index.css

* {
  margin: 0;
  padding: 0;
  overflow: hidden;
  font-family: "Courier New", Courier, monospace;
}
body {
  height: 100vh;
  width: 100vw;
  display: grid;
  justify-content: center;
  align-content: center;
  /* background: linear-gradient(rgb(9, 9, 188), rgb(14, 14, 205)); */
  background-color: rgb(14, 14, 14);
  background-size: cover;
  background-repeat: no-repeat;
}
.container {
  width: 400px;
  height: fit-content;
  background: rgb(195, 255, 0);
  padding: 20px 40px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-content: center;
  margin-top: 50px;
  border-radius: 5px;
  box-shadow: 5px 5px 10px 2px rgba(0, 0, 0, 0.1);
}
.container h2 {
  margin-bottom: 10px;
  font-size: 35px;
  text-align: center;
  color: brown;
}
form .nole {
  display: flex;
  justify-content: space-between;
  align-items: center;
}
form label {
  display: block;
  margin-bottom: 10px;
  text-align: center;
}
form input {
  width: 280px;
  height: 30px;
  padding-left: 10px;
  border: 1px solid black;
  display: inline;
}
form button {
  width: 100px;
  height: 30px;
  cursor: pointer;
  font-size: 10px;
  font-weight: 500;
  display: inline;
  background-color: brown;
  color: rgb(195, 255, 0);
  border: none;
}
.demo {
  padding-top: 10px;
  font-size: 12px;
  text-align: center;
}
.score {
  position: absolute;
  top: 20px;
  right: 20px;
  font-size: 25px;
  font-weight: 800;
  color: white;
}
.score span {
  color: rgb(195, 255, 0);
  animation: load 2s linear;
}

.score span::before {
  content: "0";
  margin-left: -15px;
}

@keyframes load {
  0% {
    opacity: 0;
  }
  20% {
    opacity: 1;
  }
  50% {
    opacity: 0.4;
  }
  100% {
    opacity: 1;
  }
}

@media only screen and (max-width: 400px) {
  .container {
    width: 250px;
    margin: auto;
  }
}