diff --git a/Application/Timerecording/login.tpl.php b/Application/Timerecording/login.tpl.php
index ea8dfb8..0a7094a 100755
--- a/Application/Timerecording/login.tpl.php
+++ b/Application/Timerecording/login.tpl.php
@@ -36,8 +36,8 @@ $head = $this->getData('head');
 
             --input-border: rgba(166, 135, 232, .4);
             --input-border-active: rgba(166, 135, 232, .7);
-            --input-color: rgba(255, 255, 255, 0.7);
-            --input-color-active: rgba(255, 255, 255, 0.7);
+            --input-color: rgba(166, 135, 232, .6);
+            --input-color-active: rgba(166, 135, 232, .8);
 
             --input-icon-color: rgba(166, 135, 232, .6);
             --input-icon-color-active: rgba(166, 135, 232, 1);
diff --git a/Controller/ApiController.php b/Controller/ApiController.php
index 82119cb..f37358e 100755
--- a/Controller/ApiController.php
+++ b/Controller/ApiController.php
@@ -180,10 +180,12 @@ final class ApiController extends Controller
 
         if ($element === null) {
             $this->fillJsonResponse($request, $response, NotificationLevel::ERROR, 'Session Element', 'You cannot create a session element for another person!', $element);
+
+            return;
         }
 
         if ($element->getStatus() === ClockingStatus::END) {
-            $session = SessionMapper::get($element->getSession()->getId());
+            $session = SessionMapper::get($element->session->getId());
             $session->addSessionElement($element);
             SessionMapper::update($session);
         }
diff --git a/Models/Session.php b/Models/Session.php
index 0855f8f..14f7f0b 100755
--- a/Models/Session.php
+++ b/Models/Session.php
@@ -14,6 +14,8 @@ declare(strict_types=1);
 
 namespace Modules\HumanResourceTimeRecording\Models;
 
+use Modules\HumanResourceManagement\Models\Employee;
+use Modules\HumanResourceManagement\Models\NullEmployee;
 use phpOMS\Contract\ArrayableInterface;
 
 /**
@@ -77,22 +79,22 @@ class Session implements \JsonSerializable, ArrayableInterface
     /**
      * Employee.
      *
-     * @var int|Employee
+     * @var Employee
      * @since 1.0.0
      */
-    private $employee = 0;
+    private Employee $employee;
 
     /**
      * Constructor.
      *
-     * @param int|Employee $employee Employee
+     * @param Employee $employee Employee
      *
      * @since 1.0.0
      */
-    public function __construct($employee = 0)
+    public function __construct(Employee $employee = null)
     {
         $this->start    = new \DateTime('now');
-        $this->employee = $employee;
+        $this->employee = $employee ?? new NullEmployee();
     }
 
     /**
@@ -110,11 +112,11 @@ class Session implements \JsonSerializable, ArrayableInterface
     /**
      * Get employee.
      *
-     * @return int|Employee
+     * @return Employee
      *
      * @since 1.0.0
      */
-    public function getEmployee()
+    public function getEmployee() : Employee
     {
         return $this->employee;
     }
@@ -122,13 +124,13 @@ class Session implements \JsonSerializable, ArrayableInterface
     /**
      * Add a session element to the session
      *
-     * @param int|SessionElement $element Session element
+     * @param SessionElement $element Session element
      *
      * @return void
      *
      * @since 1.0.0
      */
-    public function addSessionElement($element) : void
+    public function addSessionElement(SessionElement $element) : void
     {
         if ($element->getStatus() === ClockingStatus::START) {
             foreach ($this->sessionElements as $e) {
diff --git a/Models/SessionElement.php b/Models/SessionElement.php
index 21126fd..c90008b 100755
--- a/Models/SessionElement.php
+++ b/Models/SessionElement.php
@@ -53,22 +53,22 @@ class SessionElement implements \JsonSerializable, ArrayableInterface
     /**
      * Session id this element belongs to
      *
-     * @var int|Session
+     * @var Session
      * @since 1.0.0
      */
-    private $session = 0;
+    public Session $session;
 
     /**
      * Constructor.
      *
-     * @param int            $session Session id
+     * @param Session        $session Session id
      * @param null|\DateTime $dt      DateTime of the session element
      *
      * @since 1.0.0
      */
-    public function __construct($session = 0, \DateTime $dt = null)
+    public function __construct(Session $session = null, \DateTime $dt = null)
     {
-        $this->session = $session;
+        $this->session = $session ?? new NullSession();
         $this->dt      = $dt ?? new \DateTime('now');
     }
 
@@ -122,18 +122,6 @@ class SessionElement implements \JsonSerializable, ArrayableInterface
         $this->status = $status;
     }
 
-    /**
-     * Get session this element is for
-     *
-     * @return int|Session
-     *
-     * @since 1.0.0
-     */
-    public function getSession()
-    {
-        return $this->session;
-    }
-
     /**
      * {@inheritdoc}
      */
@@ -143,7 +131,7 @@ class SessionElement implements \JsonSerializable, ArrayableInterface
             'id'       => $this->id,
             'status'   => $this->status,
             'dt'       => $this->dt,
-            'session'  => \is_int($this->session) ? $this->session : $this->session->getId(),
+            'session'  => $this->session->getId(),
         ];
     }