:root {
            --primary-blue: #4a6bff;
            --bg-gradient: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            --white: #ffffff;
            --text-main: #1e293b;
            --text-sub: #64748b;
            --nav-bg: #333;
            --nav-height: 60px;
        }

        html {
            scrollbar-gutter: stable;
            overflow-y: scroll;
        }

        body, html {
            margin: 0; padding: 0;
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
            scroll-behavior: smooth;
            background: var(--bg-gradient);
            color: var(--text-main);
            min-height: 100vh;
        }

        /* --- 导航栏 --- */
        .custom-navbar {
            position: fixed;
            top: 0; left: 0; width: 100%;
            background: var(--nav-bg);
            color: white;
            z-index: 1000;
            box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
            height: var(--nav-height);
            box-sizing: border-box;
        }
        
        .navbar-content {
            width: 100%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 100%;
            box-sizing: border-box;
        }
        
        .navbar-content span { font-weight: 600; font-size: 20px; }
        .navbar-content div a {
            color: white;
            text-decoration: none;
            margin: 0 10px;
            font-size: 15px;
            transition: color 0.2s;
        }
        .navbar-content div a:hover { color: var(--primary-blue); }

        /* --- Hero 区域 --- */
        .hero { 
            display: flex; 
            align-items: center; 
            justify-content: center; 
            padding: 160px 20px 60px; 
            max-width: 1200px;
            margin: 0 auto; 
            gap: 40px; 
        }

        .hero-text { 
            flex: 0 1 auto;
            text-align: center; 
            min-width: 400px; 
        }

        .hero h1 {
            font-size: 3.5rem; 
            margin-bottom: 18px; 
            font-weight: 800;
            background: linear-gradient(90deg, #1e40af, #3b82f6);
            -webkit-background-clip: text; 
            -webkit-text-fill-color: transparent;
            line-height: 1.2;
        }

        .hero p { 
            font-size: 1.25rem; 
            color: var(--text-sub); 
            margin-bottom: 25px; 
            line-height: 1.6;
        }

        .cta-group { 
            display: flex; 
            justify-content: center; 
            gap: 15px; 
            margin-bottom: 20px;
        }

        /* --- 系统支持样式 --- */
        .system-support {
            display: flex;
            justify-content: center;
            gap: 20px;
            font-size: 0.9rem;
            color: var(--text-sub);
            margin-top: 15px;
        }
        .sys-item {
            display: flex;
            align-items: center;
            gap: 6px;
            background: rgba(255, 255, 255, 0.5);
            padding: 4px 12px;
            border-radius: 20px;
            border: 1px solid rgba(255,255,255,0.8);
        }
        .sys-item i { color: var(--primary-blue); }

        .trigger-btn {
            padding: 14px 32px; 
            background: var(--primary-blue); 
            color: white;
            border: none; 
            border-radius: 12px; 
            font-size: 16px; 
            font-weight: 600;
            cursor: pointer; 
            transition: all 0.2s;
            box-shadow: 0 4px 14px 0 rgba(74, 107, 255, 0.3);
            text-decoration: none;
        }

        .trigger-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(74, 107, 255, 0.4);
            background-color: #3a56d4;
        }

        .secondary-btn {
            padding: 14px 28px; 
            background: white; 
            color: var(--text-main);
            border: 1px solid #e2e8f0; 
            border-radius: 12px; 
            font-size: 16px; 
            font-weight: 600;
            cursor: pointer; 
            transition: all 0.2s; 
            text-decoration: none;
            display: inline-flex; 
            align-items: center;
        }

        .secondary-btn:hover { background: #f8fafc; border-color: #cbd5e1; transform: translateY(-2px); }

        .hero-img-container { flex: 0 1 auto; display: flex; justify-content: center; }
        .hero-img-card {
            width: 240px; 
            background: rgba(255, 255, 255, 0.4); 
            padding: 10px; 
            border-radius: 20px;
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
        }
        .hero-img-card img { width: 100%; border-radius: 12px; display: block; }

        /* --- 特性网格 --- */
        .features {
            display: grid; 
            grid-template-columns: repeat(3, 1fr);
            gap: 30px; 
            padding: 40px 20px 60px; 
            max-width: 1200px; 
            margin: 0 auto;
        }
        .feature-card {
            background: rgba(255, 255, 255, 0.8); 
            padding: 35px 25px;
            border-radius: 24px; 
            border: 1px solid rgba(255,255,255,0.4);
            transition: all 0.2s; 
            text-align: center;
        }
        .feature-card:hover { 
            background: white; 
            transform: translateY(-5px); 
            box-shadow: 0 15px 30px rgba(0,0,0,0.05); 
        }
        .feature-card i { 
            font-size: 2.2rem; 
            color: var(--primary-blue); 
            margin-bottom: 20px; 
            display: block;
        }
        .feature-card h3 { 
            margin-bottom: 12px; 
            font-size: 1.2rem; 
            color: var(--text-main);
        }
        .feature-card p { 
            color: var(--text-sub); 
            line-height: 1.6; 
            font-size: 0.95rem; 
            margin: 0;
        }

        /* --- 标题样式 --- */
        .after-features-header {
            text-align: center;
            padding: 60px 20px 20px;
            max-width: 800px;
            margin: 0 auto;
        }
        .after-features-title {
            font-size: 2.4rem;
            font-weight: 800;
            margin-bottom: 12px;
            color: var(--text-main);
            letter-spacing: -0.5px;
        }
        .after-features-subtitle {
            font-size: 1.15rem;
            color: var(--text-sub);
            max-width: 600px;
            margin: 0 auto;
        }

        /* --- 详情部分 --- */
        .detail-section {
            display: flex;
            align-items: center;
            justify-content: center;
            max-width: 1100px;
            margin: 20px auto 80px;
            padding: 40px 20px;
            gap: 60px;
        }
        .detail-section:nth-of-type(even) { flex-direction: row-reverse; }
        .detail-text { flex: 1; max-width: 450px; }
        .detail-text h2 { font-size: 2rem; margin-bottom: 20px; color: var(--text-main); }
        .detail-text p { font-size: 1.1rem; color: var(--text-sub); line-height: 1.7; }
        .detail-image { 
            flex: 1; max-width: 550px; background: white; padding: 10px;
            border-radius: 20px; box-shadow: 0 10px 30px rgba(0,0,0,0.05);
        }

        /* 移动端适配 */
        @media (max-width: 992px) {
            .features { grid-template-columns: repeat(2, 1fr); }
            .system-support { flex-wrap: wrap; }
        }
        @media (max-width: 600px) {
            .features { grid-template-columns: 1fr; }
            .hero { flex-direction: column; text-align: center; padding-top: 120px; }
            .hero-text { min-width: unset; width: 100%; }
            .after-features-title { font-size: 1.8rem; }
            .detail-section, .detail-section:nth-of-type(even) { flex-direction: column; text-align: center; gap: 30px; }
        }

        /* --- 弹窗样式 --- */
        .modal-overlay {
            position: fixed; top: 0; left: 0; right: 0; bottom: 0;
            background-color: rgba(0, 0, 0, 0.4);
            display: none; justify-content: center; align-items: center;
            z-index: 2000; backdrop-filter: blur(4px);
        }
        .containerMsg {
            background-color: white; padding: 25px; border-radius: 20px;
            width: 420px; max-width: 90%; position: relative;
            box-shadow: 0 20px 50px rgba(0,0,0,0.2);
            animation: fastFadeIn 0.15s ease-out; 
        }
        @keyframes fastFadeIn { from { opacity: 0; } to { opacity: 1; } }
        .download-popup .title { font-size: 22px; font-weight: 700; margin-bottom: 5px; color: var(--primary-blue); text-align: center;}
        
        /* 弹窗内的系统提示 */
        .requirement { font-size: 13px; color: var(--text-sub); text-align: center; margin-bottom: 18px; line-height: 1.4; }
        .requirement b { color: var(--text-main); }

        .download-option {
            display: flex; align-items: center; margin-bottom: 12px; padding: 15px;
            border-radius: 12px; background-color: #f8fafc; cursor: pointer;
            transition: background 0.1s; border: 1px solid #e2e8f0;
        }
        .download-option:hover { background-color: #eff6ff; border-color: var(--primary-blue); }
        .download-option-icon { margin-right: 15px; display: flex; align-items: center; }
        .download-option-title { font-weight: 600; font-size: 15px; color: #1e293b; }
        .preferred { background: #34c759; color: white; font-size: 11px; padding: 2px 6px; border-radius: 4px; margin-left: 8px; }
        .download-option-desc { font-size: 12px; color: #64748b; margin-top: 2px; }
        .buttons { display: flex; gap: 10px; }
        .btnMsg { flex: 1; padding: 12px; border-radius: 10px; border: none; font-weight: 600; cursor: pointer; color: white; }
        .btn-B { background-color: #fb7299; }
        .btn-donate { background-color: #ff9500; }
        .close-btn { position: absolute; top: 15px; right: 15px; font-size: 24px; cursor: pointer; color: #94a3b8; border: none; background: none; }

        .donate-methods { display: flex; justify-content: space-around; margin: 25px 0; }
        .donate-method img { width: 130px; height: 130px; border-radius: 12px; border: 1px solid #eee; }
        .donate-method-name { font-size: 14px; margin-top: 10px; font-weight: 500; text-align: center; color: #1e293b;}
        footer { text-align: center; padding: 60px; color: #94a3b8; font-size: 14px; background: rgba(15, 23, 42, 0.03); }
        /* --- 特性网格 --- */
.features {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    padding: 40px 20px 60px;
    max-width: 1200px;
    margin: 0 auto;
}

.feature-card {
    background: rgba(255, 255, 255, 0.8);
    padding: 35px 25px;
    border-radius: 24px;
    border: 1px solid rgba(255, 255, 255, 0.4);
    transition: all 0.2s;
    /* 核心修改点：使用 flex 布局确保内部元素垂直水平全部居中 */
    display: flex;
    flex-direction: column;
    align-items: center; 
    text-align: center;
}

.feature-card:hover {
    background: white;
    transform: translateY(-5px);
    box-shadow: 0 15px 30px rgba(0, 0, 0, 0.05);
}

.feature-card i {
    font-size: 2.2rem;
    color: var(--primary-blue);
    margin-bottom: 20px;
    /* 确保图标作为块级元素在 flex 下居中 */
    display: flex;
    justify-content: center;
    align-items: center;
}

.feature-card h3 {
    margin-bottom: 12px;
    font-size: 1.2rem;
    color: var(--text-main);
}

.feature-card p {
    color: var(--text-sub);
    line-height: 1.6;
    font-size: 0.95rem;
    margin: 0;
}