I am working through the following Trailhead and setting up Salesforce DX for the first time.
https://trailhead.salesforce.com/trails/sfdx_get_started/projects/quick-start-salesforce-dx/steps/set-up-your-salesforce-dx-environment

sfdx is installed on Mac.  sfdx --version returns: sfdx-cli/6.1.19-4341549 (darwin-x64) node-v8.9.4

When I attempt to login to the dev hub I am presented with a blank Google Chrome screen.  No URL.  Just a blank screen.
sfdx force:auth:web:login -d -a DevHub

Other posts suggested using:
- sfdx force:auth:web:login -h (-h is not valid)
- sfdx force:auth:web:login (same blank screen displayed)

Any help is appreciated.