body {
    margin: 0;
    overflow: hidden;
    background: black;
    font-family: monospace;
    color: #00ffff;
    width: 100%;
    height: 100%;
}

 .start {
  position: absolute;
  top: 45%;
  left: 50%;
  z-index: 1;
  font-size: 200%;
  width: 14em;
  margin: -4em 0 0 -7em;
  text-align: center;
  cursor: pointer;
}
  .start span {
  color: #4bd5ee;
}
.start img {
  width: 100px;
  display: block;
  margin: 0 auto 10px;
}

/* text */
.center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 2rem;
    letter-spacing: 2px;
    opacity: 1;
    transition: opacity 2s ease;
    text-align: center;
    white-space: pre-line;
}

/* pointer */
.cursor {
    display: inline-block;
    width: 10px;
    background: #00ffff;
    margin-left: 5px;
    animation: blink 1s infinite;
}

@keyframes blink {
    50% { opacity: 0; }
}

/* stars */
.star {
    position: absolute;
    background: white;
    border-radius: 50%;
    opacity: 0.8;
    animation: moveStar linear infinite, twinkle 2s infinite;
}

#scene {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    overflow: hidden;
    z-index: 0;
}

@keyframes moveStar {
    from { transform: translateY(0); }
    to { transform: translateY(100vh); }
}

@keyframes twinkle {
    50% { opacity: 0.2; }
}

/* Nebulah */
.nebula {
    position: fixed;
    width: 200%;
    height: 200%;
    background:
        radial-gradient(circle at 30% 30%, rgba(0,255,255,0.15), transparent),
        radial-gradient(circle at 70% 60%, rgba(255,0,255,0.15), transparent),
        radial-gradient(circle at 50% 80%, rgba(0,0,255,0.2), transparent);
    animation: moveNebula 60s linear infinite;
}


@keyframes moveNebula {
    from { transform: translate(0,0); }
    to { transform: translate(-20%, -20%); }
}