style.css

/*multi cursor -> alt+click*/
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: Verdana, Geneva, Tahoma, sans-serif;
}

body {
  width: 100%;
  height: 100vh; /*view height*/
  background: linear-gradient(
    to right bottom,
    #000000,
    #144272,
    /*#7b8fa1,*/ #cfb997
  );
  color: #e9f8f9;
  display: grid;
  place-items: center;
}

.container {
  width: 80%;
  max-width: 850px;
  padding: 30px;
  text-align: center;
  display: none;
}

.container h1 {
  font-size: 36px;
  margin-bottom: 40px;
  text-decoration: underline;
  text-underline-offset: 8px;
}

.container .question {
  font-size: 26px;
  margin-top: 20px;
}

.container .choices {
  margin-top: 20px;
}

.choice {
  font-size: 20px;
  background-color: #eee;
  color: #000;
  margin: 10px auto;
  padding: 10px;
  border-radius: 5px;
  text-align: left;
  width: 60%;
  cursor: pointer;
  opacity: 0;
  transform: translateY(50%);
  animation: fade-in 0.5s ease forwards;
}

.choice:hover {
  background-color: #dbe4c6;
}

.choices .selected {
  background-color: #0b2447;
  color: white;
}

.btn {
  width: 60%;
  font-size: 20px;
  padding: 12px 20px;
  font-weight: 600;
  margin: 20px auto 0 auto;
  background-color: #0b2447;
  color: #eee;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}
.btn:hover {
  background-color: #144272;
}

.scoreCard {
  font-size: 24px;
  margin-top: 20px;
}

.alert {
  background-color: #3ac251;
  border-radius: 5px;
  width: 100%;
  padding: 12px;
  position: absolute;
  top: 0;
  display: none;
}

.startBtn {
  background: linear-gradient(
    to right bottom,
    #000000,
    #144272,
    /*#7b8fa1,*/ #cfb997
  );
  width: 15%;
  padding-block: 20px;
  text-align: center;
}

.timer {
  position: absolute;
  top: 20px;
  right: 20px;
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background-color: #0b2447;
  border: 2px solid #cfb997;
  font-size: 24px;
  font-weight: 600;
  padding: 12px;
  display: flex;
  justify-content: center;
  align-items: center;
  animation: pulse 1s ease-in-out infinite;
}

/*adding animation to timer*/
@keyframes pulse {
  0% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.2);
  }
  100% {
    transform: scale(1);
  }
}

/*adding animation to choices*/
@keyframes fade-in {
  0% {
    opacity: 0;
    transform: translateY(50%);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

@media screen and (max-width: 900px) {
  .container {
    width: 100%;
    margin-top: 50px;
  }

  .container h1 {
    font-size: 24px;
  }

  .container .question {
    font-size: 22px;
  }

  .timer {
    width: 50px;
    height: 50px;
    font-size: 20px;
  }

  .startBtn {
    width: 50%;
  }
}