diff --git a/app.py b/app.py
index dc1e1fe..3f68e58 100644
--- a/app.py
+++ b/app.py
@@ -19,9 +19,24 @@ app = Flask(__name__)
 app.config["SECRET_KEY"] = config.FLASK_CONFIG["secret_key"]
 app.config["SEND_FILE_MAX_AGE_DEFAULT"] = config.FLASK_CONFIG.get("static_cache_timeout", 60)
 
-# Bez Eventlet – tryb wątkowy
 socketio = SocketIO(app, cors_allowed_origins="*", async_mode="threading", logger=False)
 
+@app.errorhandler(500)
+def server_error(error):
+    app.logger.error(f'Server error: {str(error)}')
+    return render_template('error.html', 
+                          status=500,
+                          title='Błąd serwera',
+                          message='Spróbuj ponownie za chwilę.',
+                          footer=config.FOOTER), 500 
+@app.errorhandler(400)
+@app.errorhandler(404)
+def client_error(error):
+    return render_template('error.html', 
+                          status=error.code, 
+                          title=f'Błąd {error.code}',
+                          message='Nieprawidłowe żądanie.',
+                          footer=config.FOOTER), error.code 
 
 # --------------------
 # Helpers
@@ -155,9 +170,16 @@ def favicon():
 
 @app.route("/")
 def index():
+    safe_phases = {
+        k: {
+            'label': v['label'], 
+            'color': v['color']
+        }
+        for k, v in config.PHASES.items()
+    }
     return render_template(
         "index.html",
-        phases=config.PHASES,
+        phases=safe_phases,
         time_ranges=config.TIME_RANGES,
         default_range=config.DEFAULT_TIME_RANGE,
         footer=config.FOOTER,
diff --git a/templates/base.html b/templates/base.html
index 2960368..b7efc0f 100644
--- a/templates/base.html
+++ b/templates/base.html
@@ -37,9 +37,13 @@
 
     <footer class="text-center mt-4 py-3">
       <small class="text-muted">
-        © {{ footer.year }} {{ footer.project }} |
-        Autor:
-        <a href="{{ footer.owner.url }}" target="_blank" class="text-decoration-none">{{ footer.owner.name }}</a>
+        © {% if footer %}{{ footer.year }}{% else %}2026{% endif %}
+        {% if footer %}{{ footer.project }} |{% endif %}
+        Autor: 
+        <a href="{% if footer %}{{ footer.owner.url }}{% else %}https://linuxiarz.pl{% endif %}" 
+          target="_blank" class="text-decoration-none">
+          {% if footer %}{{ footer.owner.name }}{% else %}linuxiarz.pl{% endif %}
+        </a>
         {% if footer.version %}| v{{ footer.version }}{% endif %}
       </small>
     </footer>
diff --git a/templates/error.html b/templates/error.html
new file mode 100644
index 0000000..60a374f
--- /dev/null
+++ b/templates/error.html
@@ -0,0 +1,38 @@
+<!-- templates/error.html -->
+{% extends "base.html" %}
+
+{% block content %}
+<div class="row justify-content-center">
+  <div class="col-lg-6 col-md-8 col-12">
+    <div class="card border-0 shadow-lg mx-auto" style="max-width: 500px;">
+      <div class="card-body text-center p-5">
+        
+        <div class="display-1 fw-bold text-danger mb-4">{{ status }}</div>
+        
+        <h2 class="h3 fw-bold mb-3">{{ title }}</h2>
+        
+        <p class="lead text-muted mb-4">{{ message }}</p>
+        
+        <a href="/" class="btn btn-primary btn-lg px-4">
+          <i class="fas fa-home me-2"></i>Powrót do monitora
+        </a>
+        
+        {% if config.get('DEBUG', False) %}
+        <details class="mt-4 p-3 bg-light rounded">
+          <summary class="fw-semibold text-muted cursor-pointer mb-2">Szczegóły techniczne</summary>
+          <pre class="small text-monospace bg-white p-3 rounded mt-2 overflow-auto" style="max-height: 200px;">
+{{ request.url }}
+{{ error_description if error_description else 'Brak szczegółów' }}
+{{ request.args }}
+          </pre>
+        </details>
+        {% endif %}
+        
+      </div>
+    </div>
+  </div>
+</div>
+{% endblock %}
+
+{% block scripts %}
+{% endblock %}
diff --git a/templates/index.html b/templates/index.html
index 9430db5..9b17dfc 100644
--- a/templates/index.html
+++ b/templates/index.html
@@ -197,22 +197,22 @@
 {% endblock %}
 
 {% block scripts %}
-<script src="{{ static_v('js/gauge.js') }}"></script>
+  <script src="{{ static_v('js/gauge.js') }}"></script>
 
-<script src="{{ static_v('js/state.js') }}"></script>
-<script src="{{ static_v('js/chart.js') }}"></script>
-<script src="{{ static_v('js//events.js') }}"></script>
-<script src="{{ static_v('js/data.js') }}"></script>
-<script src="{{ static_v('js/socket.js') }}"></script>
-<script src="{{ static_v('js/index.js') }}"></script>
+  <script src="{{ static_v('js/state.js') }}"></script>
+  <script src="{{ static_v('js/chart.js') }}"></script>
+  <script src="{{ static_v('js//events.js') }}"></script>
+  <script src="{{ static_v('js/data.js') }}"></script>
+  <script src="{{ static_v('js/socket.js') }}"></script>
+  <script src="{{ static_v('js/index.js') }}"></script>
 
-<script src="{{ static_v('js/modal.js') }}"></script>
-<script src="{{ static_v('js/apiHelper.js') }}"></script>
-<script src="{{ static_v('js/pageInit.js') }}"></script>
+  <script src="{{ static_v('js/modal.js') }}"></script>
+  <script src="{{ static_v('js/apiHelper.js') }}"></script>
+  <script src="{{ static_v('js/pageInit.js') }}"></script>
 
-<script>
-  document.addEventListener('DOMContentLoaded', () => {
-    initPage({{ phases|tojson }}, '{{ default_range }}');
-  });
-</script>
+  <script>
+    document.addEventListener('DOMContentLoaded', () => {
+      initPage({{ phases|tojson }}, '{{ default_range }}');
+    });
+  </script>
 {% endblock %}
\ No newline at end of file