Fix #67.

assets/styles/layouts/_page-catalog.scss

@@ -190,7 +190,7 @@ fieldset {
   }
 }
 
-@media #{$breakpoint-tablet-and-up} {
+@media #{$breakpoint-medium} {
   .filter-sort {
     width: calc(100% - 1rem);
     height: 7rem;
@@ -249,27 +249,18 @@ fieldset {
 
 @media #{$breakpoint-large} {
   .catalog #content {
-    width: 100%;
-    max-width: rem(1440);
-    background: transparent;
-  }
-
-  .catalog .book {
-    max-width: calc(100% / 3 - 1rem);
-  }
-}
-
-@media #{$breakpoint-extra-large} {
-  .catalog #content {
-    width: 100%;
+    width: calc(100% - 1rem);
+    margin-left: auto;
+    margin-right: auto;
     max-width: rem(1650);
+    background: transparent;
   }
 
   .filter-sort {
-    width: calc(25% - 1rem);
+    width: calc(25% - 2rem);
     height: auto;
     float: left;
-    margin-left: 0;
+    margin: 2rem 1rem 1rem;
   }
 
   fieldset {
@@ -294,6 +285,12 @@ fieldset {
     margin-left: 0;
   }
 
+  .catalog .book {
+    height: 16.25rem;
+    max-width: calc(100% / 3 - 1rem);
+    margin: 0 1rem 1rem 0;
+  }
+
   .catalog-navigation {
     width: 75%;
     float: right;

dist/mix-manifest.json

@@ -1,6 +1,6 @@
 {
     "/scripts/aldine.js": "/scripts/aldine.js?id=1f58027f7de9942caf57",
-    "/styles/aldine.css": "/styles/aldine.css?id=23585277fc9935ca45bb",
+    "/styles/aldine.css": "/styles/aldine.css?id=f0727f4a9964728b106e",
     "/styles/editor.css": "/styles/editor.css?id=d96762ab5918cde0c2e1",
     "/scripts/customizer.js": "/scripts/customizer.js?id=1b0d3cfc1d85f460af53",
     "/scripts/catalog-admin.js": "/scripts/catalog-admin.js?id=d25f1240496bd3607338"

page-catalog.php

@@ -26,9 +26,9 @@ $available_licenses = get_available_licenses( $catalog_data );
 $subjects = ( defined( 'PB_PLUGIN_VERSION' ) ) ? \Pressbooks\Metadata\get_thema_subjects() : [];
 $available_subjects = get_available_subjects( $catalog_data );
 
-if ( ! empty( $catalog_data['books'] ) ) : ?>
+if ( ! empty( $catalog_data['books'] ) ) :
 
-get_header(); ?>
+	get_header(); ?>
 
 	<div id="primary" class="content-area">
 		<main id="main" class="site-main">