/* Reset e configurações globais */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    --danger-color: #ef4444;
    --warning-color: #f97316;
    --success-color: #22c55e;
    
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    
    --border-color: #e5e7eb;
    --border-light: #f3f4f6;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

/* Container */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

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

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.nav-logo i {
    font-size: 1.75rem;
}

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

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover {
    color: var(--primary-color);
}

.nav-link.login-btn {
    background: var(--primary-color);
    color: white;
    padding: 0.5rem 1.5rem;
    border-radius: var(--radius-lg);
    transition: var(--transition);
}

.nav-link.login-btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Hamburger Menu */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

/* Hero Section */
.hero {
    padding: 120px 0 80px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.1;
}

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

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

.hero-title .highlight {
    background: linear-gradient(45deg, #fbbf24, #f59e0b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-description {
    font-size: 1.25rem;
    line-height: 1.6;
    margin-bottom: 2rem;
    opacity: 0.9;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 2rem;
    border: none;
    border-radius: var(--radius-lg);
    font-size: 1rem;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--accent-color);
    color: white;
}

.btn-primary:hover {
    background: #d97706;
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.2);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

/* Flashcard Demo */
.hero-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.flashcard-demo {
    perspective: 1000px;
}

.card {
    width: 300px;
    height: 200px;
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 2rem;
    color: var(--text-primary);
    cursor: pointer;
    transition: transform 0.6s;
    animation: float 3s ease-in-out infinite;
}

.card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.card-flip-hint {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-light);
    font-size: 0.875rem;
}

.card-flip-hint i {
    animation: rotate 2s linear infinite;
}

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

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* Features Section */
.features {
    padding: 80px 0;
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: 4rem;
}

.section-header h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.section-header p {
    font-size: 1.25rem;
    color: var(--text-secondary);
}

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

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    text-align: center;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
}

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

.feature-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.5rem;
    color: white;
    font-size: 2rem;
}

.feature-card h3 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

/* About Section */
.about {
    padding: 80px 0;
}

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

.about-text h2 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.about-text p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    line-height: 1.7;
}

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

.stat {
    text-align: center;
}

.stat h3 {
    font-size: 2rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.about-image {
    display: flex;
    justify-content: center;
    align-items: center;
}

.image-placeholder {
    width: 300px;
    height: 300px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 4rem;
    box-shadow: var(--shadow-xl);
}

/* Footer */
.footer {
    background: var(--text-primary);
    color: white;
    padding: 3rem 0 1rem;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
}

.footer-logo i {
    font-size: 1.75rem;
    color: var(--primary-color);
}

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

.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid #374151;
    color: var(--text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        display: none;
    }
    
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 2rem;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .stats {
        justify-content: center;
    }
    
    .footer-content {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .footer-links {
        flex-wrap: wrap;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
}