/* ============================================
   CHINA BUSINESS HUB - STATIC SITE STYLES
   Optimized for China: No external dependencies
   ============================================ */

:root {
    /* Colors - China Business Hub Brand */
    --color-primary: #dc2626;      /* Red (China flag inspired) */
    --color-secondary: #fbbf24;    /* Gold/Yellow */
    --color-accent: #2563eb;       /* Blue (Brazil flag inspired) */
    --color-success: #16a34a;
    --color-error: #dc2626;

    /* Neutrals */
    --color-bg: #ffffff;
    --color-bg-alt: #f9fafb;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-border: #e5e7eb;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2.5rem;
    --spacing-xl: 4rem;

    /* Typography */
    --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 3rem;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-base);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    padding-top: 60px;
}

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

a {
    color: var(--color-primary);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--color-secondary);
}

/* ============================================
   LAYOUT
   ============================================ */

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

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

.section-alt {
    background: var(--color-bg-alt);
}

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-text);
}

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

/* ============================================
   FLOATING HEADER
   ============================================ */

.floating-header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
    z-index: 1000;
    min-height: 60px;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0.75rem var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 60px;
}

.header-logo {
    display: flex;
    align-items: center;
    transition: opacity 0.3s ease;
}

.header-logo:hover {
    opacity: 0.8;
}

.header-logo img {
    height: 40px;
    width: auto;
}

.header-nav {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.header-btn {
    padding: 0.5rem 1.25rem;
    border: none;
    border-radius: 6px;
    font-size: var(--font-size-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    white-space: nowrap;
}

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

.header-btn.btn-primary:hover {
    background: #b91c1c;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(220, 38, 38, 0.3);
}

.header-btn.btn-secondary {
    background: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.header-btn.btn-secondary:hover {
    background: var(--color-primary);
    color: white;
}

.header-btn.btn-tertiary {
    background: #fbbf24;
    color: #1f2937;
    border: 2px solid #fbbf24;
}

.header-btn.btn-tertiary:hover {
    background: #d4a017;
    border-color: #d4a017;
    color: #1f2937;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(230, 184, 0, 0.3);
}

/* ============================================
   LANGUAGE SWITCHER (inside header)
   ============================================ */

.lang-switcher {
    display: flex;
    align-items: center;
}

.lang-switcher select {
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 2px solid var(--color-border);
    border-radius: 8px;
    background: white;
    font-size: var(--font-size-sm);
    cursor: pointer;
    transition: border-color 0.3s ease;
}

.lang-switcher select:hover,
.lang-switcher select:focus {
    border-color: var(--color-primary);
    outline: none;
}

/* ============================================
   HERO SECTION
   ============================================ */

.hero {
    position: relative;
    min-height: 90vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    color: white;
    text-align: center;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    /* background: linear-gradient(135deg, rgba(220, 38, 38, 0.85), rgba(251, 191, 36, 0.75)); */
}

.hero-content {
    position: relative;
    z-index: 10;
    padding-top: 2.5rem;
}

.hero-title {
    font-size: var(--font-size-3xl);
    font-weight: 900;
    margin-bottom: var(--spacing-md);
    text-shadow: 2px 2px 8px rgba(0,0,0,0.5);
}

.hero-subtitle {
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-lg);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
    color: white;
    background: rgba(0, 0, 0, 0.3);
    padding: var(--spacing-sm);
    border-radius: 12px;
    backdrop-filter: blur(2px);
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-lg);
}

.trust-badges {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
    flex-wrap: wrap;
    margin-top: var(--spacing-lg);
}

.trust-badge {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-md);
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50px;
    backdrop-filter: blur(10px);
    font-size: var(--font-size-sm);
    font-weight: 600;
}

.canton-banner {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-md);
    background: rgba(255, 255, 255, 0.95);
    color: var(--color-text);
    border-radius: 12px;
    font-weight: 600;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: 8px;
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

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

.btn-primary:hover {
    background: #b91c1c;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(220, 38, 38, 0.4);
}

.btn-secondary {
    background: white;
    color: var(--color-primary);
    border: 2px solid white;
}

.btn-secondary:hover {
    background: transparent;
    color: white;
}

.btn-tertiary {
    background: #fbbf24;
    border: 2px solid #fbbf24;
    color: #1f2937;
}

.btn-tertiary:hover {
    background: #d4a017;
    border-color: #d4a017;
    color: #1f2937;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(230, 184, 0, 0.4);
}

.btn-block {
    display: block;
    width: 100%;
}

/* ============================================
   ABOUT SECTION
   ============================================ */

.about-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.about-card {
    padding: var(--spacing-lg);
    background: white;
    border: 2px solid var(--color-border);
    border-radius: 12px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.about-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.1);
}

.about-card h3 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-primary);
}

.guanxi-section {
    padding: var(--spacing-lg);
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
    border-radius: 12px;
    text-align: center;
}

.guanxi-section h3 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-md);
}

/* ============================================
   SERVICES SECTION
   ============================================ */

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.service-card {
    padding: var(--spacing-lg);
    background: white;
    border-radius: 12px;
    text-align: center;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.service-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.1);
}

.service-icon {
    font-size: 2.5rem;
    margin-bottom: var(--spacing-md);
}

.service-card h3 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.service-card p {
    color: var(--color-text-light);
}

/* ============================================
   PROCESS SECTION
   ============================================ */

.process-steps {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: var(--spacing-md);
}

.process-step {
    text-align: center;
    padding: var(--spacing-md);
}

.step-number {
    width: 40px;
    height: 40px;
    margin: 0 auto var(--spacing-sm);
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-lg);
    font-weight: 700;
}

.process-step h3 {
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
}

.process-step p {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
}

/* ============================================
   CONTACT SECTION
   ============================================ */

.contact-wrapper {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.form-label {
    font-weight: 600;
    color: var(--color-text);
}

.form-input,
.form-select,
.form-textarea {
    padding: var(--spacing-sm);
    border: 2px solid var(--color-border);
    border-radius: 8px;
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: border-color 0.3s ease;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--color-primary);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

.alert {
    padding: var(--spacing-md);
    border-radius: 8px;
    margin-top: var(--spacing-md);
    font-weight: 600;
}

.alert-success {
    background: #dcfce7;
    color: #166534;
    border: 2px solid #16a34a;
}

.alert-error {
    background: #fee2e2;
    color: #991b1b;
    border: 2px solid #dc2626;
}

/* Contact Info */
.contact-info {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.contact-method {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: white;
    border: 2px solid var(--color-border);
    border-radius: 8px;
}

.contact-icon {
    width: 40px;
    height: 40px;
    background: var(--color-primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-lg);
}

.wechat-qr-container {
    text-align: center;
    padding: var(--spacing-lg);
    background: white;
    border: 2px solid var(--color-border);
    border-radius: 12px;
}

.wechat-qr-container img {
    max-width: 200px;
    margin: var(--spacing-md) auto;
}

/* ============================================
   FOOTER
   ============================================ */

.footer {
    background: var(--color-text);
    color: white;
    padding: var(--spacing-lg) 0;
    text-align: center;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
    margin-bottom: var(--spacing-md);
}

.footer-links a {
    color: white;
    font-weight: 500;
}

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

.footer-copyright {
    color: #9ca3af;
    font-size: var(--font-size-sm);
}

/* ============================================
   WECHAT FLOAT BUTTON
   ============================================ */

.wechat-float {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 60px;
    height: 60px;
    background: #09b83e;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 12px rgba(9, 184, 62, 0.4);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    z-index: 999;
    cursor: pointer;
}

.wechat-float:hover {
    transform: scale(1.1);
    box-shadow: 0 6px 20px rgba(9, 184, 62, 0.6);
}

/* ============================================
   WECHAT MODAL POPUP
   ============================================ */

.wechat-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    z-index: 10000;
    align-items: center;
    justify-content: center;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.wechat-modal-content {
    background: white;
    border-radius: 16px;
    padding: var(--spacing-xl);
    max-width: 400px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.wechat-modal-close {
    position: absolute;
    top: 15px;
    right: 15px;
    background: transparent;
    border: none;
    font-size: 2rem;
    color: #6b7280;
    cursor: pointer;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: background 0.2s, color 0.2s;
}

.wechat-modal-close:hover {
    background: #f3f4f6;
    color: #1f2937;
}

.wechat-modal-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--spacing-xs);
    text-align: center;
}

.wechat-modal-subtitle {
    font-size: var(--font-size-base);
    color: var(--color-text-light);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.wechat-modal-qr {
    width: 100%;
    max-width: 280px;
    height: auto;
    margin: 0 auto var(--spacing-md);
    display: block;
    border: 4px solid #f3f4f6;
    border-radius: 12px;
}

.wechat-modal-id {
    text-align: center;
    font-size: var(--font-size-lg);
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

.wechat-modal-close-btn {
    width: 100%;
    margin-top: var(--spacing-md);
}

/* ============================================
   RESPONSIVE
   ============================================ */

@media (max-width: 768px) {
    .hero {
        min-height: 70vh;
        background-position: center center;
        background-size: cover;
        align-items: flex-start;
    }

    .hero-content {
        padding-top: 1rem !important;
        display: flex;
        flex-direction: column;
        min-height: 70vh;
        width: 100%;
    }

    .hero-title {
        font-size: var(--font-size-2xl);
        margin-top: 0;
    }

    .hero-subtitle {
        font-size: var(--font-size-sm);
        padding: 0rem !important;
        margin-bottom: auto;
    }

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

    .hero-cta {
        flex-direction: column;
        gap: 0.5rem;
        margin-top: auto;
        margin-bottom: 1rem;
    }

    .btn {
        width: 100%;
        padding: 0.6rem 0.5rem;
        font-size: 0.9rem;
    }

    /* Hide trust badges (B2B Experts) on mobile */
    .trust-badges {
        display: none;
    }

    .contact-wrapper {
        grid-template-columns: 1fr;
    }

    /* Compact header on mobile */
    .floating-header {
        min-height: 50px;
    }

    .header-container {
        padding: 0.4rem var(--spacing-sm);
        min-height: 50px;
    }

    .header-logo img {
        height: 30px;
    }

    .header-nav {
        gap: 0.5rem;
    }

    /* Hide "About Us" and "See Our Virtual Fair" buttons on mobile */
    .header-btn.btn-secondary,
    .header-btn.btn-tertiary {
        display: none;
    }

    /* Keep "Contact Us" button visible but smaller */
    .header-btn.btn-primary {
        padding: 0.4rem 0.75rem;
        font-size: 0.75rem;
    }

    .lang-switcher select {
        padding: 0.3rem 0.5rem;
        font-size: 0.75rem;
    }

    .process-steps {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }

    body {
        padding-top: 50px;
    }
}

/* Extra small mobile devices */
@media (max-width: 480px) {
    .hero {
        min-height: 60vh;
    }

    .hero-content {
        padding-top: 1rem !important;
    }

    .hero-title {
        font-size: 1.5rem;
    }
}

/* ============================================
   ACCESSIBILITY
   ============================================ */

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Focus visible for keyboard navigation */
*:focus-visible {
    outline: 3px solid var(--color-primary);
    outline-offset: 2px;
}