body {
  font-family: 'Segoe UI', sans-serif;
  background-color: #f0f4f8;
  margin: 0;
  padding: 0;
  display: flex;
  height: 100vh;
  justify-content: center;
  align-items: center;
}

.contenedor {
  background-color: white;
  padding: 30px;
  border-radius: 15px;
  box-shadow: 0 0 20px rgba(0,0,0,0.1);
  width: 90%;
  max-width: 400px;
  text-align: center;
}

.entrada {
  display: flex;
  gap: 10px;
  margin-bottom: 20px;
}

input[type="text"] {
  flex-grow: 1;
  padding: 10px;
  border: 2px solid #ccc;
  border-radius: 8px;
  font-size: 16px;
}

button {
  padding: 10px 15px;
  background-color: #1e90ff;
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  font-weight: bold;
}

button:hover {
  background-color: #0066cc;
}

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

li {
  background-color: #e9f1ff;
  margin-bottom: 10px;
  padding: 10px;
  border-radius: 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

li.hecha {
  text-decoration: line-through;
  color: #777;
  background-color: #d3e4ff;
}