<div class="gradient">CSS Gradient</div>
<div class="gradient__css__custom">CSS Gradient with CSS Custom Property</div>
<div class="gradient__css__houdini">CSS Gradient with CSS Houdini</div>

@import url("https://fonts.googleapis.com/css2?family=Exo:wght@600&display=swap");

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

body {
  width: 100vw;
  min-height: 100vh;
  font-family: "Exo", Arial, sans-serif;
  background-color: #222;
  color: #fff;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.5rem;
  gap: 10px;
}

div {
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: 10rem;
  padding: 10px 30px;
  min-height: 90px;
  cursor: pointer;
}

.gradient {
  background-image: linear-gradient(to right, #0f9, #09f);
  transition: all 0.28s linear;
}

.gradient:hover {
  color: #f36;
  background-image: linear-gradient(to right, #09f, #0f9);
}

.gradient__css__custom {
  --colorStar: #ff9500;
  --colorStop: #b320b0;
  background-image: linear-gradient(
    to right,
    var(--colorStar),
    var(--colorStop)
  );
  transition: --colorStart 0.28s linear, --colorStop 0.28s linear;
}

.gradient__css__custom:hover {
  background-image: linear-gradient(
    to right,
    var(--colorStop),
    var(--colorStar)
  );
}

@property --startColor {
  syntax: "<color>";
  initial-value: magenta;
  inherits: false;
}

@property --stopColor {
  syntax: "<color>";
  initial-value: magenta;
  inherits: false;
}

@property --stop {
  syntax: "<percentage>";
  initial-value: 50%;
  inherits: false;
}

.gradient__css__houdini {
  --startColor: #2196f3;
  --stopColor: #ff9800;
  transition: --stop 0.5s, --startColor 0.2s, --stopColor 0.2s;
  background: linear-gradient(
    to right,
    var(--startColor) var(--stop),
    var(--stopColor)
  );
}

.gradient__css__houdini:hover {
  --startColor: #ff9800;
  --stopColor: #2196f3;
  --stop: 80%;
}