Fixed multiple bugs

【Contents of the fix】
■Fixed a bug where images could not be trimmed in the media library.
■Fixed a bug where the background color of the header bar settings> color settings2 was not reflected.
■Changed specifications of header content settings for smartphones.

【Modified file】
admin/inc/front_page_mobile.php
admin/inc/options.php
admin/js/my_script.js
functions.php
functions/head.php
functions/loading_script.php
functions/menu.php
header.php
languages/ja.mo
languages/ja.po
style.css