header: add menu dropdowns and auth-user special menu item

assets/sass/layout.scss

@@ -62,6 +62,7 @@ body {
 }
 
 body > header {
+	z-index: 0;
 	display: flex;
 	flex-direction: row;
 	justify-content: space-between;
@@ -101,6 +102,7 @@ body > header {
 			font-size: 20px;
 
 			li {
+				position: relative;
 				list-style: none;
 
 				a, button {
@@ -140,6 +142,35 @@ body > header {
 					align-items: center;
 					padding: 0;
 				}
+
+				&.auth-user {
+					img {
+						width: 48px;
+						height: 48px;
+						border-radius: 3px;
+						margin-right: 8px;
+					}
+				}
+
+				.dropdown {
+					position: absolute;
+					z-index: -1;
+					top: 100%;
+					right: 0;
+					display: none;
+
+					white-space: nowrap;
+					background: $headerBackground;
+					border-radius: 0 0 3px 3px;
+
+					a {
+						padding: 0 8px;
+					}
+				}
+
+				&:hover .dropdown {
+					display: block;
+				}
 			}
 		}
 
@@ -177,7 +208,7 @@ body > header {
 				}
 			}
 
-			ul {
+			> ul {
 				flex-direction: column;
 				position: absolute;
 				z-index: 10;
@@ -200,6 +231,12 @@ body > header {
 							font-weight: inherit;
 						}
 					}
+
+					.dropdown {
+						position: initial;
+						display: block;
+						padding-left: 32px;
+					}
 				}
 			}
 		}