#about_contest {
  width: 100%;
  position: relative;
  min-height: 55vw;
  padding: 7vw 0 0 0;

  background-image:
    url(./about_bg.webp), url(./cloud_bg.webp),
    linear-gradient(to top, #ffffff 50%, #ffd900 50%);
  background-position:
    bottom,
    0% 100%,
    center;
  background-size:
    100%,
    100%,
    100% 100%;
  background-repeat: no-repeat;
}

.item3 {
  position: absolute;
  z-index: 50;
  top: -10vw;
  right: -1vw;
  width: 11vw;
  height: auto;
}

.item4 {
  position: absolute;
  z-index: 50;
  top: -4.5vw;
  right: -8vw;
  width: 19vw;
  height: auto;
}
.item5 {
  position: absolute;
  z-index: 50;
  top: -10.5vw;
  left: -3vw;
  width: 18vw;
  height: auto;
}
.about_box {
  text-align: center;
}
.theme {
  background: #fff;
  border: 3px solid #000;
  width: 13vw;
  margin: auto;
  border-radius: 1vw;
  font-size: 1.4vw;
  height: 2.5vw;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Zen Maru Gothic", sans-serif;
  font-weight: 900;
  letter-spacing: 0.1vw;
}
.theme_ttl {
  margin: 2vw auto;
  font-size: 2.2vw;
  height: 2.9vw;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Zen Maru Gothic", sans-serif;
  font-weight: 700;
  letter-spacing: 0.2vw;
}
.concept {
  position: absolute;
  top: 27vw;
  left: 0;
  right: 0;
  margin: auto;
  width: 50%;
  text-align: center;
}
.about_contest_ttl {
  width: 80%;
  margin: 0vw auto -0.5vw auto;
}
h1 {
  font-size: 1.2vw;
  letter-spacing: 0.1vw;
  line-height: 160%;
  font-weight: 500;
}

/* Mobile View */
@media screen and (max-width: 768px) and (min-width: 480px) {
  .theme_ttl {
    margin: 4vw auto;
    font-size: 3.6vw;
  }
  #about_contest {
    min-height: 75vw;
    background-position:
      bottom,
      0% 80%,
      center;
  }
  .concept {
    width: 70%;
    top: 40vw;
  }
  h1 {
    font-size: 2vw;
  }
} /*END*/
/* モバイル用の調整（より厳密に制御したい場合） */
@media (max-width: 480px) {
  #about_contest {
    min-height: 125vw;
    background-image:
      url(./about_bg.webp), url(./cloud_bg.webp),
      linear-gradient(to top, #ffffff 40%, #ffd900 60%);
    background-position:
      bottom,
      0% 50%,
      center;
  }
  .item3 {
    top: -7vw;
    right: -3vw;
    width: 19vw;
  }
  .item4 {
    top: -3.5vw;
    width: 25vw;
    right: -15vw;
  }
  .item5 {
    top: 4.5vw;
    left: -2vw;
    width: 21vw;
  }
  .about_box {
    width: 100%;
    margin-top: 10vw;
  }
  .theme {
    font-size: 3.5vw;
    width: 31%;
    height: 8vw;
    border: 1px solid #000;
    letter-spacing: 0.3vw;
  }
  .theme_ttl {
    font-size: 5vw;
    letter-spacing: 0;
    width: 100%;
    letter-spacing: 0.1vw;
    margin: 8vw 0 0 0;
  }
  .concept {
    top: unset;
    bottom: 15vw;
    width: 80%;
  }
  .about_contest_ttl {
    width: 70%;
  }
  h1 {
    font-size: 4vw;
    line-height: 6vw;
    letter-spacing: 0;
    text-align: left;
  }
} /*END*/