Fixed bugs when viewing on a smartphone

【Contents of the fix】
■Fixed a bug that unnecessary descriptions were sometimes displayed in the footer section when viewed from a smartphone.
■Fixed the z-index of the menu when viewed from a smartphone.

The following are the files that have been modified for this update.
【Corrected files】
functions/seo.php
agent.css
style.css

For more information, please visit the AGENT (tcd033) download site for purchasers.