<button class="glow-button">
  <span>Button</span>
</button>

<!-- twitter -->
<a class="twitter" target="_top" href="https://twitter.com/aaroniker_me"><svg xmlns="http://www.w3.org/2000/svg" width="72" height="72" viewBox="0 0 72 72"><path d="M67.812 16.141a26.246 26.246 0 0 1-7.519 2.06 13.134 13.134 0 0 0 5.756-7.244 26.127 26.127 0 0 1-8.313 3.176A13.075 13.075 0 0 0 48.182 10c-7.229 0-13.092 5.861-13.092 13.093 0 1.026.118 2.021.338 2.981-10.885-.548-20.528-5.757-26.987-13.679a13.048 13.048 0 0 0-1.771 6.581c0 4.542 2.312 8.551 5.824 10.898a13.048 13.048 0 0 1-5.93-1.638c-.002.055-.002.11-.002.162 0 6.345 4.513 11.638 10.504 12.84a13.177 13.177 0 0 1-3.449.457c-.846 0-1.667-.078-2.465-.231 1.667 5.2 6.499 8.986 12.23 9.09a26.276 26.276 0 0 1-16.26 5.606A26.21 26.21 0 0 1 4 55.976a37.036 37.036 0 0 0 20.067 5.882c24.083 0 37.251-19.949 37.251-37.249 0-.566-.014-1.134-.039-1.694a26.597 26.597 0 0 0 6.533-6.774z"></path></svg></a>
.glow-button {
  --button-background: #09041e;
  --button-color: #fff;
  --button-shadow: rgba(33, 4, 104, 0.2);
  --button-shine-left: rgba(120, 0, 245, 0.5);
  --button-shine-right: rgba(200, 148, 255, 0.65);
  --button-glow-start: #B000E8;
  --button-glow-end: #009FFD;

  appearance: none;
  outline: none;
  border: none;
  font-family: inherit;
  font-size: 16px;
  font-weight: 500;
  border-radius: 11px;
  position: relative;
  line-height: 24px;
  cursor: pointer;
  color: var(--button-color);
  padding: 0;
  margin: 0;
  background: none;
  z-index: 1;
  box-shadow: 0 8px 20px var(--button-shadow);

  .gradient {
    position: absolute;
    inset: 0;
    border-radius: inherit;
    overflow: hidden;
    -webkit-mask-image: -webkit-radial-gradient(white, black);
    transform: scaleY(1.02) scaleX(1.005) rotate(-.35deg);

    &:before {
      content: '';
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      transform: scale(1.05) translateY(-44px) rotate(0deg) translateZ(0);
      padding-bottom: 100%;
      border-radius: 50%;
      background: linear-gradient(90deg, var(--button-shine-left), var(--button-shine-right));
      animation: rotate linear 2s infinite;
    }
  }

  span {
    z-index: 1;
    position: relative;
    display: block;
    padding: 10px 28px;
    box-sizing: border-box;
    width: fit-content;
    min-width: 124px;
    border-radius: inherit;
    background-color: var(--button-background);
    overflow: hidden;
    -webkit-mask-image: -webkit-radial-gradient(white, black);

    &:before {
      content: '';
      position: absolute;
      left: -16px;
      top: -16px;
      transform: translate(var(--pointer-x, 0px), var(--pointer-y, 0px)) translateZ(0);
      width: 32px;
      height: 32px;
      border-radius: 50%;
      background-color: var(--button-glow, transparent);
      opacity: var(--button-glow-opacity, 0);
      transition: opacity var(--button-glow-duration, .5s);
      filter: blur(20px);
    }
  }

  &:hover {
    --button-glow-opacity: 1;
    --button-glow-duration: .25s;
  }
}

@keyframes rotate {
  to {
    transform: scale(1.05) translateY(-44px) rotate(360deg) translateZ(0);
  }
}

html {
  box-sizing: border-box;
  -webkit-font-smoothing: antialiased;
}

* {
  box-sizing: inherit;
  &:before,
  &:after {
    box-sizing: inherit;
  }
}

// Center
body {
  min-height: 100vh;
  display: flex;
  font-family: 'Inter', Arial;
  justify-content: center;
  align-items: center;
  background-color: #020112;
  overflow: hidden;

  &:before {
    content: '';
    position: absolute;
    inset: 40% -60% 0 -60%;
    background-image: radial-gradient(ellipse at bottom, #1D0559 0%, #020112 50%);
    opacity: .4;
  }

  .twitter {
    position: fixed;
    display: block;
    right: 12px;
    bottom: 12px;
    svg {
      width: 32px;
      height: 32px;
      fill: #fff;
    }
  }
}
View Compiled
const generateGlowButtons = () => {
    document.querySelectorAll(".glow-button").forEach((button) => {
        let gradientElem = button.querySelector('.gradient');
        
        if(!gradientElem) {
            gradientElem = document.createElement("div");
            gradientElem.classList.add("gradient");

            button.appendChild(gradientElem);
        }

        button.addEventListener("pointermove", (e) => {
            const rect = button.getBoundingClientRect();

            const x = e.clientX - rect.left;
            const y = e.clientY - rect.top;

            gsap.to(button, {
                "--pointer-x": `${x}px`,
                "--pointer-y": `${y}px`,
                duration: 0.6,
            });

            gsap.to(button, {
                "--button-glow": chroma
                .mix(
                    getComputedStyle(button)
                    .getPropertyValue("--button-glow-start")
                    .trim(),
                    getComputedStyle(button).getPropertyValue("--button-glow-end").trim(),
                    x / rect.width
                )
                .hex(),
                duration: 0.2,
            });
        });
    });
}

// Set variables on loaded
document.addEventListener('DOMContentLoaded', generateGlowButtons);

// Set variables on resize
window.addEventListener('resize', generateGlowButtons);

External CSS

  1. https://cdnjs.cloudflare.com/ajax/libs/inter-ui/3.19.3/inter.css

External JavaScript

  1. https://unpkg.co/gsap@3/dist/gsap.min.js
  2. https://cdnjs.cloudflare.com/ajax/libs/chroma-js/2.4.2/chroma.min.js