HTMLify

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

*:focus {
	outline: 0;
}

html {
	-webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

body {
  background-color: #0c0c0c;
  display: grid;
  min-height: 100vh;
  overflow: hidden;
}

.modal {
  align-items: center;
  background-color: rgba(0, 0, 0, 0.9);
  display: flex;
  flex-direction: column;
  height: 100vh;
  justify-content: center;
  left: 0;
  position: absolute;
  top: 0;
  transition: opacity 0.3s ease-out,
              transform 0.3s ease-out;
  width: 100%;
  z-index: 3;
}

.modal.hide {
  opacity: 0;
  transform: scale(0);
}

.btn-start {
  background-color: #404040;
	border-radius: 2px;
	box-shadow: 1px 0px #202020,
							0px 1px #202020,
							2px 1px #202020,
							1px 2px #202020,
							3px 2px #202020,
							2px 3px #202020,
							4px 3px #202020,
							3px 4px #202020,
							5px 4px #202020,
							4px 5px #202020,
							6px 5px #202020,
							5px 6px #202020;
  border-style: none;
  color: #cdcdcd;
  cursor: pointer;
  font: normal 1.5rem 'Shrikhand', sans-serif;
  letter-spacing: 5px;
  padding: 10px 30px;
  position: relative;
  text-transform: uppercase;
}

.btn-start:hover,
.btn-start:focus {
	background-color: #5a5a5a;
}

.btn-start:active {
	box-shadow: 1px 0px #202020,
	 						0px 1px #202020,
	 						2px 1px #202020,
	 						1px 2px #202020,
	 						3px 2px #202020,
	 						2px 3px #202020,
	 						4px 3px #202020,
	 						3px 4px #202020;
  transform: translate(2px);
}

p {
  color: #cdcdcd;
  font: normal 2rem 'Shrikhand', sans-serif;
  letter-spacing: 3px;
  margin: 1.25rem 0;
  text-align: center;
  text-transform: uppercase;
}

.container-colors {
  align-items: center;
  border-radius: 50%;
  box-shadow: 0 0 0 7px #cdcdcd;
  display: flex;
  height: 90%;
  justify-content: center;
  margin: auto;
  max-height: 400px;
  max-width: 400px;
  overflow: hidden;
  position: relative;
  width: 90%;
}

.circle {
  align-items: center;
  background-color: #cdcdcd;
  border-radius: 50%;
  box-shadow: 0 0 5px #000000 inset;
  color: #0c0c0c;
  display: flex;
  font: normal 1.5rem 'Shrikhand', sans-serif;
  height: 20%;
  justify-content: center;
  left: 50%;
  position: absolute;
  text-align: center;
  top: 50%;
  transform: translate(-50%, -50%);
  width: 20%;
  z-index: 2;
}

.colors {
  box-shadow: 0 0 150px #000000 inset,
              0 0 0 7px #cdcdcd;
  cursor: pointer;
  height: 250px;
  transition: background-color 0.2s ease,
              box-shadow 0.3s ease-out;
  width: 250px;
  z-index: 1;
}

.colors:hover,
.colors:focus {
  box-shadow: 0 0 50px #000000 inset,
              0 0 0 7px #cdcdcd;
}

.colors.active,
.colors:active {
  background-color: #000000;
}

.red {
  background-color: #ff0000;
}

.green {
  background-color: #00ff00;
}

.blue {
  background-color: #0000ff;
}

.yellow {
  background-color: #ffff00;
}

@media screen and (max-width: 500px) {
  .container-colors {
    max-height: 250px;
    max-width: 250px;
  }
}