"Why only my friend's PC doesn't change CSS " ~Real story on my project~

  I fixed CSS and it was good in my local environment, but in test environment(AWS) doesn't change anything  aha  could you check it on your PC?  sure .... tadaaam css is changed on my PC  what?? yeah exactly...  Have you tried deleting cache?  Yeah, I've tried it at first  hmm... could you try to use incognito chrome?  Just moment ... it turns out same result...  on incognito chrome as well ??? Maybe CDN cache??  How can I check it ?  chrome devtool > Network > Headers > X-cacheI see I get css file from CDN(AWS cloudfront)

  and age means the time when this file was created.so I get file which is created 118 seconds ago on CDN

  How is it on your PC?  age is 279313, so almost 3days ago ! this is the reason !!