<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8">
    <title>CSS-Button hover effect</title>
    <link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.4.1/css/all.css">
  </head>
  <body>
    <div class="middle">
      <a class="btn" href="#">
        <i class="fab fa-facebook-f"></i>
      </a>
      <a class="btn" href="#">
        <i class="fab fa-twitter"></i>
      </a>
      <a class="btn" href="#">
        <i class="fab fa-google"></i>
      </a>
      <a class="btn" href="#">
        <i class="fab fa-instagram"></i>
      </a>
      <a class="btn" href="#">
        <i class="fab fa-youtube"></i>
      </a>
    </div>
  </body>
</html>

:root {
    --bg: #3a4fba;
    --btn-hover: #596dd4;
    --btn: #f2f2f2;
    --icon: #5e6dba;
}

body {
  padding: 0;
  margin: 0;
  background-color: var(--bg);
}

.middle {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 100%;
  text-align: center;
}

.btn {
  display: inline-block;
  width: 90px;
  height: 90px;
  background: var(--btn);
  margin: 10px;
  border-radius: 30%;
  box-shadow: 0 5px 15px -5px #000;
  color: var(--icon);
  overflow: hidden;
  position: relative;
  transition: 0.4s ease-in-out;
}

.btn i{
  position: relative;
  top: 30px;
  font-size: 26px;
  transition: 0.6s ease-in-out;
}

.btn:hover {
  background-color: var(--bg);
  box-shadow: none;
}

.btn:hover i {
  transform: scale(1.2);
  color: white;
}

.btn::before {
  content: "";
  position: absolute;
  width: 120%;
  height: 120%;
  background: var(--btn-hover);
  transform: rotate(45deg);
  left: -110%;
  top: 90%;
  transform-origin: 50% 50%;
  border-radius: 50%;
  opacity: 0;
}

.btn:hover::before {
  transform: scale(1.2);
  box-shadow: inset 0px 10px 46px -18px #000;
  opacity: 1;
  animation: sweet 0.7s 1;
  top: -10%;
  left: -10%;
}

@keyframes sweet {
  0%{
    left: -110%;
    top: 90%;
  }50%{
    left: 10%;
    top: -30%;
  }100%{
    top: -10%;
    left: -10%;
  }
}

External CSS

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External JavaScript

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