RNG tool

HTML

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>RNG Tool</title>
</head>
<body>
  <div class="stars"></div>
  <h1>Random Number Generator</h1>
  <p class="description">This tool randomly generates a value from 0-5000000000</p>
  <p class="reveal">Your randomly generated number is:</p>
  <p class="number"><span id="randomNum"></span></p>
  <button onclick="randomNumGen()">Generate</button>
</body>
</html>

CSS

@keyframes moveGradient {
    from {
        background-position: 0 0;
    }

    to {
        background-position: 400px 0;
    }
}

body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #1b1e24;
  color: white;
}

button {
  padding: 10px 20px;
  border: none;
  border-radius: 8px;
  color: white;
  font-size: 18px;
  cursor: pointer;

background: repeating-linear-gradient(
          145deg,
#534ed9 0px,
#a4a2e0 100px,
#534ed9 200px
);

background-size: 300% 300%;

animation: gradientMove 1s linear infinite;
}

button:hover {
transform: scale(1.05);
}

.number {
margin-bottom: 20px;
}

#randomNum {
    display: none;
  padding: 6px 12px;
  border: 3px;
  border-style: solid;
  border-color: red;
  border-radius: 8px;
  color: white;
  font-size: 16px;
  background: rgba(245, 0, 0, 0.4);
}

#randomNum.show {
  display: inline-block
}

.stars {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: -1;
}

.stars span {
    position: absolute;
    display: block;

    background: white;
    border-radius: 50%;

    animation: twinkle 2s infinite alternate;
}

@keyframes twinkle {
    from {
        opacity: 0.2;
    }

    to {
        opacity: 1;
    }
}

JavaScript

function randomNumGen() {
const randomNum = Math.floor(Math.random() * 5000000001) + 1;
console.log(randomNum);

    const output = document.getElementById("randomNum");
    output.textContent = randomNum;
    output.classList.add("show");
} ;

const stars = document.querySelector(".stars");

for (let i = 0; i < 150; i++) {
    const star = document.createElement("span");

    star.style.left = Math.random() * 100 + "%";
    star.style.top = Math.random() * 100 + "%";

    const size = Math.random() * 3 + 1;
    star.style.width = size + "px";
    star.style.height = size + "px";

    star.style.animationDelay = Math.random() * 4 + "s";

    stars.appendChild(star);
}