How to increase logo size? (Persona_free theme)

Hi all.

I’ve got a new site live at leadnurturing.email and even though I have uploaded (and tested) 2 different logo sizes (250x250px & 500x500px), it’s still showing it massively shrunken down to 69×69. I want it to show up bigger (at least 150x150px) if possible.

I realise I need to modify the css to change this, but my coding skills in this dept are almost zero.

Can anyone please help with with a code example to fix this?

Here’s the code from the main.css if it helps. If it doesn’t, pls let me know what css file you need:

.header {
-webkit-box-align: center;
-ms-flex-align: center;
align-items: center;
display: -webkit-box;
display: -ms-flexbox;
display: flex;
height: var(–navbar-height);
margin-top: 2rem;
max-width: var(–page-width);
position: relative;
}
@media all and (min-width: 80.0625em) and (min-height: 50em) {
.header {
margin-top: 3rem;
}
}

.logo {
-webkit-box-ordinal-group: 2;
-ms-flex-order: 1;
order: 1;
color: var(–dark) !important;
font-family: var(–font-logo);
font-weight: var(–font-weight-bold);
font-size: 2rem;
line-height: 1;
margin-right: auto;
white-space: nowrap;
}
@media all and (max-width: 74.9375em) {
.logo {
text-align: center;
}
}
.logo > img {
max-height: 4rem;
padding: 0.5rem 0;
width: auto;
}