Mobile styles not sticking?

My code is working on the preview in Squarespace, but not populating in live view on my phone. Here's my code:

@media screen and (max-width: 640px) {
  #block-63164f6dd76fe71b6ab8b17e h1{
    font-size:50px;
	hyphens:none !important;  
  }
}

Any help appreciated! Thanks

27 minutes ago, kc2615 said:

My code is working on the preview in Squarespace, but not populating in live view on my phone.

Your phone may have a wider viewport than the 640 pixels specified in the code. Try using a wider higher number like 768px or 800px to see if this works.

4 minutes ago, paul2009 said:

Your phone may have a wider viewport than the 640 pixels specified in the code. Try using a wider higher number like 768px or 800px to see if this works.

even when I do it without mobile styles at all, it still appears hyphenated on mobile

#block-63164f6dd76fe71b6ab8b17e h1{
    hyphens:none !important;
  }

@paul2009 that fixed it! Thank you