Why does coding changes not reflect in mobile view?

Hi, I have made several changes to the code. I want to remove the thin stripes from the borders of the product images and in the images in the descriptions. I also wanted to add a border to the add to cart button. This all works perfectly in the desktop view. However, on mobiles the changes are not visible. It is strange because in the mobile view preview the changes do appear. Please help me.

Hi @danielcorrea

Please add this code at the bottom of your base.css file

.product-form__buttons button.product-form__submit {
    border: 2px solid #131313 !important;
}
.product__accordion .rte img {
    border: unset !important;
}
@media screen and (max-width: 749px) {
.product-media-container.media-fit-cover {
    border: unset !important;
}
}

Not working. Any change on my code affects mobile view. Please help

Try to push code in theme.liquid file before tag to check