/* ====== VARIABLES & RESET ====== */
:root {
    --primary: #0066cc;
    --primary-dark: #0052a3;
    --secondary: #00a0e9;
    --accent: #ff6b35;
    --light: #ffffff;
    --light-bg: #f8fafc;
    --dark: #1a202c;
    --dark-secondary: #2d3748;
    --gray: #718096;
    --gray-light: #e2e8f0;
    --success: #38a169;
    
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    
    --gradient-primary: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
    --gradient-dark: linear-gradient(135deg, #1a2b4d 0%, #0d1a33 100%);
    --gradient-light: linear-gradient(135deg, #f8fafc 0%, #e6f0ff 100%);
    --gradient-logo: linear-gradient(135deg, #0066cc 0%, #00a0e9 50%, #00c9ff 100%);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: 100px;
}

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

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--dark);
    margin-bottom: 1rem;
}

p {
    margin-bottom: 1.25rem;
    color: var(--dark-secondary);
    font-size: 1.05rem;
}

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

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    background: var(--gradient-primary);
    color: white;
    padding: 0.875rem 2rem;
    border-radius: var(--radius);
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1rem;
    position: relative;
    overflow: hidden;
}

.btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

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

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

section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
}

.section-title h2 {
    display: inline-block;
    position: relative;
    margin-bottom: 2.5rem;
}

.section-title h2:after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--gradient-primary);
    border-radius: 2px;
}

.section-title p {
    max-width: 700px;
    margin: 1.5rem auto 0;
    font-size: 1.1rem;
}

/* ====== LANGUAGE BAR ====== */
.language-bar {
    background: rgba(0, 102, 204, 0.05);
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(0, 102, 204, 0.1);
}

.language-bar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.language-label {
    font-weight: 600;
    color: var(--primary);
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 6px;
}

.language-label i {
    color: var(--secondary);
}

.lang-switcher {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.lang-switcher a {
    font-size: 0.85rem;
    font-weight: 500;
    padding: 0.25rem 0.75rem;
    border-radius: 4px;
    background: white;
    border: 1px solid rgba(0, 102, 204, 0.2);
    color: var(--dark);
    transition: var(--transition);
}

.lang-switcher a:hover {
    background: rgba(0, 102, 204, 0.1);
    border-color: var(--primary);
    transform: translateY(-2px);
}

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

/* ====== HEADER & NAVIGATION ====== */
.header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.25rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    background: var(--gradient-logo);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    background-size: 200% auto;
    animation: gradient-shift 3s ease-in-out infinite;
    white-space: nowrap;
    letter-spacing: -0.5px;
}

@keyframes gradient-shift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    font-weight: 600;
    color: var(--dark);
    position: relative;
    padding: 0.5rem 0;
}

.nav-links a:after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.nav-links a:hover:after,
.nav-links a.active:after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.email-link {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--primary);
    font-weight: 600;
    padding: 0.5rem 1rem;
    background: rgba(0, 102, 204, 0.1);
    border-radius: var(--radius);
    border: 1px solid rgba(0, 102, 204, 0.2);
    animation: email-pulse 3s infinite ease-in-out;
}

@keyframes email-pulse {
    0%, 100% { 
        background: rgba(0, 102, 204, 0.1);
        border-color: rgba(0, 102, 204, 0.2);
    }
    50% { 
        background: rgba(0, 102, 204, 0.2);
        border-color: rgba(0, 102, 204, 0.4);
        box-shadow: 0 0 15px rgba(0, 102, 204, 0.2);
    }
}

.email-link:hover {
    background: rgba(0, 102, 204, 0.2);
    transform: translateY(-2px);
    animation: none;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--primary);
    cursor: pointer;
}

/* ====== FOOTER ====== */
.footer {
    background: var(--gradient-dark);
    color: white;
    padding: 4rem 0 2rem;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-col h3 {
    color: white;
    margin-bottom: 1.5rem;
    font-size: 1.25rem;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-logo);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    background-size: 200% auto;
    animation: gradient-shift 3s ease-in-out infinite;
    margin-bottom: 1rem;
    display: inline-block;
}

.footer-logo + p {
    color: white !important;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.9);
    transition: var(--transition);
}

.footer-links a:hover {
    color: white;
    padding-left: 5px;
}

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

.contact-list li {
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    gap: 10px;
}

.contact-list i {
    color: var(--secondary);
    margin-top: 3px;
}

.contact-list a {
    color: rgba(255, 255, 255, 0.9);
}

.contact-list a:hover {
    color: white;
}

.messaging-apps {
    display: flex;
    gap: 10px;
    margin-top: 10px;
}

.messaging-apps a {
    display: flex;
    align-items: center;
    gap: 6px;
    background: rgba(255, 255, 255, 0.1);
    padding: 8px 12px;
    border-radius: var(--radius);
    color: white;
    transition: var(--transition);
}

.messaging-apps a:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.wechat-qr {
    margin-top: 1rem;
    text-align: center;
}

.wechat-qr img {
    max-width: 150px;
    border-radius: var(--radius);
    border: 1px solid rgba(255, 255, 255, 0.2);
    background: white;
    padding: 10px;
}

.wechat-qr p {
    color: rgba(255, 255, 255, 0.9);
    margin-top: 0.75rem;
    font-size: 0.875rem;
}

.copyright {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.875rem;
}

.copyright p {
    color: rgba(255, 255, 255, 0.8);
}

/* ====== RESPONSIVE (公共部分) ====== */
@media (max-width: 1024px) {
    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }
    
    .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        max-width: 300px;
        height: 100vh;
        background: white;
        flex-direction: column;
        padding: 6rem 2rem 2rem;
        box-shadow: -5px 0 20px rgba(0, 0, 0, 0.1);
        transition: var(--transition);
        z-index: 999;
    }
    
    .nav-links.active {
        right: 0;
    }
    
    .nav-actions .email-link {
        display: none;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
    
    .lang-switcher {
        justify-content: flex-end;
    }
}

@media (max-width: 576px) {
    .language-bar .container {
        flex-direction: column;
        gap: 0.5rem;
        align-items: flex-start;
    }
    
    .lang-switcher {
        width: 100%;
        justify-content: flex-start;
    }
    
    section {
        padding: 3rem 0;
    }
}