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

        body {
            font-family: 'Courier New', monospace;
            background: #0d1117;
            color: #c9d1d9;
            min-height: 100vh;
            padding-bottom: 60px; /* Espace pour la barre fixe */
        }

        .container {
            max-width: 1000px;
            margin: 0 auto;
            padding: 2rem;
        }

        .back-btn {
            background: #238636;
            border: 2px solid #2ea043;
            color: white;
            font-family: 'Courier New', monospace;
            font-size: 1rem;
            padding: 0.75rem 1.5rem;
            cursor: pointer;
            border-radius: 6px;
            margin-bottom: 2rem;
            transition: all 0.3s ease;
            text-decoration: none;
            display: inline-block;
        }

        .back-btn:hover {
            background: #2ea043;
            transform: translateY(-1px);
            box-shadow: 0 4px 8px rgba(46, 160, 67, 0.3);
        }

        .content-area {
            background: #161b22;
            border: 2px solid #21262d;
            border-radius: 12px;
            padding: 2rem;
        }

        .content-area h1 {
            color: #58a6ff;
            margin-bottom: 1.5rem;
            font-size: 2.5rem;
            text-shadow: 0 0 10px rgba(88, 166, 255, 0.3);
        }

        .content-area h2 {
            color: #58a6ff;
            margin-bottom: 1rem;
            font-size: 1.8rem;
        }

        .content-area p {
            margin-bottom: 1.5rem;
            line-height: 1.6;
            font-size: 1.1rem;
        }
        
        .content-area pre {
            margin-bottom: 1.5rem;
            line-height: 1.4;
            font-size: 1.3rem;
        }

        .code-snippet {
            background: #0d1117;
            border: 1px solid #30363d;
            border-radius: 6px;
            padding: 1.5rem;
            margin: 1.5rem 0;
            font-family: 'Courier New', monospace;
            color: #79c0ff;
            overflow-x: auto;
            font-size: 0.95rem;
        }

        .highlight {
            background: rgba(88, 166, 255, 0.1);
            padding: 0.2rem 0.4rem;
            border-radius: 4px;
            color: #58a6ff;
        }

        .definition {
            background: #1c2128;
            border-left: 4px solid #58a6ff;
            padding: 1rem;
            margin: 1.5rem 0;
            border-radius: 0 6px 6px 0;
        }

        .letter-header {
            text-align: center;
            background: linear-gradient(135deg, #21262d, #30363d);
            padding: 1rem;
            border-radius: 8px;
            margin-bottom: 2rem;
            border: 2px solid #58a6ff;
        }

        .letter-display {
            font-size: 4rem;
            color: #58a6ff;
            font-weight: bold;
            text-shadow: 0 0 20px rgba(88, 166, 255, 0.5);
        }
        
               .alphabet-bar {
            position: fixed;
            bottom: 0;
            left: 0;
            right: 0;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 8px 0;
            box-shadow: 0 -2px 10px rgba(0, 0, 0, 0.2);
            z-index: 1000;
            gap: 2px;
        }

        .aletter-btn {
            background: rgba(255, 255, 255, 0.9);
            border: none;
            width: 32px;
            height: 32px;
            border-radius: 50%;
            font-weight: bold;
            font-size: 14px;
            color: #333;
            cursor: pointer;
            transition: all 0.2s ease;
            display: flex;
            align-items: center;
            justify-content: center;
            user-select: none;
            touch-action: manipulation;
        }

        .aletter-btn:hover {
            background: white;
            transform: scale(1.1);
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
        }

        .aletter-btn:active {
            transform: scale(0.95);
            background: #f0f0f0;
        }

        /* Responsive pour petits écrans */
        @media (max-width: 768px) {
            .aletter-btn {
                width: 28px;
                height: 28px;
                font-size: 12px;
            }
            
            .alphabet-bar {
                gap: 1px;
                padding: 6px 5px;
            }
        }

        @media (max-width: 480px) {
            .aletter-btn {
                width: 24px;
                height: 24px;
                font-size: 11px;
            }
        }