styles.css

/* control left margin */
* {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

html {
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  font-smooth: never;
  -webkit-font-smoothing : none;
}

body {
  margin: 1vw;
  background-color: hsl(302, 10%, 99%);
}

/* 16:9 */
#game {
  width: 98vw; /* 100 - (body margin * 2) */
  height: 54.25vw; /* 56.25 - (body margin * 2) */
  position: relative;
  background: black;
}

#game:after {
  content:"";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 50%;
  border-left: 0.75vw dotted white;
}

.paddle {
  position: absolute;
  width: 1vw;
  height: 5vw;
  background: white; /* default color */
}

.ball {
  position: absolute;
  width: 1vw;
  height: 1vw;
  background: white;
  /* default position to center court */
  top: 50%;
  left: 50%;
}

.blink {
  animation: blink 0.5s steps(1, end) infinite;
}

@keyframes blink {
  50% { opacity: 0.0; }
}

.score {
  font-family: 'Small 5x3 Regular';
  font-size: 8vw; /* not perfect, but close */
  color: white;
  position: absolute;
}

#a.score {
  left: 40vw
}

#b.score {
  left: 51.6vw;
}