redefined header sizes, please chang in wp from h3 -> h4

sass/base/typography/_headings.scss

@@ -40,9 +40,10 @@
 		font-size: $font__size-body*2.5;
 	}
 	h3 {
-		font-size: $font__size-body*1.9;
+		font-size: $font__size-body*2;
 	}
 	h4 {
+		font-family: $font__black;
 		font-size: $font__size-body*1.7;
 	}
 	h5 {

sass/components/navigation/_navigation.scss

@@ -208,12 +208,12 @@
 			display: inline-block;
 			content: "";
 			position: absolute;
-			left: 20%;
+			left: 5%;
 			min-height: 2px;
 			height: 100%;
-			width: 60%;
+			width: 90%;
 			margin-top: 2.3em;
-			border-bottom: 2px solid $color__black;
+			border-bottom: 0.3rem solid $color__black;
 		}
 	}
 	.secondary-navigation {

sass/layouts/_no-sidebar.scss

@@ -27,6 +27,11 @@
 				align-items: center;
 			}
 		}
+		.site-main {
+			h1,h2,h3,h4,h5,h6,.entry-content {
+				margin:0;
+			}
+		}
 	}
 }
 @media screen and (min-width: 48em) {

style.css

@@ -437,9 +437,10 @@ textarea {
 		font-size: 2.5rem;
 	}
 	h3 {
-		font-size: 1.9rem;
+		font-size: 2rem;
 	}
 	h4 {
+		font-family: "din-black", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
 		font-size: 1.7rem;
 	}
 	h5 {
@@ -755,6 +756,9 @@ textarea {
 		flex-flow: column;
 		align-items: center;
 	}
+	.no-sidebar .site-main h1, .no-sidebar .site-main h2, .no-sidebar .site-main h3, .no-sidebar .site-main h4, .no-sidebar .site-main h5, .no-sidebar .site-main h6, .no-sidebar .site-main .entry-content {
+		margin: 0;
+	}
 }
 
 @media screen and (min-width: 48em) {
@@ -964,12 +968,12 @@ textarea {
 		display: inline-block;
 		content: "";
 		position: absolute;
-		left: 20%;
+		left: 5%;
 		min-height: 2px;
 		height: 100%;
-		width: 60%;
+		width: 90%;
 		margin-top: 2.3em;
-		border-bottom: 2px solid #000;
+		border-bottom: 0.3rem solid #000;
 	}
 	.secondary-navigation {
 		padding: 1.5em 0;