Created index.html
I put it in one folder together with the CSS folder and image folder, compressed it, and sent it.
When you open index.html in the confirmation destination Chrome
CSS isn't working at all.

However, when I checked index.html, it was also a link with the CSS sent in the same file, and on the sender side, the CSS was firmly applied to both Chrome and Safari, with changes and the overall view.

What is the cause?