/**
 * 首页 - UniChat（含变量、重置，仅此一个文件）
 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #25D366;
    --primary-dark: #128C7E;
    --accent-blue: #0088CC;
    --text-primary: #111111;
    --text-secondary: #374151;
    --text-muted: #6B7280;
    --bg-light: #F8F9FA;
    --bg-white: #FFFFFF;
    --border-color: #E5E7EB;
    --font-size-body: 16px;
    --font-size-desc: 14px;
    --font-size-caption: 11px;
    --font-size-nav: 13px;
    --line-height-body: 1.5;
    --line-height-desc: 1.65;
}

html {
    overflow-x: hidden;
    scroll-behavior: smooth;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    font-size: var(--font-size-body);
    color: var(--text-primary);
    line-height: var(--line-height-body);
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
    max-width: 100vw;
}

/* 背景 */
#particles-js {
            position: fixed;
            width: 100%;
            height: 100%;
            top: 0;
            left: 0;
            z-index: -1;
            background: var(--bg-white);
        }

        /* 导航栏 */
        .navbar {
            position: fixed;
            top: 0;
            width: 100%;
            padding: 1rem 5%;
            background: var(--bg-white);
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
            z-index: 1000;
            border-bottom: 1px solid var(--border-color);
        }

        .navbar.scrolled {
            padding: 0.75rem 5%;
        }

        .nav-container {
            max-width: 1400px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            display: flex;
            align-items: center;
            text-decoration: none;
            color: var(--text-primary);
        }
        .logo-img {
            height: 36px;
            width: auto;
            display: block;
            object-fit: contain;
        }

        .nav-links {
            display: flex;
            gap: 1.5rem;
            align-items: center;
        }

        /* 首页导航语言下拉 */
        .lang-dropdown-nav {
            position: relative;
        }
        .lang-dropdown-nav .lang-dropdown-trigger {
            display: flex;
            align-items: center;
            gap: 0.4rem;
            padding: 0.5rem 1rem;
            white-space: nowrap;
            border-radius: 6px;
            background: var(--bg-light);
            border: 1px solid var(--border-color);
            color: var(--text-primary);
            font-size: var(--font-size-desc);
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s;
        }
        .lang-dropdown-nav .lang-dropdown-trigger:hover {
            background: #E5E7EB;
        }
        .lang-dropdown-nav .lang-dropdown-trigger i {
            font-size: 0.65rem;
            transition: transform 0.2s;
        }
        .lang-dropdown-nav.open .lang-dropdown-trigger i {
            transform: rotate(180deg);
        }
        .lang-dropdown-nav .lang-dropdown-menu {
            position: absolute;
            top: calc(100% + 6px);
            left: 0;
            min-width: 100%;
            background: white;
            border-radius: 8px;
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
            padding: 4px 0;
            opacity: 0;
            visibility: hidden;
            transform: translateY(-4px);
            transition: opacity 0.2s, visibility 0.2s, transform 0.2s;
            z-index: 200;
        }
        .lang-dropdown-nav.open .lang-dropdown-menu {
            opacity: 1;
            visibility: visible;
            transform: translateY(0);
        }
        .lang-dropdown-nav .lang-dropdown-item {
            display: block;
            width: 100%;
            padding: 0.5rem 1rem;
            border: none;
            background: none;
            color: var(--text-primary);
            font-size: var(--font-size-desc);
            text-align: left;
            cursor: pointer;
            transition: background 0.15s;
            white-space: nowrap;
        }
        .lang-dropdown-nav .lang-dropdown-item:hover {
            background: #F3F4F6;
        }
        .lang-dropdown-nav .lang-dropdown-item.active {
            color: var(--primary-color);
            font-weight: 600;
        }

        .nav-links a {
            color: var(--text-primary);
            text-decoration: none;
            font-weight: 500;
            font-size: var(--font-size-nav);
            transition: color 0.3s;
            position: relative;
        }

        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: -5px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--text-primary);
            transition: width 0.2s;
        }

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

        .btn-primary, .btn-secondary {
            padding: 0.75rem 1.5rem;
            border-radius: 5px;
            font-weight: 600;
            text-decoration: none;
            transition: all 0.3s;
            display: inline-block;
            border: none;
            cursor: pointer;
            font-size: 1rem;
        }

        .nav-btn-login {
            padding: 0.5rem 1rem;
            border-radius: 6px;
            font-weight: 500;
            text-decoration: none;
            transition: all 0.2s;
            display: inline-block;
            border: 1px solid var(--border-color);
            background: transparent;
            color: var(--text-primary);
            font-size: var(--font-size-nav);
        }

        .nav-btn-login:hover {
            border-color: var(--text-primary);
            color: var(--text-primary);
        }

        .nav-btn-trial {
            padding: 0.5rem 1rem;
            border-radius: 6px;
            font-weight: 600;
            text-decoration: none;
            transition: all 0.2s;
            display: inline-block;
            background: var(--text-primary);
            color: #fff;
            font-size: var(--font-size-nav);
            border: none;
        }

        .nav-links .nav-btn-trial,
        .nav-links .nav-btn-trial:hover {
            color: #fff;
        }

        .nav-btn-trial:hover {
            background: #333;
        }

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

        .btn-primary:hover {
            background: #333;
        }

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

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

        /* Hero Section */
        .hero {
            min-height: 700px;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            padding: 120px 5% 80px;
            position: relative;
            overflow: hidden;
            background: radial-gradient(ellipse 80% 60% at 50% 40%, rgba(37, 211, 102, 0.06) 0%, transparent 55%),
                        radial-gradient(ellipse 60% 80% at 85% 20%, rgba(0, 136, 204, 0.05) 0%, transparent 50%),
                        radial-gradient(ellipse 50% 50% at 15% 70%, rgba(37, 211, 102, 0.04) 0%, transparent 45%);
        }

        .hero-bg {
            position: absolute;
            inset: 0;
            pointer-events: none;
            z-index: 0;
        }

        .hero-blob {
            position: absolute;
            border-radius: 50%;
            filter: blur(70px);
            opacity: 0.35;
            will-change: transform;
        }

        .hero-blob-1 {
            width: 320px;
            height: 320px;
            background: var(--primary-color);
            top: 10%;
            left: 15%;
            animation: heroBlobFloat 18s ease-in-out infinite;
        }

        .hero-blob-2 {
            width: 280px;
            height: 280px;
            background: var(--accent-blue);
            top: 25%;
            right: 10%;
            animation: heroBlobFloat 22s ease-in-out infinite reverse;
            animation-delay: -5s;
        }

        .hero-blob-3 {
            width: 240px;
            height: 240px;
            background: var(--primary-dark);
            bottom: 15%;
            left: 25%;
            animation: heroBlobFloat 20s ease-in-out infinite;
            animation-delay: -8s;
        }

        .hero-blob-4 {
            width: 200px;
            height: 200px;
            background: var(--primary-color);
            bottom: 25%;
            right: 20%;
            animation: heroBlobFloat 16s ease-in-out infinite reverse;
            animation-delay: -3s;
        }

        .hero-blob-5 {
            width: 160px;
            height: 160px;
            background: var(--accent-blue);
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            animation: heroBlobPulse 12s ease-in-out infinite;
        }

        @keyframes heroBlobFloat {
            0%, 100% { transform: translate(0, 0) scale(1); }
            33% { transform: translate(30px, -25px) scale(1.05); }
            66% { transform: translate(-20px, 20px) scale(0.95); }
        }

        @keyframes heroBlobPulse {
            0%, 100% { opacity: 0.2; transform: translate(-50%, -50%) scale(1); }
            50% { opacity: 0.4; transform: translate(-50%, -50%) scale(1.15); }
        }

        .hero-content {
            max-width: 1200px;
            z-index: 10;
            position: relative;
            animation: fadeInUp 1s ease;
        }

        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .hero h1 {
            font-size: 2.5rem;
            font-weight: 700;
            margin-bottom: 1rem;
            color: var(--text-primary);
            line-height: 1.25;
            letter-spacing: -0.02em;
        }

        .hero .subtitle {
            font-size: 1.125rem;
            color: var(--text-secondary);
            margin-bottom: 1.5rem;
            font-weight: 400;
            letter-spacing: 0.02em;
        }

        .hero .description {
            font-size: var(--font-size-desc);
            color: var(--text-muted);
            margin-bottom: 2.5rem;
            max-width: 720px;
            margin-left: auto;
            margin-right: auto;
            line-height: var(--line-height-desc);
            letter-spacing: 0.01em;
        }

        .hero-download-block {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 1rem;
        }

        .hero-buttons {
            display: flex;
            gap: 1.5rem;
            justify-content: center;
            flex-wrap: wrap;
        }

        .hero-download-versions {
            margin: 0;
            font-size: 0.875rem;
            color: var(--text-muted);
            letter-spacing: 0.02em;
            text-align: center;
            line-height: 1.55;
            max-width: 32rem;
        }

        .hero-download-versions[hidden] {
            display: none !important;
        }

        .hero-version-lines {
            display: flex;
            flex-direction: column;
            gap: 0.25rem;
            align-items: center;
        }

        .hero-version-lines--inline {
            flex-direction: row;
            flex-wrap: wrap;
            justify-content: center;
            align-items: baseline;
            gap: 0;
            max-width: 100%;
        }

        .hero-version-pair {
            display: inline-flex;
            flex-wrap: wrap;
            align-items: baseline;
            justify-content: center;
        }

        .hero-version-between {
            padding: 0 20px;
            color: var(--text-muted);
            opacity: 0.85;
            user-select: none;
        }

        .hero-version-label {
            font-weight: 500;
        }

        .hero-version-sep {
            margin: 0 0.1em;
        }

        .hero-version-value {
            font-variant-numeric: tabular-nums;
        }

        .hero-buttons .btn-primary {
            padding: 0.75rem 2rem;
            font-size: var(--font-size-body);
        }

        /* 浮动动画 */
        .floating {
            animation: floating 3s ease-in-out infinite;
        }

        @keyframes floating {
            0%, 100% { transform: translateY(0px); }
            50% { transform: translateY(-20px); }
        }

        /* 特性卡片 */
        .features {
            padding: 120px 5%;
            background: var(--bg-light);
            position: relative;
        }

        @media (max-width: 768px) {
            .features {
                padding: 80px 5%;
            }
        }

        .section-title {
            text-align: center;
            font-size: 2rem;
            font-weight: 700;
            margin-bottom: 0.75rem;
            color: var(--text-primary);
            letter-spacing: -0.02em;
        }

        .section-subtitle {
            text-align: center;
            font-size: var(--font-size-desc);
            color: var(--text-secondary);
            margin-bottom: 3rem;
            font-weight: 400;
            line-height: var(--line-height-desc);
        }

        .features-grid {
            max-width: 1400px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 1fr;
            gap: 4rem;
        }

        .feature-card {
            background: white;
            padding: 5rem 4rem;
            border-radius: 5px;
            box-shadow: 0 12px 40px rgba(0, 0, 0, 0.08);
            transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            position: relative;
            overflow: hidden;
            border: 2px solid rgba(0, 0, 0, 0.03);
            display: grid;
            grid-template-columns: auto 1fr;
            gap: 3rem;
            align-items: start;
        }

        @media (max-width: 968px) {
            .feature-card {
                grid-template-columns: 1fr;
                padding: 4rem 2.5rem;
                text-align: center;
            }

            .feature-icon {
                margin: 0 auto 2rem;
            }

            .feature-card h3 {
                font-size: 1.35rem;
            }

            .feature-card p {
                font-size: var(--font-size-desc);
            }
        }

        .feature-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 4px;
            height: 100%;
            background: var(--text-primary);
            transform: scaleY(0);
            transition: transform 0.3s;
        }

        .feature-card:nth-child(2)::before { background: var(--primary-color); }
        .feature-card:nth-child(5)::before { background: var(--accent-blue); }

        .feature-card:hover {
            transform: translateX(6px);
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
            border-color: #D1D5DB;
        }

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

        .feature-icon {
            width: 72px;
            height: 72px;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 2rem;
            background: var(--text-primary);
            color: white;
            flex-shrink: 0;
            transition: all 0.3s;
        }

        .feature-card:nth-child(2) .feature-icon { background: var(--primary-color); }
        .feature-card:nth-child(5) .feature-icon { background: var(--accent-blue); }

        .feature-card:hover .feature-icon {
            transform: scale(1.05);
        }

        .feature-content {
            display: flex;
            flex-direction: column;
        }

        .feature-card h3 {
            font-size: 1.35rem;
            margin-bottom: 0.75rem;
            color: var(--text-primary);
            font-weight: 700;
            line-height: 1.3;
            letter-spacing: -0.02em;
        }

        .feature-card p {
            color: var(--text-secondary);
            line-height: var(--line-height-desc);
            font-size: var(--font-size-desc);
        }

        /* 平台支持 */
        .platforms {
            padding: 100px 5%;
            background: var(--bg-white);
        }

        .platforms-grid {
            max-width: 1400px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 2rem;
        }

        .platform-item {
            background: white;
            padding: 3rem;
            border-radius: 12px;
            text-align: center;
            transition: all 0.2s;
            border: 1px solid var(--border-color);
        }

        .platform-item:hover {
            border-color: var(--primary-color);
        }

        .platform-icon {
            font-size: 3rem;
            margin-bottom: 1rem;
            color: var(--primary-color);
        }

        .platform-name {
            font-size: var(--font-size-body);
            font-weight: 600;
            color: var(--text-primary);
        }

        .platform-desc {
            font-size: var(--font-size-desc);
            color: var(--text-secondary);
            line-height: var(--line-height-desc);
            margin-top: 0.75rem;
        }

        /* CTA Section */
        .cta-section {
            padding: 80px 5%;
            background: var(--text-primary);
            text-align: center;
            color: white;
        }

        .cta-section h2 {
            font-size: 1.75rem;
            margin-bottom: 0.5rem;
            font-weight: 700;
        }

        .cta-section p {
            font-size: var(--font-size-desc);
            margin-bottom: 2rem;
            opacity: 0.9;
            line-height: var(--line-height-desc);
        }

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

        .cta-section .btn-primary:hover {
            background: #E5E7EB;
            color: var(--text-primary);
        }

        /* Footer */
        .footer {
            background: #1F2937;
            color: #9CA3AF;
            padding: 60px 5% 30px;
        }

        .footer-content {
            max-width: 1400px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 3rem;
            margin-bottom: 2rem;
        }

        .footer-section h4 {
            color: white;
            margin-bottom: 0.75rem;
            font-size: var(--font-size-body);
            font-weight: 600;
        }

        .footer-section ul {
            list-style: none;
        }

        .footer-section ul li {
            margin-bottom: 0.35rem;
        }

        .footer-section a,
        .footer-section p {
            font-size: var(--font-size-desc);
            color: #9CA3AF;
            text-decoration: none;
            transition: color 0.3s;
            line-height: var(--line-height-desc);
        }

        .footer-section a:hover {
            color: white;
        }

        .footer-bottom {
            text-align: center;
            padding-top: 1.5rem;
            border-top: 1px solid #374151;
            font-size: var(--font-size-caption);
            color: #6B7280;
        }


        /* 响应式：平板与手机 */
        @media (max-width: 768px) {
            .navbar {
                padding: 0.75rem 4%;
            }
            .nav-container {
                flex-wrap: wrap;
                gap: 0.5rem;
            }
            .logo-img {
                height: 32px;
            }
            .nav-links {
                gap: 0.75rem;
                flex-wrap: wrap;
                justify-content: flex-end;
            }
            .hero {
                padding: 100px 4% 80px;
            }
            .hero-blob {
                opacity: 0.25;
                filter: blur(50px);
            }
            .hero-blob-1 { width: 220px; height: 220px; }
            .hero-blob-2 { width: 180px; height: 180px; }
            .hero-blob-3 { width: 160px; height: 160px; }
            .hero-blob-4 { width: 140px; height: 140px; }
            .hero-blob-5 { width: 100px; height: 100px; }
            .hero h1 {
                font-size: 1.75rem;
                line-height: 1.3;
            }
            .hero .subtitle {
                font-size: 1rem;
            }
            .hero .description {
                font-size: 0.95rem;
            }
            .features {
                padding: 60px 4%;
            }
            .features-grid {
                grid-template-columns: 1fr;
            }
            .section-title {
                font-size: 1.5rem;
            }
            .section-subtitle {
                font-size: var(--font-size-desc);
                margin-bottom: 2rem;
            }
            .pricing-section {
                padding: 60px 4% 80px;
            }
            .pricing-section .packages-grid {
                grid-template-columns: 1fr !important;
                gap: 1.5rem;
                margin-top: 2rem;
            }
            .pricing-section .package-card.featured {
                transform: none !important;
            }
            .package-card {
                padding: 1.5rem 1.25rem;
            }
            .footer {
                padding: 40px 4% 24px;
            }
            .footer-content {
                grid-template-columns: 1fr 1fr;
                gap: 2rem;
            }
            .cta-section {
                padding: 50px 4%;
            }
            .cta-section h2 {
                font-size: 1.5rem;
            }
        }

        @media (max-width: 480px) {
            .navbar {
                padding: 0.6rem 3%;
            }
            .logo-img {
                height: 28px;
            }
            .nav-links {
                gap: 0.5rem;
            }
            .nav-btn-login,
            .nav-btn-trial {
                padding: 0.4rem 0.75rem;
                font-size: 12px;
            }
            .lang-dropdown-nav .lang-dropdown-trigger {
                padding: 0.35rem 0.6rem;
                font-size: 12px;
            }
            .hero {
                padding: 85px 3% 60px;
            }
            .hero h1 {
                font-size: 1.45rem;
            }
            .hero .subtitle {
                font-size: 0.9rem;
            }
            .hero .description {
                font-size: 0.875rem;
            }
            .hero-buttons .btn-primary {
                padding: 0.65rem 1.5rem;
                font-size: 0.95rem;
            }
            .pricing-section {
                padding: 40px 3% 60px;
            }
            .pricing-section .packages-grid {
                gap: 1.25rem;
            }
            .package-card {
                padding: 1.25rem 1rem;
            }
            .price-amount {
                font-size: 1.75rem !important;
            }
            .footer-content {
                grid-template-columns: 1fr;
                gap: 1.5rem;
                text-align: center;
            }
            .footer-section h4 {
                margin-bottom: 0.5rem;
            }
            .footer-bottom {
                font-size: 12px;
            }
        }

        /* 套餐/价格区描述与列表统一 12px */
        .pricing-section .package-name {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: 0.35rem;
        }
        .pricing-section .package-tagline {
            color: var(--text-secondary);
            margin-bottom: 1rem;
            font-size: var(--font-size-desc);
            line-height: var(--line-height-desc);
        }
        .pricing-section .price-unit,
        .pricing-section .package-features li {
            font-size: var(--font-size-desc);
            line-height: var(--line-height-desc);
        }

        /* 滚动动画 */
        .fade-in {
            opacity: 0;
            transform: translateY(30px);
            transition: all 0.6s ease;
        }

        .fade-in.visible {
            opacity: 1;
            transform: translateY(0);
        }

        /* 客户支持浮动栏：仅图标按钮 */
        .customer-bar {
            position: fixed;
            right: 20px;
            bottom: 20px;
            z-index: 999;
            display: flex;
            flex-direction: column;
            gap: 10px;
            align-items: flex-end;
        }

        .customer-item {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 52px;
            height: 52px;
            background: white;
            border-radius: 50%;
            box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
            cursor: pointer;
            transition: transform 0.2s, box-shadow 0.2s;
            position: relative;
        }

        .customer-item:hover {
            transform: scale(1.08);
            box-shadow: 0 6px 20px rgba(0, 0, 0, 0.18);
        }

        .customer-item .customer-icon {
            width: 28px;
            height: 28px;
            object-fit: contain;
        }

        .weChart {
            position: relative;
        }

        .weChartModal {
            position: absolute;
            bottom: calc(100% + 10px);
            right: 0;
            background: white;
            padding: 20px;
            border-radius: 5px;
            box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2);
            display: none;
            flex-direction: column;
            align-items: center;
            gap: 12px;
            min-width: 200px;
            animation: slideUp 0.3s ease;
            z-index: 1000;
        }

        .weChartModal.show {
            display: flex;
        }

        @keyframes slideUp {
            from {
                opacity: 0;
                transform: translateY(10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .weChartModal img {
            width: 100px;
            height: 100px;
            border-radius: 5px;
            border: 1px solid #e5e7eb;
        }

        .weChartModal p {
            font-size: var(--font-size-desc);
            color: var(--text-primary);
            margin: 0;
            text-align: center;
        }

        @media (max-width: 768px) {
            .customer-bar {
                right: 15px;
                bottom: 15px;
                gap: 8px;
            }

            .customer-item {
                width: 46px;
                height: 46px;
            }

            .customer-item .customer-icon {
                width: 24px;
                height: 24px;
            }
        }