* {
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    box-sizing: border-box;
}

body, html {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: #f4f4f9; /* Light grey background */
}

.container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.calculator {
    background: #333333; /* White background for the calculator */
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1); /* Subtle shadow for 3D effect */
    width: 100%;
    max-width: 360px;
}

.calculator form .display input {
    width: 100%;
    height: 60px;
    font-size: 2rem;
    text-align: right;
    margin-bottom: 20px;
    background: #e8e8e8; /* Light gray for input display */
    color: #333; /* Darker text for better readability */
    border: none;
    outline: none;
    border-radius: 5px; /* Rounded corners for the display */
}

.calculator form .button-row {
    display: flex;
    justify-content: space-between;
}

.calculator form .button {
    flex: 1 0 21%;
    margin: 3px;
    font-size: 1.5rem;
    height: 60px;
    border: none;
    outline: none;
    cursor: pointer;
    border-radius: 10px;
    color: white;
    box-shadow: 2px 2px 10px rgba(0, 0, 0, 0.2);
}

/* Style for number buttons */
.calculator form .number {
    background: #7dbcf9; /* Light blue */
}

/* Style for operator buttons */
.calculator form .operator {
    background: #ff927b; /* Soft coral */
}

/* Style for function buttons like clear, memory */
.calculator form .memory, .clear, .delete, .trig {
    background: #facc6b; /* Yellow for visibility */
}

/* Equal button should stand out */
.calculator form .equal {
    background: #4caf50; /* Green */
    color: white;
}

/* Change color for sin, cos, tan buttons */
.calculator form .trig {
    background: #facc6b; /* Yellow */
}

/* Change color for dot button */
.calculator form .decimal {
    background: #7dbcf9; /* Light blue */
}

/* Responsive adjustments */
@media (max-width: 600px) {
    .calculator {
        max-width: 95%;
        padding: 15px;
    }

    .calculator form .button {
        font-size: 1.2rem;
        height: 50px;
    }

    .calculator form .display input {
        font-size: 1.5rem;
        height: 50px;
    }
}