style.css

body {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin:0;
    padding: 0;
    
    font-family: Arial, sans-serif;
    background-color: black;
}
.container {
    text-align: center;
}

.heading {
    font-size: 28px;
    margin-bottom: 20px;
    color: white;
}

.calculator {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    grid-gap: 8px;
    max-width: 300px;
    padding: 20px;
    background-color: #eaeaea;
    border-radius: 8px;
    box-shadow: 0px 2px 5px rgba(0, 0, 0, 0.2);
}

.display {
    grid-column: 1 / span 4;
    text-align: right;
    height: 36px;
    font-size: 36px;
    padding: 10px;
    background-color: #fff;
    border: 1px solid #ccc;
    border-radius: 4px;
    box-shadow: 0px 1px 3px rgba(0, 0, 0, 0.1);
}

button {
    font-size: 24px;
    padding: 10px;
    border: 1px solid #ccc;
    background-color: #fff;
    color: #444;
    cursor: pointer;
    border-radius: 4px;
    transition: background-color 0.2s ease;

}

button:hover {
    background-color: #f0f0f0;
}

button.operator {
    background-color: #ff9a00;
    color: #fff;
    
}

button.operator:hover {
    background-color: #ffa726;
}

button.equals {
    background-color: #4285f4;
    color: #fff;
}

button.equals:hover {
    background-color: #05a640;
}

button.clear {
    grid-column: 1 / span 2;
    width: 145px;
    
}

button.clear:hover {
    background-color: #ff5f5f;
}

button.decimal {
    background-color: #888;
    color: #fff;
}

button.decimal:hover {
    background-color: #999;
}