.bg_about {
  background-image: url('/2021/assets/img/index/bg_about.jpg');
  background-position-y: 40%;
  background-size: cover;
  background-repeat: no-repeat;
}

.section_content h3::after {
  position: absolute;
  content: "";
  left: 0;
  right: 0;
  bottom: -5px;
  height: 4px;
  width: auto;
  margin: auto;
  background-image: url('/2021/assets/img/index/349.png');
  background-repeat: no-repeat;
  background-size: contain;
  background-position-x: center;
}

.section_content.flex img {
  text-align: center;
  margin: 0 auto 100px;
  filter: grayscale(100%);
  transition: .5s;
  border: #333 2px solid;
  box-shadow: #666 0px 0px 10px 2px;
  width: 26%;
  min-width: 400px;
}

.section_content.flex img:hover {
  filter: grayscale(0%);
}

.theme_img {
  height: 10vh;
  width: auto;
}

/* 900px以下 タブレット用 */
@media screen and (max-width: 900px) {
  .section_content.flex img {
    filter: grayscale(0%);
  }
}

/* 600px以下 スマホ用 */
@media screen and (max-width: 600px) {
  .section_content.flex img {
    margin: 0 auto 50px;
    min-width: unset;
    width: 80vw;
  }
}