/* body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif; } */
.bg-rhein-blue { background-color: #1665D8; }
.bg-rhein-footer { background-color: #003366; }
.text-rhein-blue { color: #1665D8; }

#navbar.scrolled{background: #0f4ca5;}

/* 自然减速曲线（Apple-like easing） */
.element-transition {
    transition: all 0.5s cubic-bezier(0.25, 1, 0.5, 1);
}

.img-transition {
    transition: transform 0.8s cubic-bezier(0.25, 1, 0.5, 1);
}

/* 首屏 Swiper 内部元素的错峰动画 */
/* 轮播文字基础状态：默认隐藏并下移 */
.hero-element {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s cubic-bezier(0.25, 1, 0.5, 1), 
              transform 0.8s cubic-bezier(0.25, 1, 0.5, 1);
}

/* 激活进场动画 */
.swiper-slide-active .hero-title.animate-in {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.2s; /* 标题延迟 0.2s */
}

.swiper-slide-active .hero-sub.animate-in {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.4s; /* 副标题延迟 0.4s */
}
.swiper-slide-active .hero-sub1.animate-in {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.6s; /* 副标题延迟 0.4s */
}

.swiper-slide-active .hero-btn.animate-in {
  opacity: 1;
  transform: translateY(0);
  transition-delay: 0.8s; /* 按钮延迟 0.6s */
}

/* 顺便将背景图加一个缩放淡入动效 */
.swiper-slide img {
  transform: scale(1.08);
  transition: transform 6s ease-out;
}
.swiper-slide-active img {
  transform: scale(1);
}

/* 视频按钮柔和光晕 */
@keyframes pulse-glow {
    0% { box-shadow: 0 0 0 0 rgba(22, 101, 216, 0.6); }
    70% { box-shadow: 0 0 0 16px rgba(22, 101, 216, 0); }
    100% { box-shadow: 0 0 0 0 rgba(22, 101, 216, 0); }
}
.video-glow-btn { animation: pulse-glow 2.5s infinite; }

/* 导航下划线 */
.nav-link-el {
    position: relative;
}
.nav-link-el::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 50%;
    width: 0;
    height: 2px;
    background-color: #1665D8;
    transition: all 0.3s cubic-bezier(0.25, 1, 0.5, 1);
    transform: translateX(-50%);
}
.nav-link-el:hover::after {
    width: 100%;
}