/* ========== CSS Reset & Variables ========== */
:root {
    --primary: #e83131;
    --primary-dark: #c41e1e;
    --primary-light: #fff0f0;
    --accent: #ff6b35;
    --text: #333;
    --text-light: #666;
    --text-lighter: #999;
    --bg: #fff;
    --bg-gray: #f5f7fa;
    --bg-dark: #1a1a2e;
    --border: #eee;
    --shadow: 0 4px 20px rgba(0,0,0,.08);
    --shadow-hover: 0 8px 30px rgba(232,49,49,.15);
    --radius: 12px;
    --transition: .3s cubic-bezier(.4,0,.2,1);
}

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

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--text); line-height: 1.6;
    background: var(--bg); overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { text-decoration: none; color: inherit; transition: color var(--transition); }
img { max-width: 100%; height: auto; display: block; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font: inherit; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }
.text-center { text-align: center; }

.svg-icon {
    display: inline-flex; align-items: center; justify-content: center;
    flex-shrink: 0;
}
.svg-icon svg { width: 100%; height: 100%; }

/* ========== Header ========== */
.header {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    background: rgba(255,255,255,.97);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: 0 2px 20px rgba(0,0,0,.06);
    transition: box-shadow var(--transition);
}

.header .container {
    display: flex; align-items: center; justify-content: space-between;
    height: 72px;
}

.logo img { height: 42px; width: auto; }

.nav ul { display: flex; gap: 8px; }
.nav li { position: relative; }
.nav a {
    display: block; padding: 8px 18px;
    border-radius: 8px; font-size: 15px; font-weight: 500;
    color: var(--text); transition: all var(--transition);
}
.nav a:hover, .nav li.active a {
    color: var(--primary); background: var(--primary-light);
}

.header-actions { display: flex; align-items: center; gap: 12px; }
.btn-login {
    padding: 8px 24px; border-radius: 8px;
    border: 1.5px solid var(--primary); color: var(--primary);
    font-size: 14px; font-weight: 500; transition: all var(--transition);
}
.btn-login:hover { background: var(--primary); color: #fff; }

.btn-register {
    padding: 8px 24px; border-radius: 8px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: #fff; font-size: 14px; font-weight: 600;
    box-shadow: 0 4px 15px rgba(232,49,49,.3);
    transition: all var(--transition);
}
.btn-register:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(232,49,49,.4); }

.menu-toggle {
    display: none; flex-direction: column; gap: 5px;
    width: 30px; padding: 4px;
}
.menu-toggle span {
    display: block; height: 2.5px; background: var(--text);
    border-radius: 2px; transition: all var(--transition);
}
.menu-toggle.active span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.menu-toggle.active span:nth-child(2) { opacity: 0; }
.menu-toggle.active span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

.mobile-nav {
    display: none; position: fixed; top: 72px; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,.5); z-index: 999;
    opacity: 0; visibility: hidden; transition: all var(--transition);
}
.mobile-nav.active { opacity: 1; visibility: visible; }
.mobile-nav-inner {
    background: #fff; padding: 20px; transform: translateY(-20px);
    transition: transform var(--transition);
}
.mobile-nav.active .mobile-nav-inner { transform: translateY(0); }
.mobile-nav-inner a {
    display: block; padding: 14px 16px; font-size: 16px;
    border-bottom: 1px solid var(--border); color: var(--text);
    transition: all var(--transition);
}
.mobile-nav-inner a:last-of-type { border-bottom: none; }
.mobile-nav-inner a:hover { color: var(--primary); background: var(--primary-light); }
.mobile-nav-actions { display: flex; gap: 12px; margin-top: 16px; }
.mobile-nav-actions a { flex: 1; text-align: center; padding: 12px; border-radius: 8px; font-weight: 600; }

/* ========== Hero Banner ========== */
.hero {
    margin-top: 72px; position: relative;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    min-height: 520px; display: flex; align-items: center;
    overflow: hidden;
}

.hero::before {
    content: ''; position: absolute; top: -50%; right: -20%;
    width: 600px; height: 600px;
    background: radial-gradient(circle, rgba(232,49,49,.15) 0%, transparent 70%);
    border-radius: 50%;
}

.hero::after {
    content: ''; position: absolute; bottom: -30%; left: -10%;
    width: 400px; height: 400px;
    background: radial-gradient(circle, rgba(255,107,53,.1) 0%, transparent 70%);
    border-radius: 50%;
}

.hero .container {
    position: relative; z-index: 1;
    display: flex; align-items: center; gap: 60px;
}

.hero-content { flex: 1; color: #fff; }
.hero-badge {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 6px 16px; border-radius: 20px;
    background: rgba(255,255,255,.1); border: 1px solid rgba(255,255,255,.2);
    font-size: 13px; color: rgba(255,255,255,.9); margin-bottom: 20px;
    backdrop-filter: blur(4px);
}
.hero-badge .svg-icon { width: 14px; height: 14px; color: #4ade80; }
.hero h1 {
    font-size: 48px; font-weight: 800; line-height: 1.2; margin-bottom: 16px;
    background: linear-gradient(to right, #fff, #ffd4d4);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}
.hero p { font-size: 18px; color: rgba(255,255,255,.7); margin-bottom: 32px; line-height: 1.8; }

.hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
.btn-primary {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 36px; border-radius: 10px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: #fff; font-size: 16px; font-weight: 600;
    box-shadow: 0 8px 25px rgba(232,49,49,.35);
    transition: all var(--transition);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 12px 35px rgba(232,49,49,.45); }

.btn-secondary {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 14px 36px; border-radius: 10px;
    border: 2px solid rgba(255,255,255,.3); color: #fff;
    font-size: 16px; font-weight: 500; transition: all var(--transition);
    background: rgba(255,255,255,.05); backdrop-filter: blur(4px);
}
.btn-secondary:hover { background: rgba(255,255,255,.15); border-color: rgba(255,255,255,.5); }

.hero-stats {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px;
    margin-top: 40px;
}
.hero-stat {
    background: rgba(255,255,255,.08);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,.1);
    border-radius: 12px; padding: 16px 12px;
    text-align: center;
}
.hero-stat .stat-value {
    font-size: 28px; font-weight: 800; color: #fff;
    font-variant-numeric: tabular-nums;
}
.hero-stat .stat-label {
    font-size: 12px; color: rgba(255,255,255,.6); margin-top: 4px;
}

.hero-visual { flex: 0 0 380px; position: relative; }
.hero-card {
    background: rgba(255,255,255,.1);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255,255,255,.15);
    border-radius: 20px; padding: 32px;
    color: #fff; text-align: center;
}
.hero-card h3 { font-size: 20px; margin-bottom: 8px; }
.hero-card > p { font-size: 14px; color: rgba(255,255,255,.6); margin-bottom: 20px; }

.quick-login {
    background: rgba(255,255,255,.12); border-radius: 12px; padding: 20px;
}
.quick-login-btn {
    display: block; width: 100%; padding: 12px;
    border-radius: 8px; font-size: 15px; font-weight: 600;
    margin-bottom: 10px; transition: all var(--transition);
}
.quick-login-btn.primary {
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: #fff; box-shadow: 0 4px 15px rgba(232,49,49,.3);
}
.quick-login-btn.primary:hover { transform: translateY(-2px); }
.quick-login-btn.outline {
    border: 1.5px solid rgba(255,255,255,.3); color: #fff;
}
.quick-login-btn.outline:hover { background: rgba(255,255,255,.1); }

.quick-links {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px;
    margin-top: 16px;
}
.quick-link {
    display: flex; flex-direction: column; align-items: center; gap: 6px;
    padding: 12px 4px; border-radius: 10px;
    background: rgba(255,255,255,.06); transition: all var(--transition);
    font-size: 12px; color: rgba(255,255,255,.8);
}
.quick-link:hover { background: rgba(255,255,255,.12); color: #fff; }
.quick-link .svg-icon { width: 22px; height: 22px; }

/* ========== Section Title ========== */
.section-header { text-align: center; margin-bottom: 48px; }
.section-header h2 {
    font-size: 36px; font-weight: 800; color: var(--text);
    margin-bottom: 12px; position: relative; display: inline-block;
}
.section-header h2::after {
    content: ''; position: absolute; bottom: -8px; left: 50%; transform: translateX(-50%);
    width: 60px; height: 4px; border-radius: 2px;
    background: linear-gradient(to right, var(--primary), var(--accent));
}
.section-header p { font-size: 16px; color: var(--text-light); margin-top: 16px; }

/* ========== Features ========== */
.features { padding: 80px 0; background: var(--bg-gray); }

.feature-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 20px; }

.feature-card {
    background: #fff; border-radius: var(--radius);
    padding: 36px 20px 28px; text-align: center;
    box-shadow: var(--shadow); transition: all var(--transition);
    position: relative; overflow: hidden;
}
.feature-card::before {
    content: ''; position: absolute; top: 0; left: 0; right: 0;
    height: 4px; background: linear-gradient(to right, var(--primary), var(--accent));
    transform: scaleX(0); transition: transform var(--transition);
}
.feature-card:hover::before { transform: scaleX(1); }
.feature-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }

.feature-icon {
    width: 64px; height: 64px; margin: 0 auto 16px;
    border-radius: 16px; display: flex; align-items: center; justify-content: center;
    background: linear-gradient(135deg, var(--primary-light), #fff5f0);
    color: var(--primary);
}
.feature-icon .svg-icon { width: 30px; height: 30px; }
.feature-card h3 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: var(--text-light); line-height: 1.6; }

/* ========== 支持电商平台 ========== */
.platforms { padding: 80px 0; background: #fff; }

.platform-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }

.platform-card {
    background: #fff;
    border-radius: var(--radius);
    padding: 32px 24px;
    text-align: center;
    box-shadow: var(--shadow);
    transition: all var(--transition);
    position: relative;
    overflow: hidden;
}
.platform-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(to right, var(--primary), var(--accent));
    transform: scaleX(0);
    transition: transform var(--transition);
}
.platform-card:hover::before { transform: scaleX(1); }
.platform-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-hover); }

.platform-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 16px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--primary-light);
    color: var(--primary);
}
.platform-icon .svg-icon { width: 32px; height: 32px; }

.platform-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 10px; color: var(--text); }
.platform-card p { font-size: 14px; color: var(--text-light); line-height: 1.8; }

/* ========== Products ========== */
.products { padding: 80px 0; }

.product-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 20px; }

.product-card {
    border: 1px solid var(--border); border-radius: var(--radius);
    overflow: hidden; background: #fff;
    transition: all var(--transition); position: relative;
}
.product-card:hover {
    transform: translateY(-5px); box-shadow: 0 12px 35px rgba(0,0,0,.1);
    border-color: transparent;
}

.product-img {
    aspect-ratio: 1; overflow: hidden; background: var(--bg-gray);
    display: flex; align-items: center; justify-content: center;
    padding: 16px;
}
.product-img img {
    width: 100%; height: 100%; object-fit: contain;
    transition: transform var(--transition);
}
.product-card:hover .product-img img { transform: scale(1.05); }

.product-info { padding: 16px; }
.product-name {
    font-size: 14px; font-weight: 600; color: var(--text);
    margin-bottom: 10px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.product-meta {
    display: flex; align-items: center; justify-content: space-between;
    flex-wrap: wrap; gap: 6px;
}
.product-price { font-size: 18px; font-weight: 800; color: var(--primary); }
.product-price small { font-size: 12px; font-weight: 400; color: var(--text-lighter); }
.product-shipping {
    font-size: 11px; color: var(--text-light);
    background: var(--bg-gray); padding: 2px 8px; border-radius: 4px;
}

.product-tag {
    position: absolute; top: 12px; left: 12px;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: #fff; font-size: 11px; font-weight: 600;
    padding: 3px 10px; border-radius: 4px;
}

/* ========== Advantages ========== */
.advantages { padding: 80px 0; background: var(--bg-gray); }

.adv-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }

.adv-card {
    background: #fff; border-radius: var(--radius); padding: 32px 24px;
    text-align: center; box-shadow: var(--shadow); transition: all var(--transition);
}
.adv-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-hover); }
.adv-icon {
    width: 72px; height: 72px; margin: 0 auto 16px;
    border-radius: 50%; display: flex; align-items: center; justify-content: center;
    background: var(--primary-light); color: var(--primary);
}
.adv-icon .svg-icon { width: 32px; height: 32px; }
.adv-card h3 { font-size: 20px; font-weight: 700; margin-bottom: 10px; }
.adv-card p { font-size: 14px; color: var(--text-light); line-height: 1.8; }

/* ========== FAQ / Articles ========== */
.faq-section { padding: 80px 0; }

.faq-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }

.faq-card {
    background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
    padding: 28px 24px; transition: all var(--transition);
}
.faq-card:hover { box-shadow: var(--shadow); border-color: transparent; }

.faq-tag {
    display: inline-block; padding: 3px 12px; border-radius: 4px;
    font-size: 12px; font-weight: 600; margin-bottom: 12px;
}
.faq-tag.red { background: #fff0f0; color: var(--primary); }
.faq-tag.blue { background: #eef4ff; color: #2563eb; }
.faq-tag.green { background: #f0fdf4; color: #16a34a; }
.faq-tag.orange { background: #fff7ed; color: #ea580c; }
.faq-tag.purple { background: #f5f3ff; color: #7c3aed; }

.faq-card h3 { font-size: 17px; font-weight: 700; margin-bottom: 10px; line-height: 1.5; }
.faq-card p { font-size: 14px; color: var(--text-light); line-height: 1.8; }
.faq-date { font-size: 12px; color: var(--text-lighter); margin-top: 12px; }

/* ========== CTA ========== */
.cta-section {
    padding: 80px 0;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    position: relative; overflow: hidden;
}
.cta-section::before {
    content: ''; position: absolute; top: -50%; right: -10%;
    width: 500px; height: 500px;
    background: radial-gradient(circle, rgba(232,49,49,.12) 0%, transparent 70%);
    border-radius: 50%;
}
.cta-content { position: relative; z-index: 1; text-align: center; color: #fff; }
.cta-content h2 { font-size: 36px; font-weight: 800; margin-bottom: 16px; }
.cta-content p { font-size: 18px; color: rgba(255,255,255,.7); margin-bottom: 32px; }
.cta-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ========== Partners ========== */
.partners { padding: 60px 0; background: var(--bg-gray); }
.partners-grid {
    display: flex; align-items: center; justify-content: center;
    flex-wrap: wrap; gap: 32px;
}
.partners-grid img {
    height: 40px; width: auto; object-fit: contain;
    filter: grayscale(100%); opacity: .6;
    transition: all var(--transition);
}
.partners-grid img:hover { filter: grayscale(0%); opacity: 1; }

/* ========== Footer ========== */
.footer {
    background: var(--bg-dark); color: rgba(255,255,255,.7); padding: 60px 0 30px;
}

.footer-grid {
    display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
    margin-bottom: 40px;
}

.footer-brand h3 {
    font-size: 20px; font-weight: 700; color: #fff; margin-bottom: 12px;
}
.footer-brand p { font-size: 14px; line-height: 1.8; }

.footer-col h4 {
    font-size: 15px; font-weight: 600; color: #fff; margin-bottom: 16px;
    position: relative; padding-bottom: 8px;
}
.footer-col h4::after {
    content: ''; position: absolute; bottom: 0; left: 0;
    width: 30px; height: 2px; background: var(--primary);
}
.footer-col ul li { margin-bottom: 10px; }
.footer-col a {
    font-size: 14px; color: rgba(255,255,255,.6); transition: all var(--transition);
}
.footer-col a:hover { color: #fff; padding-left: 4px; }

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,.1); padding-top: 24px;
    text-align: center; font-size: 13px; color: rgba(255,255,255,.4);
}
.footer-bottom a { color: rgba(255,255,255,.5); }
.footer-bottom a:hover { color: #fff; }

/* ========== Back to Top ========== */
.back-to-top {
    position: fixed; bottom: 30px; right: 30px; z-index: 999;
    width: 48px; height: 48px; border-radius: 50%;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    color: #fff; box-shadow: 0 4px 15px rgba(232,49,49,.3);
    display: flex; align-items: center; justify-content: center;
    opacity: 0; visibility: hidden; transform: translateY(20px);
    transition: all var(--transition);
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { transform: translateY(-3px); box-shadow: 0 6px 20px rgba(232,49,49,.4); }
.back-to-top .svg-icon { width: 20px; height: 20px; }

/* ========== Animations ========== */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}
.animate-in { animation: fadeInUp .6s ease forwards; }

/* ========== Responsive ========== */
@media (max-width: 1024px) {
    .feature-grid { grid-template-columns: repeat(3, 1fr); }
    .adv-grid { grid-template-columns: repeat(2, 1fr); }
    .faq-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .platform-grid { grid-template-columns: repeat(2, 1fr); }
    .hero-visual { flex: 0 0 320px; }
}

@media (max-width: 768px) {
    .nav, .header-actions { display: none; }
    .menu-toggle { display: flex; }

    .hero { min-height: auto; padding: 40px 0; }
    .hero .container { flex-direction: column; text-align: center; }
    .hero h1 { font-size: 28px; }
    .hero p { font-size: 15px; }
    .hero-visual { flex: none; width: 100%; max-width: 380px; margin: 0 auto; }
    .hero-stats { grid-template-columns: repeat(4, 1fr); gap: 10px; }
    .hero-stat .stat-value { font-size: 20px; }
    .hero-stat .stat-label { font-size: 11px; }

    .feature-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .feature-card { padding: 24px 12px 20px; }
    .feature-icon { width: 52px; height: 52px; }
    .feature-icon .svg-icon { width: 24px; height: 24px; }
    .feature-card h3 { font-size: 15px; }
    .feature-card p { font-size: 12px; }

    .platform-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .platform-card { padding: 24px 16px; }
    .platform-icon { width: 56px; height: 56px; }
    .platform-icon .svg-icon { width: 26px; height: 26px; }
    .platform-card h3 { font-size: 17px; }
    .platform-card p { font-size: 13px; }

    .product-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .product-info { padding: 12px; }
    .product-name { font-size: 13px; }
    .product-price { font-size: 16px; }

    .adv-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
    .adv-card { padding: 24px 16px; }

    .faq-grid { grid-template-columns: 1fr; gap: 16px; }

    .section-header h2 { font-size: 24px; }

    .cta-content h2 { font-size: 24px; }
    .cta-content p { font-size: 15px; }

    .footer-grid { grid-template-columns: 1fr; gap: 30px; }

    .hero-buttons { justify-content: center; }
    .cta-buttons { justify-content: center; }
}

@media (max-width: 480px) {
    .container { padding: 0 14px; }
    .hero h1 { font-size: 24px; }
    .hero-stats { grid-template-columns: repeat(2, 1fr); }
    .feature-grid { grid-template-columns: 1fr 1fr; }
    .platform-grid { grid-template-columns: 1fr; }
    .adv-grid { grid-template-columns: 1fr; }
    .product-grid { grid-template-columns: repeat(2, 1fr); gap: 10px; }
    .btn-primary, .btn-secondary { padding: 12px 24px; font-size: 14px; }
}

/* ========== Loading Skeleton ========== */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%; animation: shimmer 1.5s infinite;
}
@keyframes shimmer { to { background-position: -200% 0; } }