style.css

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
body {
  background-color: rgb(169, 188, 189);
  display: flex;
  justify-content: center;
  font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
}

.main-container {
  background-color: white;
  border-radius: 5px;
  margin: 25px;
  width: 350px;
  height: auto;
  padding: 25px;
  display: flex;
  flex-direction: column;
}

form {
  margin: 25px 0;
  display: flex;
  justify-content: flex-start;
  align-items: center;
}
form input {
  background-color: rgb(169, 188, 189);
  border-radius: 5px;
  border: none;
  height: 30px;
  width: 200px;
  padding: 10px;
  outline: none;
  margin-right: 20px;
}
form button {
  height: 30px;
  width: 30px;
  border-radius: 50%;
  font-size: 20px;
  font-weight: 800;
  border: none;
  cursor: pointer;
}

button:hover{
    background-color: rgb(112, 107, 107);
    color: white;
}

.task{
    background-color: rgb(169, 188, 189);
    height: 40px;
    border-radius: 5px;
    display: flex;
    align-items: center;
    padding: 15px;
    margin: 10px 0;
}

.done{
    background-color: rgb(102, 114, 114);
    text-decoration: line-through;
    color:white;
}