body {
  font-family: Arial;
  max-width: 500px;
  margin: 50px auto;
}
h1{
    text-align: center;
    span{
        color: rgb(17, 17, 255);
    }
}
input {
  padding: 10px;
  width: 70%;
  
}
button {
  padding: 10px;
  cursor: pointer;
  
}
li {
  padding: 10px;
  border-bottom: 1px solid #ccc;
}
.concluida {
  text-decoration: line-through;
  color: gray;
}