:root {
            --primary: #2c3e50;
            --secondary: #3498db;
            --accent: #e74c3c;
            --light: #ecf0f1;
            --dark: #2c3e50;
            --gray: #95a5a6;
            --bg-color: #f9f9f9;
            --card-bg: white;
            --text-color: #2c3e50;
            --border-radius: 8px;
            --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
            --transition: all 0.3s ease;
        }

        /* Темная тема */
        [data-theme="dark"] {
            --primary: #3498db;
            --secondary: #2980b9;
            --accent: #e74c3c;
            --light: #2c3e50;
            --dark: #ecf0f1;
            --gray: #7f8c8d;
            --bg-color: #1a1a1a;
            --card-bg: #2c3e50;
            --text-color: #ecf0f1;
            --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
        }

        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            line-height: 1.6;
            color: var(--text-color);
            background-color: var(--bg-color);
            margin: 0;
            padding: 0;
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px;
            transition: background-color 0.3s ease, color 0.3s ease;
        }

        header {
            text-align: center;
            margin-bottom: 30px;
            padding: 20px 0;
            border-bottom: 1px solid var(--light);
        }

        h1 {
            color: var(--primary);
            font-size: 2.5rem;
            margin-bottom: 10px;
        }

        h2 {
            color: var(--secondary);
            font-size: 1.8rem;
            margin: 40px 0 20px;
            padding-bottom: 10px;
            border-bottom: 2px solid var(--light);
        }

        h3 {
            color: var(--dark);
            font-size: 1.4rem;
            margin-top: 0;
        }

        .platform-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
            gap: 25px;
            margin-bottom: 40px;
        }

        .client-card {
            background: var(--card-bg);
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            padding: 25px;
            transition: var(--transition);
            border-top: 4px solid var(--secondary);
        }

        .client-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
        }

        .protocols {
            color: var(--gray);
            font-size: 0.9rem;
            margin: 10px 0;
        }

        .btn-group {
            margin-top: 15px;
            display: flex;
            flex-wrap: wrap;
            gap: 10px;
        }

        .btn {
            display: inline-block;
            background: var(--secondary);
            color: white;
            padding: 8px 16px;
            border-radius: var(--border-radius);
            text-decoration: none;
            font-weight: 500;
            transition: var(--transition);
            font-size: 0.9rem;
        }

        .btn:hover {
            background: var(--primary);
            transform: translateY(-2px);
        }

        .btn-outline {
            background: transparent;
            border: 1px solid var(--secondary);
            color: var(--secondary);
        }

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

        .btn-accent {
            background: var(--accent);
        }

        .btn-accent:hover {
            background: #c0392b;
        }

        details {
            margin-top: 15px;
        }

        summary {
            cursor: pointer;
            font-weight: 600;
            color: var(--primary);
            padding: 8px 0;
        }

        .back-link {
            text-align: center;
            margin: 50px 0 30px;
        }

        .back-btn {
            padding: 10px 25px;
            font-size: 1rem;
        }

        /* Кнопка переключения темы */
        .theme-toggle {
            position: fixed;
            bottom: 20px;
            right: 20px;
            background-color: var(--secondary);
            color: white;
            border: none;
            border-radius: 50%;
            width: 50px;
            height: 50px;
            font-size: 20px;
            cursor: pointer;
            box-shadow: var(--shadow);
            display: flex;
            align-items: center;
            justify-content: center;
            z-index: 1000;
            transition: all 0.3s ease;
        }

        .theme-toggle:hover {
            transform: scale(1.1);
            background-color: var(--primary);
        }

        @media (max-width: 768px) {
            .platform-grid {
                grid-template-columns: 1fr;
            }
            
            h1 {
                font-size: 2rem;
            }
            
            h2 {
                font-size: 1.5rem;
            }
        }