*::after, *::before {
  box-sizing: border-box;
}

*{
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background: #222;
}

h2 {
  position: relative;
  font-size: 3em;
  letter-spacing: .05em;
  cursor: default;
  text-transform: uppercase;
  font-weight: 500;
}

h2 span {
  color: #555;
  transition: .25s;
}

h2:hover span {
  color: #0f0;
  text-shadow: 0 0 5px #0f0,
    0 0 15px #0f0,
    0 0 30px #0f0;
}