body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f0f2f5;
  margin: 0;
  padding: 20px;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  background: white;
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

h1 {
  color: #1a73e8;
  text-align: center;
  margin-bottom: 2rem;
}

.input-group {
  display: flex;
  gap: 10px;
  margin-bottom: 2rem;
}

#taskInput {
  flex: 1;
  padding: 12px;
  border: 2px solid #ddd;
  border-radius: 8px;
  font-size: 16px;
}

button {
  padding: 12px 24px;
  background: #1a73e8;
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background: #1557b0;
}

#taskList {
  list-style: none;
  padding: 0;
  margin: 0;
}

.task-item {
  display: flex;
  align-items: center;
  padding: 16px;
  background: #f8f9fa;
  margin-bottom: 8px;
  border-radius: 8px;
  transition: transform 0.2s;
}

.task-item:hover {
  transform: translateX(5px);
}

.task-item.completed {
  background: #e8f0fe;
  opacity: 0.7;
}

.task-item.completed span {
  text-decoration: line-through;
}

@media (max-width: 480px) {
  .container {
    padding: 1rem;
  }
  
  .input-group {
    flex-direction: column;
  }
}