style.css

*{
  box-sizing: border-box;
  font-family: sans-serif;
}

body{
  background-color: lightcoral;
}

h1{
  margin: 0px auto 25px;
  text-align: center;
}

.app{
  max-width: 333px;
  margin: 10px auto 0px;
  background-color: white;
  border: 5px solid #cc4646;
  border-radius: 50px 10px;
  padding: 30px;
}

.btn-link{
  border: 0px;
  background-color: transparent;
  color: blue;
  text-decoration: underline;
  padding: 0px;
  margin: 0px;
  margin-left: 10px;
  font-size: 1rem;
  float: right;
}

ul.todo{
  list-style: none;
  padding: 0px;
}

ul.todo li{
  padding: 10px 0;
  border-bottom: 1px solid #ccc;
  overflow: hidden;
}

ul.todo li:last-child{
  border-bottom: 0px;
}

form.add input[type="text"]{
  font-size: 1em;
  border-radius: 5px;
  border: 1px solid #CCC;
  padding: 5px;
}

form.add input[type="submit"]{
  font-size: 1em;
  border-radius: 5px;
  padding: 5px 7px;
  border: 1px solid lightcoral;
  background-color: #cc4646;
  color: #ffffff;
}