feat: New bound class io

This is a change of paradigm!

- Add io class bound to header element

elements/_sections.scss

@@ -180,6 +180,31 @@ header {}
 	}
 }
 
+header.io {
+	z-index: map.get($z-indexes, "content-top");
+	padding: $space_basic;
+
+	h1 {
+		margin: 0;
+	}
+
+	input {
+		@extend .input_io;
+	}
+
+	textarea {
+		@extend .io_textarea;
+	}
+
+	select {
+		@extend .io_select;
+	}
+
+	button {
+		@extend .button_io;
+	}
+}
+
 // Footer
 // -----------------------------------------------------------------------------
 footer {}