diff --git a/core/themes/seven/css/components/entity-meta.css b/core/themes/seven/css/components/entity-meta.css
index 9877ec3..2b5aefb 100644
--- a/core/themes/seven/css/components/entity-meta.css
+++ b/core/themes/seven/css/components/entity-meta.css
@@ -1,4 +1,4 @@
-/**
+  /**
  * Entity meta settings.
  */
 .entity-meta {
@@ -57,3 +57,21 @@
 .entity-meta details .summary {
  display: none; /* Hide JS summaries. @todo Rethink summaries. */
 }
+/* Collapse animation on details. */
+details {
+  max-height: 40px;
+  overflow: hidden;
+  -moz-transition: max-height 0.225s ease-in-out;
+  -ms-transition: max-height 0.225s ease-in-out;
+  -o-transition: max-height 0.225s ease-in-out;
+  -webkit-transition: max-height 0.225s ease-in-out;
+  transition: max-height 0.225s ease-in-out;
+}
+/**
+ * CSS3 max-height transitions need a specific height.
+ * @see http://stackoverflow.com/a/19341648
+ */
+details[open] {
+  max-height: 10000px; /* To account for blocks of any size, we choose something of improbable size. */
+}
+
diff --git a/core/themes/seven/css/layout/layout.css b/core/themes/seven/css/layout/layout.css
index eb7c2bf..f0f96e6 100644
--- a/core/themes/seven/css/layout/layout.css
+++ b/core/themes/seven/css/layout/layout.css
@@ -1,4 +1,10 @@
 /**
+ * Prevent scroll-bar from repositioning the page when details are expanded.
+ */
+body {
+  overflow-y: scroll;
+}
+/**
  * Add spacing to bottom of pages
  */
 .page-content {