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

/* PC端 */
@media (min-width: 768px) {
  .img-a { height: 600px; width: auto; display: block; }
  .scroll-box {
    height: 600px;
    overflow: hidden;
    display: inline-block;
  }
  .scroll-wrapper {
    display: block;
    animation: scrollUp 120s linear infinite;
  }
  .img-b {
    display: block;
    height: auto;
    width: auto;
  }
  .carousel-container { display: none; }
}

@keyframes scrollUp {
  0% { transform: translateY(0); }
  100% { transform: translateY(-50%); }
}

/* 移动端 */
@media (max-width: 767px) {
  .custom-container { flex-direction: row; justify-content: center; align-items: flex-start; }
  .img-a { display: none; }
  .scroll-box { display: none; }

  .carousel-container {
    width: 100%;
    overflow: hidden;
    position: relative;
  }
  .carousel-track {
    display: flex;
    width: max-content;
    animation: scrollHorizontal 60s linear infinite;
  }
  .carousel-item {
    display: block;
    height: 200px;
    width: auto;
    margin-right: 5px;
    object-fit: cover;
  }
  @keyframes scrollHorizontal {
    0% { transform: translateX(0); }
    100% { transform: translateX(-100%); }
  }
}