display:block; defined against the description. 'block' comes after 'inline-block' so you're resetting it (inline-block is being overridden)
Also, the width of the <a> is 300px, and the width of the description is also 300px plus 10px extra on each side form padding, so its already wider than its parent element. As I previously advised, the total combined widths of the title and description, plus any paddings/margins, need to be smaller than the parent - if you want them to sit side-by-side, there needs to be room to accommodate them both. This will be more predictable if you set widths on BOTH the title and description - so far there is only a width defined on the description - and set the <a> extra wide for the sake of troubleshooting.
Moderator's Note - If you need more help, please post a link to your actual web page. If you do not wish to post the link to your actual website, you should set up a demo elsewhere on a temporary page that can be deleted afterwards.