Media queries CSS doesn't work for text size

Hello,

I created a slider using slick.js with several call to action modules on the same row.

I first positioned everything from within Divi (button position, text size for desktop, tablet and smartphone screens, margin-top ...). It works fine but when I change the title from H2 (by default) to H3, the margin-top is not working anymore, like it was disables or unrecognized by Divi.

Even if I add some code in the advanced > customize CSS > Tile field, it's not recognized at all.

I need to change the CTA title to H3 because I have a text title above as a H2.

First I added this class to my sole column : h3-header-title

Then I tried to add some CSS media queries code which is :

<style>
@Media all and (min-width: 1627px) {
.h3-header-title .et_pb_promo_description .et_pb_module_header {
margin-top: -100px!important;
}}
@Media all and (min-width: 1405px) and (max-width: 1626px) {
.h3-header-title .et_pb_promo_description .et_pb_module_header {
margin-top: -90px!important;
font-size: 28px!important;
}}
</style>

Here the margin-top is working (it doesn't work if I remove the .et_pb_promo_description), but there is no impact at all on the text size (by default it's set at 38px in Divi for Desktop screen size) !!

I also changes @Media all by @Media only screen without any success.

Thank you for your help.