:root {
    /* Theme Colors - Dark Mode Default */
    --bg-dark: #050812;
    --bg-light: #ffffff;
    --accent-primary: #3b82f6; /* Blue-500 */
    --accent-secondary: #8b5cf6; /* Violet-500 */
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --glass-bg: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.1);
    --card-bg: rgba(15, 23, 42, 0.8);
    --shadow-soft: 0 10px 30px -10px rgba(0, 0, 0, 0.5);
    
    /* Animation Timing */
    --transition-smooth: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
    --bg-dark: #ffffff;
    --text-primary: #050812;
    --text-secondary: #4b5563;
    --glass-bg: rgba(0, 0, 0, 0.05);
    --glass-border: rgba(0, 0, 0, 0.1);
    --card-bg: #f3f4f6;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

[data-theme="dark"] ::-webkit-scrollbar-track {
    background: var(--bg-dark);
}

[data-theme="light"] ::-webkit-scrollbar-track {
    background: #f1f5f9;
}

::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 10px;
    border: 3px solid transparent;
    background-clip: content-box;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--accent-secondary);
    background-clip: content-box;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    transition: background-color 0.5s ease;
}

/* Loading Overlay */
#loader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--bg-dark);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.5s ease, visibility 0.5s ease;
}

.loader-spinner {
    width: 50px;
    height: 50px;
    border: 3px solid var(--glass-border);
    border-top: 3px solid var(--accent-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Typography */
h1, h2, h3, h4 {
    font-weight: 700;
    line-height: 1.2;
}

.section-title {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    text-align: center;
    margin-bottom: 4rem;
    background: linear-gradient(to right, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Layout */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section {
    padding: 8rem 0;
    position: relative;
}

/* Floating Blobs */
.blob {
    position: absolute;
    width: 400px;
    height: 400px;
    background: linear-gradient(45deg, var(--accent-primary), var(--accent-secondary));
    filter: blur(80px);
    border-radius: 50%;
    opacity: 0.15;
    z-index: -1;
    animation: float 20s infinite alternate;
}

@keyframes float {
    from { transform: translate(0, 0) scale(1); }
    to { transform: translate(10%, 10%) scale(1.1); }
}

/* Navbar */
nav {
    position: fixed;
    top: 0;
    width: 100%;
    padding: 1.5rem 0;
    z-index: 1000;
    transition: var(--transition-smooth);
}

nav.scrolled {
    background: var(--bg-dark);
    backdrop-filter: blur(15px);
    padding: 1rem 0;
    border-bottom: 1px solid var(--glass-border);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--text-primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: var(--transition-smooth);
    font-size: 0.95rem;
}

.nav-links a:hover {
    color: var(--accent-primary);
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

/* Theme Toggle */
.theme-toggle {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary) !important; /* Force visibility */
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 12px;
    transition: var(--transition-smooth);
}

.theme-toggle i {
    color: inherit;
}

.theme-toggle:hover {
    background: var(--glass-bg);
}

/* Mobile Toggle */
.mobile-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.5rem;
    cursor: pointer;
}

/* Responsive Overrides */
.nav-links a.active {
    color: var(--accent-primary);
}

@media (max-width: 968px) {
    .nav-links {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(5, 8, 18, 0.95);
        backdrop-filter: blur(20px);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        padding: 2rem;
        gap: 2rem;
        z-index: 999;
        transition: var(--transition-smooth);
    }

    [data-theme="light"] .nav-links {
        background: rgba(255, 255, 255, 0.95);
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        font-size: 1.25rem;
        color: var(--text-primary);
    }

    .mobile-toggle {
        display: block;
        z-index: 1001;
        width: 36px;
        height: 36px;
        display: flex;
        align-items: center;
        justify-content: center;
    }

    .mobile-toggle i {
        width: 24px;
        height: 24px;
    }

    .nav-actions {
        gap: 0.5rem;
    }

    .nav-actions .btn-secondary {
        padding: 0.5rem 0.8rem;
        font-size: 0.8rem;
        display: inline-block;
    }
    
    @media (min-width: 480px) {
        .nav-actions {
            gap: 0.75rem;
        }
    }

    .theme-toggle {
        width: 36px;
        height: 36px;
        border-radius: 10px;
    }

    .theme-toggle i {
        width: 18px;
        height: 18px;
    }

    .container {
        padding: 0 1.25rem;
    }

    .hero {
        padding-top: 100px;
        min-height: auto;
        padding-bottom: 3rem;
    }

    .hero-grid {
        grid-template-columns: 1fr !important;
        padding-top: 1rem;
        text-align: center;
        gap: 3rem;
    }

    .hero-content {
        display: flex;
        flex-direction: column;
        align-items: center;
        width: 100%;
    }

    .hero-content h1 {
        font-size: 2.2rem;
        margin-bottom: 1rem;
    }

    .hero-content p {
        margin: 0 auto 2rem;
        font-size: 1rem;
        max-width: 340px;
    }

    .hero-visual {
        display: none;
    }

    .dashboard-preview {
        transform: none !important;
    }

    .cta-group {
        justify-content: center;
    }

    .section {
        padding: 4rem 0;
    }

    .section-title {
        font-size: 1.8rem;
        margin-bottom: 2.5rem;
    }

    .btn {
        padding: 0.8rem 1.5rem;
        font-size: 0.9rem;
    }

    /* Fix Contact Grid on Mobile */
    #contact .hero-grid {
        display: flex;
        flex-direction: column;
        gap: 2rem;
        text-align: center; /* Center text on mobile for better balance */
    }

    #contact .hero-grid div:first-child {
        order: 2;
    }

    #contact .hero-grid div:first-child p {
        justify-content: center; /* Center icons with text */
    }

    #contact .feature-card {
        order: 1;
        width: 100%;
        text-align: left; /* Keep form items left-aligned */
    }

    .feature-card {
        padding: 1.5rem;
    }

    .feature-icon {
        width: 48px;
        height: 48px;
        font-size: 1.2rem;
        margin-bottom: 1rem;
    }

    .stat-item h2 {
        font-size: 2.5rem;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 1.8rem;
    }

    .cta-group {
        flex-direction: column;
        width: 100%;
        gap: 0.75rem;
    }

    .btn {
        width: 100%;
        text-align: center;
    }
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 120px;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.hero-content h1 {
    font-size: clamp(3rem, 6vw, 4.5rem);
    margin-bottom: 1.5rem;
}

.hero-content p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 2.5rem;
    max-width: 500px;
}

.cta-group {
    display: flex;
    gap: 1rem;
}

.btn {
    padding: 1rem 2.5rem;
    border-radius: 9999px;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition-smooth);
    display: inline-block;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--accent-primary);
    color: white;
    box-shadow: 0 10px 20px -10px var(--accent-primary);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 30px -12px var(--accent-primary);
}

.btn-secondary {
    background: var(--glass-bg);
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: var(--glass-border);
}

/* Dashboard Mockup (CSS Illustation) */
.hero-visual {
    position: relative;
}

.dashboard-preview {
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-radius: 20px;
    box-shadow: var(--shadow-soft);
    padding: 1.5rem;
    backdrop-filter: blur(20px);
    transform: perspective(1000px) rotateY(-5deg) rotateX(5deg);
    transition: transform 0.5s ease;
}

.dashboard-preview:hover {
    transform: perspective(1000px) rotateY(0deg) rotateX(0deg);
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    padding: 2.5rem;
    border-radius: 24px;
    transition: var(--transition-smooth);
}

.feature-card:hover {
    background: rgba(255, 255, 255, 0.05);
    transform: translateY(-10px);
    border-color: var(--accent-primary);
}

.feature-icon {
    width: 60px;
    height: 60px;
    background: rgba(59, 130, 246, 0.1);
    border-radius: 16px;
    display: flex;
    justify-content: center;
    align-items: center;
    color: var(--accent-primary);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
}

/* Teachers Section */
.teachers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.teacher-card {
    background: var(--card-bg);
    border: 1px solid var(--glass-border);
    border-radius: 24px;
    overflow: hidden;
    transition: var(--transition-smooth);
}

.teacher-img {
    width: 100%;
    height: 250px;
    background: #1e293b;
    object-fit: cover;
}

.teacher-info {
    padding: 1.5rem;
}

/* Pricing Section */
.pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.pricing-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: 32px;
    padding: 3rem;
    text-align: center;
    position: relative;
    transition: var(--transition-smooth);
}

.pricing-card.recommended {
    background: rgba(59, 130, 246, 0.05);
    border-color: var(--accent-primary);
    transform: scale(1.05);
}

.badge {
    position: absolute;
    top: 1.5rem;
    right: 1.5rem;
    background: var(--accent-primary);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 100px;
    font-size: 0.75rem;
    font-weight: 700;
}

/* Stats Section */
.stats-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 4rem;
    text-align: center;
}

.stat-item h2 {
    font-size: 4rem;
    margin-bottom: 0.5rem;
}

/* FAQ Accordion */
.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    margin-bottom: 1rem;
    border: 1px solid var(--glass-border);
    border-radius: 16px;
    overflow: hidden;
}

.faq-question {
    padding: 1.5rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-weight: 600;
    transition: var(--transition-smooth);
}

.faq-question:hover {
    background: var(--glass-bg);
}

.faq-answer {
    padding: 0 1.5rem;
    max-height: 0;
    overflow: hidden;
    transition: var(--transition-smooth);
    color: var(--text-secondary);
}

.faq-item.faq-open .faq-answer {
    padding-bottom: 1.5rem;
    max-height: 500px;
}

.faq-item.faq-open .faq-question i {
    transform: rotate(180deg);
}

/* Slider */
.slider-container {
    overflow: hidden;
    position: relative;
    padding: 2rem 0;
}

.slider-track {
    display: flex;
    transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.testimonial-card {
    flex: 0 0 100%;
    max-width: 100%;
    padding: 0 1rem;
}

/* Back to Top */
#backToTop {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: var(--accent-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-smooth);
    z-index: 1000;
}

#backToTop.visible {
    opacity: 1;
    visibility: visible;
}

/* Scroll Reveal Classes */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s ease-out;
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}