* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
  font-family: Arial, Helvetica, sans-serif;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #f0f0f0;
}

 .hide {
  display: none;
} 

.welcome {
  font-weight: bolder;
  font-size: 50px;
  margin-bottom: 10px;
}

.html-btn {
  height: 35px;
  width: 100px;
  padding: 5px 7px;
  border: 1px solid black;
  border-radius: 20px;
  font-weight: bold;
  font-size: 18px;
  transition: all 0.3s ease;
  margin-bottom: 10px;
}
.html-btn:hover {
  background-color: black;
  color: white;
}

.opt-button{
  border: 1px solid;
  display: block;
  padding: 5px 7px ;
  margin: 5px auto;
  border-radius: 10px;
  width: 250px;
  height: 50px;
  font-size: 1.1rem;
}

.end-message {
  font-weight: bolder;
  font-size: 50px;
  margin-bottom: 10px;
}

.score-board {
  font-size: 18px;
}

.quiz-app{
  background: white;
  padding: 2rem;
  border-radius: 12px;
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
  width: 100%;
  max-width: 400px;
  text-align: center;
}

.timer{
  font-weight: bold;
  color: #d63031;
  margin-bottom: 15px;
  font-size: 1.2rem;
}

.questionleft{
  display: inline-block;
  font-weight: bold;
}
.num{
  font-size: 18px;
}

@media (max-width: 450px) {
  .quiz-app{
    width: 90%;
    padding: 15px;
  }

  button{
    font-size: 1.1rem;
    padding: 6px;
  }
}