* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "Poppins", sans-serif;
    background: linear-gradient(135deg, #f9f7fe 0%, plum 100%);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
}

.calculator-container {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.calculator {
    background: white;
    border-radius: 20px;
    padding: 30px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 450px;
}

.calculator h2 {
    text-align: center;
    color: #333;
    margin-bottom: 20px;
    font-size: 28px;
    font-family: "Playfair Display", serif;
    font-weight: bold;
}

#display {
    width: 100%;
    height: 70px;
    border: none;
    background: #f5f5f5;
    border-radius: 10px;
    text-align: right;
    font-size: 32px;
    padding: 15px;
    margin-bottom: 20px;
    font-weight: bold;
    color: #333;
    outline: none;
    font-family: "Poppins", sans-serif;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}

.btn {
    padding: 20px;
    font-size: 20px;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: bold;
    font-family: "Poppins", sans-serif;
}

.btn:hover {
    transform: translateY(-2px);
    filter: brightness(0.95);
}

.btn:active {
    transform: translateY(0);
}

.number {
    background: #f0f0f0;
    color: #333;
}

.operator {
    background: plum;
    color: white;
}

.clear {
    background: #ff6b6b;
    color: white;
}

.delete {
    background: #ffa502;
    color: white;
}

.equals {
    background: #2ed573;
    color: white;
    grid-column: span 1;
}

.zero {
    grid-column: span 2;
}

/* Mobile Responsive */
@media (max-width: 500px) {
    .calculator {
        padding: 20px;
        max-width: 350px;
    }

    .calculator h2 {
        font-size: 24px;
        margin-bottom: 15px;
    }

    .btn {
        padding: 15px;
        font-size: 18px;
    }

    #display {
        font-size: 28px;
        height: 60px;
        padding: 12px;
    }

    .buttons {
        gap: 10px;
    }
}

@media (max-width: 380px) {
    .calculator {
        padding: 15px;
        max-width: 300px;
    }

    .calculator h2 {
        font-size: 20px;
    }

    .btn {
        padding: 12px;
        font-size: 16px;
    }

    #display {
        font-size: 24px;
        height: 50px;
        padding: 10px;
    }

    .buttons {
        gap: 8px;
    }
}