<?php
// ============================================================
// 网站配置
// ============================================================
$siteName = '我的网站';
$downloadsDir = __DIR__ . '/downloads';      // 下载文件存放目录
$statsFile = __DIR__ . '/download_stats.json'; // 下载统计文件

// ============================================================
// 初始化下载目录和统计文件
// ============================================================
if (!is_dir($downloadsDir)) {
    mkdir($downloadsDir, 0755, true);
    // 创建 .htaccess 防止直接访问下载目录
    file_put_contents($downloadsDir . '/.htaccess', "Require all denied\n");
    // 创建示例文件
    file_put_contents($downloadsDir . '/示例文档.txt', "这是一个示例文本文件。\n您可以下载此文件进行测试。\n\n感谢您的访问！\n");
    file_put_contents($downloadsDir . '/使用说明.pdf', "%PDF-1.4\n% 这是一个模拟的PDF文件\n1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n3 0 obj\n<< /Type /Page /Parent 2 0 R /MediaBox [0 0 612 792] >>\nendobj\nxref\n0 4\ntrailer\n<< /Size 4 /Root 1 0 R >>\nstartxref\n%%EOF");
    file_put_contents($downloadsDir . '/项目源码.zip', "PK\x03\x04\n-- 模拟的ZIP文件内容 --\n此文件仅用于演示下载功能");
    file_put_contents($downloadsDir . '/图片素材.png', base64_decode('iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mNk+M9QDwADhgGAWjR9awAAAABJRU5ErkJggg=='));
}
if (!is_file($statsFile)) {
    file_put_contents($statsFile, json_encode([], JSON_PRETTY_PRINT));
}

// ============================================================
// 辅助函数
// ============================================================
function formatFileSize($bytes) {
    if ($bytes >= 1073741824) return round($bytes / 1073741824, 2) . ' GB';
    if ($bytes >= 1048576)    return round($bytes / 1048576, 2) . ' MB';
    if ($bytes >= 1024)       return round($bytes / 1024, 2) . ' KB';
    return $bytes . ' B';
}

function getFileIcon($filename) {
    $ext = strtolower(pathinfo($filename, PATHINFO_EXTENSION));
    $icons = [
        'pdf'  => '📕', 'doc' => '📘', 'docx' => '📘',
        'xls'  => '📗', 'xlsx' => '📗', 'ppt' => '📙',
        'txt'  => '📄', 'md' => '📄', 'csv' => '📊',
        'zip'  => '📦', 'rar' => '📦', '7z' => '📦', 'gz' => '📦',
        'jpg'  => '🖼️', 'jpeg' => '🖼️', 'png' => '🖼️', 'gif' => '🖼️', 'svg' => '🖼️',
        'mp3'  => '🎵', 'wav' => '🎵', 'flac' => '🎵',
        'mp4'  => '🎬', 'avi' => '🎬', 'mkv' => '🎬',
        'php'  => '💻', 'js' => '💻', 'html' => '💻', 'css' => '💻',
        'exe'  => '⚙️', 'dmg' => '⚙️', 'apk' => '📱',
    ];
    return $icons[$ext] ?? '📁';
}

// ============================================================
// 处理文件下载请求
// ============================================================
if (isset($_GET['download'])) {
    $requestedFile = basename($_GET['download']); // 安全过滤，防止路径穿越
    $filePath = $downloadsDir . '/' . $requestedFile;

    if (file_exists($filePath) && is_file($filePath)) {
        // 更新下载统计
        $stats = json_decode(file_get_contents($statsFile), true) ?: [];
        $stats[$requestedFile] = ($stats[$requestedFile] ?? 0) + 1;
        file_put_contents($statsFile, json_encode($stats, JSON_PRETTY_PRINT));

        // 获取MIME类型
        $finfo = finfo_open(FILEINFO_MIME_TYPE);
        $mimeType = finfo_file($finfo, $filePath);
        finfo_close($finfo);
        if (!$mimeType) $mimeType = 'application/octet-stream';

        $fileSize = filesize($filePath);

        // 设置响应头并输出文件
        header('Content-Type: ' . $mimeType);
        header('Content-Disposition: attachment; filename="' . $requestedFile . '"');
        header('Content-Length: ' . $fileSize);
        header('Cache-Control: no-cache, must-revalidate');
        header('Pragma: no-cache');
        header('Expires: 0');
        ob_clean();
        flush();
        readfile($filePath);
        exit;
    } else {
        // 文件不存在
        header('HTTP/1.1 404 Not Found');
        echo '<!DOCTYPE html><html><head><meta charset="UTF-8"><title>404</title></head><body><h1>文件不存在</h1><p>您请求的文件未找到。</p><a href="?page=downloads">返回下载页面</a></body></html>';
        exit;
    }
}

// ============================================================
// 确定当前页面
// ============================================================
$currentPage = $_GET['page'] ?? 'home';
$allowedPages = ['home', 'downloads'];
if (!in_array($currentPage, $allowedPages)) {
    $currentPage = 'home';
}

// 获取下载统计
$stats = json_decode(file_get_contents($statsFile), true) ?: [];

// 获取下载文件列表
$downloadFiles = [];
if (is_dir($downloadsDir)) {
    $files = scandir($downloadsDir);
    foreach ($files as $file) {
        if ($file === '.' || $file === '..' || $file === '.htaccess') continue;
        $filePath = $downloadsDir . '/' . $file;
        if (is_file($filePath)) {
            $downloadFiles[] = [
                'name'     => $file,
                'size'     => filesize($filePath),
                'modified' => filemtime($filePath),
                'downloads'=> $stats[$file] ?? 0,
                'icon'     => getFileIcon($file),
            ];
        }
    }
    // 按文件名排序
    usort($downloadFiles, function($a, $b) {
        return strcasecmp($a['name'], $b['name']);
    });
}
?>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title><?php echo $siteName; ?> - <?php echo $currentPage === 'home' ? '首页' : '下载'; ?></title>
    <style>
        /* ============================================================
           全局样式 & CSS变量
           ============================================================ */
        :root {
            --sidebar-width: 260px;
            --sidebar-bg: #1a1d23;
            --sidebar-hover: #252830;
            --sidebar-active: #2c3039;
            --accent-color: #4f8ff7;
            --accent-hover: #3a7be8;
            --download-btn: #10b981;
            --download-btn-hover: #059669;
            --text-primary: #e2e8f0;
            --text-secondary: #94a3b8;
            --text-dark: #1e293b;
            --bg-main: #f1f5f9;
            --bg-card: #ffffff;
            --border-color: #e2e8f0;
            --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
            --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
            --shadow-lg: 0 10px 30px rgba(0,0,0,0.12);
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
            --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            background: var(--bg-main);
            color: var(--text-dark);
            display: flex;
            min-height: 100vh;
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
        }

        /* ============================================================
           左侧导航栏
           ============================================================ */
        .sidebar {
            width: var(--sidebar-width);
            min-width: var(--sidebar-width);
            background: var(--sidebar-bg);
            color: var(--text-primary);
            display: flex;
            flex-direction: column;
            position: fixed;
            top: 0;
            left: 0;
            height: 100vh;
            z-index: 100;
            box-shadow: 2px 0 20px rgba(0,0,0,0.25);
            transition: transform var(--transition);
        }

        .sidebar-header {
            padding: 28px 24px 20px;
            border-bottom: 1px solid rgba(255,255,255,0.08);
        }

        .sidebar-header .logo {
            display: flex;
            align-items: center;
            gap: 12px;
            text-decoration: none;
            color: #fff;
        }

        .sidebar-header .logo-icon {
            width: 40px;
            height: 40px;
            background: var(--accent-color);
            border-radius: var(--radius-sm);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 20px;
            flex-shrink: 0;
        }

        .sidebar-header .logo-text {
            font-size: 18px;
            font-weight: 700;
            letter-spacing: -0.3px;
        }

        .sidebar-header .logo-sub {
            font-size: 11px;
            color: var(--text-secondary);
            font-weight: 400;
            letter-spacing: 0.5px;
            text-transform: uppercase;
        }

        .sidebar-nav {
            flex: 1;
            padding: 16px 12px;
            list-style: none;
            display: flex;
            flex-direction: column;
            gap: 4px;
        }

        .sidebar-nav li a {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 13px 16px;
            text-decoration: none;
            color: var(--text-secondary);
            border-radius: var(--radius-sm);
            font-size: 15px;
            font-weight: 500;
            transition: all var(--transition);
            position: relative;
            letter-spacing: 0.2px;
        }

        .sidebar-nav li a:hover {
            background: var(--sidebar-hover);
            color: #fff;
            transform: translateX(2px);
        }

        .sidebar-nav li a.active {
            background: var(--sidebar-active);
            color: #fff;
            font-weight: 600;
            box-shadow: inset 3px 0 0 var(--accent-color);
        }

        .sidebar-nav li a .nav-icon {
            font-size: 20px;
            width: 24px;
            text-align: center;
            flex-shrink: 0;
            transition: transform var(--transition);
        }

        .sidebar-nav li a:hover .nav-icon {
            transform: scale(1.1);
        }

        .sidebar-nav li a .badge {
            margin-left: auto;
            background: var(--accent-color);
            color: #fff;
            font-size: 11px;
            padding: 3px 9px;
            border-radius: 20px;
            font-weight: 600;
            letter-spacing: 0.3px;
        }

        .sidebar-footer {
            padding: 16px 20px;
            border-top: 1px solid rgba(255,255,255,0.08);
            font-size: 12px;
            color: var(--text-secondary);
            text-align: center;
        }

        /* ============================================================
           主内容区域
           ============================================================ */
        .main-content {
            margin-left: var(--sidebar-width);
            flex: 1;
            padding: 32px 36px;
            min-height: 100vh;
            max-width: 1000px;
            width: 100%;
        }

        /* 页面标题 */
        .page-header {
            margin-bottom: 32px;
        }

        .page-header h1 {
            font-size: 28px;
            font-weight: 700;
            color: #0f172a;
            letter-spacing: -0.5px;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .page-header .breadcrumb {
            font-size: 13px;
            color: var(--text-secondary);
            margin-top: 6px;
        }

        .page-header .breadcrumb a {
            color: var(--accent-color);
            text-decoration: none;
        }

        .page-header .breadcrumb a:hover {
            text-decoration: underline;
        }

        /* 卡片样式 */
        .card {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 24px 28px;
            margin-bottom: 20px;
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border-color);
            transition: box-shadow var(--transition);
        }

        .card:hover {
            box-shadow: var(--shadow-md);
        }

        .card h2 {
            font-size: 18px;
            font-weight: 600;
            margin-bottom: 12px;
            color: #1e293b;
        }

        .card p {
            color: #475569;
            font-size: 14px;
            line-height: 1.7;
        }

        /* ============================================================
           首页特色区域
           ============================================================ */
        .hero-section {
            background: linear-gradient(135deg, #1e3a5f 0%, #1a1d23 50%, #0f2027 100%);
            color: #fff;
            border-radius: var(--radius-lg);
            padding: 40px 36px;
            margin-bottom: 28px;
            box-shadow: var(--shadow-lg);
            position: relative;
            overflow: hidden;
        }

        .hero-section::after {
            content: '';
            position: absolute;
            top: -50%;
            right: -20%;
            width: 300px;
            height: 300px;
            background: rgba(79, 143, 247, 0.1);
            border-radius: 50%;
            pointer-events: none;
        }

        .hero-section h1 {
            font-size: 30px;
            font-weight: 700;
            margin-bottom: 10px;
            position: relative;
            z-index: 1;
        }

        .hero-section p {
            color: #cbd5e1;
            font-size: 15px;
            position: relative;
            z-index: 1;
            max-width: 600px;
        }

        .hero-section .hero-actions {
            margin-top: 20px;
            display: flex;
            gap: 12px;
            position: relative;
            z-index: 1;
        }

        .btn {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            padding: 11px 22px;
            border-radius: 25px;
            font-size: 14px;
            font-weight: 600;
            text-decoration: none;
            cursor: pointer;
            border: none;
            transition: all var(--transition);
            letter-spacing: 0.3px;
        }

        .btn-primary {
            background: var(--accent-color);
            color: #fff;
        }
        .btn-primary:hover {
            background: var(--accent-hover);
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(79, 143, 247, 0.35);
        }

        .btn-outline {
            background: transparent;
            color: #fff;
            border: 2px solid rgba(255,255,255,0.3);
        }
        .btn-outline:hover {
            border-color: #fff;
            background: rgba(255,255,255,0.08);
        }

        /* 统计小卡片 */
        .stats-row {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
            gap: 16px;
            margin-bottom: 28px;
        }

        .stat-card {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 20px 22px;
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border-color);
            text-align: center;
            transition: all var(--transition);
        }

        .stat-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-md);
        }

        .stat-card .stat-icon {
            font-size: 32px;
            margin-bottom: 8px;
        }

        .stat-card .stat-value {
            font-size: 26px;
            font-weight: 700;
            color: #0f172a;
        }

        .stat-card .stat-label {
            font-size: 12px;
            color: var(--text-secondary);
            margin-top: 2px;
            text-transform: uppercase;
            letter-spacing: 0.5px;
        }

        /* ============================================================
           下载页面 - 文件列表
           ============================================================ */
        .download-table {
            width: 100%;
            border-collapse: collapse;
        }

        .download-table thead th {
            text-align: left;
            padding: 14px 16px;
            font-size: 12px;
            text-transform: uppercase;
            letter-spacing: 0.6px;
            color: var(--text-secondary);
            border-bottom: 2px solid var(--border-color);
            font-weight: 600;
            background: #f8fafc;
            border-radius: var(--radius-sm) var(--radius-sm) 0 0;
        }

        .download-table tbody td {
            padding: 15px 16px;
            border-bottom: 1px solid var(--border-color);
            font-size: 14px;
            vertical-align: middle;
        }

        .download-table tbody tr {
            transition: background var(--transition);
        }

        .download-table tbody tr:hover {
            background: #f8fafc;
        }

        .download-table tbody tr:last-child td {
            border-bottom: none;
        }

        .file-name-cell {
            display: flex;
            align-items: center;
            gap: 10px;
            font-weight: 500;
            color: #1e293b;
        }

        .file-name-cell .file-icon {
            font-size: 28px;
            flex-shrink: 0;
        }

        .file-size {
            color: #64748b;
            font-size: 13px;
            white-space: nowrap;
        }

        .file-downloads {
            color: #64748b;
            font-size: 13px;
            white-space: nowrap;
        }

        .file-modified {
            color: #94a3b8;
            font-size: 12px;
            white-space: nowrap;
        }

        .btn-download {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 8px 18px;
            background: var(--download-btn);
            color: #fff;
            border-radius: 20px;
            text-decoration: none;
            font-size: 13px;
            font-weight: 600;
            transition: all var(--transition);
            white-space: nowrap;
            letter-spacing: 0.3px;
        }

        .btn-download:hover {
            background: var(--download-btn-hover);
            transform: translateY(-1px);
            box-shadow: 0 4px 14px rgba(16, 185, 129, 0.3);
        }

        .btn-download:active {
            transform: scale(0.96);
        }

        /* 空状态 */
        .empty-state {
            text-align: center;
            padding: 50px 20px;
            color: #94a3b8;
        }

        .empty-state .empty-icon {
            font-size: 56px;
            margin-bottom: 16px;
        }

        .empty-state h3 {
            font-size: 18px;
            color: #64748b;
            margin-bottom: 6px;
        }

        .empty-state p {
            font-size: 13px;
        }

        /* 提示信息条 */
        .info-banner {
            background: #eff6ff;
            border: 1px solid #bfdbfe;
            border-radius: var(--radius-sm);
            padding: 14px 18px;
            font-size: 13px;
            color: #1e40af;
            display: flex;
            align-items: center;
            gap: 10px;
            margin-bottom: 20px;
        }

        .info-banner .info-icon {
            font-size: 20px;
            flex-shrink: 0;
        }

        /* ============================================================
           响应式设计 - 移动端
           ============================================================ */
        @media (max-width: 768px) {
            .sidebar {
                transform: translateX(-100%);
                width: 260px;
                min-width: 260px;
            }
            .sidebar.open {
                transform: translateX(0);
            }
            .main-content {
                margin-left: 0;
                padding: 20px 16px;
            }
            .mobile-menu-btn {
                display: flex !important;
            }
            .stats-row {
                grid-template-columns: repeat(2, 1fr);
                gap: 10px;
            }
            .hero-section {
                padding: 28px 20px;
            }
            .hero-section h1 {
                font-size: 22px;
            }
            .download-table thead {
                display: none;
            }
            .download-table tbody td {
                display: block;
                text-align: right;
                padding: 10px 12px;
                border-bottom: 1px solid #e2e8f0;
            }
            .download-table tbody td::before {
                content: attr(data-label);
                float: left;
                font-weight: 600;
                color: #64748b;
                font-size: 12px;
                text-transform: uppercase;
            }
            .download-table tbody tr {
                display: block;
                margin-bottom: 10px;
                border: 1px solid var(--border-color);
                border-radius: var(--radius-sm);
                overflow: hidden;
            }
            .file-name-cell {
                justify-content: flex-end;
            }
        }

        /* 移动端菜单按钮 */
        .mobile-menu-btn {
            display: none;
            position: fixed;
            top: 16px;
            left: 16px;
            z-index: 200;
            width: 42px;
            height: 42px;
            background: var(--sidebar-bg);
            color: #fff;
            border: none;
            border-radius: 50%;
            font-size: 20px;
            cursor: pointer;
            box-shadow: var(--shadow-md);
            align-items: center;
            justify-content: center;
        }

        /* 遮罩层 */
        .sidebar-overlay {
            display: none;
            position: fixed;
            inset: 0;
            background: rgba(0,0,0,0.5);
            z-index: 99;
        }
        .sidebar-overlay.show {
            display: block;
        }

        /* ============================================================
           滚动条美化
           ============================================================ */
        ::-webkit-scrollbar {
            width: 6px;
        }
        ::-webkit-scrollbar-track {
            background: transparent;
        }
        ::-webkit-scrollbar-thumb {
            background: #cbd5e1;
            border-radius: 3px;
        }
        ::-webkit-scrollbar-thumb:hover {
            background: #94a3b8;
        }
    </style>
</head>
<body>

    <!-- 移动端菜单按钮 -->
    <button class="mobile-menu-btn" onclick="toggleSidebar()" aria-label="菜单">
        ☰
    </button>

    <!-- 遮罩层 -->
    <div class="sidebar-overlay" id="sidebarOverlay" onclick="toggleSidebar()"></div>

    <!-- ============================================================
    左侧导航栏
    ============================================================ -->
    <aside class="sidebar" id="sidebar">
        <!-- Logo区域 -->
        <div class="sidebar-header">
            <a href="?page=home" class="logo">
                <div class="logo-icon">🚀</div>
                <div>
                    <div class="logo-text"><?php echo $siteName; ?></div>
                    <div class="logo-sub">资源中心</div>
                </div>
            </a>
        </div>

        <!-- 导航菜单 -->
        <ul class="sidebar-nav">
            <li>
                <a href="?page=home" class="<?php echo $currentPage === 'home' ? 'active' : ''; ?>">
                    <span class="nav-icon">🏠</span>
                    首页
                </a>
            </li>
            <li>
                <a href="?page=downloads" class="<?php echo $currentPage === 'downloads' ? 'active' : ''; ?>">
                    <span class="nav-icon">📥</span>
                    下载
                    <?php if (count($downloadFiles) > 0): ?>
                        <span class="badge"><?php echo count($downloadFiles); ?></span>
                    <?php endif; ?>
                </a>
            </li>
        </ul>

        <!-- 底部信息 -->
        <div class="sidebar-footer">
            © <?php echo date('Y'); ?> <?php echo $siteName; ?><br>
            共 <?php echo count($downloadFiles); ?> 个文件可供下载
        </div>
    </aside>

    <!-- ============================================================
    主内容区域
    ============================================================ -->
    <main class="main-content">

        <?php if ($currentPage === 'home'): ?>
        <!-- ==================== 首页 ==================== -->
        <div class="hero-section">
            <h1>👋 欢迎来到 <?php echo $siteName; ?></h1>
            <p>这里提供了丰富的资源文件供您下载。使用左侧导航栏可以快速切换到下载页面，浏览并获取您需要的文件。</p>
            <div class="hero-actions">
                <a href="?page=downloads" class="btn btn-primary">📥 立即下载</a>
                <a href="?page=home" class="btn btn-outline">了解更多</a>
            </div>
        </div>

        <!-- 统计卡片 -->
        <div class="stats-row">
            <div class="stat-card">
                <div class="stat-icon">📁</div>
                <div class="stat-value"><?php echo count($downloadFiles); ?></div>
                <div class="stat-label">可用文件</div>
            </div>
            <div class="stat-card">
                <div class="stat-icon">📥</div>
                <div class="stat-value"><?php echo array_sum(array_column($downloadFiles, 'downloads')); ?></div>
                <div class="stat-label">总下载次数</div>
            </div>
            <div class="stat-card">
                <div class="stat-icon">💾</div>
                <div class="stat-value">
                    <?php
                    $totalSize = array_sum(array_column($downloadFiles, 'size'));
                    echo formatFileSize($totalSize);
                    ?>
                </div>
                <div class="stat-label">总文件大小</div>
            </div>
            <div class="stat-card">
                <div class="stat-icon">🕐</div>
                <div class="stat-value">
                    <?php
                    $latestTime = 0;
                    foreach ($downloadFiles as $f) {
                        if ($f['modified'] > $latestTime) $latestTime = $f['modified'];
                    }
                    echo $latestTime > 0 ? date('m/d', $latestTime) : '--';
                    ?>
                </div>
                <div class="stat-label">最近更新</div>
            </div>
        </div>

        <!-- 简介卡片 -->
        <div class="card">
            <h2>📋 关于本站</h2>
            <p>
                这是一个简洁的资源下载站点。所有文件均通过左侧导航栏的<strong>「下载」</strong>页面进行管理和获取。
                点击任意文件旁的下载按钮即可开始下载。系统会自动记录每个文件的下载次数，方便您了解热门资源。
            </p>
            <p style="margin-top:10px;">
                如需添加更多文件，只需将文件放入服务器上的 <code>downloads/</code> 目录即可自动出现在下载列表中。
            </p>
        </div>

        <!-- 快速跳转 -->
        <div class="card" style="text-align:center; padding: 30px;">
            <h2>🚀 准备好开始了吗？</h2>
            <p style="margin-bottom:18px;">前往下载页面，浏览所有可用文件。</p>
            <a href="?page=downloads" class="btn btn-primary" style="font-size:15px; padding:13px 30px;">
                📥 前往下载页面
            </a>
        </div>

        <?php elseif ($currentPage === 'downloads'): ?>
        <!-- ==================== 下载页面 ==================== -->
        <div class="page-header">
            <h1>📥 下载中心</h1>
            <div class="breadcrumb">
                <a href="?page=home">首页</a> &raquo; 下载
            </div>
        </div>

        <?php if (count($downloadFiles) > 0): ?>
        <div class="info-banner">
            <span class="info-icon">💡</span>
            共 <strong><?php echo count($downloadFiles); ?></strong> 个文件可供下载。点击右侧按钮即可开始下载，所有文件均存储在服务器 <code>downloads/</code> 目录中。
        </div>

        <div class="card" style="padding: 8px 0; overflow-x: auto;">
            <table class="download-table">
                <thead>
                    <tr>
                        <th>文件名称</th>
                        <th>大小</th>
                        <th>下载次数</th>
                        <th>更新日期</th>
                        <th>操作</th>
                    </tr>
                </thead>
                <tbody>
                    <?php foreach ($downloadFiles as $file): ?>
                    <tr>
                        <td data-label="文件名称">
                            <div class="file-name-cell">
                                <span class="file-icon"><?php echo $file['icon']; ?></span>
                                <span><?php echo htmlspecialchars($file['name']); ?></span>
                            </div>
                        </td>
                        <td data-label="大小" class="file-size">
                            <?php echo formatFileSize($file['size']); ?>
                        </td>
                        <td data-label="下载次数" class="file-downloads">
                            <?php echo $file['downloads']; ?> 次
                        </td>
                        <td data-label="更新日期" class="file-modified">
                            <?php echo date('Y-m-d H:i', $file['modified']); ?>
                        </td>
                        <td data-label="操作">
                            <a href="?download=<?php echo urlencode($file['name']); ?>"
                               class="btn-download"
                               title="下载 <?php echo htmlspecialchars($file['name']); ?>">
                                ⬇ 下载
                            </a>
                        </td>
                    </tr>
                    <?php endforeach; ?>
                </tbody>
            </table>
        </div>
        <?php else: ?>
        <!-- 空状态 -->
        <div class="card">
            <div class="empty-state">
                <div class="empty-icon">📭</div>
                <h3>暂无文件可供下载</h3>
                <p>请将文件放入服务器上的 <code>downloads/</code> 目录，它们将自动出现在这里。</p>
            </div>
        </div>
        <?php endif; ?>

        <?php endif; ?>

    </main>

    <!-- ============================================================
    移动端侧边栏切换脚本
    ============================================================ -->
    <script>
        function toggleSidebar() {
            var sidebar = document.getElementById('sidebar');
            var overlay = document.getElementById('sidebarOverlay');
            sidebar.classList.toggle('open');
            overlay.classList.toggle('show');
        }

        // 点击导航链接后自动关闭移动端侧边栏
        document.querySelectorAll('.sidebar-nav a').forEach(function(link) {
            link.addEventListener('click', function() {
                if (window.innerWidth <= 768) {
                    var sidebar = document.getElementById('sidebar');
                    var overlay = document.getElementById('sidebarOverlay');
                    sidebar.classList.remove('open');
                    overlay.classList.remove('show');
                }
            });
        });
    </script>

</body>
</html>