Multiple bug fixes

【Contents of the fix】
■Fixed a bug that caused an error when installing or posting in some environments.
■Fixed a bug that in some environments, the first two lines of the output HTML may contain blank lines.
■Fixed a bug in the fixed page template “RECRUIT” where the second body text of content 1 was overwritten by the first when saving.
■Fixed an issue where the footer logo (for mobile) would not reflect the image/text switch.
■Fixed a bug in the fixed page template “ABOUT” where the background image (for mobile) was set, but the background for PC was displayed when viewed on a smartphone.

The following files have been modified for this update.
【Corrected files】
css/responsive.css
functions/loading_script.php
functions/page_design3.php
js/parallax.js
style.css