:root {
    /* Colors - Duolingo/Yazio inspired */
    --primary: #58CC02;
    --primary-shadow: #58A700;
    --secondary: #1CB0F6;
    --secondary-shadow: #1899D6;
    --accent: #FF4B4B;
    --accent-shadow: #D33131;
    --text-main: #4B4B4B;
    --text-muted: #777777;
    --bg-main: #FFFFFF;
    --bg-soft: #F7F7F7;
    --border-color: #E5E5E5;
    
    /* Feature Colors */
    --color-orange: #FF9600;
    --color-blue: #1CB0F6;
    --color-purple: #CE82FF;

    /* Typography */
    --font-family: 'Nunito', sans-serif;
    
    /* Border Radius */
    --radius-sm: 12px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-round: 99px;
}

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

body {
    font-family: var(--font-family);
    color: var(--text-main);
    background-color: var(--bg-main);
    line-height: 1.5;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

/* Header */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 100;
    border-bottom: 2px solid var(--border-color);
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    display: flex;
    align-items: center;
    gap: 8px;
    letter-spacing: -0.5px;
}

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

/* Buttons (Duolingo Style 3D) */
.btn {
    font-family: var(--font-family);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: transform 0.1s, box-shadow 0.1s, filter 0.2s;
    text-align: center;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    outline: none;
    text-decoration: none;
}

.btn:active {
    transform: translateY(4px);
    box-shadow: 0 0px 0 transparent !important;
}

.btn:hover {
    filter: brightness(1.05);
}

.btn-primary {
    background-color: var(--primary);
    color: white;
    box-shadow: 0 4px 0 var(--primary-shadow);
}

.btn-secondary {
    background-color: var(--bg-main);
    color: var(--secondary);
    border: 2px solid var(--border-color);
    box-shadow: 0 4px 0 var(--border-color);
}
.btn-secondary:active {
    border-color: var(--border-color);
}

.btn-sm {
    padding: 10px 16px;
    font-size: 0.9rem;
    border-radius: var(--radius-sm);
}

.btn-lg {
    padding: 16px 32px;
    font-size: 1.1rem;
    border-radius: var(--radius-md);
    width: 100%;
    max-width: 300px;
}

/* Main Content */
main {
    margin-top: 70px; /* Space for fixed header */
    padding-bottom: 40px;
}

/* Hero Section */
.hero {
    padding: 40px 20px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 32px;
    max-width: 1200px;
    margin: 0 auto;
}

.hero-text {
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 16px;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.highlight {
    color: var(--primary);
}

.hero-subtitle {
    font-size: 1.1rem;
    color: var(--text-muted);
    margin-bottom: 32px;
    font-weight: 600;
    max-width: 500px;
}

.hero-visual {
    width: 100%;
    max-width: 450px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-img {
    width: 100%;
    height: auto;
    border-radius: var(--radius-lg);
    /* Soft shadow to ground the 3D element */
    filter: drop-shadow(0 20px 30px rgba(0,0,0,0.08));
}

/* Common Section */
.section-title {
    font-size: 1.5rem;
    font-weight: 800;
    text-align: center;
    margin-bottom: 24px;
    padding: 0 20px;
}

/* Features Section */
.features {
    padding: 40px 20px;
    background-color: var(--bg-soft);
}

.features-grid {
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-width: 600px;
    margin: 0 auto;
}

.feature-card {
    background: var(--bg-main);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    box-shadow: 0 4px 0 var(--border-color);
    transition: transform 0.2s;
}

.feature-card:hover {
    transform: translateY(-2px);
}

.feature-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin-bottom: 16px;
    color: white;
}

.bg-orange { background-color: var(--color-orange); }
.bg-blue { background-color: var(--color-blue); }
.bg-purple { background-color: var(--color-purple); }

.feature-card h3 {
    font-size: 1.2rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.feature-card p {
    color: var(--text-muted);
    font-weight: 600;
    font-size: 0.95rem;
}

/* How It Works */
.how-it-works {
    padding: 60px 20px;
    max-width: 600px;
    margin: 0 auto;
}

.steps-container {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.step {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    background: var(--bg-main);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    box-shadow: 0 4px 0 var(--border-color);
}

.step-number {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--primary);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    font-size: 1.2rem;
    flex-shrink: 0;
    box-shadow: 0 2px 0 var(--primary-shadow);
}

.step-content h3 {
    font-size: 1.1rem;
    font-weight: 800;
    margin-bottom: 4px;
}

.step-content p {
    color: var(--text-muted);
    font-size: 0.9rem;
    font-weight: 600;
}

/* CTA Section */
.cta-section {
    padding: 20px;
    margin-bottom: 40px;
}

.cta-card {
    background-color: var(--primary);
    border-radius: var(--radius-lg);
    padding: 40px 20px;
    text-align: center;
    color: white;
    max-width: 600px;
    margin: 0 auto;
    box-shadow: 0 6px 0 var(--primary-shadow);
}

.cta-card h2 {
    font-size: 1.8rem;
    font-weight: 800;
    margin-bottom: 8px;
}

.cta-card p {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 24px;
    opacity: 0.9;
}

.cta-card .btn-primary {
    background-color: white;
    color: var(--primary);
    box-shadow: 0 4px 0 #E5E5E5;
}

.cta-card .btn-primary:active {
    box-shadow: 0 0px 0 transparent;
}

/* Footer */
.footer {
    padding: 32px 20px;
    background-color: #FAFAFA;
    border-top: 2px solid var(--border-color);
    text-align: center;
}

.logo-footer {
    justify-content: center;
    color: #C0C0C0;
    margin-bottom: 16px;
    filter: grayscale(100%);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 16px;
    margin-bottom: 24px;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 700;
    font-size: 0.9rem;
}

.copyright {
    color: #B0B0B0;
    font-size: 0.8rem;
    font-weight: 600;
}

/* Animations */
@keyframes float {
    0% { transform: translateY(0px); }
    50% { transform: translateY(-10px); }
    100% { transform: translateY(0px); }
}

.floating {
    animation: float 3s ease-in-out infinite;
}

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

.cta-pulse {
    animation: pulse 2s infinite;
}

/* Scroll Animation Classes */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease-out, transform 0.6s ease-out;
}

.animate-on-scroll.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Desktop adjustments */
@media (min-width: 768px) {
    .hero {
        flex-direction: row;
        text-align: left;
        justify-content: space-between;
        padding: 80px 40px;
        gap: 60px;
    }

    .hero-text {
        text-align: left;
        align-items: flex-start;
        flex: 1;
    }

    .hero-title {
        font-size: 3.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }

    .hero-visual {
        flex: 1;
        max-width: 500px;
    }

    .features-grid {
        flex-direction: row;
        max-width: 1000px;
    }
    
    .feature-card {
        flex: 1;
    }
}