@media (max-width: 400px) {
    .calculator {
        width: 100%;
        padding: 10px;
    }
    
    .function-buttons {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .scientific-buttons {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .btn {
        padding: 12px 0;
        font-size: 1rem;
    }
    
    .btn-function {
        font-size: 0.8rem;
        padding: 8px 0;
    }
    
    .btn-sci {
        font-size: 0.8rem;
        padding: 8px 0;
    }
}

@media (min-width: 768px) {
    .calculator {
        width: 400px;
    }
    
    .display-container {
        min-height: 100px;
    }
    
    .main-display {
        font-size: 2.5rem;
    }
}