.rule_big_box {
  width: 1200px;
  margin: 110px auto 0;
}
.rule_big_box .ru_item .ru_i_top {
  margin-bottom: 42px;
}
.rule_big_box .ru_item .ru_i_top .ru_it_img {
  margin: 0 auto;
  width: 187px;
  height: 70px;
}
.rule_big_box .ru_item .ru_i_top .ru_it_img img {
  width: 187px;
  height: 70px;
}
.rule_big_box .ru_item .ru_i_top .ru_it_text {
  margin-top: 24px;
  text-align: center;
  font-family: Noto Sans JP, Noto Sans JP;
  font-weight: bold;
  font-size: 50px;
  color: #000000;
}
.rule_big_box .ru_item .ru_i_text {
  margin-top: 144px;
  font-family: Noto Sans JP, Noto Sans JP;
  font-weight: 400;
  font-size: 16px;
  color: #000000;
  line-height: 150%;
}
.rule_big_box .ru_item .ru_i_bom {
  margin-top: 100px;
  text-align: right;
  font-family: Noto Sans JP, Noto Sans JP;
  font-weight: 400;
  font-size: 16px;
  color: #000000;
  line-height: 150%;
}
.rule_big_box .ru_item .ru_mb_back {
  display: none;
}
@media screen and (max-width: 750px) {
  .rule_big_box {
    width: 100%;
    margin-top: 70px;
  }
  .rule_big_box .ru_item {
    width: 320px;
    margin: 0 auto;
  }
  .rule_big_box .ru_item .ru_i_top {
    margin-bottom: 42px;
  }
  .rule_big_box .ru_item .ru_i_top .ru_it_img {
    width: 75px;
    height: auto;
  }
  .rule_big_box .ru_item .ru_i_top .ru_it_img img {
    width: 75px;
    height: auto;
  }
  .rule_big_box .ru_item .ru_i_top .ru_it_text {
    font-size: 24px;
    margin-top: 12px;
  }
  .rule_big_box .ru_item .ru_i_text {
    margin-top: 25px;
    font-size: 14px;
  }
  .rule_big_box .ru_item .ru_i_bom {
    margin-top: 100px;
    text-align: right;
    font-family: Noto Sans JP, Noto Sans JP;
    font-weight: 400;
    font-size: 16px;
    color: #000000;
    line-height: 150%;
  }
  .rule_big_box .ru_item .ru_mb_back {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin-top: 50px;
    margin-left: 190px;
    width: fit-content;
  }
  .rule_big_box .ru_item .ru_mb_back img {
    width: 16px;
    height: 16px;
  }
  .rule_big_box .ru_item .ru_mb_back span {
    font-family: Noto Sans JP, Noto Sans JP;
    font-weight: bold;
    font-size: 12px;
    color: #777;
  }
}