Hueman Child Theme

Hello, this is just a general question. I’m already using the Hueman child theme and I downloaded it from the official site (https://alxmedia.se/themes/hueman/). I’m just wondering if I need to modify anything on the functions.php and style.css files or is it good as it is? What I mean is would it change any major style of function on the parent theme (such as mobile friendliness of the site)? I noticed that the style.css file on the child theme has this:
/* Global */
.mystyle {}
/* Tablet – 800px, 768px & 720px */
@media only screen and (min-width: 720px) and (max-width: 800px) {
.mystyle {}
}
/* Mobile – 480px & 320px */
@media only screen and (max-width: 719px) {
.mystyle {}
}
/* Mobile – 320px */
@media only screen and (max-width: 479px) {
.mystyle {}
}

Thank you.