.logo {
display: flex;
place-items: center;
gap: .5ch;
font-size: 20vmin;
}
.logo > img {
max-block-size: 1.25em;
}
logo img height is 125% of a responsive font-size (20vmin) letter M.. relative units are so cool!
https://codepen.io/argyleink/pen/VwaQGxB