitor, keyboard, mouse and charger to Raspberry pi
Power on charger and monitor
Open Chromium 65.0.3325.181
Go to snap.berkeley.edu
Click "Log in"
Type in account name and password correctly
Actual results: "Join" and "Log in" buttons remain as user is not logged in
Correct results: User name appears on top bar
When I have problems like that (not on Snap!), in which I click on something and just get the same page back, it's because one of my browser extensions, NoScript or something, has prevented the Javascript behind the button I clicked from running. I don't have access to a Pi, so I can't experiment myself. Can you try starting your browser with extensions turned off and see if it still fails?