body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    background-color: #f0f2f5;
}

.calculator-container {
    background: #ffffff;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    width: 100%;
    max-width: 400px;
    text-align: center;
}

h1 {
    color: #333;
    margin-bottom: 25px;
}

.input-group {
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.date-inputs {
    display: flex;
    align-items: center;
}

.date-inputs span {
    margin: 0 10px 0 5px;
    color: #555;
}

.date-inputs input:last-of-type + span {
    margin-right: 0;
}

.input-group label {
    font-weight: 500;
    color: #555;
    line-height: 1.4;
    text-align: center;
}

.input-group input[type="number"] {
    width: 60px;
    padding: 8px;
    border: 1px solid #ccc;
    border-radius: 5px;
    text-align: center;
    font-size: 16px;
}

.input-group input#days-to-add {
    width: 100px;
}

.input-group span {
    margin-left: 10px;
    font-weight: 500;
    color: #555;
}

button {
    width: 100%;
    padding: 12px;
    background-color: #007bff;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 18px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #0056b3;
}

.result-container {
    margin-top: 25px;
    padding: 15px;
    background-color: #f9f9f9;
    border: 1px solid #eee;
    border-radius: 5px;
}

.result-container h2 {
    font-size: 18px;
    color: #333;
    margin: 0 0 10px 0;
}

#result-date {
    font-size: 24px;
    font-weight: bold;
    color: #007bff;
    margin: 0;
}