index.css

html, body {
  margin: 0;
  padding: 0;
}

.page {
  background-color: #000000;
  font-style: normal;
  font-weight: 900;
  color: #FFFFFF;
}

.page__content {
  max-width: 700px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.header {
  margin: 0;
  padding: 0 96px 0 54px;
}

.header__title {
  font-weight: 900;
  font-size: 60px;
  line-height: 73px;
  text-align: center;
}

.todos {
  flex-grow: 1;
}

.todos__form {
  margin-bottom: 30px;
  display: flex;
}

.todos__input{
  flex-grow: 1;
  background: #FFFFFF;
  border-radius: 5px;
  font-weight: 900;
  font-size: 24px;
  line-height: 29px;
  color: #000000;
  border: 0;
  padding: 20px;
  outline: 0;
}

.todos__submit-btn {
  width: 180px;
  padding: 20px 0;
  background: #FFFFFF;
  border-radius: 5px;
  font-weight: 900;
  font-size: 24px;
  line-height: 29px;
  border: 0;
  flex-shrink: 0;
  margin-left: 10px;
  cursor: pointer;
}

.todos__list {
  list-style-type: none;
  padding: 0;
}

.todo {
  display: flex;
  padding: 44px;
  align-items: center;
  margin-bottom: 10px;
  border: 1px solid #6F6F6F;
  box-sizing: border-box;
  border-radius: 5px;
}

.todo:last-child {
  margin-bottom: 0;
}

.todo__text{
  font-weight: 900;
  font-size: 24px;
  line-height: 29px;
  color: #FFFFFF;
  margin: 0;
  flex-grow: 1;
}

.todo__btn {
  width: 23px;
  height: 23px;
  margin-right: 30px;
  background-color: transparent;
  cursor: pointer;
  flex-shrink: 0;
  border: 0;
}

.todo__btn:last-child {
  margin-right: 0;
}

.footer {
  padding: 120px 0 54px 0;
  font-size: 18px;
  line-height: 150%;
  text-align: center;
  color: #898989;
}

.button {
  opacity: 1;
  transition: opacity .15s ease-in-out;
  outline: 0;
}

.button:hover {
  opacity: .7;
}