Add CSS classes

public/css/app.css

@@ -38,6 +38,11 @@ details h2 {
  *  Layout
  */
 
+.page-header {
+    background-color: #a4ecfc;
+    border-bottom: 5px solid black;
+}
+
 .other-links {
     display: block;
     margin: auto;
@@ -86,16 +91,29 @@ details h2 {
     grid-column-end: 3;
 }
 
-details {
+.checkin {
     border-top: 1px solid black;
     padding: 1em 0;
 }
 
-details[open] summary {
+.checkin__summary {
+    cursor: pointer;
+}
+
+.checkin[open] .checkin__summary {
+    margin-bottom: 1em;
+    border-bottom: 1px solid gray;
+}
+
+.checkin__meta {
+    margin: 0;
+}
+
+.checkin[open] .checkin__meta {
     margin-bottom: 1em;
 }
 
-#checkinList li:first-child details {
+#checkinList li:first-child .checkin {
     border-top: none;
 }