The code looks quite decent to me.
I would recommend to use an external style sheet instead of styling internal (style tag in head) and inline (style attribute on elements, for instance line 50).
Visit
w3schools to find out how to add an external stylesheet in HTML this is also a great resource to find other things about HTML5 and CSS3.
Also spaces in filenames can be unsafe, these spaces arent allowed in an URL because they are unsafe characters.
See the accepted answer
here for more information.
There is however a mechanism to allow these unsafe characters in an URl this is called
URL encoding these spaces are then encoded in the URL with %20.
All unsafe characters begin with a % sign followed by the heximal code from that character in the
ASCII table, abbreviation hx on that site.
In brief, spaces are allowed in URLs but are unsafe and should be avoided.
You can find out which filenames contains these unsafe spaces by using a validator as mentioned above, this also generates a warning which is worth to solve.
Finally im not quite sure if the quotes around PC in line 19 are allowed, these are after all reserved characters in HTML, it's probably better to use
HTML entities for that.