styles.css

* {
  margin: 0;
  padding: 0;
}

html {
  box-sizing: border-box;
  font-size: 20px;
}

*, *:before, *:after {
  box-sizing: inherit;
}

main {
  display: flex;
  flex-direction: column;
  align-items: center;

  max-width: 800px;
  margin: 0 auto;
  padding: 20px;
}

.heading {
  margin-bottom: 30px;
  font-family: Georgia, 'Times New Roman', Times, serif;
  font-size: 2rem;
}

.items {
  width: 100%;

  display: flex;
  flex-direction: column;
  list-style: none;
}

.item {
  display: flex;
  align-items: center;

  margin-bottom: 15px;
}

.item__checkbox {
  margin-right: 20px;
  transform: scale(2);
}

.item__text {
  padding: 5px;
  flex: 1;
  display: block;
  white-space: nowrap;
  overflow: hidden;
  max-width: 100%;
  text-overflow: ellipsis;
}

.item--done .item__text {
  text-decoration: line-through;
}

.item__edit {
  padding: 5px;
  font-size: 1rem;
  flex: 1;
}

.item__button {
  padding: 5px;
  font-size: 1rem;
}

.form__input {
  padding: 5px;
  font-size: 1rem;
}

.form__button {
  padding: 5px;
  font-size: 1rem;
}