html {
  background-color: #f4f6f9;
  font-size: 1rem;
}

* {
  max-width: 100%;
  height: auto;
  box-sizing: border-box;
}

.container {
  padding-left: 5px;
  padding-right: 5px;
}

.required:after {
  position: absolute;
  top: 13px;
  right: 0;
  content: '';
  /*何も入れない*/
  width: 12px;
  /*画像の幅*/
  height: 12px;
  /*画像の高さ*/
  background-image: url("../img/required.svg");
  background-size: contain;
}