@charset "UTF-8";

/*  */
.about-history-section {
  background-color: #f7f7f7;
}

.about-history {
  margin: 50px auto 0;
  max-width: 980px;
  width: 100%;
}

.about-history-content {
  position: relative;
  z-index: 1;
  background: #fff;
  width: 100%;
}

.about-history-ctrl {
  position: absolute;
  bottom: 25px;
  left: calc(50% + 20px);
  width: 120px;
  height: 50px;
  z-index: 2;
}

.about-history-content .swiper-slide {
  opacity: 0;
  visibility: hidden;
  transition:
    opacity 0.3s,
    visibility 0.3s;
}

.about-history-poster {
  width: 50%;
}

.about-history-poster img {
  display: block;
  width: 100%;
  height: auto;
}

.about-history-content .item-content {
  position: relative;
  width: 50%;
  padding: 30px;
}

.about-history-content .item-content h2 {
  font-size: 24px;
  margin-bottom: 15px;
}

/*  */
.about-history-year {
  margin-top: 40px;
}

.about-history-line {
  flex-direction: column-reverse;
}

.about-history-line .item-lines {
  justify-content: space-between;
  align-items: flex-end;
  height: 120px;
}

.about-history-line .item-year {
  text-align: center;
}

.about-history-line .item-line {
  width: 2px;
  background-color: #434343;
  background: linear-gradient(to bottom, #ccc, transparent);
  border-radius: 4px;
}

.about-history-line .item-line:nth-child(1) {
  height: 50%;
}

.about-history-line .item-line:nth-child(2),
.about-history-line .item-line:nth-child(10) {
  height: 60%;
}

.about-history-line .item-line:nth-child(3),
.about-history-line .item-line:nth-child(9) {
  height: 70%;
}

.about-history-line .item-line:nth-child(4),
.about-history-line .item-line:nth-child(8) {
  height: 80%;
}

.about-history-line .item-line:nth-child(5),
.about-history-line .item-line:nth-child(7) {
  height: 90%;
}

.about-history-line .item-line:nth-child(6) {
  width: 2px;
  height: 100%;
  background: linear-gradient(to bottom, #ccc, transparent);
}

.about-history-line .item-line:nth-child(11) {
  width: 0;
}

.about-history-year .swiper-slide-active .item-year {
  color: var(--color-primary);
}

.about-history-year .swiper-slide-active .item-line:nth-child(6) {
  background: linear-gradient(
    to bottom,
    var(--color-primary),
    #a0c8ff,
    transparent
  );
}

.about-history-content .swiper-slide-active {
  opacity: 1;
  visibility: visible;
}

/* 平板：保持海报+文字左右并列，按钮移右 */
@media (max-width: 1024px) {
  .about-history {
    margin-top: 30px;
  }
}

/* 移动端：海报与文字上下堆叠，控件移到卡片下方居中 */
@media (max-width: 768px) {
  .about-history {
    padding-bottom: 40px;
  }

  .about-history-slide {
    flex-direction: column;
    align-items: stretch;
  }

  .about-history-poster,
  .about-history-content .item-content {
    width: 100%;
  }

  .about-history-line .item-lines {
    height: 50px;
  }

  .about-history-ctrl {
    left: 50%;
    right: auto;
    bottom: -60px;
    transform: translateX(-50%);
  }
}