01.up_to_the_sky.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Up to the sky</title>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/3.9.1/gsap.min.js"></script>
    <style>
        body, html {
            margin: 0;
            padding: 0;
            overflow: hidden;
            width: 100%;
            height: 100%;
            background-color: #000;
        }
        .particle {
            position: absolute;
            width: 5px;
            height: 100%;
            background-color: #00FFFF;
        }
    </style>
</head>
<body>
    <script>

        function createParticle() {
            const particle = document.createElement('div');
            particle.classList.add('particle');
            particle.style.left = Math.random() * window.innerWidth + 'px';
            particle.style.top = window.innerHeight + 'px';
            document.body.appendChild(particle);
            return particle;
        }

        function animateParticles() {
            const particles = document.querySelectorAll('.particle');
            gsap.to(particles, {
                duration: 1,
                y: "-100%", // Move particles up by 100% of the window height
                ease: "power1.inOut", // Use a smooth ease in and out
                stagger: 0.01, // Apply a small delay between each particle animation
                repeat: -1, // Repeat the animation indefinitely
                yoyo: true // Make the animation play in reverse
            });
        }

        // Create particles and start the animation when the window loads
        window.onload = function() {
            const particleCount = 500;
            for (let i = 0; i < particleCount; i++) {
                createParticle();
            }
            animateParticles();
        };
    </script>
</body>
</html>