/* EduSmart - Interactive Education Platform */
:root {
    --primary: #667eea;
    --primary-dark: #5a67d8;
    --secondary: #764ba2;
    --accent: #f093fb;
    --success: #10b981;
    --warning: #f59e0b;
    --white: #ffffff;
    --light: #f8fafc;
    --gray: #64748b;
    --dark: #1e293b;
    --font-main: 'DM Sans', sans-serif;
}

*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { font-family: var(--font-main); background: var(--white); color: var(--dark); line-height: 1.7; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 2rem; }

/* Navbar */
.navbar { position: fixed; top: 0; left: 0; right: 0; z-index: 1000; padding: 1rem 0; background: var(--white); box-shadow: 0 2px 20px rgba(0,0,0,0.05); }
.nav-container { max-width: 1200px; margin: 0 auto; padding: 0 2rem; display: flex; align-items: center; justify-content: space-between; }
.logo { display: flex; align-items: center; gap: 0.5rem; font-size: 1.5rem; font-weight: 700; color: var(--dark); text-decoration: none; }
.logo-icon { font-size: 1.5rem; }
.logo span { color: var(--primary); }
.nav-menu { display: flex; list-style: none; gap: 2rem; }
.nav-link { color: var(--dark); text-decoration: none; font-size: 0.95rem; font-weight: 500; transition: color 0.3s; }
.nav-link:hover { color: var(--primary); }
.nav-right { display: flex; align-items: center; gap: 1rem; }
.language-selector { position: relative; }
.lang-btn { padding: 0.4rem 0.75rem; background: var(--light); border: none; color: var(--dark); font-size: 0.8rem; font-weight: 600; cursor: pointer; border-radius: 6px; }
.lang-dropdown { position: absolute; top: calc(100% + 5px); right: 0; background: var(--white); min-width: 110px; opacity: 0; visibility: hidden; transition: all 0.3s; box-shadow: 0 10px 30px rgba(0,0,0,0.15); border-radius: 10px; overflow: hidden; z-index: 1001; }
.language-selector.active .lang-dropdown { opacity: 1; visibility: visible; }
.lang-option { display: block; width: 100%; padding: 0.6rem 1rem; background: transparent; border: none; text-align: left; cursor: pointer; font-size: 0.85rem; color: var(--dark); transition: all 0.3s; }
.lang-option:hover, .lang-option.active { background: var(--light); color: var(--primary); }
.btn-login { padding: 0.6rem 1.25rem; color: var(--primary); font-size: 0.9rem; font-weight: 600; text-decoration: none; transition: color 0.3s; }
.btn-login:hover { color: var(--primary-dark); }
.btn-signup { padding: 0.6rem 1.25rem; background: var(--primary); color: var(--white); font-size: 0.9rem; font-weight: 600; text-decoration: none; border-radius: 50px; transition: all 0.3s; }
.btn-signup:hover { background: var(--primary-dark); }
.mobile-toggle { display: none; flex-direction: column; gap: 5px; background: transparent; border: none; cursor: pointer; }
.mobile-toggle span { width: 25px; height: 2px; background: var(--dark); transition: all 0.3s; }

/* Hero Slider */
.hero { padding-top: 80px; min-height: 100vh; background: var(--light); overflow: hidden; position: relative; }
.hero-slider { height: calc(100vh - 80px); }
.slide { position: absolute; top: 0; left: 0; width: 100%; height: 100%; opacity: 0; visibility: hidden; transition: all 0.6s ease; }
.slide.active { opacity: 1; visibility: visible; }
.slide-content { height: 100%; max-width: 1200px; margin: 0 auto; padding: 0 2rem; display: grid; grid-template-columns: 1fr 1fr; align-items: center; gap: 4rem; }
.slide-badge { display: inline-block; padding: 0.5rem 1rem; background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%); color: var(--white); font-size: 0.8rem; font-weight: 600; border-radius: 50px; margin-bottom: 1.5rem; }
.slide-text h1 { font-size: clamp(2.5rem, 5vw, 3.5rem); font-weight: 700; line-height: 1.2; margin-bottom: 1.5rem; color: var(--dark); }
.slide-text p { font-size: 1.1rem; color: var(--gray); margin-bottom: 2rem; max-width: 500px; }
.slide-actions { display: flex; gap: 1rem; align-items: center; }
.btn-primary { display: inline-block; padding: 1rem 2rem; background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%); color: var(--white); font-size: 0.95rem; font-weight: 600; text-decoration: none; border-radius: 50px; transition: all 0.3s; }
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 10px 30px rgba(102,126,234,0.4); }
.btn-primary.large { padding: 1.25rem 2.5rem; font-size: 1rem; }
.btn-video { display: flex; align-items: center; gap: 0.75rem; color: var(--dark); font-weight: 600; text-decoration: none; }
.play-icon { width: 50px; height: 50px; display: flex; align-items: center; justify-content: center; background: var(--white); border-radius: 50%; box-shadow: 0 5px 20px rgba(0,0,0,0.1); font-size: 0.8rem; padding-left: 3px; }
.btn-secondary { display: inline-block; padding: 1rem 2rem; background: transparent; border: 2px solid var(--primary); color: var(--primary); font-size: 0.95rem; font-weight: 600; text-decoration: none; border-radius: 50px; transition: all 0.3s; }
.btn-secondary:hover { background: var(--primary); color: var(--white); }
.btn-secondary.large { padding: 1.25rem 2.5rem; font-size: 1rem; }

/* Slide Visual */
.slide-visual { position: relative; height: 500px; }
.visual-card { position: absolute; border-radius: 20px; color: var(--white); }
.visual-card.main-card { width: 300px; height: 350px; top: 50%; left: 50%; transform: translate(-50%, -50%); display: flex; align-items: center; justify-content: center; }
.main-card .card-content { text-align: center; }
.main-card .card-icon { font-size: 4rem; margin-bottom: 1rem; display: block; }
.main-card h4 { font-size: 1.5rem; font-weight: 600; margin-bottom: 0.5rem; }
.main-card p { font-size: 0.95rem; opacity: 0.9; }
.visual-card.floating-card-1, .visual-card.floating-card-2 { padding: 1rem 1.5rem; display: flex; align-items: center; gap: 0.75rem; font-weight: 600; font-size: 0.9rem; animation: float 3s ease-in-out infinite; }
.visual-card.floating-card-1 { top: 20%; left: 10%; }
.visual-card.floating-card-2 { bottom: 20%; right: 10%; animation-delay: 1.5s; }
@keyframes float { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

/* Slider Nav */
.slider-nav { position: absolute; bottom: 3rem; left: 50%; transform: translateX(-50%); }
.slider-dots { display: flex; gap: 0.75rem; }
.dot { width: 12px; height: 12px; background: rgba(0,0,0,0.2); border-radius: 50%; cursor: pointer; transition: all 0.3s; }
.dot.active { background: var(--primary); transform: scale(1.2); }

/* Stats */
.stats { padding: 60px 0; background: var(--white); }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
.stat-item { text-align: center; padding: 2rem; background: var(--light); border-radius: 20px; }
.stat-icon { font-size: 2.5rem; margin-bottom: 1rem; display: block; }
.stat-num { font-size: 2.5rem; font-weight: 700; color: var(--primary); display: inline; }
.stat-suffix { font-size: 1.5rem; font-weight: 700; color: var(--primary); }
.stat-label { display: block; font-size: 0.9rem; color: var(--gray); margin-top: 0.5rem; }

/* Sections */
section { padding: 100px 0; }
.section-tag { display: inline-block; font-size: 0.8rem; font-weight: 600; letter-spacing: 1px; text-transform: uppercase; color: var(--primary); background: rgba(102,126,234,0.1); padding: 0.4rem 1rem; border-radius: 50px; margin-bottom: 1rem; }
.section-title { font-size: clamp(2rem, 4vw, 2.75rem); font-weight: 700; line-height: 1.2; color: var(--dark); }
.section-header { display: flex; justify-content: space-between; align-items: flex-end; margin-bottom: 3rem; }
.section-header.centered { display: block; text-align: center; margin-bottom: 4rem; }
.view-all { font-size: 0.9rem; font-weight: 600; color: var(--primary); text-decoration: none; }
.view-all:hover { text-decoration: underline; }

/* Categories */
.categories { background: var(--light); }
.categories-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.category-card { background: var(--white); padding: 2rem; border-radius: 20px; text-align: center; cursor: pointer; transition: all 0.3s; border: 2px solid transparent; }
.category-card:hover { border-color: var(--accent); transform: translateY(-5px); box-shadow: 0 15px 40px rgba(0,0,0,0.1); }
.category-icon { font-size: 3rem; margin-bottom: 1rem; }
.category-card h3 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.5rem; }
.category-card p { font-size: 0.9rem; color: var(--gray); }

/* Courses */
.courses-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }
.course-card { background: var(--white); border-radius: 20px; overflow: hidden; box-shadow: 0 5px 30px rgba(0,0,0,0.08); transition: all 0.3s; }
.course-card:hover { transform: translateY(-10px); box-shadow: 0 20px 50px rgba(0,0,0,0.12); }
.course-image { position: relative; height: 180px; }
.course-badge { position: absolute; top: 1rem; left: 1rem; padding: 0.4rem 0.75rem; font-size: 0.7rem; font-weight: 600; border-radius: 50px; }
.course-badge.bestseller { background: var(--warning); color: var(--dark); }
.course-badge.new { background: var(--success); color: var(--white); }
.course-price { position: absolute; bottom: 1rem; right: 1rem; padding: 0.5rem 1rem; background: var(--white); font-weight: 700; border-radius: 50px; font-size: 1rem; }
.course-info { padding: 1.5rem; }
.course-meta { display: flex; justify-content: space-between; align-items: center; margin-bottom: 0.75rem; }
.course-meta .category { font-size: 0.75rem; font-weight: 600; color: var(--primary); background: rgba(102,126,234,0.1); padding: 0.25rem 0.75rem; border-radius: 50px; }
.course-meta .rating { font-size: 0.8rem; color: var(--gray); }
.course-info h3 { font-size: 1rem; font-weight: 600; margin-bottom: 0.5rem; line-height: 1.4; }
.course-info .instructor { font-size: 0.85rem; color: var(--gray); margin-bottom: 1rem; }
.course-stats { display: flex; gap: 1rem; font-size: 0.75rem; color: var(--gray); }

/* Features */
.features { background: var(--light); }
.features-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 5rem; align-items: center; }
.features-content p { color: var(--gray); margin: 1.5rem 0 2rem; line-height: 1.8; }
.features-list { display: flex; flex-direction: column; gap: 1.5rem; }
.feature-item { display: flex; gap: 1rem; }
.feature-item .feature-icon { font-size: 2rem; }
.feature-item h4 { font-size: 1rem; font-weight: 600; margin-bottom: 0.25rem; }
.feature-item p { font-size: 0.9rem; color: var(--gray); margin: 0; }
.features-visual { position: relative; height: 500px; }
.visual-main { width: 100%; height: 100%; border-radius: 20px; }
.visual-accent { position: absolute; width: 200px; height: 200px; bottom: -30px; left: -30px; border-radius: 20px; }

/* Instructors */
.instructors-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
.instructor-card { background: var(--white); border-radius: 20px; overflow: hidden; box-shadow: 0 5px 30px rgba(0,0,0,0.08); transition: all 0.3s; }
.instructor-card:hover { transform: translateY(-10px); }
.instructor-image { height: 200px; }
.instructor-info { padding: 1.5rem; text-align: center; }
.instructor-info h4 { font-size: 1.1rem; font-weight: 600; margin-bottom: 0.25rem; }
.instructor-info .specialty { font-size: 0.85rem; color: var(--primary); font-weight: 500; }
.instructor-stats { display: flex; justify-content: center; gap: 1rem; margin-top: 1rem; font-size: 0.75rem; color: var(--gray); }

/* About */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 5rem; align-items: center; }
.about-content p { color: var(--gray); margin: 1.5rem 0 2rem; line-height: 1.9; }
.about-features { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-bottom: 2rem; }
.about-feature { display: flex; align-items: center; gap: 0.75rem; font-weight: 500; }
.about-feature .check { color: var(--success); font-size: 1.25rem; }
.about-image .image-placeholder { width: 100%; height: 450px; border-radius: 20px; }

/* Testimonials */
.testimonials { background: var(--light); }
.testimonials-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.testimonial-card { background: var(--white); padding: 2rem; border-radius: 20px; }
.rating { color: #fbbf24; margin-bottom: 1rem; letter-spacing: 2px; }
.testimonial-card p { font-size: 0.95rem; color: var(--gray); line-height: 1.8; margin-bottom: 1.5rem; }
.testimonial-author { display: flex; align-items: center; gap: 1rem; }
.author-avatar { width: 50px; height: 50px; display: flex; align-items: center; justify-content: center; color: var(--white); font-weight: 600; border-radius: 50%; }
.author-info h4 { font-size: 0.95rem; font-weight: 600; }
.author-info span { font-size: 0.8rem; color: var(--gray); }

/* CTA */
.cta-section { background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%); padding: 80px 0; }
.cta-content { text-align: center; color: var(--white); }
.cta-content h2 { font-size: clamp(2rem, 4vw, 2.75rem); font-weight: 700; margin-bottom: 1rem; }
.cta-content p { font-size: 1.1rem; opacity: 0.9; margin-bottom: 2rem; }
.cta-actions { display: flex; justify-content: center; gap: 1rem; }
.cta-section .btn-primary { background: var(--white); color: var(--primary); }
.cta-section .btn-primary:hover { background: var(--light); box-shadow: 0 10px 30px rgba(0,0,0,0.2); }
.cta-section .btn-secondary { border-color: var(--white); color: var(--white); }
.cta-section .btn-secondary:hover { background: var(--white); color: var(--primary); }

/* Footer */
.footer { background: var(--dark); color: var(--white); padding: 80px 0 40px; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 4rem; margin-bottom: 4rem; }
.footer-brand .logo { font-size: 1.5rem; margin-bottom: 1rem; }
.footer-brand p { color: rgba(255,255,255,0.6); margin-top: 1rem; font-size: 0.95rem; }
.social-links { display: flex; gap: 0.75rem; margin-top: 1.5rem; }
.social-links a { width: 40px; height: 40px; display: flex; align-items: center; justify-content: center; background: rgba(255,255,255,0.1); border-radius: 50%; color: var(--white); font-size: 0.8rem; font-weight: 600; text-decoration: none; transition: all 0.3s; }
.social-links a:hover { background: var(--primary); }
.footer-links h4 { font-size: 0.9rem; font-weight: 600; margin-bottom: 1.5rem; color: var(--white); }
.footer-links a { display: block; color: rgba(255,255,255,0.6); text-decoration: none; font-size: 0.9rem; padding: 0.4rem 0; transition: color 0.3s; }
.footer-links a:hover { color: var(--white); }
.footer-bottom { padding-top: 2rem; border-top: 1px solid rgba(255,255,255,0.1); text-align: center; }
.footer-bottom p { font-size: 0.85rem; color: rgba(255,255,255,0.4); }

/* Responsive */
@media (max-width: 1024px) {
    .slide-content, .features-grid, .about-grid { grid-template-columns: 1fr; gap: 3rem; }
    .slide-visual { display: none; }
    .slide-text { text-align: center; }
    .slide-text p { margin-left: auto; margin-right: auto; }
    .slide-actions { justify-content: center; }
    .categories-grid { grid-template-columns: repeat(2, 1fr); }
    .courses-grid { grid-template-columns: repeat(2, 1fr); }
    .instructors-grid { grid-template-columns: repeat(2, 1fr); }
    .testimonials-grid { grid-template-columns: 1fr; }
    .features-visual { height: 350px; }
    .footer-grid { grid-template-columns: 1fr 1fr; gap: 3rem; }
}
@media (max-width: 768px) {
    .nav-menu { position: fixed; top: 0; right: -100%; width: 100%; height: 100vh; background: var(--white); flex-direction: column; justify-content: center; align-items: center; gap: 2rem; transition: right 0.4s; }
    .nav-menu.active { right: 0; }
    .mobile-toggle { display: flex; z-index: 1001; }
    .btn-login { display: none; }
    .hero-slider { height: auto; min-height: calc(100vh - 80px); }
    .slide-content { padding: 3rem 2rem; }
    .slide-actions { flex-direction: column; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); }
    .categories-grid, .courses-grid, .instructors-grid { grid-template-columns: 1fr; }
    .about-features { grid-template-columns: 1fr; }
    .cta-actions { flex-direction: column; align-items: center; }
    .footer-grid { grid-template-columns: 1fr; text-align: center; }
    .social-links { justify-content: center; }
}