Can't upload a csv to SSVC-calc

[sei-renae]

Describe the bug
SSVC gives error "Reading data in file as text failed, Sorry check format and try again" when I try to upload a csv.

To Reproduce

1. Go to https://certcc.github.io/SSVC/ssvc-calc/
2. Click on 'Import tree'
3. Select a csv [ideally one that you know other software can parse]
4. See error

Expected behavior
The upload is successful, and the program shows a decision tree.

Screenshots

Platform details
firefox on macos