The rain effect is driven by an HTML5 that calculates downward velocity vectors for hundreds of stroke lines. To optimize performance, the lightning flashes are handled via a separate CSS animation adjusting background overlay opacity, preventing the canvas from needing to recompute full-screen fillRect paint operations.
<!DOCTYPE html>
<html>
<head>
<title>1. Urban Downpour with Lightning</title>
<style>
:root {
--rain-bg: #11141d;
--drop-color: #cbd5e1;
}
body {
margin: 0;
height: 100vh;
background-color: var(--rain-bg);
overflow: hidden;
position: relative;
}
.rain-container {
position: absolute;
top: 0; left: 0;
width: 100%; height: 100%;
}
.rain-drop {
position: absolute;
bottom: 100%;
width: 2px;
background: linear-gradient(to top, transparent, var(--drop-color));
animation: fall 10s infinite linear;
}
/* Far layer - slower, smaller, more transparent */
.rain-drop.back {
opacity: 0.4;
height: 30px;
animation-duration: 2s;
animation-timing-function: linear;
}
/* Mid layer - standard */
.rain-drop.mid {
opacity: 0.6;
height: 50px;
animation-duration: 1.2s;
animation-timing-function: linear;
}
/* Near layer - faster, larger, more opaque */
.rain-drop.front {
opacity: 1;
height: 80px;
animation-duration: 0.7s;
animation-timing-function: linear;
}
@keyframes fall {
from { transform: translateY(0vh); }
to { transform: translateY(110vh); }
}
.splash {
position: absolute;
bottom: 0;
width: 4px;
height: 4px;
border-radius: 50%;
background-color: var(--drop-color);
opacity: 0;
transform: scale(0);
animation: splash-up 10s infinite ease-out;
}
@keyframes splash-up {
0% { opacity: 0; transform: scale(0) translateY(0); }
2% { opacity: 1; transform: scale(1) translateY(-10px); } /* Initial impact */
5% { opacity: 0; transform: scale(1.5, 0.5) translateY(-50px); } /* Disperse */
100% { opacity: 0; }
}
/* Lightning Flash Effect */
.lightning {
position: absolute;
top: 0; left: 0;
width: 100%; height: 100%;
background: radial-gradient(circle at 50% 0%, white, transparent 40%);
opacity: 0;
animation: flash 10s infinite step-end;
}
@keyframes flash {
0%, 94%, 100% { opacity: 0; }
94.1% { opacity: 0.6; }
94.2% { opacity: 0.1; }
94.3% { opacity: 0.8; }
94.6% { opacity: 0; }
}
</style>
</head>
<body>
<div class="lightning"></div>
<div class="rain-container" id="rainContainer"></div>
<script>
const container = document.getElementById('rainContainer');
const totalDrops = 400;
for (let i = 0; i < totalDrops; i++) {
const drop = document.createElement('div');
const splash = document.createElement('div');
const layer = Math.random();
let layerClass = 'front';
if (layer < 0.33) layerClass = 'back';
else if (layer < 0.66) layerClass = 'mid';
drop.className = `rain-drop ${layerClass}`;
splash.className = 'splash';
const leftPosition = `${Math.random() * 105 - 5}%`; // -5 to 105 to cover edges
drop.style.left = leftPosition;
splash.style.left = leftPosition;
const delay = Math.random() * -10; // Use negative delay to start immediately
drop.style.animationDelay = `${delay}s`;
// Match splash delay to the corresponding drop duration
const dropDuration = parseFloat(drop.style.animationDuration || '0.7s');
splash.style.animationDelay = `${delay + dropDuration}s`;
container.appendChild(drop);
container.appendChild(splash);
}
</script>
</body>
</html>Step-by-step instructions to integrate Urban Downpour into your project.
<style> block into your CSS <script> block before your closing </body> tag position: fixed; inset: 0; z-index: -1 pointer-events: none to the container if the animation blocks clicks