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

body{
    min-height: 100vh;
    background-color: #0c192c;
}

.container{
    position: relative;
    width: 100%;
    height: 100vh;
    overflow: hidden;
    z-index: 1;
}

.bubbles{
    position: relative;
    display: flex;
}

.bubbles span{
    position: relative;
    min-width: 20px;
    min-height: 20px;
    background: #4fc3dc;
    margin: 0 4px;
    border-radius: 50%;
    box-shadow: 0 0 0 10px #4fc3dc44, 0 0 50px #4fc3dc, 0 0 100px #4fc3dc;
    animation: animate 15s linear infinite;
    animation-duration: calc(125s / var(--i));
}

.bubbles span:nth-child(even){
    background: #ff2d75;
    box-shadow: 0 0 0 10px #ff2d7544, 0 0 50px #ff2d75, 0 0 100px #ff2d75;
}

@keyframes animate{
    0%{
        transform: translateY(100vh) scale(0);
    }
    100%{
        transform: translateY(-10vh) scale(1);
    }
}
.app{
    background: #fff;
    width: 90%;
    max-width: 600px;
    margin: 100px auto 0;
    border-radius: 10px;
    padding: 30px;
    position: relative; 
    z-index: 2; 
}

.app h1{
    font-size: 25px;
    color: #0c2cbb;
    font-weight: 600;
    border-bottom: 1px solid #333;
    padding-bottom: 30px;
}

.quiz{
    padding: 20px 0; 
}

.quiz h2{
font-size: 18px;
color: #0c2cbb;
font-weight: 600;
}

.btn{
    background: #fff;
    color: #222;
    font-weight: 550;
    width: 100%;
    border: 1px solid #222;
    padding: 10px;
    margin: 10px 0;
    text-align: left;
    border-radius: 4px;
    cursor: pointer;
    transition: 0.3s ease;
}

.btn:hover([disabled]){
    background: #222;
    color: #fff;
}

.btn:disabled{
    cursor: no-drop;
}

#next-btn{
    background: #0c2cbb;
    color: #fff;
    font-weight: 500;
    width: 150px;
    border: 0;
    padding: 10px;
    margin: 20px auto 0;
    border-radius: 4px;
    cursor: pointer;
    display: none;
}

.correct{
    background: #3ee267;
}

.incorrect{
    background: #df4343;
}