Change Heading and Subtitle font size on mobile Dawn theme

I like the font size of my website when viewed from a laptop but when viewed on a phone the font size is way to big. Specifically, all of the titles and the subtitle text is very large. The body text looks fine. How do I change the font size of the title and subtitle text only in the mobile version, while keeping the desktop version the same as it currently is?

My website is sisubracelets.us

For context the home page is all title and subtitle text.

The paragraph under “Life in the Hoopa Valley” in the shop page is body text.

@sanjivp27

Could you provide me store URL? I should be able to answer your question.

Yours faithfully!

Hey @sanjivp27 ,
Welcome to the Shopify community!
You can follow the instruction below:
Go to Online Store->Theme->Edit code->base.css->paste bellow code in bottom of file.

@media only screen and (max-width: 680px) {
 .h0 {
    font-size: 5rem !important;
 }
 .subtitle {
  font-size: 2rem !important;
 }
}

If you feel like my answer is helpful, please Like and mark it as a solution**.** Let me know if you have any further questions.
Thank you!
Raman

Thank you very much for the help. However, adding this code didn’t seem to change anything. Any additional help will be appreciated.

store url: sisubracelets.us

Try bellow code.
Go to Online Store->Theme->Edit code->base.css->paste bellow code in bottom of file.

@media only screen and (max-width: 680px) {
 .banner__box > *:first-child {
   font-size: 3rem !important;
 }
.subtitle {
  font-size: 2rem !important;
 }
}