Custom HTML code is typically used to adjust the design of the control panel or add additional features such as a live chat widget.
You should never use this component to add an custom messages or notices to the control panel, since this may break the display or function of the MediaCP interface. Such notices should be added as Announcements instead.
The HTML stored in these fields is stored on the file system in /usr/local/mediacp/content in either the header.html or footer.html files. It is safe to delete these files.
In the case where changes have broken the display of the MediaCP, and you are unable to access the System Config page; it is possible to revert the changes simply by deleting the Custom HTML files stored in /usr/local/mediacp/content/header.html and /usr/local/mediacp/content/footer.html
HTML here is placed before the <body> element, which is ideal for adding additional styling such as a <style> element.
Adding custom styles
It is possible to apply custom styles to the control panel by using the normal <style> html element. Example below: