body {
            font-family: 'Inter', sans-serif;
            background: linear-gradient(135deg, #0f172a 0%, #1e1b4b 50%, #311042 100%);
        }
        .display-font {
            font-family: 'JetBrains Mono', monospace;
        }
        /* Custom scrollbar for history/display */
        .custom-scroll::-webkit-scrollbar {
            height: 4px;
            width: 4px;
        }
        .custom-scroll::-webkit-scrollbar-thumb {
            background: rgba(255, 255, 255, 0.2);
            border-radius: 4px;
        }
        .glass-container {
            background: rgba(15, 23, 42, 0.75);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            border: 1px solid rgba(255, 255, 255, 0.12);
            box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
        }
        .calc-btn {
            transition: all 0.15s ease-in-out;
            user-select: none;
            -webkit-tap-highlight-color: transparent;
        }
        .calc-btn:active {
            transform: scale(0.94);
        }
        /* Glow effect on hover */
        .btn-op:hover {
            box-shadow: 0 0 12px rgba(139, 92, 246, 0.4);
        }
        .btn-sci:hover {
            box-shadow: 0 0 10px rgba(59, 130, 246, 0.3);
        }
        .btn-num:hover {
            box-shadow: 0 0 10px rgba(255, 255, 255, 0.1);
        }