src/styles/transition.css

/* ==========================================================================
   Page Transition Animations (Swup) & Global Animations
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Swup Page Transitions
   -------------------------------------------------------------------------- */

/* Main Content Transition */
.transition-main {
    transition: 
        opacity 200ms cubic-bezier(0.25, 0.46, 0.45, 0.94),
        transform 200ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

/* Leaving Animation */
.transition-leaving {
    transition:
        transform 200ms cubic-bezier(0.55, 0.055, 0.675, 0.19),
        opacity 200ms cubic-bezier(0.55, 0.055, 0.675, 0.19);
}

/* State: Changing (Swup) */
html.is-changing .transition-main {
    transition: 
        opacity 200ms cubic-bezier(0.25, 0.46, 0.45, 0.94),
        transform 200ms cubic-bezier(0.25, 0.46, 0.45, 0.94);
}

html.is-leaving .transition-main {
    transition: 
        opacity 200ms cubic-bezier(0.55, 0.055, 0.675, 0.19),
        transform 200ms cubic-bezier(0.55, 0.055, 0.675, 0.19);
}

/* State: Animating (Entering) */
html.is-animating .transition-main {
    opacity: 0;
    transform: translateY(1.5rem) translateX(0.5rem);
}

/* State: Leaving */
html.is-animating.is-leaving .transition-leaving {
    transform: translateY(-1rem) translateX(-0.5rem);
    opacity: 0;
}

/* Swup Fade Fallback */
html.is-changing .transition-swup-fade {
    transition: all 300ms ease-out;
}

html.is-animating .transition-swup-fade {
    opacity: 0;
    transform: translateY(1.5rem);
}

/* --------------------------------------------------------------------------
   2. Keyframes
   -------------------------------------------------------------------------- */

@keyframes fade-in-up {
    from {
        opacity: 0;
        transform: translateY(1.5rem) translateX(0.5rem);
    }
    to {
        opacity: 1;
        transform: translateY(0) translateX(0);
    }
}

/* --------------------------------------------------------------------------
   3. Onload Animations
   -------------------------------------------------------------------------- */

.onload-animation {
    opacity: 0;
    animation: fade-in-up 200ms ease-out forwards;
}

/* 渐进式动画延迟 */
.onload-animation:nth-child(1) { animation-delay: 0ms; }
.onload-animation:nth-child(2) { animation-delay: 50ms; }
.onload-animation:nth-child(3) { animation-delay: 100ms; }
.onload-animation:nth-child(4) { animation-delay: 150ms; }
.onload-animation:nth-child(5) { animation-delay: 200ms; }