Remove unused site header properties for week 1 exercises

Author: NateWr

css/week1.css

@@ -31,9 +31,6 @@ html {
 
 /* Site title and top navigation */
 .site-header {
-	display: flex;
-	justify-content: space-between;
-	align-items: center;
 	padding: 0.5rem 1rem;
 	color: rgba(255,255,255,0.9);
 	background: #4491db;