Ok, so we need to split the site-description into two HTML elements, to do that requires some PHP.
Add this PHP Snippet to your site:
add_filter( 'generate_site_description_output', function(){
return sprintf(
'<p class="site-description"%1$s>
line one of description
</p>
<p class="site-description"%1$s>
line two of description
</p>
',
'microdata' === generate_get_schema_type() ? ' itemprop="description"' : ''
)
});
change the two lines to your requirements.
Then add this CSS:
/* inline title and 2 descriptions */
.site-branding {
display: flex;
align-items: end;
flex-wrap: wrap;
}
/* Optional Add some space after title */
.main-title {
margin-right: 10px;
}
/* Make it wrap on mobile */
@media(max-width: 768px) {
.site-branding {
max-width: 300px;
}
}
Note the last CSS rule, you can adjust the @media(max-width: 768px) to a screen size when you want the description to wrap, and you will need to adjust the max-width: 300px; to force it to wrap.