<div class="box-input">
  <div class="border">
    <input type="text" name="text" class="input" placeholder="Name">
  </div>
</div>

<style>
/* From Uiverse.io by Rodrypaladin - Tags: animation, form, input, animated, colorful */
.box-input {
  position: relative;
}

.border {
  background-image: linear-gradient(to right bottom, #e300ff, #ff00aa, #ff5956, #ffb900, #fffe00);
  box-shadow: -25px -10px 30px -5px rgba(225, 0, 255, 0.5),
    25px -10px 30px -5px rgba(255, 0, 212, 0.5),
    25px 10px 30px -5px rg