Include your css with the following statement.
<head>
<link rel="stylesheet" type="text/css" href="../css/abc.css">
</head>
"../css/abc.css" is a relative path.
"../" represents one directory up. i.e., Login.jsp is in "jsp" directory "../" will make the directory as "Webcontent"
"../css" will traverse you upto "css" directory in the "Webcontent".
"../css/abc.css" will give the abc.css file.