body {
    font-family: Arial, sans-serif;
    background-color: #f0f0f0;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.container {
    background-color: #ffffff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 400px;
    text-align: center;
}

h1 {
    font-size: 24px;
    margin-bottom: 20px;
}

.mode-switch {
    display: flex;
    justify-content: space-around;
    margin-bottom: 20px;
}

.calculator {
    margin-top: 20px;
}

label {
    display: block;
    margin-bottom: 10px;
}

input[type="number"] {
    width: calc(100% - 22px);
    padding: 10px;
    font-size: 16px;
    margin-bottom: 20px;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    background-color: #0070ba;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

button:hover {
    background-color: #005fa3;
}

.result {
    margin-top: 20px;
    font-size: 18px;
    font-weight: bold;
}