Increase space between "by" in the "last updated" section.

Hello,

I'm using a code snippet to display the "last updated" date instead of the "posted on" date. I have the author name listed next to it, but there's no space between the date and the "by author name" section. I'm sure there's just a space I'm missing in the code. Can someone assist?

Here is the code snippet I'm using:

add_filter( 'generate_post_date_output', function( $output, $time_string ) {
printf( '<span class="posted-on">%s</span>',
$time_string
);
}, 10, 2 );

And here is the CSS I'm using:

}
.posted-on .updated {
display: inline-block;
}
.posted-on .updated:before {
content: "Last Updated: ";
}
time.entry-date.published {
display: none;
}