I bet you are using a relative path for your css include
instead of a root path. So if you have the following in your
http://localhost/demo/index.cfm
<link href="../styles/main.css" rel="stylesheet"
type="text/css" />
then it will look in the next folder up for a folder called
styles with a file called main.css
If you have the same line of code in
http://localhost/demo/index.cfm/about-our-company
then it will look for a folder in the root called demo with a
folder in called index.cfm with a folder in called styles with a
file in called main.css.
To solve this you need to reference your style sheet as
follows:-
<link href="/styles/main.css" rel="stylesheet"
type="text/css" />
Notice how the href begins with a forward slash (/) this
means to always access it from the webroot. You will need to do
this for all your internal links as well because they will not
work, this means links and image references the works.
HTH