body {
    font-family: Arial, sans-serif;
    color: #333;
    background-color: #FFF;
    font-size: 1.5em;
    margin: 0;
    height: 100vh;
    
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
}

body > div {
    margin: 15px 15px;
}

#target-div {
    align-items: center;
    margin-bottom: 50px;
    font-size: 5rem;
    font-weight: bold;
}

#target-binary-div {
    display: none; /* Hidden by default */
    font-size: 3rem;
}

button {
    background-color: #7B68EE;
    color: #FFF;
    padding: 15px 30px;
    border: none;
    border-radius: 30px;
    font-size: 1.2rem;
    font-weight: bold;
    cursor: pointer;
    transition: 0.2s ease;
}

button:hover {
    background-color: #6A5ACD;
    transform: scale(1.05);
}

button:active {
    transform: scale(1);
}

#board-div {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
}

#board-div > div {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
    font-size: 2rem;
    font-weight: bold;
}

#result-number, .number {
    background-color: #FFF;
    border: 2px solid #333;
    border-radius: 5px;
    padding: 5px;
    width: 55px;
    text-align: center;
}

.number {
    background-color: #CCC;
}

.div-operator {
    margin-top: 5px;
}

.toggle-number {
    width: 20px;
    height: 20px;
    margin-top: 10px;
    border: 2px solid #333;
}