Multiple bug fixes

【Contents of the fix】
■Fixed a bug that CSS may not be applied when accessing a page that is still http (mixed content) when using the CSS code optimization function in an SSL environment.
■【iPhone】Fixed an issue where the Hatena bookmark icon was not displayed on the share button in the fixed footer bar.
■Fixed an issue where the side content buttons may extend beyond the display area on devices with narrow screen widths.

The following are the files that have been fixed in this update.

【Modified file】
css/footer-bar.css
functions/acceleration.php
style.css
template-parts/footer-bar.php

【Added files】
img/common/hatenabookmark-logomark.svg