style.css

body {
  background-color: #F2EDD8;
  font-family: 'Lato', sans-serif;
}

h1 {
  max-width: 500px;
  margin: 2rem auto 2rem auto;
  font-size: 4rem;
  text-align: center;
  font-family: 'Erica One', cursive;
}

.game-board {
  width: 350px;
  margin: 2rem auto auto auto;
  position: relative;
}

.game-btns {
  width: 265px;
  height: 265px;
  background-color: #fcfbf7;
  border-radius: 10px;
  box-shadow: 0px 0px 10px 10px #aea5a2;
}

.display-wrapper {
  margin: 3rem auto 2rem auto;
}

.display {
  width: 265px;
  height: 50px;
  background-color: #dcf9de;
  color: #5D4C46;
  font-weight: bold;
  border-radius: 5px;
  border: 3px inset #D3D3D3;
  align-items: center;
  display: flex;
}

.game-btn {
  width: 110px;
  height: 110px;
  border-radius: 5px;
  margin: 3px;
  border: none;
}

.game-btn:active, .game-btn:focus, .strict-btn:focus {
  outline: none;
}

#btn1 {
  background-color: #5D4C46;
  margin-top: 19px;
}

#btn2 {
  background-color: #44B3C2;
  margin-top: 19px;
}

#btn3 {
  background-color: #F1A94E;
}

#btn4 {
  background-color: #E45641;
}

.strict-btn-on {
  border: 2px solid #F31431;
  color: #F31431 !important;
}

.ctrl-btns {
  width: 250px;
  margin: 2rem auto 20rem auto;
}

.ctrl-btn {
  border-radius: 5px;
  height: 45px;
  width: 70px;
  font-weight: bold;
  color: #5D4C46;
}

.footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 23px;
  font-size: 15px;
  color: x000000;
  background-color: #c3bfae;
}