/* styles.css */
body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #2c3e50;
    padding: 20px;
    font-family: 'Segoe UI', Arial, sans-serif;
}

.calculator {
    background: #34495e;
    width: 100%;
    max-width: 400px;
    min-height: 100%;
    padding: 15px;
    border-radius: 12px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.3);
}

.display {
    background: #ecf0f1;
    border-radius: 8px;
    height: 120px;
    font-size: 3.5rem;
    text-align: right;
    padding: 20px;
    margin-bottom: 20px;
    overflow: auto;
    display: flex;
    align-items: center;
    justify-content: flex-end;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 10px;
    grid-auto-rows: 1fr;
}

.button {
    background: #95a5a6;
    border: none;
    border-radius: 8px;
    font-size: 1.6rem;
    cursor: pointer;
    transition: all 0.2s;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px 0;
}

.button.operator {
    background: #e67e22;
}

.button.equal {
    background: #2ecc71;
}

.button.special {
    background: #e74c3c;
}

.button:active {
    transform: scale(0.95);
}

/* মোবাইল রেস্পন্সিভ */
@media (max-width: 768px) {
    .calculator {
        min-height: 100%;
        padding: 10px;
    }

    .display {
        height: 100px;
        font-size: 2.8rem !important;
        padding: 15px !important;
    }

    .buttons {
        gap: 8px;
    }

    .button {
        font-size: 1.4rem !important;
        padding: 15px 0;
    }
}

@media (max-width: 400px) {
    .display {
        font-size: 2.2rem !important;
    }
    
    .button {
        padding: 12px 0;
    }
}