refactor the name of css file

_sass/_isabelline.scss

@@ -126,6 +126,8 @@ header {
 	nav {
 		color: $header-color;
 		font-family: $header-serif;
+		font-size: 80%;
+		font-weight: normal;
 		margin: .5em 0;
 		float: right;
 		
@@ -143,7 +145,8 @@ header {
 				&:first-child:before { content: ''; padding-right: 0; }
 
 				a {
-					&, &:hover, &:active, &:visited {
+					&:hover { text-decoration: underline; }
+					&, &:active, &:visited {
 						text-decoration: none;
 						color: darken($header-link-color,20%);
 					}