style.css

@import url('https://fonts.googleapis.com/css2?family=Itim&display=swap');

body {
  font-family: 'Itim', cursive;
  background-color: #dfe6e9;
  -webkit-tap-highlight-color: rgba(0,0,0,0);
  user-select: none;
}

section {
  text-align: center;
}

.game--title {
  margin-top: 40px;
  font-size: 40px;
  color: #2d3436;
}

.game--container {
  display: grid;
  grid-template-columns: repeat(3, auto);
  width: 306px;
  margin: 40px auto;
}

.cell {
  width: 100px;
  height: 100px;
  box-shadow: 0 0 0 1px #2d3436;
  border: 1px solid #2d3436;
  cursor: pointer;
  line-height: 100px;
  font-size: 60px;
}

.game--status {
  color: #636e72;
  margin-bottom: 35px;
}

.game--restart {
  position: relative;
  background-color: #fdcb6e;
  border: none;
  border-radius: 25px;
  font-size: 17px;
  color: #2d3436;
  padding: 15px;
  width: 150px;
  text-align: center;
  -webkit-transition-duration: 0.5s; /* Safari */
  transition-duration: 0.5s;
  text-decoration: none;
  overflow: hidden;
  cursor: pointer;
}

.game--restart:after {
  content: "";
  background: #ffeaa7;
  display: block;
  position: absolute;
  border-radius: 25px;
  padding-top: 300%;
  padding-left: 350%;
  margin-left: -20px !important;
  margin-top: -120%;
  opacity: 0;
  transition: all 1.5s;
}

.game--restart:active:after {
  padding: 0;
  margin: 0;
  opacity: 1;
  transition: 0s;
}