body {
    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
    background-color: #f9fafb;
    color: #333;
    margin: 0;
    padding: 0;
    line-height: 1.6;
}

header, footer {
    background-color: #fff;
    color: #555;
    text-align: center;
    padding: 1em 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

nav {
    background-color: #ffffff;
    display: flex;
    justify-content: center;
    padding: 1em 0;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav a {
    color: #4a90e2;
    text-decoration: none;
    margin: 0 15px;
    font-weight: 600;
}

nav a:hover {
    text-decoration: underline;
}

.container {
    max-width: 960px;
    margin: 20px auto;
    padding: 0 20px;
}

h1, h2, h3 {
    font-weight: 600;
}

h1 {
    margin-top: 0;
}

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

table {
    width: 100%;
    border-collapse: collapse;
    margin: 1em 0;
}

td, th {
    border: 1px solid #ccc;
    padding: 10px;
    text-align: left;
}

button {
    background-color: #4a90e2;
    color: white;
    border: none;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
}

button:hover {
    background-color: #357ABD;
}

form {
    background: #fff;
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    max-width: 480px;
    margin: 1em auto;
}

input[type='text'], input[type='email'], input[type='number'] {
    width: 100%;
    padding: 10px;
    margin: 10px 0 20px 0;
    border: 1px solid #ccc;
    border-radius: 5px;
}

@media (max-width: 600px) {
    nav {
        flex-direction: column;
    }
    nav a {
        margin: 10px 0;
    }
}