How can I change the Text size in a section?

[NikosBat]

Hello guys, how can I adjust the size of this text?

[Mustafa_Ali]

.slider-mobile-gutter .multicolumn-list__item h3.inline-richtext {
    font-size: 15px !important;
}

Go to online store ----> themes ----> go to three Dots ----> edit code ---->find theme.liquid files ----> place the code ---->
under the tag before the body ----->
if this code work please do not forget to like and mark it solution

[NikosBat]

Hello Mustufaali, thanks for your help!