<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Page Not Found</title>
    <link rel="icon" type="image/x-icon" href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>📚</text></svg>">
    <link rel="stylesheet" href="/lib/fonts/dingtalkjinbuti.css">
    <style>
        :root {
            --primary-color: #667eea;
            --secondary-color: #764ba2;
            --accent-color: #f093fb;
            --text-color: #2d3748;
            --bg-color: #f7fafc;
            --card-bg: #ffffff;
            --footer-bg: #4a5568;
            --footer-text: #e2e8f0;
            --shadow: 0 4px 6px rgba(0, 0, 0, 0.07);
            --transition: all 0.3s ease;
            --font-primary: 'dingtalk_jinbutiregular', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }

        .dark-theme {
            --primary-color: #7e6ff9;
            --secondary-color: #5a4fcf;
            --accent-color: #a78bfa;
            --text-color: #e2e8f0;
            --bg-color: #1a202c;
            --card-bg: #2d3748;
            --footer-bg: #2d3748;
            --footer-text: #cbd5e0;
            --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
        }

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

        body {
            background-color: var(--bg-color);
            color: var(--text-color);
            transition: var(--transition);
            min-height: 100vh;
            display: flex;
            flex-direction: column;
            font-family: var(--font-primary);
            text-align: center;
        }

        header {
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
            text-align: center;
            padding: 2rem 1rem;
            box-shadow: var(--shadow);
        }

        h1 {
            font-size: 2.5rem;
            margin-bottom: 0.5rem;
            letter-spacing: 1px;
            font-weight: normal;
            font-family: var(--font-primary);
        }

        .subtitle {
            font-size: 1.2rem;
            opacity: 0.9;
            font-weight: normal;
            font-family: var(--font-primary);
        }

        .theme-switcher {
            position: absolute;
            top: 20px;
            right: 20px;
        }

        .theme-toggle {
            background: rgba(255, 255, 255, 0.2);
            border: none;
            border-radius: 50px;
            padding: 8px 15px;
            color: white;
            cursor: pointer;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: var(--transition);
            font-weight: normal;
            font-family: var(--font-primary);
        }

        .theme-toggle:hover {
            background: rgba(255, 255, 255, 0.3);
        }

        .theme-icon {
            font-size: 1.2rem;
        }

        .error-container {
            flex: 1;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            padding: 3rem 2rem;
            max-width: 800px;
            margin: 0 auto;
        }

        .error-code {
            font-size: 8rem;
            font-weight: bold;
            background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            margin-bottom: 1rem;
            line-height: 1;
        }

        .error-icon {
            font-size: 6rem;
            margin-bottom: 2rem;
            opacity: 0.8;
        }

        .error-title {
            font-size: 2.5rem;
            margin-bottom: 1rem;
            color: var(--primary-color);
            font-family: var(--font-primary);
        }

        .error-message {
            font-size: 1.2rem;
            margin-bottom: 3rem;
            line-height: 1.6;
            max-width: 600px;
            opacity: 0.8;
            font-family: var(--font-primary);
        }

        .action-buttons {
            display: flex;
            gap: 1.5rem;
            flex-wrap: wrap;
            justify-content: center;
            margin-bottom: 3rem;
        }

        .home-button {
            background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
            color: white;
            border: none;
            border-radius: 15px;
            padding: 1rem 2rem;
            font-size: 1.1rem;
            font-weight: normal;
            cursor: pointer;
            transition: var(--transition);
            box-shadow: var(--shadow);
            text-decoration: none;
            font-family: var(--font-primary);
        }

        .home-button:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
        }

        .back-button {
            background: var(--card-bg);
            color: var(--text-color);
            border: 2px solid var(--primary-color);
            border-radius: 15px;
            padding: 1rem 2rem;
            font-size: 1.1rem;
            font-weight: normal;
            cursor: pointer;
            transition: var(--transition);
            text-decoration: none;
            font-family: var(--font-primary);
        }

        .back-button:hover {
            background: var(--primary-color);
            color: white;
            transform: translateY(-3px);
        }

        .search-suggestions {
            background: var(--card-bg);
            padding: 2rem;
            border-radius: 15px;
            box-shadow: var(--shadow);
            max-width: 500px;
            margin: 0 auto;
        }

        .search-suggestions h3 {
            color: var(--primary-color);
            margin-bottom: 1rem;
            font-family: var(--font-primary);
        }

        .suggestion-list {
            list-style: none;
            text-align: left;
        }

        .suggestion-list li {
            margin-bottom: 0.5rem;
            padding: 0.5rem;
            border-left: 3px solid var(--accent-color);
            background: rgba(0,0,0,0.02);
            border-radius: 0 5px 5px 0;
            font-family: var(--font-primary);
        }

        .suggestion-list a {
            color: var(--text-color);
            text-decoration: none;
            transition: var(--transition);
        }

        .suggestion-list a:hover {
            color: var(--primary-color);
        }

        footer {
            background-color: var(--footer-bg);
            color: var(--footer-text);
            text-align: center;
            padding: 1.5rem;
            margin-top: auto;
            font-family: var(--font-primary);
        }

        @media (max-width: 768px) {
            .error-code {
                font-size: 6rem;
            }
            
            .error-icon {
                font-size: 4rem;
            }
            
            .error-title {
                font-size: 2rem;
            }
            
            .action-buttons {
                flex-direction: column;
                align-items: center;
            }
            
            .home-button, .back-button {
                width: 100%;
                max-width: 300px;
            }
        }

        @media (max-width: 480px) {
            .error-code {
                font-size: 4rem;
            }
            
            .error-title {
                font-size: 1.5rem;
            }
            
            .error-message {
                font-size: 1rem;
            }
        }
    </style>
</head>
<body>
    <header>
        <div class="theme-switcher">
            <button class="theme-toggle" id="themeToggle">
                <span class="theme-icon">☀️</span>
                <span>Light Mode</span>
            </button>
        </div>
        <h1>Class Library</h1>
        <p class="subtitle">Digital Repository</p>
    </header>

    <div class="error-container">
        <div class="error-code">404</div>
        <div class="error-icon">🔍</div>
        <h2 class="error-title">Page Not Found</h2>
        <p class="error-message">
            Oops! The page you're looking for seems to have wandered off into the digital wilderness. 
            It might have been moved, deleted, or perhaps it never existed in the first place.
        </p>
        
        <div class="action-buttons">
            <a href="/" class="home-button">🏠 Back to Home</a>
            <a href="javascript:history.back()" class="back-button">↩️ Go Back</a>
        </div>

        <!--<div class="search-suggestions">
            <h3>You might be looking for:</h3>
            <ul class="suggestion-list">
                <li><a href="index.html">Home Page</a></li>
                <li><a href="wss.pet">Upload Files</a></li>
                <li><a href="sharepoint.com">View Files</a></li>
            </ul>
        </div>-->
    </div>

    <footer>
        <p>&copy; 2025 xiaobsh</p>
    </footer>

    <script>
        const themeToggle = document.getElementById('themeToggle');
        const themeIcon = themeToggle.querySelector('.theme-icon');
        const themeText = themeToggle.querySelector('span:last-child');
        
        // Check for saved theme preference or default to light
        const currentTheme = localStorage.getItem('theme') || 'light';
        
        // Apply the saved theme on page load
        if (currentTheme === 'dark') {
            document.body.classList.add('dark-theme');
            themeIcon.textContent = '🌙';
            themeText.textContent = 'Dark Mode';
        }
        
        themeToggle.addEventListener('click', () => {
            document.body.classList.toggle('dark-theme');
            
            if (document.body.classList.contains('dark-theme')) {
                localStorage.setItem('theme', 'dark');
                themeIcon.textContent = '🌙';
                themeText.textContent = 'Dark Mode';
            } else {
                localStorage.setItem('theme', 'light');
                themeIcon.textContent = '☀️';
                themeText.textContent = 'Light Mode';
            }
        });
    </script>
</body>
</html>