* { box-sizing: border-box; margin: 0; padding: 0; }
        body {
            background: #090d16;
            color: #c9d1d9;
            font-family: monospace;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            min-height: 100vh;
            padding: 16px;
        }
        .card {
            background: rgba(2, 4, 10, 0.85);
            border: 1px solid rgba(34, 211, 238, 0.3);
            border-radius: 12px;
            padding: 20px;
            text-align: center;
            max-width: 360px;
            width: 100%;
            box-shadow: 0 0 20px rgba(34, 211, 238, 0.15);
        }
        h1 { font-size: 14px; color: #38bdf8; margin-bottom: 12px; letter-spacing: 0.05em; }
        canvas {
            background: repeating-conic-gradient(#161b22 0% 25%, #0d1117 0% 50%) 50% / 14px 14px;
            border-radius: 8px;
            border: 1px solid rgba(34, 211, 238, 0.3);
            display: block;
            margin: 12px auto;
            max-width: 100%;
        }
        .btn {
            background: rgba(74, 222, 128, 0.15);
            border: 1px solid #4ade80;
            color: #4ade80;
            padding: 10px 16px;
            border-radius: 6px;
            cursor: pointer;
            font-family: inherit;
            font-size: 11px;
            font-weight: bold;
            width: 100%;
            margin-top: 12px;
            transition: all 0.2s;
        }
        .btn:hover { background: rgba(74, 222, 128, 0.3); }
        .info { font-size: 10px; color: #8b949e; margin-top: 6px; }
        .error { color: #f43f5e; font-size: 11px; margin-top: 10px; }