Leave a Reply on same line as date

The CSS below might work.

If your theme provides a way to enter custom CSS, use that. Otherwise, you should create a Child theme or use a CSS plugin such as Simple Custom CSS to make your changes. If you do not, all of your changes will be lost if you update your theme.

You can test this by adding it to the end of your theme’s style.css, but to make it permanent, you should do as suggested above:

#content .comments-link {
    position: absolute;
    bottom: 3em;
    right: 0;
}