So just change you child theme css and it should work.
I make description visible and little bit smaller so it will fit in.
display: block – this element you don’t need there.
.site-description {
font-size: 1.3rem;
}
From this element you can take out this
.site-title {
display: inline-block;
float: left;
}
.site-branding {
display: inline-block;
}
.header-wrapper {
display: block;
width: 49%;
}
Hope it will help.