Neon

<button class="btn-gradient-neon" type="button">
  <span>Get started</span>
</button>

.btn-gradient-neon {
  --btn-bg: #0b0b12;
  --btn-bg2: #22d3ee;
  --btn-fg: #22d3ee;
  --btn-font: inherit;
  --btn-size: 15px;
  --btn-weight: 600;
  --btn-px: 22px;
  --btn-py: 11px;
  --btn-w: auto;
  --btn-h: auto;
  --btn-bw: 0px;
  --btn-line: #8b6cff;
  --btn-radius: 10px;
  --btn-glow: 18px;
  --btn-speed: 180ms;
}

.btn-gradient-neon {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  box-sizing: border-box;
  width: var(--btn-w);
  height: var(--btn-h);
  padding: var(--btn-py) var(--btn-px);
  font-family: var(--btn-font);
  font-size: var(--btn-size);
  font-weight: var(--btn-weight);
  line-height: 1.2;
  color: var(--btn-fg);
  background: var(--btn-bg);
  border: var(--btn-bw) solid var(--btn-line);
  border-radius: var(--btn-radius);
  box-shadow: 0 0 var(--btn-glow) color-mix(in srgb, var(--btn-bg2) 60%, transparent), inset 0 0 0 1.5px var(--btn-bg2);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: all var(--btn-speed) ease;
  text-shadow: 0 0 10px var(--btn-bg2);
}

.btn-gradient-neon:focus-visible {
  outline: 2px solid var(--btn-bg);
  outline-offset: 2px;
}

.btn-gradient-neon:disabled {
  opacity: 0.5;
  pointer-events: none;
}

.btn-gradient-neon__icon {
  width: 1.15em;
  height: 1.15em;
  flex-shrink: 0;
}

.btn-gradient-neon:hover {
  box-shadow: 0 0 calc(var(--btn-glow) * 2) var(--btn-bg2), inset 0 0 0 1.5px var(--btn-bg2);
}

@media (prefers-reduced-motion: reduce) {
  .btn-gradient-neon {
    animation: none !important;
    transition: none !important;
  }
}

// No JavaScript needed: this one is CSS only.

import type React from "react";
import "./gradient-neon.css"; // the CSS tab

export function BtnGradientNeon({ children = "Get started", ...props }: React.ComponentProps<"button">) {
  return (
    <button className="btn-gradient-neon" type="button" {...props}>
      <span>{children}</span>
    </button>
  );
}

<button class="relative inline-flex items-center justify-center gap-[0.5em] [box-sizing:border-box] [padding:11px_22px] [font-family:inherit] text-[15px] font-[600] [line-height:1.2] text-[#22d3ee] bg-[#0b0b12] [border:0px_solid_#8b6cff] rounded-[10px] [box-shadow:0_0_18px_color-mix(in_srgb,_#22d3ee_60%,_transparent),_inset_0_0_0_1.5px_#22d3ee] cursor-pointer no-underline whitespace-nowrap [transition:all_180ms_ease] [text-shadow:0_0_10px_#22d3ee] focus-visible:[outline:2px_solid_#0b0b12] focus-visible:[outline-offset:2px] disabled:[opacity:0.5] disabled:[pointer-events:none] hover:[box-shadow:0_0_calc(18px_*_2)_#22d3ee,_inset_0_0_0_1.5px_#22d3ee] motion-reduce:[transition:none!important]" type="button">
  <span>Get started</span>
</button>