body {
  letter-spacing: 0px;
}

.mgb-48 {
  margin-bottom: 48px;
}

.flex-center {
  display: flex;
  justify-content: center;
  align-items: center;
}

.space-between {
  justify-content: space-between;
}

.flex-justify-content-center {
  justify-content: center;
}

.flex-align-items-center {
  align-items: center;
}

.flex-column {
  display: flex;
  flex-direction: column;
}

.flex-row {
  display: flex;
  flex-direction: row;
}

/* BANNER */
.box_19 {
  display: flex;
  align-items: center;
  justify-content: center;
  width: auto;
  min-width: 1220px;
  height: 400px;
  background: url(../img/demonstration/banner.png) center no-repeat;
  background-size: cover;
}

.sticky-tab {
  position: sticky;
  top: 50px; /* 可以根据需要调整距离顶部的距离 */
  z-index: 10;
  margin-top: 0;
  margin-bottom: 0;
}

.text_8 {
  text-align: left;
  font-weight: bold;
  font-size: 60px;
  color: #FFFFFF;
  line-height: 80px;
  text-shadow: 1px 1px 1px #000000;
}

#demonstration {
  padding-top: 80px;
  padding-bottom: 48px;
}

.demo_block {
  padding-bottom: 41px;
  width: 368px;
  background: #F0F2F7;
  border-radius: 10px;
  display: flex;
  flex-direction: column;
}

.demo_img {
  position: relative;
  /* overflow: hidden; */
}

.play-btn {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  cursor: pointer;
  display: none;
}

.demo_img:hover::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  border-radius: 10px 10px 0px 0px;
  z-index: 1;
}

.demo_img:hover .play-btn {
  display: block;
  z-index: 2;
}


.demo_title {
  margin-top: 25px;
  margin-bottom: 15px;
  margin-left: 24px;
  font-weight: bold;
  font-size: 24px;
  color: #333333;
  text-align: left;
}

.demo_steps {
  margin-right: 24px;
  margin-left: 24px;
  font-weight: bold;
  font-size: 20px;
  color: rgba(70, 27, 158, 1);
  text-align: left;
}

.demo_num {
  margin-right: 4px;
  font-size: 30px;
}

.demo_desc {
  margin-top: 5px;
  margin-left: 24px;
  margin-right: 24px;
  font-weight: 400;
  font-size: 16px;
  color: #666666;
  line-height: 30px;
  text-align: left;
}

/* 视频播放模态框样式 */
.video-modal {
  display: none;
  position: fixed;
  z-index: 1000;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.9);
  overflow: auto;
}

.video-modal-content {
  position: relative;
  margin: 5% auto;
  width: 80%;
  max-width: 1200px;
  height: auto;
  background-color: #000;
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 5px 30px rgba(0, 0, 0, 0.5);
}

.close-btn {
  position: absolute;
  top: 0px;
  right: 0px;
  color: #fff;
  font-size: 40px;
  font-weight: bold;
  cursor: pointer;
  z-index: 1001;
  transition: opacity 0.3s ease;
}

.close-btn:hover {
  opacity: 0.7;
}

#videoPlayer {
  width: 100%;
  height: auto;
  display: block;
  z-index: 1;
}

.video-modal-mask {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100px;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.8), transparent);
  z-index: 2;
  pointer-events: none;
}

#new-release {
  padding-bottom: 80px;
  cursor: pointer;
}

.release_text {
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: 400;
  font-size: 30px;
  color: #666666;
  line-height: 48px;
  height: 194px;
  background: #F0F2F7;
  border-radius: 10px;
}