You need to add a line that specifies ‘line-height’ in the same block you have ‘font-size’ if you want the larger font not to get cut off on the top and bottom. Make it a few pixels bigger than the font so you dont have to specify the spacing separately. I use the glance card for suff like this because you can easily define columns and show/hide title, state, icons.
card_mod:
style: |
ha-card {
border: 2px solid gold !important;
font-size: 50px !important;
}
ha-card .entity {
line-height: 74px;
font-size: 70px;
color: gold;
}