body {
  background-color: rgb(125, 230, 19);
}

.container {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.item {
  width: 500px;
  max-width: 90%;
  padding: 10px;
  border: 2px solid red;
  margin-top: 5px;
  border-radius: 5px;
  background-color: rgb(185, 230, 140);
}

input:checked + label {
  color: #f00;
  text-decoration: line-through;
}