html {
    scroll-behavior: smooth;
}

.perspective-1000 { perspective: 1200px; }
.preserve-3d { transform-style: preserve-3d; }
.backface-hidden { backface-visibility: hidden; }
.book-inner { 
    transform: rotateY(-30deg) rotateX(10deg); 
    transform-origin: center left;
    transition: transform 0.6s cubic-bezier(0.2, 0.8, 0.2, 1);
}
.book-container:hover .book-inner {
    transform: rotateY(-10deg) rotateX(5deg) !important;
}

.font-siliguri { font-family: 'Hind Siliguri', sans-serif; }

/* Smooth transitions for dark mode */
body { transition: background-color 0.3s, color 0.3s; }

/* Animation System */
.fade-up, .fade-left, .fade-right, .scale-in {
    opacity: 0;
    transition: all 0.8s cubic-bezier(0.2, 0.8, 0.2, 1);
    will-change: transform, opacity;
}

.fade-up { transform: translateY(30px); }
.fade-left { transform: translateX(-50px); }
.fade-right { transform: translateX(50px); }
.scale-in { transform: scale(0.9); }

.is-visible {
    opacity: 1 !important;
    transform: translate(0, 0) scale(1) !important;
}

/* Stagger Delays */
.delay-100 { transition-delay: 100ms; }
.delay-200 { transition-delay: 200ms; }
.delay-300 { transition-delay: 300ms; }
.delay-400 { transition-delay: 400ms; }
.delay-500 { transition-delay: 500ms; }

/* Language Toggle Logic */
[data-lang="en"] .bn-text { display: none !important; }
[data-lang="bn"] .en-text { display: none !important; }

/* FAQ Accordion */
.faq-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease-out;
    opacity: 0;
}
.faq-item.open .faq-content {
    opacity: 1;
}
.faq-item.open .faq-icon {
    transform: rotate(180deg);
}

/* Testimonial Marquee */
@keyframes marquee {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

.marquee-wrapper {
    display: flex;
    width: max-content;
    animation: marquee 40s linear infinite;
}

.marquee-wrapper:hover {
    animation-play-state: paused;
}

.testimonial-card {
    width: 300px;
    flex-shrink: 0;
}

@media (min-width: 768px) {
    .testimonial-card {
        width: 350px;
    }
}

@media (max-width: 768px) {
    .marquee-wrapper {
        animation-duration: 25s;
    }
}

/* Custom Selection */
::selection {
    background-color: #10b981;
    color: #ecfdf5;
}