Create mixins for reusuable landing page elements like iframe and gallery

src/styles/_cards.sass

@@ -1,10 +1,6 @@
 .container.card-container
 	max-width: 1200px
 	margin-top: 56px
-  // pending media query decision
-	// .col-md-4
-	// 	+media-breakpoint-up(lg)
-	// 		padding: 0 20px
 	.col-md-4
 		padding: 0 20px
 		&:focus

src/styles/_gallery.sass

@@ -0,0 +1,9 @@
+.gallery
+  h2
+    margin-bottom: 40px
+  .container
+    max-width: 1190px
+    .col-sm-3
+      padding: 0 20px 40px
+    img
+      width: 100%

src/styles/_iframe.sass

@@ -0,0 +1,13 @@
+.iframe-container
+  position: relative
+  padding-top: 25px
+  padding-bottom: 52%
+  height: 0
+  margin-top: 16px
+  margin-bottom: 32px
+  iframe
+    position: absolute
+    top: 0
+    left: 0
+    width: 100%
+    height: 100%

src/styles/project-landing.sass

@@ -4,6 +4,8 @@
 @import ../styles/navbar
 @import ../styles/jumbotron
 @import ../styles/navbar-secondary
+@import ../styles/iframe
+@import ../styles/gallery
 @import ../styles/cards
 @import ../styles/footer
 
@@ -12,32 +14,10 @@
 .node-details-title
   &.container
     max-width: 730px
-.iframe-container
-  position: relative
-  padding-top: 25px
-  padding-bottom: 52%
-  height: 0
-  margin-top: 16px
-  margin-bottom: 32px
-  iframe
-    position: absolute
-    top: 0
-    left: 0
-    width: 100%
-    height: 100%
 section
   margin-top: 152px
   &:first-child
     margin-top: 0
-.gallery
-  h2
-    margin-bottom: 40px
-  .container
-    max-width: 1190px
-    .col-sm-3
-      padding: 0 20px 40px
-    img
-      width: 100%
 .node-extra
   h2
     margin-bottom: 40px