:root {
            --bg-primary: #ffffff;
            --bg-secondary: #f5f7fa;
            --bg-card: #ffffff;
            --text-primary: #2c3e50;
            --text-secondary: #7f8c8d;
            --accent-color: #e74c3c;
            --border-color: #ecf0f1;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
            --transition: all 0.3s ease;
        }

        .dark-theme {
            --bg-primary: #121826;
            --bg-secondary: #1a2236;
            --bg-card: #1e293b;
            --text-primary: #e2e8f0;
            --text-secondary: #94a3b8;
            --accent-color: #f87171;
            --border-color: #2d3748;
            --shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
        }

        body {
            background-color: var(--bg-primary);
            color: var(--text-primary);
            line-height: 1.6;
            transition: var(--transition);
            min-height: 100vh;
        }

        .container {
            max-width: 800px;
            margin: 0 auto;
            padding: 20px;
        }

        header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 20px 0;
            margin-bottom: 30px;
            border-bottom: 1px solid var(--border-color);
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 12px;
        }

        .logo-icon {
            color: var(--accent-color);
            font-size: 1.8rem;
        }

        .logo-text {
            font-size: 1.5rem;
            font-weight: 700;
        }

        .logo-subtext {
            font-size: 0.9rem;
            color: var(--text-secondary);
            margin-top: 2px;
        }

        /* 主题切换按钮 */
        .theme-toggle {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 50px;
            padding: 10px 20px;
            display: flex;
            align-items: center;
            gap: 8px;
            cursor: pointer;
            transition: var(--transition);
            color: var(--text-primary);
            font-weight: 500;
            box-shadow: var(--shadow);
        }

        .theme-toggle:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(0, 0, 0, 0.12);
        }

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

        .content-card {
            background: var(--bg-card);
            border-radius: 12px;
            padding: 30px;
            margin-bottom: 25px;
            box-shadow: var(--shadow);
            border: 1px solid var(--border-color);
            transition: var(--transition);
        }

        .content-card:hover {
            transform: translateY(-3px);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
        }

        .question-header {
            display: flex;
            align-items: center;
            gap: 12px;
            margin-bottom: 15px;
        }

        .question-icon {
            background: var(--accent-color);
            color: white;
            width: 36px;
            height: 36px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            flex-shrink: 0;
        }

        .question-text {
            font-size: 1.2rem;
            font-weight: 600;
            line-height: 1.4;
        }

        .question-meta {
            display: flex;
            align-items: center;
            gap: 15px;
            margin-top: 10px;
            color: var(--text-secondary);
            font-size: 0.9rem;
        }

        .meta-item {
            display: flex;
            align-items: center;
            gap: 5px;
        }

        /* 底部信息 */
        footer {
            text-align: center;
            padding: 30px 0;
            margin-top: 40px;
            color: var(--text-secondary);
            border-top: 1px solid var(--border-color);
            font-size: 0.9rem;
        }

        .footer-info {
            display: flex;
            justify-content: center;
            gap: 20px;
            margin-top: 15px;
            flex-wrap: wrap;
        }

        @media (max-width: 768px) {
            .container {
                padding: 15px;
            }
            
            header {
                flex-direction: column;
                align-items: flex-start;
                gap: 15px;
            }
            
            .content-card {
                padding: 20px;
            }
            
            .question-text {
                font-size: 1.1rem;
            }
        }

        @media (max-width: 480px) {
            .question-header {
                flex-direction: column;
                align-items: flex-start;
                gap: 10px;
            }
            
            .question-meta {
                flex-direction: column;
                align-items: flex-start;
                gap: 8px;
            }
            
            .theme-toggle {
                padding: 8px 16px;
                font-size: 0.9rem;
            }
        }

        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(20px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .content-card {
            animation: fadeInUp 0.6s ease forwards;
        }
.home-button {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 50px;
    padding: 10px 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
    font-weight: 500;
    box-shadow: var(--shadow);
    text-decoration: none;
    margin-right: 15px;
}

.home-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.12);
    background: var(--accent-color);
    color: white;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 30px;
    border-bottom: 1px solid var(--border-color);
}

.header-right {
    display: flex;
    align-items: center;
    gap: 10px;
}
        .content-card:nth-child(1) { animation-delay: 0.1s; }
        .content-card:nth-child(2) { animation-delay: 0.2s; }
        .content-card:nth-child(3) { animation-delay: 0.3s; }
        .content-card:nth-child(4) { animation-delay: 0.4s; }
        .content-card:nth-child(5) { animation-delay: 0.5s; }
        .content-card:nth-child(6) { animation-delay: 0.6s; }
        .content-card:nth-child(7) { animation-delay: 0.7s; }
        .content-card:nth-child(8) { animation-delay: 0.8s; }
        .content-card:nth-child(9) { animation-delay: 0.9s; }
        .content-card:nth-child(10) { animation-delay: 1.0s; }
        .content-card:nth-child(11) { animation-delay: 1.1s; }
        .content-card:nth-child(12) { animation-delay: 1.2s; }
        .content-card:nth-child(13) { animation-delay: 1.3s; }
        .content-card:nth-child(14) { animation-delay: 1.4s; }