/* ===== CSS Variables (Design System) ===== */
:root {
    /* Colors */
    --primary: #3390ec;
    --primary-dark: #2070cc;
    --primary-light: #5aa8f0;
    --accent: #ff6b6b;
    --accent-hover: #ff5252;

    /* Dark Theme */
    --dark: #0a0e27;
    --dark-secondary: #151b35;
    --dark-tertiary: #1e2640;
    --gray: #2a3454;
    --gray-light: #3d4a6b;
    --text-primary: #ffffff;
    --text-secondary: #b8c5db;
    --text-muted: #7a8ba8;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #3390ec 0%, #5aa8f0 100%);
    --gradient-accent: linear-gradient(135deg, #ff6b6b 0%, #ff8e53 100%);
    --gradient-dark: linear-gradient(180deg, #0a0e27 0%, #151b35 100%);
    --gradient-hero: radial-gradient(ellipse at top, rgba(51, 144, 236, 0.15) 0%, transparent 60%);

    /* 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;
    --font-size-xs: 0.875rem;
    --font-size-sm: 1rem;
    --font-size-md: 1.125rem;
    --font-size-lg: 1.25rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 2.5rem;
    --font-size-4xl: 3rem;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 40px rgba(51, 144, 236, 0.3);

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background: var(--gradient-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ===== Container ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ===== Language Switcher ===== */
.lang-switcher {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    display: flex;
    gap: 8px;
    background: rgba(26, 35, 62, 0.8);
    backdrop-filter: blur(10px);
    padding: 6px;
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.lang-btn {
    padding: 8px 16px;
    background: transparent;
    border: none;
    color: var(--text-secondary);
    font-size: var(--font-size-xs);
    font-weight: 600;
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

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

.lang-btn:hover:not(.active) {
    color: var(--text-primary);
}

/* ===== Header ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 999;
    padding: var(--spacing-md) 0;
    transition: all var(--transition-normal);
}

.header.scrolled {
    background: rgba(10, 14, 39, 0.95);
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow-md);
    padding: var(--spacing-sm) 0;
}

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

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 800;
    color: var(--text-primary);
    text-decoration: none;
}

.logo img {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
}

.nav {
    display: flex;
    gap: var(--spacing-lg);
}

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

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

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

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

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-sm);
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 4px 16px rgba(51, 144, 236, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 24px rgba(51, 144, 236, 0.4);
}

.btn-secondary {
    background: var(--dark-tertiary);
    color: var(--text-primary);
    border: 2px solid var(--gray);
}

.btn-secondary:hover {
    border-color: var(--primary);
    background: var(--dark-secondary);
}

.btn-large {
    padding: 16px 32px;
    font-size: var(--font-size-md);
}

.btn-header {
    display: none;
}

/* ===== Mobile Menu ===== */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.mobile-menu-btn span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-fast);
}

.mobile-menu {
    display: none;
    position: fixed;
    top: 80px;
    left: 0;
    right: 0;
    background: rgba(10, 14, 39, 0.98);
    backdrop-filter: blur(20px);
    padding: var(--spacing-lg);
    flex-direction: column;
    gap: var(--spacing-md);
    z-index: 998;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.mobile-menu.active {
    display: flex;
}

.mobile-menu-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: var(--font-size-md);
    padding: var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.mobile-menu-link:hover {
    background: var(--dark-tertiary);
    color: var(--primary-light);
}

/* ===== Hero Section ===== */
.hero {
    position: relative;
    padding: calc(var(--spacing-3xl) + 60px) 0 var(--spacing-3xl);
    overflow: hidden;
}

.hero-bg-gradient {
    position: absolute;
    top: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 100%;
    height: 100%;
    background: var(--gradient-hero);
    pointer-events: none;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-2xl);
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-text {
    animation: fadeInUp 0.8s ease;
}

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, #ffffff 0%, #b8c5db 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: var(--font-size-md);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInRight 0.8s ease;
}

.phone-mockup {
    width: 300px;
    height: 600px;
    background: var(--dark-secondary);
    border-radius: 40px;
    padding: 20px;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border: 8px solid var(--dark-tertiary);
    position: relative;
}

.phone-mockup::before {
    content: '';
    position: absolute;
    top: 10px;
    left: 50%;
    transform: translateX(-50%);
    width: 100px;
    height: 20px;
    background: var(--dark);
    border-radius: 0 0 20px 20px;
}

.phone-screen {
    width: 100%;
    height: 100%;
    background: linear-gradient(180deg, #1e2640 0%, #151b35 100%);
    border-radius: 30px;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
}

.chat-message {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    animation: messageSlideIn 0.5s ease;
}

.message-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: var(--font-size-sm);
    flex-shrink: 0;
}

.message-content {
    flex: 1;
}

.message-text {
    background: var(--dark-tertiary);
    padding: var(--spacing-sm);
    border-radius: var(--radius-md);
    font-size: 13px;
    line-height: 1.5;
    color: var(--text-secondary);
}

.bot-message .message-text {
    background: rgba(51, 144, 236, 0.15);
    border: 1px solid rgba(51, 144, 236, 0.3);
}

.user-message {
    flex-direction: row-reverse;
}

.user-message .message-text {
    background: var(--gradient-primary);
    color: white;
}

/* ===== Section Styles ===== */
section {
    padding: var(--spacing-3xl) 0;
}

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    text-align: center;
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, #ffffff 0%, #b8c5db 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-subtitle {
    font-size: var(--font-size-md);
    color: var(--text-secondary);
    text-align: center;
    margin-bottom: var(--spacing-xl);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

/* ===== Features Section ===== */
.features {
    background: var(--dark-secondary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.feature-card {
    background: var(--dark-tertiary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform var(--transition-normal);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(51, 144, 236, 0.3);
}

.feature-card:hover::before {
    transform: scaleX(1);
}

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

.feature-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.feature-list {
    list-style: none;
}

.feature-list li {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    padding-left: var(--spacing-md);
    position: relative;
    line-height: 1.7;
}

.feature-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--primary);
    font-weight: 700;
}

.feature-list li strong {
    color: var(--text-primary);
}

/* ===== AI Section ===== */
.ai-section {
    background: linear-gradient(180deg, var(--dark) 0%, var(--dark-secondary) 100%);
    position: relative;
}

.ai-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--primary), transparent);
}

.ai-header {
    margin-bottom: var(--spacing-2xl);
}

.ai-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.ai-feature {
    text-align: center;
    padding: var(--spacing-xl);
    background: rgba(51, 144, 236, 0.05);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(51, 144, 236, 0.1);
    transition: all var(--transition-normal);
}

.ai-feature:hover {
    background: rgba(51, 144, 236, 0.1);
    border-color: rgba(51, 144, 236, 0.3);
    transform: scale(1.05);
}

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

.ai-feature-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.ai-feature-text {
    color: var(--text-secondary);
    line-height: 1.7;
}

.ai-feature-text code {
    background: rgba(51, 144, 236, 0.2);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.9em;
    color: var(--primary-light);
}

.ai-demo {
    max-width: 600px;
    margin: 0 auto;
}

.chat-demo {
    background: var(--dark-tertiary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* ===== Use Cases Section ===== */
.use-cases {
    background: var(--dark-secondary);
}

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

.use-case-card {
    background: var(--dark-tertiary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
}

.use-case-card:hover {
    transform: translateY(-8px);
    border-color: rgba(51, 144, 236, 0.3);
    box-shadow: var(--shadow-md);
}

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

.use-case-title {
    font-size: var(--font-size-lg);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.use-case-text {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===== Pricing Section ===== */
.pricing-table {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-2xl);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.pricing-card {
    background: var(--dark-tertiary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 2px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
    position: relative;
}

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

.pricing-pro {
    border-color: var(--primary);
    background: linear-gradient(180deg, rgba(51, 144, 236, 0.1) 0%, var(--dark-tertiary) 100%);
}

.pricing-badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--gradient-primary);
    padding: 6px 20px;
    border-radius: 20px;
    font-size: var(--font-size-xs);
    font-weight: 700;
    color: white;
}

.pricing-header {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

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

.pricing-name {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.pricing-subtitle {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
}

.pricing-price {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-lg) 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.price-from {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
    margin-right: 4px;
}

.price-amount {
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-primary);
}

.price-currency {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    margin-left: 4px;
}

.price-period {
    font-size: var(--font-size-sm);
    color: var(--text-muted);
    margin-left: 4px;
}

.pricing-features {
    list-style: none;
    margin-bottom: var(--spacing-xl);
}

.pricing-features li {
    padding: var(--spacing-sm) 0;
    color: var(--text-secondary);
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
}

.pricing-features li:last-child {
    border-bottom: none;
}

.pricing-features li strong {
    color: var(--primary-light);
}

/* ===== FAQ Section ===== */
.faq {
    background: var(--dark-secondary);
}

.faq-list {
    max-width: 800px;
    margin: var(--spacing-2xl) auto 0;
}

.faq-item {
    background: var(--dark-tertiary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-md);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: all var(--transition-normal);
}

.faq-item:hover {
    border-color: rgba(51, 144, 236, 0.3);
}

.faq-question {
    font-size: var(--font-size-lg);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.faq-answer {
    color: var(--text-secondary);
    line-height: 1.8;
}

.faq-answer strong {
    color: var(--primary-light);
}

/* ===== CTA Section ===== */
.cta-section {
    background: linear-gradient(135deg, rgba(51, 144, 236, 0.1) 0%, rgba(90, 168, 240, 0.05) 100%);
    border-top: 1px solid rgba(51, 144, 236, 0.2);
    border-bottom: 1px solid rgba(51, 144, 236, 0.2);
}

.cta-content {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.cta-title {
    font-size: var(--font-size-3xl);
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.cta-text {
    font-size: var(--font-size-md);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

/* ===== Footer ===== */
.footer {
    background: var(--dark);
    padding: var(--spacing-2xl) 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

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

.footer-logo {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 800;
    margin-bottom: var(--spacing-lg);
}

.footer-logo img {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
}

.footer-links {
    margin-bottom: var(--spacing-md);
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    margin: 0 var(--spacing-md);
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary-light);
}

.footer-copyright {
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }

    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes messageSlideIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    opacity: 0;
    animation: fadeInUp 0.6s ease forwards;
}

/* ===== Responsive Design ===== */
@media (max-width: 968px) {
    .nav {
        display: none;
    }

    .btn-header {
        display: none;
    }

    .mobile-menu-btn {
        display: flex;
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .hero-visual {
        order: -1;
    }

    .phone-mockup {
        width: 250px;
        height: 500px;
    }

    .hero-title {
        font-size: var(--font-size-3xl);
    }

    .section-title {
        font-size: var(--font-size-2xl);
    }

    .features-grid,
    .ai-features,
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 640px) {
    :root {
        --spacing-3xl: 3rem;
        --spacing-2xl: 2rem;
    }

    .hero-title {
        font-size: var(--font-size-2xl);
    }

    .hero-subtitle {
        font-size: var(--font-size-sm);
    }

    .section-title {
        font-size: var(--font-size-xl);
    }

    .btn-large {
        padding: 14px 24px;
        font-size: var(--font-size-sm);
    }

    .pricing-table {
        grid-template-columns: 1fr;
    }

    .phone-mockup {
        width: 220px;
        height: 440px;
    }
}

/* ===== Utility Classes ===== */
.text-center {
    text-align: center;
}

.mt-1 {
    margin-top: var(--spacing-sm);
}

.mt-2 {
    margin-top: var(--spacing-md);
}

.mt-3 {
    margin-top: var(--spacing-lg);
}

.mb-1 {
    margin-bottom: var(--spacing-sm);
}

.mb-2 {
    margin-bottom: var(--spacing-md);
}

.mb-3 {
    margin-bottom: var(--spacing-lg);
}