body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background-color: #f2f2f2;
}

.calculator {
    background-color: #333;
    border-radius: 10px;
    box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.5);
    overflow: hidden;
    width: 500px;
    max-width: 100%;
    text-align: center;
}

.display {
    padding: 15px;
}

input[type="text"] {
    width: 100%;
    font-size: 20px;
    border: none;
    background: none;
    color: white;
    outline: none;
}

.buttons{
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    padding: 10px;
}

button{
    border: none;
    background: #555;
    color: white;
    font-size: 18px;
    padding: 8px;
    cursor: pointer;
    transition: background 0.2s;
}

button:hover {
    background: #777;
}

button.number, button.operation{
    grid-column: span 1;
}
button.number1{
    font-size: 1rem;
    font-weight: 800;
}
button.operation, button.conversion{
    background: #f44336;
}

button.conversion:hover,
 button.operation:hover
 {
    background: #ff6659;
}

#sizeConversionOption {
    width: 100%;
    padding: 10px;
    font-size: 16px;
    border: 1px solid #ccc;
    border-radius: 5px;
    background-color: #666;
    color: #fff;
    outline: none;
    cursor: pointer;
}

#sizeConversionOption option {
    background-color: #666;
    color: #fff;
    font-size: 16px;
}

#sizeConversionOption:hover {
    border-color: #555;
}

/* Style for when the dropdown is open */
#sizeConversionOption:focus {
    border-color: #555;
    box-shadow: 0 0 5px rgba(85, 85, 85, 0.5);
}