Web Development Question for iPhone 13 Pro Media Query

I have a portfolio website that I'm working on improving, but I'm trying to make the font size on my website render in a larger typesize for a particular media query: @media all and (min-width: 390px) and (max-width: 484.9px). This is for the viewport size of the iPhone 13 Pro (390 px wide viewport), which is what I have as a device to test the website on. I know this is the correct viewport size for the iPhone 13 Pro according to https://whatismyviewport.com. Whenever I try to make changes to the font in this media query and re-post the website though, though, the changes are not visible on my iPhone screen. The changes are visible, however, on my 4th gen. iPad Pro when I make changes to the font size on the media query that corresponds with that device's viewport width: @media all and (min-width: 1200px) and (max-width: 1427.9px). They are also visible on my laptop screen when I resize the browser window to be 390 px by right-clicking, going to Inspect (on Microsoft Edge), and clicking and dragging the browser window to the left.

Just to be clear, I've tried:

-Looking for typos in my code and missing characters

-Clearing search history, cache, and cookies on my iPhone 13 Pro on three different browsers

-Clearing search history, cache, and cookies on my laptop's browser

-Rebooting my phone

-Including !important after the font size in the external stylesheet file for the 399px media query

-Testing another attribute besides font size to see if any changes made in the media query are visible (i.e. font color). This was also not visible in the media query corresponding to the iPhone 13 Pro's viewport width, but was visible in the media query corresponding to the 4th gen. iPad Pro's viewport width.

I use Adobe Dreamweaver 2021 to develop my website.

Help with this would be much appreciated!