body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
    color: #333;
}

header {
    background: #333;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}

header h1 {
    margin: 0;
}

nav ul {
    padding: 0;
    list-style: none;
    display: flex;
    justify-content: center;
}

nav ul li {
    margin: 0 1rem;
}

nav a {
    color: #fff;
    text-decoration: none;
    font-weight: bold;
}

main {
    padding: 2rem;
    max-width: 960px;
    margin: auto;
}

section {
    background: #fff;
    padding: 2rem;
    margin-bottom: 2rem;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}

h2, h3 {
    color: #555;
    border-bottom: 2px solid #eee;
    padding-bottom: 0.5rem;
}

.calculator-container {
    padding: 1.5rem;
    background: #f9f9f9;
    border-radius: 8px;
}

form label, form input, form button {
    display: block;
    width: 100%;
    margin-bottom: 1rem;
}

form input[type="number"], form input[type="date"] {
    padding: 0.5rem;
    border: 1px solid #ccc;
    border-radius: 4px;
}

form button {
    background: #007bff;
    color: #fff;
    border: none;
    padding: 0.75rem;
    cursor: pointer;
    border-radius: 4px;
}

form button:hover {
    background: #0056b3;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

table th, table td {
    border: 1px solid #ddd;
    padding: 8px;
    text-align: left;
}

table th {
    background-color: #f2f2f2;
}

.button {
    display: inline-block;
    background-color: #28a745;
    color: white;
    padding: 10px 20px;
    text-align: center;
    text-decoration: none;
    border-radius: 5px;
    margin-top: 1rem;
}

.button:hover {
    background-color: #218838;
}

article img {
    max-width: 100%;
    height: auto;
    border-radius: 8px;
    margin: 1rem 0;
}

.author-profile {
    text-align: center;
}

.author-photo {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: 1rem;
}

footer {
    text-align: center;
    padding: 1rem;
    background: #333;
    color: #fff;
    margin-top: 2rem;
}