.banner-container {
  position: relative;
  width: 100%;
  height: 100px;
  overflow: hidden;
  background: #fff; /* ← 背景色に合わせて変更 */
  z-index: 0;
}

/* 左側の霞 */
.banner-container::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 30%;
  height: 100px;
  pointer-events: none;
  background: linear-gradient(to right, #f0f0f0 0%, rgba(255,255,255,0) 100%);
  z-index: 10; /* バナーより前面に */
}

/* 右側の霞 */
.banner-container::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  width: 20%;
  height: 100px;
  pointer-events: none;
  background: linear-gradient(to left, #f0f0f0 0%, rgba(255,255,255,0) 100%);
  z-index: 10; /* バナーより前面に */
}

.banner-track {
  position: relative;
  display: flex;
  transition: transform 0.5s ease;
  z-index: 1; /* バナーを前面に */
}

.banner {
  width: auto;
  height: auto;
  background: #ccc;
  margin-right: 10px;
}

.banner img {
  width: 345px;
  height: 98px;
}