#hero {
  text-align: center;
  background-image: url(../img/japan-poker.png);
  background-position: center;
  background-size: cover;
  /* ビューポート全体を覆う設定 */
  height: 100vh;
  padding: 20px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
}
#hero > .container {
  background-color: #ffffd6;
  padding-top: 30px;
  padding-bottom: 35px;
  width: 780px;
  max-width: 90vw;
  border-radius: 20px;
}
#hero > .container > h2 {
  font-size: 2em;
  color: #ff4040;
  margin-bottom: 20px;
}
#hero > .container > a {
  margin: 5px;
  padding: 10px 40px;
  font-size: 1em;
  background: #ff4040;
  color: #fff;
  border-radius: 20px;
}

/* SP */
@media screen and (max-width: 500px) {
  #hero > .container > h2 {
    font-size: 1.6em;
  }
}