body {
    margin: 0;
    font-family: Arial;
    background: linear-gradient(120deg, #0f2027, #203a43);
    color: white;
    text-align: center;
}

/* pages */
.page {
    display: none;
    animation: fade 0.5s ease;
}

.active {
    display: block;
}

@keyframes fade {
    from {opacity: 0;}
    to {opacity: 1;}
}

/* layout */
.layout, .layout2 {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap;
}

/* cards */
.card {
    background: rgba(255,255,255,0.1);
    padding: 12px;
    border-radius: 15px;
    transition: 0.3s;
    cursor: pointer;
}

.card:hover {
    transform: scale(1.3);
    box-shadow: 0 0 20px #00c6ff;
}

.card img {
    width: 150px;
}

/* 3D box */
iframe {
    width: 420px;
    height: 420px;
    border-radius: 20px;
}

/* breathing animation */
.breathing-box {
    animation: breathe 4s infinite;
}

@keyframes breathe {
    0% {transform: scale(1);}
    50% {transform: scale(1.05);}
    100% {transform: scale(1);}
}

/* buttons */
.nav {
    margin: 10px;
    padding: 10px 20px;
    border: none;
    background: #00c6ff;
    border-radius: 10px;
    cursor: pointer;
    transition: 0.3s;
}

.nav:hover {
    background: #0072ff;
}

/* quiz */
.quiz-box {
    margin-top: 20px;
}

.option {
    display: block;
    margin: 10px;
    padding: 10px;
    background: #1c1c1c;
    border-radius: 10px;
    cursor: pointer;
}

.option:hover {
    background: #00c6ff;
}