html {
  font-size: 100%;
}
body {
  background-image: url("../images/background.png");
  background-size: auto 2500px;
  font-family: "ヒラギノ丸ゴ Pro W4", "ヒラギノ丸ゴ Pro",
    "Hiragino Maru Gothic Pro", "ヒラギノ角ゴ Pro W3",
    "Hiragino Kaku Gothic Pro", "HG丸ｺﾞｼｯｸM-PRO", "HGMaruGothicMPRO";
  font-size: xx-large;
  padding: 10px;
  margin: 30px auto;
}

section.main-content {
  width: 100%;
  margin-right: auto;
  margin-left: auto;
  text-align: center;
  background-color: #ffffff;
  padding: 2%;
}
section.main-content img {
  text-align: right;
  max-width: 80%;
}
h1.correct {
  text-align: center;
  color: red;
}
h1.incorrect {
  text-align: center;
  color: blue;
}
h1.error {
  text-align: center;
  color: red;
}
p.title-image {
  text-align: center;
  max-width: 800px;
}
p.title-image img {
  width: 100%;
}

select {
  width: 30%;
  font-size: xx-large;
}

input {
  font-size: xx-large;
}