diff --git a/lernplattform/__init__.py b/lernplattform/__init__.py
index efea60a..61d0497 100644
--- a/lernplattform/__init__.py
+++ b/lernplattform/__init__.py
@@ -1,9 +1,22 @@
 from flask import Flask
 from flask_sqlalchemy import SQLAlchemy
 
+# Initialize a new Flask app instance with the name of the current module (main).
 app = Flask(__name__)
+
+# Set the secret key for this application. This is required for session management in Flask.
+# The secret key should be a cryptographically secure random value, and it's used to sign cookies.
+# For more information: https://flask.palletsprojects.com/en/2.3.x/config/#SECRET_KEY
+app.secret_key = 'faab0674dd8d9a4554cbeb53da2dad1414cc4c64b778e282da0b1662df7e0f85'
+
+# Configure the database URI for SQLAlchemy. Here, it uses an SQLite database named 'learn.db'.
 app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///learn.db'
+
+# Disable tracking modifications to the database, which is not necessary in this case and can improve performance.
 app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
+
+# Initialize SQLAlchemy with the Flask app instance for database management.
 db = SQLAlchemy(app)
 
+# Import the routes module from the lernplattform package, which is assumed to be in the same directory.
 import lernplattform.routes
\ No newline at end of file
diff --git a/lernplattform/classes.py b/lernplattform/classes.py
index c89c380..ce0c17d 100644
--- a/lernplattform/classes.py
+++ b/lernplattform/classes.py
@@ -1,4 +1,4 @@
-from flask import Flask, request
+from flask import Flask, request, session
 from lernplattform import app
 from lernplattform.models import User
 
@@ -17,11 +17,16 @@ class login():
     def __init__(self, user_name=None):
         self.user_name = user_name  # Initialize the user name attribute for the login class
 
-    @staticmethod
     def check(user_name):
         if user_name is None:
+            session['logged_in'] = False
+            session['user_name'] = 'Gast'
             return False  # Return False if the user name is not provided
         else:
+            session['logged_in'] = True
+            session['user_name'] = user_name
+            
             return True  # Otherwise, return True indicating a valid user name
+        
     def login(self):
         print("Login")  # Print "Login" to indicate that the login method has been called
diff --git a/lernplattform/routes.py b/lernplattform/routes.py
index f35096b..a27c063 100644
--- a/lernplattform/routes.py
+++ b/lernplattform/routes.py
@@ -1,4 +1,4 @@
-from flask import render_template, url_for, flash, redirect, jsonify, request
+from flask import render_template, url_for, flash, redirect, jsonify, request, session
 from lernplattform import app
 from lernplattform.models import User
 
@@ -16,14 +16,10 @@ def index():
     Returns:
         A rendered HTML template with the current username.
     """
-    if login.check(request.cookies.get('user_name')):
-        user_name = User.query.filter_by(username=request.cookies.get('user_name')).first().username 
-    else:
-        # If not logged in, default to 'Gast'
-        user_name = 'Gast'
+    login.check(request.cookies.get('user_name'))
 
     # Render the main page with the current username
-    return render_template('index.html', user_name=user_name)
+    return render_template('index.html', user_name=session['user_name'])
 
 @app.route('/users', methods=['GET'])
 def get_users():
diff --git a/lernplattform/templates/index.html b/lernplattform/templates/index.html
index 312ac37..607e547 100644
--- a/lernplattform/templates/index.html
+++ b/lernplattform/templates/index.html
@@ -18,10 +18,11 @@
             }
             body {
                 color: #ffffff;
+                background-color: var(--background-color);
             }
             .light {
-                color: #888888;
-                font-weight: 100;
+                color: #cdcdcd;
+                font-weight: 400;
                 font-size: small;
             }
             .sidebar {
@@ -72,7 +73,7 @@
                 background-color: var(--nav-background-color);
                 padding: 0;
             }
-            .navbar-nav .nav-link {
+            .navbar-nav .nav-link  {
                 color: var(--link-default-color)
             }
 
@@ -83,6 +84,14 @@
             .navbar-nav .nav-link.active {
                 color: var(--link-active-color);
             }
+
+            a  {
+                color: #ffcc00;
+            }
+            a:hover {
+                color: #c07427;
+            }
+
             .logo {
                 display:inline;
                 width: 50px;
@@ -95,10 +104,6 @@
                 padding: 0;
                 box-shadow: 0 -4px 8px rgba(0, 0, 0, 0.3);
             }
-
-            body {
-                background-color: var(--background-color);
-            }
         </style>
     </head>
     <body>
@@ -110,6 +115,34 @@
                 <!-- Sidebar -->
                 <div class="col-12 col-md-3 sidebar mb-3">
                     <div class="profile-card text-center p-3">
+
+<!-- wenn logged out -->
+                        {% if not session['logged_in'] %}
+                        <h5>{{ user_name }}</h5>
+                        <p>Login oder <a href="#">Registrieren</a></p>
+                        <p class="light">Warum registrieren? Zum Schutz der Daten und dem Speichern deines Lernfortschrittes.</p>
+                        
+                        <form>
+                            <div class="row mb-3">
+                              <label for="inputEmail3" class="col-sm-3 col-form-label">Benutzer</label>
+                              <div class="col-sm-8">
+                                <input type="email" class="form-control" id="inputEmail3">
+                              </div>
+                            </div>
+                            <div class="row mb-3">
+                              <label for="inputPassword3" class="col-sm-3 col-form-label">Password</label>
+                              <div class="col-sm-8">
+                                <input type="password" class="form-control" id="inputPassword3">
+                              </div>
+                            </div>
+
+                            <button type="submit" class="btn btn-primary">Einloggen</button>
+                          </form>
+                          {% endif %}
+<!-- wenn logged out -->
+
+<!-- wenn logged in -->
+                        {% if session['logged_in'] %}
                         <!--<img src="https://via.placeholder.com/100" alt="Profile Picture" />-->
                         <h5>{{ user_name }}</h5>
                         <p>Web Developer at Webestica</p>
@@ -119,6 +152,9 @@
                             <span>2.5K Followers</span>
                             <span>365 Following</span>
                         </div>
+                        {% endif %}
+<!-- wenn logged in -->
+
                     </div>
 <!--
                     <div class="list-group">
@@ -162,11 +198,18 @@
                             <img
                                 src="../static/images/logo.png"
                                 class="rounded-circle me-3"
-                                style="width: 300px;"
+                                style="width: 300px; height: 300px;"
                                 alt="Profile Picture" />
-                            <div>
+                            <div class="my-3">
                                 <h6>Lernplattform für <br>Rettungs- und Notfallsanitäter</h6>
-                                <small class="light">Hier kann man lernen und üben, Wiessen festigen und sich aktiv an der Datenbank beteiligen.</small>
+                                <p class="light" style="text-align: justify;">
+                                    Willkommen auf unserer Lernplattform für Rettungssanitäter und Notfallsanitäter, 
+                                    basierend auf dem bewährten Kartensystem nach Leitner. 
+                                    Unsere Plattform bietet Dir die Möglichkeit, 
+                                    Deine Kenntnisse und Fähigkeiten effektiv zu vertiefen und zu erweitern. <br><br>
+                                    Bei Interesse bist Du herzlich eingeladen, an der Entwicklung von Fragen und Aufgaben mitzuwirken. 
+                                    Unsere Plattform ist und bleibt kostenlos, um alle Mitarbeiter im Rettungsdienst bestmöglich zu unterstützen.
+                                </p>
                             </div>
                         </div>