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


body {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    overflow: hidden;
}

body::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(rgba(0,0,50,0.6), rgba(0,0,0,0.7)),
                url("bcd.jpg") no-repeat center center/cover;
    filter: blur(3px);
    transform: scale(1.1);
    z-index: -1;
}
.app {
    background: rgba(255, 255, 255, 0.15);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    width: 90%;
    max-width: 650px;
    border-radius: 20px;
    padding: 40px 30px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.3);
    color: #fff;
    animation: fadeIn 0.8s ease-in-out;
}

.app h1 {
    font-size: 28px;
    color: #fff;
    text-align: center;
    font-weight: 700;
    margin-bottom: 25px;
    border-bottom: 2px solid rgba(255,255,255,0.2);
    padding-bottom: 15px;
}


.quiz h2 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 18px;
    color: #f0f0f0;
}


.btn {
    background: rgba(255,255,255,0.1);
    color: #fff;
    font-weight: 500;
    width: 100%;
    border: 1px solid rgba(255,255,255,0.2);
    padding: 12px;
    margin: 12px 0;
    text-align: left;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
}
.btn:hover:not([disabled]) {
    background: linear-gradient(135deg, #667eea, #764ba2);
    transform: scale(1.02);
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
}

.btn:disabled {
    cursor: not-allowed;
    opacity: 0.7;
}

#next-btn {
    background: linear-gradient(135deg, #00c6ff, #0072ff);
    color: #fff;
    font-weight: 600;
    font-size: 16px;
    width: 180px;
    border: none;
    padding: 12px;
    margin: 20px auto 0;
    border-radius: 30px;
    cursor: pointer;
    display: none;
    transition: all 0.3s ease;
}

#next-btn:hover {
    transform: scale(1.05);
    box-shadow: 0 5px 15px rgba(0, 114, 255, 0.5);
}


.correct {
    background: linear-gradient(135deg, #56ab2f, #a8e063);
    color: #fff !important;
}

.incorrect {
    background: linear-gradient(135deg, #eb3349, #f45c43);
    color: #fff !important;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}