/* ============================================
   NarrateAI Landing Page Styles
   ============================================ */

/* ===== Navigation ===== */

.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-fixed);
    background: var(--surface);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.nav.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) 0;
}

.nav-logo {
    text-decoration: none;
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    color: var(--text-primary);
    transition: transform var(--transition-fast);
}

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

.logo-text {
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-8);
}

.nav-links .theme-toggle {
    margin-left: var(--space-4);
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform var(--transition-base);
}

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

.nav-link:hover::after {
    transform: scaleX(1);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: var(--space-2);
}

.nav-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-base);
}

.nav-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.nav-toggle.active span:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== Hero Section ===== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0.05;
    z-index: -1;
}

.hero-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 50%, rgba(102, 126, 234, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(118, 75, 162, 0.1) 0%, transparent 50%);
}

.hero-content {
    text-align: center;
    max-width: 900px;
    margin: 0 auto;
    padding: var(--space-8) 0;
    animation: fadeInUp 0.8s ease-out;
}

.hero-title {
    font-size: var(--text-6xl);
    font-weight: var(--font-extrabold);
    line-height: var(--leading-tight);
    margin-bottom: var(--space-6);
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: var(--text-xl);
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-10);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.hero-cta {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    margin-bottom: var(--space-16);
    flex-wrap: wrap;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-12);
    flex-wrap: wrap;
}

.stat {
    text-align: center;
}

.stat-value {
    font-size: var(--text-5xl);
    font-weight: var(--font-bold);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--space-2);
}

.stat-label {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: var(--font-semibold);
}

/* ===== Section Styling ===== */

.section {
    padding: var(--space-20) 0;
}

.section-header {
    text-align: center;
    max-width: 700px;
    margin: 0 auto var(--space-16);
}

.section-subtitle {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
    margin-top: var(--space-4);
}

/* ===== Features Section ===== */

.section-features {
    background: var(--surface-muted);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-8);
}

.feature-card {
    background: var(--surface-card);
    padding: var(--space-8);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    border-radius: var(--radius-xl);
    margin-bottom: var(--space-6);
    color: var(--white);
}

.feature-title {
    font-size: var(--text-xl);
    font-weight: var(--font-semibold);
    margin-bottom: var(--space-4);
    color: var(--text-primary);
}

.feature-description {
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
}

/* ===== Technology Section ===== */

.section-technology {
    background: var(--surface-background);
}

.technology-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-16);
    align-items: center;
}

.technology-text {
    max-width: 540px;
}

.text-large {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-8);
}

.tech-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.tech-list li {
    display: flex;
    align-items: start;
    gap: var(--space-3);
    margin-bottom: var(--space-4);
    font-size: var(--text-base);
    color: var(--text-primary);
}

.tech-list svg {
    flex-shrink: 0;
    color: var(--success);
    margin-top: 2px;
}

.technology-visual {
    display: flex;
    justify-content: center;
}

.tech-card {
    background: var(--surface-card);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    width: 100%;
    max-width: 400px;
}

.tech-card-header {
    background: var(--gradient-primary);
    color: var(--white);
    padding: var(--space-5);
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    text-align: center;
}

.tech-card-body {
    padding: var(--space-6);
}

.pipeline-step {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-4);
    background: var(--surface-muted);
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
}

.pipeline-step:hover {
    background: var(--surface-card-hover);
    transform: translateX(8px);
}

.step-number {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-primary);
    color: var(--white);
    border-radius: var(--radius-full);
    font-weight: var(--font-bold);
    flex-shrink: 0;
}

.step-content {
    flex: 1;
}

.step-title {
    font-weight: var(--font-semibold);
    color: var(--text-primary);
    margin-bottom: var(--space-1);
}

.step-desc {
    font-size: var(--text-sm);
    color: var(--text-secondary);
}

.pipeline-arrow {
    text-align: center;
    color: var(--primary-start);
    font-size: var(--text-2xl);
    margin: var(--space-2) 0;
}

/* ===== Samples Section ===== */

.section-samples {
    background: var(--surface-muted);
}

.language-filter {
    display: flex;
    justify-content: center;
    gap: var(--space-3);
    margin-bottom: var(--space-12);
    flex-wrap: wrap;
}

.filter-btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    background: var(--surface-card);
    color: var(--text-secondary);
    border: 2px solid var(--gray-300);
    border-radius: var(--radius-full);
    font-weight: var(--font-medium);
    cursor: pointer;
    transition: all var(--transition-base);
}

.filter-btn:hover {
    border-color: var(--primary-start);
    color: var(--primary-start);
}

.filter-btn.active {
    background: var(--gradient-primary);
    color: var(--white);
    border-color: transparent;
}

.filter-flag {
    width: 20px;
    height: 15px;
    object-fit: cover;
    border-radius: 2px;
}

.samples-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: var(--space-6);
    margin-bottom: var(--space-12);
    min-height: 400px;
}

.sample-card {
    background: var(--surface-card);
    border-radius: var(--radius-xl);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    cursor: pointer;
    opacity: 1;
    animation: scaleIn 0.3s ease-out;
}

.sample-card.hidden-filter {
    display: none;
}

.sample-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-xl);
}

.sample-cover {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.sample-body {
    padding: var(--space-5);
}

.sample-title {
    font-size: var(--text-lg);
    font-weight: var(--font-semibold);
    color: var(--text-primary);
    margin-bottom: var(--space-2);
}

.sample-author {
    font-size: var(--text-sm);
    color: var(--text-secondary);
    margin-bottom: var(--space-3);
}

.sample-description {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    margin-bottom: var(--space-4);
}

.sample-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.samples-cta {
    text-align: center;
    margin-top: var(--space-12);
}

/* ===== Use Cases Section ===== */

.section-use-cases {
    background: var(--surface-background);
}

.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: var(--space-10);
}

.use-case-card {
    padding: var(--space-10);
    background: var(--gradient-primary);
    border-radius: var(--radius-2xl);
    color: var(--white);
}

.use-case-card:nth-child(2) {
    background: var(--gradient-accent);
}

.use-case-icon {
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-xl);
    margin-bottom: var(--space-6);
}

.use-case-title {
    font-size: var(--text-2xl);
    font-weight: var(--font-bold);
    margin-bottom: var(--space-4);
}

.use-case-description {
    font-size: var(--text-base);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-6);
    opacity: 0.95;
}

.use-case-benefits {
    list-style: none;
    padding: 0;
    margin: 0;
}

.use-case-benefits li {
    padding-left: var(--space-6);
    margin-bottom: var(--space-3);
    position: relative;
    line-height: var(--leading-relaxed);
}

.use-case-benefits li::before {
    content: '✓';
    position: absolute;
    left: 0;
    font-weight: var(--font-bold);
    color: rgba(255, 255, 255, 0.9);
}

/* ===== Contact Section ===== */

.section-contact {
    background: var(--surface-muted);
}

.contact-form {
    background: var(--surface-card);
    padding: var(--space-10);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-xl);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-6);
}

.form-message {
    margin-top: var(--space-4);
    padding: var(--space-4);
    border-radius: var(--radius-lg);
    text-align: center;
    font-weight: var(--font-medium);
}

.form-message.success {
    background: var(--success-light);
    color: var(--success-strong);
}

.form-message.error {
    background: var(--error-light);
    color: var(--error-strong);
}

/* ===== Footer ===== */

.footer {
    background: var(--surface-contrast);
    color: var(--gray-300);
    padding: var(--space-16) 0 var(--space-8);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: var(--space-12);
    margin-bottom: var(--space-12);
}

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

.footer-logo {
    margin-bottom: var(--space-4);
}

.footer-logo .logo-text {
    color: var(--white);
}

.footer-tagline {
    color: var(--gray-400);
    line-height: var(--leading-relaxed);
}

.footer-social {
    display: flex;
    gap: var(--space-4);
    margin-top: var(--space-6);
}

.social-link {
    color: var(--gray-400);
    transition: color var(--transition-fast);
}

.social-link:hover {
    color: var(--white);
}

.footer-heading {
    color: var(--white);
    font-size: var(--text-base);
    font-weight: var(--font-semibold);
    margin-bottom: var(--space-4);
}

.footer-column ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-column li {
    margin-bottom: var(--space-3);
}

.footer-column a {
    color: var(--gray-400);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-column a:hover {
    color: var(--white);
}

.footer-bottom {
    border-top: 1px solid var(--surface-border);
    padding-top: var(--space-8);
    text-align: center;
    color: var(--gray-500);
    font-size: var(--text-sm);
}

/* ===== Scroll Animations ===== */

.fade-in-section {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease-out;
}

.fade-in-section.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ===== Responsive Design ===== */

@media (max-width: 1024px) {
    .hero-title {
        font-size: var(--text-5xl);
    }
    
    .technology-content {
        grid-template-columns: 1fr;
        gap: var(--space-10);
    }
    
    .technology-text {
        max-width: 100%;
    }
    
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr 1fr;
        gap: var(--space-8);
    }
    
    .footer-brand {
        grid-column: 1 / -1;
        max-width: 100%;
    }
}

@media (max-width: 768px) {
    .nav-toggle {
        display: flex;
    }
    
    .nav-links {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: var(--surface-card);
        flex-direction: column;
        gap: 0;
        padding: var(--space-4) 0;
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: all var(--transition-base);
    }

    .nav-links .theme-toggle {
        width: calc(100% - 2 * var(--space-4));
        margin: var(--space-2) var(--space-4);
        justify-content: center;
    }
    
    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    
    .nav-link {
        padding: var(--space-4) var(--space-6);
        width: 100%;
        text-align: center;
    }
    
    .nav-link::after {
        display: none;
    }
    
    .hero {
        min-height: auto;
        padding: var(--space-20) 0;
    }
    
    .hero-title {
        font-size: var(--text-4xl);
    }
    
    .hero-subtitle {
        font-size: var(--text-base);
    }
    
    .hero-cta {
        flex-direction: column;
        align-items: center;
    }
    
    .hero-cta .btn {
        width: 100%;
        max-width: 300px;
    }
    
    .section {
        padding: var(--space-16) 0;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .samples-grid {
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .contact-form {
        padding: var(--space-6);
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    .hero-title {
        font-size: var(--text-3xl);
    }
    
    .stat-value {
        font-size: var(--text-4xl);
    }
    
    .language-filter {
        gap: var(--space-2);
    }
    
    .filter-btn {
        font-size: var(--text-sm);
        padding: var(--space-2) var(--space-4);
    }
    
    .samples-grid {
        grid-template-columns: 1fr;
    }
}