/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Colors */
    --primary-color: #4947c4;
    --primary-dark: #3735a0;
    --secondary-color: #111111;
    --text-primary: #1A1A2E;
    --text-secondary: #666672;
    --background: #FFFFFF;
    --background-light: #F8F9FD;
    --border-light: #E5E7EB;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #4947c4 0%, #111111 100%);
    --gradient-accent: linear-gradient(135deg, #4947c4 0%, #111111 100%);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
}

body {
    font-family: var(--font-family);
    color: var(--text-primary);
    background: var(--background);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    z-index: 1000;
    padding: 0;
    transition: all 0.3s ease;
}

.navbar:hover {
    background: rgba(255, 255, 255, 0.95);
}

.nav-wrapper {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 72px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

.logo-img {
    height: 40px;
    width: 40px;
    object-fit: contain;
    filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.1));
}

.logo-text {
    font-size: 1.625rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 8px;
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.975rem;
    padding: 10px 20px;
    border-radius: 8px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-primary);
    opacity: 0;
    transition: opacity 0.3s ease;
    z-index: -1;
}

.nav-link:hover {
    color: var(--text-primary);
    background: rgba(73, 71, 196, 0.08);
    transform: translateY(-1px);
}

.nav-link.active {
    color: white !important;
    background: var(--gradient-primary);
    font-weight: 600;
}

/* Special styling for Contact button */
.nav-menu li:last-child .nav-link {
    background: var(--gradient-primary);
    color: white;
    font-weight: 600;
    padding: 10px 24px;
    box-shadow: 0 4px 12px rgba(73, 71, 196, 0.2);
}

.nav-menu li:last-child .nav-link:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(73, 71, 196, 0.3);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
}

.mobile-menu-toggle span {
    width: 25px;
    height: 2px;
    background: var(--text-primary);
    transition: 0.3s;
}

/* Hero Section */
.hero {
    padding: calc(var(--spacing-3xl) + 100px) 0 var(--spacing-3xl);
    background: linear-gradient(135deg, #F8F9FD 0%, #FFFFFF 100%);
}

.hero-content {
    text-align: center;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.gradient-text {
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.8;
}

/* Hero Visual */
.hero-visual {
    display: flex;
    justify-content: center;
    margin-top: var(--spacing-2xl);
}

.app-screenshot {
    width: 100%;
    max-width: 400px;
    height: auto;
    border-radius: 40px;
    box-shadow: 0 30px 60px rgba(0, 0, 0, 0.15);
    transition: transform 0.3s ease;
}

.app-screenshot:hover {
    transform: scale(1.02);
}

/* Placeholder Boxes */
.placeholder-box {
    background: linear-gradient(135deg, #F3F4F6 0%, #E5E7EB 100%);
    border: 2px dashed #D1D5DB;
    border-radius: 20px;
    padding: var(--spacing-3xl);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #9CA3AF;
    font-size: 1.125rem;
    font-weight: 500;
    min-height: 400px;
    position: relative;
    overflow: hidden;
}

.placeholder-box.small {
    min-height: 250px;
    padding: var(--spacing-xl);
}

.placeholder-box::before {
    content: "";
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent 30%, rgba(255, 255, 255, 0.1) 50%, transparent 70%);
    animation: shimmer 3s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%) translateY(-100%) rotate(45deg); }
    100% { transform: translateX(100%) translateY(100%) rotate(45deg); }
}

.hero-visual-placeholder,
.feature-visual-placeholder {
    margin-top: var(--spacing-xl);
}

/* Learning Path Chart */
.method-visual {
    margin-top: var(--spacing-2xl);
    background: var(--background);
    padding: var(--spacing-xl);
    border-radius: 20px;
    box-shadow: var(--shadow-md);
}

.chart-title {
    font-size: 1.75rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.chart-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.chart-container {
    position: relative;
    height: 350px;
    width: 100%;
    padding: var(--spacing-md) 0;
}

/* Section Headers */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-2xl);
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Method Section */
.method {
    padding: var(--spacing-3xl) 0;
    background: var(--background);
}

.method-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.method-card {
    background: var(--background-light);
    padding: var(--spacing-xl);
    border-radius: 16px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.method-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.method-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.method-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.method-card p {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Features Section */
.features {
    padding: var(--spacing-3xl) 0;
    background: var(--background-light);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(500px, 1fr));
    gap: var(--spacing-xl);
}

.feature-item {
    background: var(--background);
    padding: var(--spacing-xl);
    border-radius: 20px;
    box-shadow: var(--shadow-sm);
    transition: box-shadow 0.3s ease;
}

.feature-item:hover {
    box-shadow: var(--shadow-lg);
}

.feature-content h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.feature-content p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--spacing-lg);
}

/* Fluency Definition Section */
.fluency-definition {
    padding: var(--spacing-3xl) 0;
    background: var(--background);
}

.fluency-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto;
}

.fluency-item {
    background: var(--background-light);
    padding: var(--spacing-lg);
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s ease;
}

.fluency-item:hover {
    transform: scale(1.05);
}

.fluency-icon {
    font-size: 2rem;
    display: block;
    margin-bottom: var(--spacing-sm);
}

.fluency-item p {
    color: var(--text-secondary);
    font-weight: 500;
}

/* Contact Section */
.contact {
    padding: var(--spacing-3xl) 0;
    background: var(--background-light);
}

.contact-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.contact-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.contact-options {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-xl);
}

.contact-button {
    display: inline-block;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
}

.contact-button.primary {
    background: var(--gradient-accent);
    color: white;
}

.contact-button.primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.contact-button.secondary {
    background: var(--background);
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.contact-button.secondary:hover {
    background: var(--primary-color);
    color: white;
}

.contact-info {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: var(--spacing-2xl) 0 var(--spacing-xl);
}

.footer-content {
    text-align: center;
}

.footer-brand {
    margin-bottom: var(--spacing-lg);
}

.footer-brand .logo-text {
    display: block;
    margin-bottom: var(--spacing-sm);
}

.footer-brand p {
    color: rgba(255, 255, 255, 0.7);
    max-width: 400px;
    margin: 0 auto;
}

.footer-links {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: center;
    margin-bottom: var(--spacing-lg);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-options {
        flex-direction: column;
    }
    
    .footer-links {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .fluency-grid {
        grid-template-columns: 1fr;
    }
    
    .method-grid {
        grid-template-columns: 1fr;
    }
}