prevent long menus from dropping to the next line

spearhead/assets/sass/_header.scss

@@ -44,6 +44,7 @@ $site-branding-height: 68px;
 	}
 
 	.site-branding {
+		flex-basis: 30%;
 		flex-grow: 1;
 		text-align: left;
 
@@ -64,6 +65,7 @@ $site-branding-height: 68px;
 	}
 
 	.primary-navigation {
+		flex-basis: 70%;
 		flex-grow: 4;
 		margin-top: 0;
 

spearhead/style-rtl.css

@@ -252,6 +252,7 @@ Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-me
 }
 
 .site-header .site-branding {
+	flex-basis: 30%;
 	flex-grow: 1;
 	text-align: right;
 }
@@ -272,6 +273,7 @@ Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-me
 }
 
 .site-header .primary-navigation {
+	flex-basis: 70%;
 	flex-grow: 4;
 	margin-top: 0;
 }

spearhead/style.css

@@ -252,6 +252,7 @@ Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-me
 }
 
 .site-header .site-branding {
+	flex-basis: 30%;
 	flex-grow: 1;
 	text-align: left;
 }
@@ -272,6 +273,7 @@ Tags: one-column, flexible-header, accessibility-ready, custom-colors, custom-me
 }
 
 .site-header .primary-navigation {
+	flex-basis: 70%;
 	flex-grow: 4;
 	margin-top: 0;
 }