body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f8f9fa;
    color: #495057;
}
header {
    background-color: #212529;
    color: #ffffff;
    padding: 0;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}
header h1 {
    text-align: center;
    margin: 0;
    padding: 20px 0 10px 0;
    font-size: 2.5em;
    font-weight: 300;
    letter-spacing: 2px;
}
nav {
    background-color: #343a40;
}
nav ul {
    padding: 0;
    list-style: none;
    text-align: center;
    margin: 0;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
}
nav li {
    display: block;
}
nav a {
    color: #f8f9fa;
    text-decoration: none;
    font-size: 15px;
    padding: 15px 20px;
    display: block;
    transition: background-color 0.3s ease;
}
nav a:hover {
    background-color: #495057;
    color: #fff;
}
main {
    padding: 40px;
    background: white;
    margin: 40px auto;
    max-width: 900px;
    box-shadow: 0 5px 15px rgba(0,0,0,0.05);
    border-radius: 8px;
}
img {
    max-width: 100%;
    height: auto;
    border-radius: 4px;
    margin: 10px 0;
}
h2, h3, h4 {
    color: #212529;
}
a {
    color: #007bff;
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}
table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}
table, th, td {
    border: 1px solid #dee2e6;
}
th, td {
    padding: 12px;
    text-align: left;
}
th {
    background-color: #f8f9fa;
}