.about-video-wrap { width:100%; margin-top:30px; position:relative; }
.about-video {
  width:100%;
  aspect-ratio:16 / 9;
  object-fit:contain;
  display:block;
  background:#000;
}
.video-sound-btn {
  position:absolute;
  right:10px;
  bottom:10px;
  z-index:5;
  padding:6px 12px;
  font-size:14px;
  line-height:1;
  color:#fff;
  background:rgba(0,0,0,0.55);
  border:1px solid rgba(255,255,255,0.6);
  border-radius:18px;
  cursor:pointer;
  -webkit-tap-highlight-color: transparent;
  user-select:none;
}
.video-sound-btn:hover { background:rgba(0,0,0,0.78); }

.video-title {
  margin-top:30px;
  font-size:18px;
  font-weight:500;
  color:#ff7a00;
  text-align:center;
  line-height:1.5;
}

/* 平板/手机端：增加容器边距、缩小按钮与标题 */
@media (max-width: 768px) {
  .about-video-wrap { margin-top:8px; padding:0 12px; }
  .video-title { font-size:16px; margin-top:20px; }
  .video-sound-btn {
    right:18px;
    bottom:12px;
    padding:5px 10px;
    font-size:12px;
    border-radius:14px;
  }
}

/* 小屏手机：进一步缩小 */
@media (max-width: 414px) {
  .about-video-wrap { padding:0 10px; }
  .video-title { font-size:15px; margin-top:16px; }
  .video-sound-btn {
    right:16px;
    bottom:10px;
    padding:4px 8px;
    font-size:11px;
    border-radius:12px;
  }
}