The size of the logo is calculated incorrectly.
The original size of my logo: 206x64px
JA Atoms displays the logo with 206x48 pixels
Check:
Site Settings
Put in Logo: logo.png
Unfortunately I did not find out where the image size is calculated. Neither in the template nor in t4 configuration I found a corresponding function
OK Found it!
Wrong CSS In Template!
in Tools ->Edit custom SCSS ->Edit-> Custom Style add:
.navbar-brand.logo-image img {
max-height: 48px;
width:auto
}