added source file headers to all css files

index.html

@@ -1,6 +1,7 @@
 <!DOCTYPE html>
 <html lang="en">
 <head>
+    <meta NAME="author" CONTENT="Lukas Heiligenbrunner">
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>Lukas Heiligenbrunner</title>