diff --git a/resources/celerity/map.php b/resources/celerity/map.php
--- a/resources/celerity/map.php
+++ b/resources/celerity/map.php
@@ -9,7 +9,7 @@
   'names' => array(
     'conpherence.pkg.css' => '2f25eb4f',
     'conpherence.pkg.js' => '020aebcf',
-    'core.pkg.css' => '3471f5d3',
+    'core.pkg.css' => 'f66b80a1',
     'core.pkg.js' => '2eeda9e0',
     'dark-console.pkg.js' => '187792c2',
     'differential.pkg.css' => '6d3700f0',
@@ -158,7 +158,7 @@
     'rsrc/css/phui/phui-form.css' => '1f177cb7',
     'rsrc/css/phui/phui-formation-view.css' => 'd2dec8ed',
     'rsrc/css/phui/phui-head-thing.css' => 'd7f293df',
-    'rsrc/css/phui/phui-header-view.css' => '36c86a58',
+    'rsrc/css/phui/phui-header-view.css' => '5cfd0f9b',
     'rsrc/css/phui/phui-hovercard.css' => '39fd2e14',
     'rsrc/css/phui/phui-icon-set-selector.css' => '19e0253b',
     'rsrc/css/phui/phui-icon.css' => '084ac612',
@@ -851,7 +851,7 @@
     'phui-form-view-css' => '57edecb7',
     'phui-formation-view-css' => 'd2dec8ed',
     'phui-head-thing-view-css' => 'd7f293df',
-    'phui-header-view-css' => '36c86a58',
+    'phui-header-view-css' => '5cfd0f9b',
     'phui-hovercard' => '6199f752',
     'phui-hovercard-list' => 'de4b4919',
     'phui-hovercard-view-css' => '39fd2e14',
diff --git a/src/view/phui/PHUIBoxView.php b/src/view/phui/PHUIBoxView.php
--- a/src/view/phui/PHUIBoxView.php
+++ b/src/view/phui/PHUIBoxView.php
@@ -6,6 +6,7 @@
   private $padding = array();
   private $border = false;
   private $color;
+  private $collapsible;
 
   const BLUE = 'phui-box-blue';
   const GREY = 'phui-box-grey';
@@ -30,6 +31,17 @@
     return $this;
   }
 
+  /**
+   * Render PHUIBoxView as a <details> instead of a <div> HTML tag.
+   * To be used for collapse/expand in combination with PHUIHeaderView.
+   *
+   * @param bool True to wrap in <summary> instead of <div> HTML tag.
+   */
+  public function setCollapsible($collapsible) {
+    $this->collapsible = $collapsible;
+    return $this;
+  }
+
   protected function getTagAttributes() {
     require_celerity_resource('phui-box-css');
     $outer_classes = array();
@@ -51,10 +63,20 @@
       $outer_classes[] = $this->color;
     }
 
-    return array('class' => $outer_classes);
+    $tag_classes = array('class' => $outer_classes);
+
+    if ($this->collapsible) {
+      $attribute = array('open' => ''); // expand column by default
+      $tag_classes = array_merge($tag_classes, $attribute);
+    }
+
+    return $tag_classes;
   }
 
   protected function getTagName() {
+    if ($this->collapsible) {
+      return 'details';
+    }
     return 'div';
   }
 
diff --git a/src/view/phui/PHUIHeaderView.php b/src/view/phui/PHUIHeaderView.php
--- a/src/view/phui/PHUIHeaderView.php
+++ b/src/view/phui/PHUIHeaderView.php
@@ -24,6 +24,7 @@
   private $href;
   private $actionList;
   private $actionListID;
+  private $collapsible;
 
   public function setHeader($header) {
     $this->header = $header;
@@ -90,6 +91,17 @@
     return $this;
   }
 
+  /**
+   * Render PHUIHeaderView as a <summary> instead of a <div> HTML tag.
+   * To be used for collapse/expand in combination with PHUIBoxView.
+   *
+   * @param bool True to wrap in <summary> instead of <div> HTML tag.
+   */
+  public function setCollapsible($collapsible) {
+    $this->collapsible = $collapsible;
+    return $this;
+  }
+
   public function setPolicyObject(PhabricatorPolicyInterface $object) {
     $this->policyObject = $object;
     return $this;
@@ -156,6 +168,9 @@
   }
 
   protected function getTagName() {
+    if ($this->collapsible) {
+      return 'summary';
+    }
     return 'div';
   }
 
diff --git a/src/view/phui/PHUIWorkpanelView.php b/src/view/phui/PHUIWorkpanelView.php
--- a/src/view/phui/PHUIWorkpanelView.php
+++ b/src/view/phui/PHUIWorkpanelView.php
@@ -81,7 +81,8 @@
 
     $header = id(new PHUIHeaderView())
       ->setHeader($this->header)
-      ->setSubheader($this->subheader);
+      ->setSubheader($this->subheader)
+      ->setCollapsible(true);
 
     foreach ($this->headerActions as $action) {
       $header->addActionItem($action);
@@ -112,6 +113,7 @@
     $view = id(new PHUIBoxView())
       ->setColor(PHUIBoxView::GREY)
       ->addClass('phui-workpanel-view-inner')
+      ->setCollapsible(true)
       ->appendChild(
         array(
           $header,
diff --git a/webroot/rsrc/css/phui/phui-header-view.css b/webroot/rsrc/css/phui/phui-header-view.css
--- a/webroot/rsrc/css/phui/phui-header-view.css
+++ b/webroot/rsrc/css/phui/phui-header-view.css
@@ -56,6 +56,24 @@
   border-top-width: 0;
 }
 
+details > summary.phui-header-shell {
+  list-style: none;
+}
+
+details > summary.phui-header-shell::marker {
+  content: none;
+}
+
+.device-phone details > summary.phui-header-shell::after {
+  font-family: FontAwesome;
+  content: "\f061";
+}
+
+.device-phone details[open] > summary.phui-header-shell::after {
+  font-family: FontAwesome;
+  content: "\f063";
+}
+
 .phui-property-list-view + .diviner-document-section {
   margin-top: -1px;
 }