diff --git a/src/App.jsx b/src/App.jsx
index e9bc2ca..e6b0afb 100644
--- a/src/App.jsx
+++ b/src/App.jsx
@@ -1 +1,180 @@
-import React from 'react';export default function App(){const n="{{ Nazwa }}",d="{{ Opis }}",s="{{ Styl }}",f="{{ Funkcje }}".split(", ");return(<div style={{padding:40,maxWidth:600,margin:'auto',fontFamily:'system-ui',color:'#333'}}><h1>{n}</h1><p>{d}</p><ul>{f.map(x=><li key={x}>{x}</li>)}</ul><hr style:{{border:'none',borderTop:'1px solid #eee'}}/><p><em>Style: {s}</em></div>);}
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+import React, { useState, useEffect } from 'react';
+
+/**
+ * Główny komponent aplikacji React.
+ * Zmodyfikowany w celu zapewnienia pełnej funkcjonalności zarządzania zadaniami
+ * z nowoczesnym interfejsem użytkownika i obsługą stanu.
+ */
+const App = () => {
+  const [tasks, setTasks] = useState([
+    { id: 1, text: 'Zainstalować zależności', completed: true },
+    { id: 2, text: 'Zaimplementować logikę biznesową', completed: false }
+  ]);
+  const [inputValue, setInputValue] = useState('');
+
+  const handleAddTask = (e) => {
+    e.preventDefault();
+    if (inputValue.trim() === '') return;
+
+    const newTask = {
+      id: Date.now(),
+      text: inputValue,
+      completed: false
+    };
+
+    setTasks([...tasks, newTask]);
+    setInputValue('');
+  };
+
+  const toggleTask = (id) => {
+    setTasks(tasks.map(task => 
+      task.id === id ? { ...task, completed: !task.completed } : task
+    ));
+  };
+
+  const deleteTask = (id) => {
+    setTasks(tasks.filter(task => task.id !== id));
+  };
+
+  const clearCompleted = () => {
+    setTasks(tasks.filter(task => !task.completed));
+  };
+
+  return (
+    <div style={{ 
+      fontFamily: 'Segoe UI, Roboto, Helvetica, Arial, sans-serif', 
+      backgroundColor: '#f4f7f6', 
+      minHeight: '100vh', 
+      display: 'flex', 
+      justifyContent: 'center', 
+      padding: '40px 20px' 
+    }}>
+      <div style={{ 
+        width: '100%', 
+        maxWidth: '500px', 
+        backgroundColor: 'white', 
+        borderRadius: '12px', 
+        boxShadow: '0 10px 25px rgba(0,0,0,0.05)', 
+        padding: '30px' 
+      }}>
+        <h1 style={{ color: '#2c3e50', marginBottom: '25px', textAlign: 'center', fontSize: '24px' }}>
+          Menedżer Projektu
+        </h1>
+
+        <form onSubmit={handleAddTask} style={{ display: 'flex', gap: '10px', marginBottom: '30px' }}>
+          <input
+            type="text"
+            value={inputValue}
+            onChange={(e) => setInputValue(e.target.value)}
+            placeholder="Co należy zrobić?"
+            style={{ 
+              flex: 1, 
+              padding: '12px 15px', 
+              borderRadius: '8px', 
+              border: '1px solid #dfe6e9', 
+              fontSize: '16px', 
+              outline: 'none' 
+            }}
+          />
+          <button 
+            type="submit"
+            style={{ 
+              padding: '10px 20px', 
+              backgroundColor: '#3498db', 
+              color: 'white', 
+              border: 'none', 
+              borderRadius: '8px', 
+              cursor: 'pointer', 
+              fontWeight: '600', 
+              transition: 'background 0.2s' 
+            }}
+            onMouseOver={(e) => e.target.style.backgroundColor = '#2980b9'}
+            onMouseOut={(e) => e.target.style.backgroundColor = '#3498db'}
+          >
+            Dodaj
+          </button>
+        </form>
+
+        <div style={{ display: 'flex', flexDirection: 'column', gap: '12px' }}>
+          {tasks.length === 0 ? (
+            <p style={{ textAlign: 'center', color: '#b2bec3' }}>Brak zadań do wyświetlenia.</p>
+          ) : (
+            tasks.map(task => (
+              <div 
+                key={task.id} 
+                style={{ 
+                  display: 'flex', 
+                  alignItems: 'center', 
+                  justifyContent: 'space-between', 
+                  padding: '12px 15px', 
+                  backgroundColor: task.completed ? '#f9f9f9' : 'white', 
+                  border: '1px solid #f1f2f6', 
+                  borderRadius: '8px', 
+                  transition: 'transform 0.1s' 
+                }}
+              >
+                <div style={{ display: 'flex', alignItems: 'center', gap: '12px' }}>
+                  <input
+                    type="checkbox"
+                    checked={task.completed}
+                    onChange={() => toggleTask(task.id)}
+                    style={{ width: '18px', height: '18px', cursor: 'pointer' }}
+                  />
+                  <span style={{ 
+                    textDecoration: task.completed ? 'line-through' : 'none', 
+                    color: task.completed ? '#b2bec3' : '#2d3436', 
+                    fontSize: '16px' 
+                  }}>
+                    {task.text}
+                  </span>
+                </div>
+                <button 
+                  onClick={() => deleteTask(task.id)}
+                  style={{ 
+                    background: 'none', 
+                    border: 'none', 
+                    color: '#ff7675', 
+                    cursor: 'pointer', 
+                    fontSize: '14px', 
+                    fontWeight: '500' 
+                  }}
+                >
+                  Usuń
+                </button>
+              </div>
+            ))
+          )}
+        </div>
+
+        {tasks.length > 0 && (
+          <div style={{ 
+            marginTop: '25px', 
+            paddingTop: '20px', 
+            borderTop: '1px solid #f1f2f6', 
+            display: 'flex', 
+            justifyContent: 'space-between', 
+            alignItems: 'center', 
+            color: '#636e72', 
+            fontSize: '14px' 
+          }}>
+            <span>Pozostało: {tasks.filter(t => !t.completed).length}</span>
+            <button 
+              onClick={clearCompleted}
+              style={{ 
+                background: 'none', 
+                border: 'none', 
+                color: '#3498db', 
+                cursor: 'pointer', 
+                fontSize: '14px' 
+              }}
+            >
+              Wyczyść ukończone
+            </button>
+          </div>
+        )}
+      </div>
+    </div>
+  );
+};
+
+export default App;
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