body {
  background-image: url(img/background.png);
  text-align: center;
  font-family: "M PLUS Rounded 1c";
  color: #24211c;
  margin: 0;
}

main {
  background-image: url(img/balloon.png);
  background-repeat: no-repeat;
  background-size: contain;
  padding-top: 270px;
}

.ABOUT {
  max-width: 1366px;
  margin-left: auto;
  margin-right: auto;
}

header {
  position: fixed;
  width: 100%;
}

nav {
  margin: 0 auto;
  display: flex;
  align-items: center;
  flex-direction: column;
}
nav ul {
  display: flex;
  padding: 0;
  margin: 0;
  list-style: none;
}
nav ul li {
  padding: 20px 40px;
  font-size: 20px;
}
a {
  text-decoration: none;
}
a:link {
  color: #24211c;
}
a:visited {
  color: #24211c;
}

.triangle {
  position: relative;
  background-color: #ffffff;
  height: 80px;
}

.triangle::before {
  content: "";
  position: absolute;
  bottom: 0;
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 22px 22px 0 22px;
  border-color: #ffffff transparent transparent transparent;
  left: 50%;
  transform: translateX(-50%) translateY(100%);
}

.title_logo {
  width: 700px;
  height: auto;
}

main img {
  left: 0;
}

.introduction {
  background-color: #ffffff;
  margin: 100px 100px;
  padding: 80px;
  background-image: url(img/lion.png);
  background-repeat: no-repeat;
  background-position: 95% 100%;
  background-size: 13%;
}

.introduction p {
  line-height: 45px;
}

.introduction p:first-child {
  font-size: 1.7em;
}

h3 {
  font-size: 2em;
  font-weight: lighter;
}

h4 {
  font-size: 1.5em;
  font-weight: lighter;
  padding-top: 50px;
  text-decoration: underline;
  text-decoration-color: #87cefa;
}

.explanation {
  background-color: #ffffff;
  margin: 100px 100px;
  padding: 80px;
  background-image: url(img/kirin.png), url(img/garland.png);
  background-repeat: no-repeat, repeat-x;
  background-position: 5% 100%, 0% 0%;
  background-size: 12%, 13%;
}
.explanation p {
  line-height: 45px;
}

.problem {
  background-color: #ffffff;
  margin: 100px 100px;
  padding: 80px;
  background-image: url(img/koara.png), url(img/koara2.png);
  background-repeat: no-repeat, no-repeat;
  background-position: 5% 100%, 95% 100%;
  background-size: 13%;
}

.problem p {
  line-height: 45px;
}

.howtouse {
  background-color: #ffffff;
  margin: 100px 100px;
  padding: 80px;
  background-image: url(img/garland2.png);
  background-repeat: repeat-x;
  background-position: 0% 0%;
  background-size: 13%;
}

.howtouse p {
  line-height: 45px;
}

.phone_Home,
.phone_Setting,
.phone_GameMain,
.phone_ToyList,
.phone_CheckBox,
.phone_StampGet,
.phone_StampCard {
  width: 200px;
  height: auto;
}

footer {
  background-image: url(img/tree.png);
  height: 240px;
}

footer p {
  padding-top: 190px;
}

@media screen and (max-width: 520px) {
  /* 520px以下に適用されるCSS*/
  body {
    text-align: center;
    margin: 0;
    padding: 0;
  }

  main {
    padding-top: 150px;
    background-image: none;
  }

  br {
    display: none;
  }

  .ABOUT {
    max-width: 520px;
    margin-left: auto;
    margin-right: auto;
  }

  .title_logo {
    width: 320px;
    height: auto;
  }

  .introduction {
    margin: 40px 40px;
    padding-top: 40px;
    padding-bottom: 80px;
    background-position: 95% 100%;
    background-size: 20%;
  }

  .introduction p:nth-child(1) {
    font-size: 1.5em;
  }

  .introduction p:nth-child(2) {
    font-size: 15px;
    text-align: left;
    line-height: 40px;
  }

  .explanation {
    margin: 40px 40px;
    padding-top: 40px;
    padding-bottom: 90px;
    background-position: 5% 100%, 0% 0%;
    background-size: 18%, 25%;
  }

  .explanation h3 {
    font-size: 1.5em;
  }

  .explanation p {
    font-size: 15px;
    text-align: left;
    line-height: 40px;
  }

  .problem {
    margin: 40px 40px;
    padding-top: 40px;
    padding-bottom: 80px;
    background-position: 5% 100%, 95% 100%;
    background-size: 24%;
  }

  .problem h3 {
    font-size: 1.5em;
  }

  .problem p {
    font-size: 15px;
    text-align: left;
    line-height: 40px;
  }

  .howtouse {
    margin: 40px 40px;
    padding-top: 40px;
    padding-bottom: 80px;
    background-position: 0% 0%;
    background-size: 25%;
  }

  .howtouse h3 {
    font-size: 1.5em;
  }

  .howtouse h4 {
    font-size: 1.2em;
  }

  .howtouse p {
    font-size: 15px;
    text-align: left;
    line-height: 40px;
  }
}