.about-us {
  padding: 15px;
  line-height: 1.2em;
  position: relative;
  background: url('../images/about_us_bg.jpg') center/cover no-repeat;
  color: #fff;
  background-attachment: fixed;
}

.about-us::after {
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.3);
  /* 半透明黑遮罩 */
}
.about-us::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7); /* 半透明白色蒙版 */
  mix-blend-mode: multiply; /* 蒙版混合模式 */
}

.about-us .tw-container {
  position: relative;
  z-index: 1;
}

.about-us section {
  position: relative;
  padding: 15px 0;
  font-size: 14px;

}

.about-us section:first-child::before {
  content: '';
  position: absolute;
  border-left: 5px dotted #fff;
  left: 0;
  top: 40px;
  bottom: 30px;
}

.about-us section:first-child::after {
  content: '';
  position: absolute;
  border-top: 5px dotted #fff;
  top: 10px;
  left: 120px;
  right: 0;
}

.about-us .decoration {
  font-size: 24px;
  position: absolute;
  left: 0;
  top: 0;
  font-weight: bold;
}

.about-us .paragraph {
  display: flex;
  flex-wrap: wrap;
  padding: 25px 0 25px 25px;
}

.about-us .text {
  padding-bottom: 20px;
  padding-right: 20px;
}

.about-us .paragraph .title {
  font-size: 20px;
  font-weight: 900;
  line-height: 1.5em;
  margin-bottom: 20px;
}

.about-us .paragraph .responsive-image-box {
  width: 100%;
}

.about-us .paragraph .responsive-image-box video {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
}

.about-us .responsive-image-box .responsive-box {
  padding-top: 66%;
  background-color: red;
}

@media (min-width: 768px) {
  .about-us .text {
    width: 40%;
    flex-grow: 1;
    padding-bottom: 0;
  }
  .about-us .paragraph .responsive-image-box {
    width: 45%;
    flex-grow: 1;
  }

  .about-us section:nth-child(2n) .text {
    order: 1;
    padding-left: 25px;
  }
}