@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');
        body {
            font-family: 'Inter', sans-serif;
        }
        .calc-btn {
            transition: all 0.15s ease;
            user-select: none;
        }
        .calc-btn:active {
            transform: scale(0.95);
        }
        .scientific-mode {
            animation: slideIn 0.3s ease-out;
        }
        @keyframes slideIn {
            from { opacity: 0; transform: translateY(-10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        .memory-indicator {
            animation: pulse 0.5s ease-in-out;
        }
        @keyframes pulse {
            0%, 100% { opacity: 1; }
            50% { opacity: 0.5; }
        }