head of each document, there would be no centralized location to make your changes and you’d have to search for all the various rules across multiple locations. See Placing Styles and Scripts Directly in a Document for more information.
The following shows where to place our links to our external script file(s) and CSS file(s). Typically this is done directly after the
title tag, but could be placed anywhere in the
head of the document.
Advanced HTML Template
link tag is used to link to external style sheets. The type attribute tells the browser what kind of document to expect and the href attribute is the target URL for where the document lives.
Non-crucial scripts can be placed just before the closing
/body tag which can speed up the page load time because the page can first render before applying the scripts.