.todo-app {
  max-width: 400px;
  margin: 50px auto;
  background: #fff;
  padding: 20px;
  border-radius: 12px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  font-family: sans-serif;
}
.todo-app h1 {
  text-align: center;
  color: #333;
}
.todo-app .input-section {
  display: flex;
  margin-bottom: 15px;
}
.todo-app .input-section input {
  flex: 1;
  padding: 8px 12px;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 16px;
}
.todo-app .input-section button {
  margin-left: 8px;
  padding: 8px 16px;
  background-color: #4CAF50;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 16px;
}
.todo-app .input-section button:hover {
  background-color: #45a049;
}
.todo-app .task-list li {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 12px;
  margin-bottom: 8px;
  background: #f9f9f9;
  border: 1px solid #eee;
  border-radius: 4px;
}
.todo-app .task-list li.completed {
  text-decoration: line-through;
  color: #888;
  background: #e9e9e9;
}
.todo-app .task-list li .remove-btn {
  background-color: #ff4d4d;
  border: none;
  color: white;
  padding: 4px 8px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 14px;
}
.todo-app .task-list li .remove-btn:hover {
  background-color: #e60000;
}