Hi
Best way to understand inline style is that there is a hierarchy to CSS and three types. External, Internal and inline.
CSS stand for Cascading Style Sheet and it may be used externally or internall or inline. It tells the HTML how to behave. The closer the CSS is to the tags the more precedent it has. inline trumps all but is the least efficient.
External CSS is in a separate place than the web page. It is merely linked to your web page on an "external" file.
Internal CSS is place on the web page between the <style></style> tags
Inline styling in placed directly in the HTML tag itself.
Hope this clarifies