/* ===================================
   CSS Variables
   =================================== */
:root {
    /* Colors */
    --primary-color: #3B82F6;
    --primary-dark: #2563EB;
    --primary-light: #60A5FA;
    --accent-color: #F59E0B;
    --text-dark: #1a1a2e;
    --text-light: #666666;
    --text-white: #ffffff;
    --bg-light: #ffffff;
    --bg-gray: #f8f9fa;
    --bg-dark: #1a1a2e;

    /* Logo Colors */
    --logo-primary: #3B82F6;
    --logo-accent: #F59E0B;
    --logo-accent-light: #FBBF24;
    
    /* Gradients */
    --primary-gradient: linear-gradient(135deg, #3B82F6 0%, #2563EB 100%);
    --accent-gradient: linear-gradient(135deg, #F59E0B 0%, #FBBF24 100%);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-xxl: 4rem;
    
    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.12);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.16);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB',
        'Microsoft YaHei', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-fast);
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

ul {
    list-style: none;
}

/* Mobile-only utility class - hidden on desktop by default */
.mobile-only {
    display: none !important;
}

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

.gradient-text {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 0.6rem 1.2rem;
    font-size: 0.9rem;
    font-weight: 600;
    border-radius: var(--radius-md);
    border: 1.5px solid transparent;
    cursor: pointer;
    transition: all var(--transition-normal);
    text-transform: none;
    height: 40px;
    white-space: nowrap;
    flex-shrink: 0;
}

.nav-actions .btn {
    width: 90px;
}

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

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

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: var(--text-white);
    transform: translateY(-2px);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

/* ===================================
   Header & Navigation
   =================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: var(--text-white);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-normal);
}

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

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0.9rem var(--spacing-md);
    min-height: 70px;
    box-sizing: border-box;
    flex-wrap: nowrap;
}

.logo a {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.logo-img {
    height: 45px;
    width: auto;
    display: block;
}

.logo-text-container {
    display: flex;
    flex-direction: column;
    line-height: 1.1;
}

.logo-text-zh {
    font-size: 1.4rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo-text-en {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-light);
    letter-spacing: 0.5px;
}

.nav-menu {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
    flex-wrap: nowrap;
    white-space: nowrap;
    margin: 0;
    padding: 0;
}

.nav-link {
    font-weight: 500;
    color: var(--text-dark);
    position: relative;
    min-width: 80px;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 0;
}

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

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

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

.nav-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    justify-content: flex-end;
    flex-wrap: nowrap;
    white-space: nowrap;
    min-width: auto;
    flex-shrink: 0;
}

/* Language Switcher */
.language-switcher {
    position: relative;
}

.lang-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem 1rem;
    background: var(--bg-light);
    border: 1.5px solid var(--primary-color);
    border-radius: var(--radius-md);
    color: var(--primary-color);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
    height: 40px;
    white-space: nowrap;
    width: auto;
    min-width: 140px;
    flex-shrink: 0;
}

/* Medium screen optimization (900px - 769px) */
@media (max-width: 900px) and (min-width: 769px) {
    .nav-container {
        padding: 0.9rem var(--spacing-sm);
    }
    
    .nav-menu {
        gap: var(--spacing-md);
    }
    
    .lang-toggle {
        min-width: 120px;
        width: auto;
        padding: 0.6rem 0.8rem;
    }
    
    .lang-toggle .fa-globe {
        margin-right: 0.5rem;
    }
    
    .nav-actions .btn {
        padding: 0.6rem 1rem;
        min-width: auto;
        width: 80px;
        font-size: 0.85rem;
    }
}

.lang-toggle:hover {
    background: var(--primary-color);
    color: var(--text-white);
}

.lang-toggle .fas {
    font-size: 1rem;
}

.lang-toggle .fa-chevron-down {
    font-size: 0.75rem;
    transition: transform var(--transition-fast);
    margin-left: 0.25rem;
}

.language-switcher.active .lang-toggle .fa-chevron-down {
    transform: rotate(180deg);
}

.lang-dropdown {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    background: var(--text-white);
    border: 1.5px solid var(--primary-color);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    min-width: 140px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-normal);
    z-index: 1100;
}

.lang-dropdown.active {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.lang-option {
    padding: 0.75rem 1rem;
    cursor: pointer;
    transition: background var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-dark);
    font-size: 0.9rem;
    font-weight: 500;
}

.lang-option:hover {
    background: var(--bg-gray);
}

.lang-option.active {
    background: var(--primary-color);
    color: var(--text-white);
}

.lang-option .fa-check {
    display: none;
    font-size: 0.8rem;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-dark);
    cursor: pointer;
    padding: var(--spacing-xs);
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 6rem var(--spacing-md) 4rem;
    overflow: hidden;
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 20% 80%, rgba(0, 102, 204, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(255, 107, 53, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xxl);
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

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

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    color: var(--text-dark);
}

.hero-subtitle {
    font-size: 1.2rem;
    line-height: 1.8;
    color: var(--text-light);
    margin-bottom: var(--spacing-xl);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.hero-trust {
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.trust-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-light);
    font-size: 0.95rem;
}

.trust-item i {
    color: var(--primary-color);
    font-size: 1.2rem;
}

/* ===================================
   3D Card Animation
   =================================== */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeInRight 0.8s ease;
}

.card-3d {
    perspective: 1000px;
    width: 380px;
    height: 230px;
    margin: 0 auto;
}

.card-front {
    width: 100%;
    height: 100%;
    background: var(--primary-gradient);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    color: var(--text-white);
    position: relative;
    transform-style: preserve-3d;
    animation: cardFloat 6s ease-in-out infinite;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    overflow: hidden;
}

.card-chip {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-sm);
    opacity: 0.9;
    flex-shrink: 0;
}

.card-number {
    font-size: 1.3rem;
    letter-spacing: 3px;
    margin-bottom: var(--spacing-md);
    font-family: 'Courier New', monospace;
    word-break: break-all;
    flex-shrink: 0;
}

.card-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: var(--spacing-sm);
    flex-shrink: 0;
}

.card-holder,
.card-expiry {
    display: flex;
    flex-direction: column;
}

.card-holder .label,
.card-expiry .label {
    font-size: 0.65rem;
    opacity: 0.8;
    margin-bottom: 2px;
}

.card-holder .value,
.card-expiry .value {
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 1px;
}

.card-brand {
    position: absolute;
    bottom: var(--spacing-md);
    right: var(--spacing-md);
    font-size: 1.5rem;
    font-weight: 800;
    font-style: italic;
    opacity: 0.9;
}

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

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

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto;
}

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

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

.feature-card {
    background: var(--text-white);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-normal);
    text-align: center;
}

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

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

.feature-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

.feature-desc {
    color: var(--text-light);
    line-height: 1.8;
}

/* ===================================
   Scenarios Section
   =================================== */
.scenarios {
    background: var(--bg-light);
}

.scenarios-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-lg);
}

.scenario-item {
    background: var(--bg-gray);
    padding: var(--spacing-xl);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
    border: 2px solid transparent;
}

.scenario-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.scenario-icon {
    width: 70px;
    height: 70px;
    background: var(--accent-gradient);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
    font-size: 2rem;
    color: var(--text-white);
}

.scenario-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

.scenario-desc {
    color: var(--text-light);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.scenario-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.scenario-tags li {
    background: var(--text-white);
    padding: 0.4rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--primary-color);
    font-weight: 500;
    box-shadow: var(--shadow-sm);
}

/* ===================================
   Advantages Section
   =================================== */
.advantages {
    background: linear-gradient(135deg, #0066CC 0%, #004499 100%);
    color: var(--text-white);
}

.advantages .section-title,
.advantages .section-subtitle {
    color: var(--text-white);
}

.advantages .section-subtitle {
    opacity: 0.9;
}

.advantages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.advantage-item {
    text-align: center;
}

.advantage-number {
    font-size: 3rem;
    font-weight: 800;
    opacity: 0.3;
    margin-bottom: var(--spacing-sm);
}

.advantage-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.advantage-desc {
    opacity: 0.9;
    line-height: 1.8;
}

/* ===================================
   How It Works Section
   =================================== */
.how-it-works {
    background: var(--bg-gray);
}

.steps-container {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
    align-items: center;
    margin-bottom: var(--spacing-xxl);
}

.step-item {
    text-align: center;
}

.step-number {
    width: 80px;
    height: 80px;
    background: var(--primary-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-md);
    font-size: 2rem;
    color: var(--text-white);
}

.step-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--text-dark);
}

.step-desc {
    color: var(--text-light);
    line-height: 1.6;
}

.step-arrow {
    display: flex;
    justify-content: center;
    font-size: 1.5rem;
    color: var(--primary-color);
}

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

.faq-container {
    max-width: 800px;
    margin: 0 auto;
}

.faq-item {
    background: var(--bg-gray);
    border-radius: var(--radius-md);
    margin-bottom: var(--spacing-sm);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.faq-question {
    padding: var(--spacing-lg);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background var(--transition-fast);
}

.faq-question:hover {
    background: #e9ecef;
}

.faq-question h3 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-dark);
    flex: 1;
}

.faq-question i {
    transition: transform var(--transition-fast);
    color: var(--primary-color);
}

.faq-item.active .faq-question i {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-normal);
}

.faq-answer p {
    padding: 0 var(--spacing-lg) var(--spacing-lg);
    color: var(--text-light);
    line-height: 1.8;
}

.faq-answer a {
    color: var(--primary-color);
    text-decoration: underline;
}

.faq-item.active .faq-answer {
    max-height: 500px;
}

/* ===================================
   CTA Section
   =================================== */
.cta-section-full {
    background: var(--primary-gradient);
    padding: var(--spacing-xxl) 0;
    text-align: center;
    color: var(--text-white);
}

.cta-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.cta-subtitle {
    font-size: 1.2rem;
    margin-bottom: var(--spacing-xl);
    opacity: 0.9;
}

.cta-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.cta-buttons .btn {
    background: var(--text-white);
    color: var(--primary-color);
}

.cta-buttons .btn:hover {
    background: #f8f9fa;
}

.cta-section {
    text-align: center;
    padding: var(--spacing-xl) 0;
}

/* ===================================
   Footer
   =================================== */
.footer {
    background: var(--bg-dark);
    color: var(--text-white);
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section {
    padding: 0 var(--spacing-md);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
    font-weight: 700;
}

.footer-logo-img {
    height: 35px;
    width: auto;
    display: block;
}

.footer-logo .logo-icon {
    color: var(--primary-color);
    font-size: 1.8rem;
}

.footer-desc {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.footer-social {
    display: flex;
    gap: var(--spacing-sm);
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.footer-social a:hover {
    background: var(--primary-color);
    transform: translateY(-2px);
}

.footer-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

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

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    transition: color var(--transition-fast);
}

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

.footer-contact li {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
    color: rgba(255, 255, 255, 0.7);
}

.footer-contact i {
    color: var(--primary-color);
}

.footer-contact a {
    color: rgba(255, 255, 255, 0.7);
}

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

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg) var(--spacing-md) 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.footer-copyright,
.footer-legal {
    color: rgba(255, 255, 255, 0.5);
    font-size: 0.9rem;
}

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

.footer-legal a {
    color: rgba(255, 255, 255, 0.5);
}

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

/* ===================================
   Back to Top Button
   =================================== */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: var(--primary-gradient);
    color: var(--text-white);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-normal);
    z-index: 999;
    box-shadow: var(--shadow-md);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* ===================================
   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 cardFloat {
    0%, 100% {
        transform: translateY(0) rotateX(0) rotateY(0);
    }
    25% {
        transform: translateY(-10px) rotateX(2deg) rotateY(-2deg);
    }
    50% {
        transform: translateY(-5px) rotateX(0) rotateY(0);
    }
    75% {
        transform: translateY(-10px) rotateX(-2deg) rotateY(2deg);
    }
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-xl);
    }
    
    .hero-content {
        order: 2;
    }
    
    .hero-visual {
        order: 1;
        display: flex;
        justify-content: center;
        align-items: center;
        width: 100%;
    }
    
    .hero-cta {
        justify-content: center;
    }
    
    .hero-trust {
        justify-content: center;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .steps-container {
        grid-template-columns: 1fr;
    }
    
    .step-arrow {
        transform: rotate(90deg);
        margin: var(--spacing-sm) 0;
    }
    
    .card-3d {
        width: 340px;
        height: 210px;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--text-white);
        flex-direction: column;
        padding: 0.75rem 1rem;
        gap: 0;
        transform: translateY(-150%);
        transition: transform var(--transition-normal);
        box-shadow: var(--shadow-md);
        z-index: 999;
        max-height: calc(100vh - 70px);
        overflow-y: auto;
    }
    
    .nav-menu.active {
        transform: translateY(0);
    }
    
    .nav-actions {
        gap: 0.5rem;
    }
    
    .nav-actions .btn {
        display: none;
    }
    
    .nav-actions .language-switcher {
        display: none;
    }
    
    .mobile-menu-btn {
        display: block;
        background: transparent;
        border: none;
        font-size: 1.5rem;
        color: var(--text-dark);
        cursor: pointer;
        padding: var(--spacing-xs);
        transition: color var(--transition-fast);
        z-index: 1001;
    }
    
    .mobile-menu-btn:hover {
        color: var(--primary-color);
    }
    
    /* Mobile menu specific styles */
    .nav-menu {
        align-items: stretch;
    }
    
    .nav-menu > li {
        border-bottom: 1px solid rgba(0, 0, 0, 0.05);
        padding: 0;
        margin: 0;
    }
    
    .nav-menu > li:last-child {
        border-bottom: none;
    }
    
    .nav-link {
        min-width: auto;
        text-align: left;
        padding: 0.5rem 0;
        font-size: 1rem;
        justify-content: flex-start;
        margin: 0;
        display: block;
        width: 100%;
    }
    
    .nav-link::after {
        display: none;
    }
    
.nav-link:hover {
        color: var(--primary-color);
        background-color: transparent;
    }

    /* Show mobile-only items in mobile menu */
    .mobile-only {
        display: block !important;
    }

    /* Mobile language switcher */
    .mobile-language-switcher {
        position: relative;
        width: 100%;
    }
    
    .mobile-lang-toggle {
        display: flex;
        align-items: center;
        gap: 0.5rem;
        width: 100%;
        padding: 0.75rem 0;
        background: none;
        border: none;
        font-size: 1rem;
        color: var(--text-dark);
        cursor: pointer;
        text-align: left;
        margin: 0;
    }
    
    .mobile-lang-toggle:hover {
        color: var(--primary-color);
    }
    
    .mobile-lang-toggle .fas {
        font-size: 1.2rem;
        color: var(--primary-color);
    }
    
    .mobile-lang-dropdown {
        position: static;
        background: var(--bg-gray);
        border-radius: var(--radius-md);
        margin: 0.25rem 0;
        padding: 0.25rem 0;
        display: none;
        box-shadow: none;
        border: 1px solid var(--bg-gray);
        width: 100%;
    }
    
    .mobile-lang-dropdown.active {
        display: block;
    }
    
    .mobile-lang-option {
        padding: 0.5rem var(--spacing-md);
        cursor: pointer;
        transition: background var(--transition-fast);
        color: var(--text-dark);
        font-size: 0.95rem;
        display: flex;
        align-items: center;
        gap: 0.5rem;
        margin: 0;
    }
    
    .mobile-lang-option:hover {
        background: rgba(59, 130, 246, 0.1);
    }
    
    .mobile-lang-option.active {
        background: var(--primary-color);
        color: var(--text-white);
    }
    
    .mobile-lang-option .fa-check {
        font-size: 0.9rem;
        display: none;
    }
    
    .mobile-lang-option.active .fa-check {
        display: inline;
    }
    
    /* Mobile login/register links */
    .mobile-login-link,
    .mobile-register-link {
        display: block;
        width: 100%;
        text-align: center;
        padding: 0.75rem;
        border-radius: var(--radius-md);
        margin: 0.25rem 0;
        font-weight: 600;
        font-size: 0.95rem;
    }
    
    .mobile-login-link {
        background: var(--text-white);
        color: var(--primary-color);
        border: 2px solid var(--primary-color);
    }
    
    .mobile-register-link {
        background: var(--primary-gradient);
        color: var(--text-white);
        border: 2px solid var(--primary-color);
    }
    
    .mobile-login-link:hover,
    .mobile-register-link:hover {
        transform: translateY(-2px);
        box-shadow: var(--shadow-sm);
    }
    
    .hero {
        padding: 5rem var(--spacing-sm) 3rem;
    }
    
    .hero-container {
        gap: var(--spacing-lg);
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .section-subtitle {
        font-size: 1rem;
    }
    
    .features-grid,
    .scenarios-container,
    .advantages-grid {
        grid-template-columns: 1fr;
    }
    
    .card-3d {
        width: 280px;
        height: 180px;
        margin: 0 auto;
    }
    
    .card-chip {
        font-size: 1.8rem;
        margin-bottom: var(--spacing-sm);
    }
    
    .card-number {
        font-size: 1rem;
        letter-spacing: 2px;
        word-break: keep-all;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }
    
    .card-info {
        margin-top: auto;
    }
    
    .card-brand {
        font-size: 1.2rem;
        bottom: var(--spacing-sm);
        right: var(--spacing-sm);
    }
    
    .cta-buttons {
        flex-direction: column;
    }
    
    .cta-buttons .btn {
        width: 100%;
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-legal {
        flex-direction: column;
        gap: var(--spacing-sm);
    }
    
    .back-to-top {
        bottom: 1rem;
        right: 1rem;
        width: 45px;
        height: 45px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 0.95rem;
    }
    
    .btn {
        padding: 0.6rem 1.2rem;
        font-size: 0.95rem;
    }
    
    .btn-large {
        padding: 0.8rem 1.5rem;
        font-size: 1rem;
    }
    
    .card-3d {
        width: 100%;
        max-width: 280px;
        height: 160px;
    }
    
    .card-front {
        padding: var(--spacing-md);
    }
    
    .card-chip {
        font-size: 1.6rem;
        margin-bottom: var(--spacing-xs);
    }
    
    .card-number {
        font-size: 0.8rem;
        letter-spacing: 1.5px;
    }
    
    .card-holder .label,
    .card-expiry .label {
        font-size: 0.6rem;
    }
    
    .card-holder .value,
    .card-expiry .value {
        font-size: 0.75rem;
    }
    
    .card-brand {
        font-size: 1rem;
        bottom: var(--spacing-xs);
        right: var(--spacing-xs);
    }
    
    .section-title {
        font-size: 1.75rem;
    }
    
    .cta-title {
        font-size: 1.75rem;
    }
}

/* ===================================
   Print Styles
   =================================== */
@media print {
    .header,
    .footer,
    .back-to-top {
        display: none;
    }
    
    section {
        page-break-inside: avoid;
    }
}