body {
  background: linear-gradient(to right, #a1c4fd, #c2e9fb);
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
}

.container {
  background: #ffffff;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 4px 20px rgba(0,0,0,0.1);
  width: 100%;
  max-width: 500px;
  text-align: center;
}

h1 {
  margin-bottom: 20px;
  color: #333;
}

.input-container {
  display: flex;
  justify-content: center;
  margin-bottom: 20px;
}

#taskInput {
  padding: 10px;
  width: 70%;
  border: 2px solid #ccc;
  border-radius: 8px;
  font-size: 16px;
}

button {
  padding: 10px 15px;
  margin-left: 10px;
  font-size: 16px;
  background-color: #28a745;
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

button:hover {
  background-color: #218838;
}

ul {
  list-style-type: none;
  padding: 0;
}

li {
  background: #f9f9f9;
  margin-top: 10px;
  padding: 12px 15px;
  border-radius: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: all 0.3s ease;
  border: 1px solid #ddd;
}

li.completed {
  text-decoration: line-through;
  color: gray;
  background-color: #e9ecef;
}

li input[type="checkbox"] {
  margin-right: 10px;
}

li button {
  background-color: transparent;
  border: none;
  color: red;
  font-size: 18px;
  cursor: pointer;
}