/* 基础动画类 */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* 从左侧滑入 */
.slide-in-left {
    opacity: 0;
    transform: translateX(-100px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.slide-in-left.visible {
    opacity: 1;
    transform: translateX(0);
}

/* 从右侧滑入 */
.slide-in-right {
    opacity: 0;
    transform: translateX(100px);
    transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.slide-in-right.visible {
    opacity: 1;
    transform: translateX(0);
}

/* 时间轴动画 */
.timeline-year-item {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease-out, transform 0.5s ease-out;
    transition-delay: calc(var(--animation-order) * 0.2s);
}

.timeline-year-item.visible {
    opacity: 1;
    transform: translateY(0);
}