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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: #000000;
    color: #ffffff;
    line-height: 1.6;
    overflow-x: hidden;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(0, 0, 0, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    z-index: 1000;
    padding: 1rem 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: #ffffff;
    text-decoration: none;
    transition: color 0.3s ease;
}

.nav-logo:hover {
    color: #6366f1;
}

.logo-icon {
    font-size: 1.8rem;
}

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

.nav-link {
    color: #ffffff;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    position: relative;
}

.nav-link:hover {
    color: #6366f1;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, #6366f1, #8b5cf6);
    transition: width 0.3s ease;
}

.nav-link:hover::after {
    width: 100%;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #000000 0%, #1a1a1a 100%);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 80%, rgba(99, 102, 241, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 80% 20%, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-content {
    max-width: 600px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    color: #ffffff;
}

.gradient-text {
    background: linear-gradient(135deg, #6366f1, #8b5cf6, #ec4899);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    color: #a1a1aa;
    margin-bottom: 2.5rem;
    line-height: 1.7;
}

.download-buttons {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
}

.download-buttons-centered {
    justify-content: center;
}

.download-btn {
    display: inline-block;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border-radius: 12px;
    overflow: hidden;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(99, 102, 241, 0.3);
}

.download-img {
    height: 60px;
    width: auto;
    display: block;
}

.hero-stats {
    display: flex;
    gap: 2rem;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: #6366f1;
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.875rem;
    color: #a1a1aa;
}

/* Hero Visual */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.phone-mockup {
    width: 300px;
    height: 600px;
    background: linear-gradient(145deg, #1a1a1a, #2a2a2a);
    border-radius: 40px;
    padding: 20px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.5);
    position: relative;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: #000000;
    border-radius: 30px;
    overflow: hidden;
    position: relative;
}

.app-preview {
    padding: 2rem;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

.app-header {
    text-align: center;
    margin-bottom: 2rem;
}

.app-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #6366f1;
    margin-bottom: 0.5rem;
}

.app-subtitle {
    color: #a1a1aa;
    font-size: 0.875rem;
}

.flashcard-demo {
    position: relative;
    width: 200px;
    height: 120px;
    perspective: 1000px;
}

.card {
    position: absolute;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #1a1a1a, #2a2a2a);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid rgba(99, 102, 241, 0.3);
    transition: transform 0.6s;
    transform-style: preserve-3d;
}

.card.front {
    animation: flipCard 4s infinite;
}

.card.back {
    transform: rotateY(180deg);
    animation: flipCardBack 4s infinite;
}

@keyframes flipCard {
    0%, 40% { transform: rotateY(0deg); }
    50%, 90% { transform: rotateY(180deg); }
    100% { transform: rotateY(0deg); }
}

@keyframes flipCardBack {
    0%, 40% { transform: rotateY(180deg); }
    50%, 90% { transform: rotateY(0deg); }
    100% { transform: rotateY(180deg); }
}

.word {
    font-size: 1.25rem;
    font-weight: 600;
    color: #ffffff;
    text-align: center;
}

.meaning {
    font-size: 0.875rem;
    color: #a1a1aa;
    text-align: center;
    padding: 1rem;
}

/* Features Section */
.features {
    padding: 6rem 0;
    background: #0a0a0a;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    color: #ffffff;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: linear-gradient(135deg, #1a1a1a, #2a2a2a);
    padding: 2rem;
    border-radius: 16px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(99, 102, 241, 0.2);
    border-color: rgba(99, 102, 241, 0.3);
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #ffffff;
}

.feature-description {
    color: #a1a1aa;
    line-height: 1.6;
}

/* How It Works Section */
.how-it-works {
    padding: 6rem 0;
    background: #000000;
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.step {
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding: 2rem;
}

.step-number {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, #6366f1, #8b5cf6);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 1.5rem;
}

.step-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: #ffffff;
}

.step-description {
    color: #a1a1aa;
    line-height: 1.6;
}

/* CTA Section */
.cta {
    padding: 6rem 0;
    background: linear-gradient(135deg, #1a1a1a, #2a2a2a);
    text-align: center;
}

.cta-content {
    max-width: 600px;
    margin: 0 auto;
}

.cta-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: #ffffff;
}

.cta-description {
    font-size: 1.25rem;
    color: #a1a1aa;
    margin-bottom: 2.5rem;
    line-height: 1.7;
}

/* Footer */
.footer {
    background: #000000;
    padding: 3rem 0 1rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 3rem;
    margin-bottom: 2rem;
}

.footer-brand {
    max-width: 300px;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 1rem;
}

.footer-description {
    color: #a1a1aa;
    line-height: 1.6;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.footer-title {
    font-size: 1rem;
    font-weight: 600;
    color: #ffffff;
    margin-bottom: 1rem;
}

.footer-link {
    display: block;
    color: #a1a1aa;
    text-decoration: none;
    margin-bottom: 0.5rem;
    transition: color 0.3s ease;
}

.footer-link:hover {
    color: #6366f1;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.copyright {
    color: #a1a1aa;
    font-size: 0.875rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: flex;
        gap: 1rem;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        gap: 2rem;
        text-align: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .phone-mockup {
        width: 250px;
        height: 500px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .steps-container {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .download-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .download-buttons-centered {
        justify-content: center;
    }
    
    .download-img {
        height: 50px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-description {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .cta-title {
        font-size: 2rem;
    }
    
    .phone-mockup {
        width: 200px;
        height: 400px;
    }
    
    .app-preview {
        padding: 1rem;
    }
    
    .flashcard-demo {
        width: 150px;
        height: 90px;
    }
}

/* Smooth Animations */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.feature-card,
.step {
    animation: fadeInUp 0.6s ease-out;
}

/* Loading Animation */
.loading {
    opacity: 0;
    animation: fadeInUp 0.8s ease-out forwards;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #1a1a1a;
}

::-webkit-scrollbar-thumb {
    background: #6366f1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #8b5cf6;
}