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

html,
body {
    width: 100%;
    height: 100%;
    /* background: linear-gradient(limegreen,yellow); */
}

#starCanvas {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  z-index: -1;
  background: radial-gradient(ellipse at bottom, #0d1b2a 0%, #000000 100%);
}

#main {
    height: 100%;
    width: 100%;
    display: flex;
    justify-content: center;
    align-content: center;
}

#rulesScreen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.85);
    color: white;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 20px;
    z-index: 999;
}

#rulesScreen h2 {
    margin-bottom: 10px;
}

#rulesScreen p {
    max-width: 600px;
    margin-bottom: 20px;
}

#startBtn {
    padding: 10px 20px;
    font-size: 18px;
    cursor: pointer;
    background-color: #00bbd4d3;
    border: none;
    border-radius: 5px;
    color: white;
    transition: background-color 0.3s;
}

#startBtn:hover {
    background-color: #0096a7d6;
}

.gamebox {
    align-items: center;
    justify-items: center;
}

.input {
    border: 4px solid violet;
    box-shadow:
        0 0 5px whitesmoke,
        0 0 10px whitesmoke,
        0 0 20px whitesmoke;
    transition: box-shadow 0.3s ease-in-out;
}

.hint p {
    justify-content: center;
    color: aliceblue;
    font-size: 1.5rem;
    white-space: wrap;
    margin-inline: auto;
    overflow: hidden;
    animation: typing 3s steps(220) forwards;
}

@keyframes typing {
    from {
        width: 0;
    }

    to {
        width: 100%;
    }
}

.numbers {
    display: grid;
    grid-template-rows: repeat(4, 70px);
    grid-template-columns: repeat(3, 66px);
}

.switch {
    width: 50px;

}

#number{
    width: 130px;
    height: 100px;
    font-size: 5rem;
}

/* button */
.btn {
  font-size: 2rem;
  border: 1px solid black;
  outline: none;
  color: black;
  cursor: pointer;
  position: relative;
  z-index: 0;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
}
.btn::after {
  content: "";
  z-index: -1;
  position: absolute;
  width: 100%;
  height: 100%;
  background-color: #fcfcfc;
  left: 0;
  top: 0;
  border-radius: 50%;
}
/* glow */
.btn::before {
  content: "";
  background: linear-gradient(
    45deg,
    #FF0000, #FF7300, #FFFB00, #48FF00,
    #00FFD5, #002BFF, #FF00C8, #FF0000
  );
  position: absolute;
  top: -2px;
  left: -2px;
  background-size: 600%;
  z-index: -1;
  width: calc(100% + 4px);
  height:  calc(100% + 4px);
  filter: blur(8px);
  animation: glowing 20s linear infinite;
  transition: opacity .3s ease-in-out;
  border-radius: 50%;
  opacity: 0;
}

@keyframes glowing {
  0% {background-position: 0 0;}
  50% {background-position: 400% 0;}
  100% {background-position: 0 0;}
}

/* hover */
.btn:hover::before,
.btn:active::before,
.btn:focus-visible::before {
  opacity: 1;
}

.btn:active:after {
  background: transparent;
}

.btn:active {
  color: #000;
  font-weight: bold;
}