https://react.semantic-ui.com/ shows a white page after loading, tested in Chrome and Firefox.
I see the same thing. Here's an animated GIF showing my browser window as I reload the page:

I think one of the URLs the docs website is using is missing a period (.) character.
Here's a screenshot showing the URL according to CDNJS (top) and the URL the docs website is using (bottom):

Same here
I think I found the line containing the bug. I think the new line 72 here is missing the period:
https://github.com/Semantic-Org/Semantic-UI-React/commit/470c7b50310e84b5849207febd0a340de682dc9b#diff-ca761db59bf3bc241d74bbbe4b51c0a2
I'll submit a PR with a fix in 5 mins.
Here's the workaround I'm using to view the docs website while the issue persists:
top>react.semantic-ui.com>(index) file.In the DevTools panel, click the "Console" tab and run the following commands:
var script = document.createElement('script'); script.type = 'text/javascript'; script.src = 'https://cdnjs.cloudflare.com/ajax/libs/prop-types/15.5.10/prop-types.min.js'; document.head.appendChild(script);
In the DevTools panel, click the "Sources" tab and click the Play/Pause icon to resume execution. The docs website will load normally.
Here's a depiction of the above instructions:

nice ty @gitname ! ;)
Its still showing the same error.
This was a good opportunity to build the docs locally.
git clone https://github.com/Semantic-Org/Semantic-UI-React.git
cd Semantic-UI-React
yarn install
yarn run docs
Then open http://localhost:8080.
I set up a mirror on my own server temporarily:
http://sur.lt-lab.cc

thanks @lightning-zgc
Most helpful comment
:construction: Workaround in Google Chrome :construction:
Here's the workaround I'm using to view the docs website while the issue persists:
top>react.semantic-ui.com>(index)file.In the DevTools panel, click the "Console" tab and run the following commands:
In the DevTools panel, click the "Sources" tab and click the Play/Pause icon to resume execution. The docs website will load normally.
Here's a depiction of the above instructions: