* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Open Sans', sans-serif;
    color: #333;
    font-size: 18px;
    line-height: 1.6;
    background: linear-gradient(135deg, #f4f4f4, #e0e0e0);
}

h1, h2, h3 {
    margin-bottom: 0.5em;
    margin-top: 0;
    color: #333;
}

a {
    color: #007acc;
    text-decoration: none;
    transition: color 0.3s ease, text-decoration 0.3s ease;
}

a:hover {
    color: #005fa3;
    text-decoration: underline;
}

.page-wrapper {
    display: flex;
    flex-wrap: wrap;
    margin: 0 auto;
    max-width: 1200px;
    padding: 20px;
}

.intro {
    background: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 12px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.intro h1 {
    font-size: 2.5em;
    color: #333;
    margin-bottom: 10px;
    font-weight: 700;
    line-height: 1.2;
}

.intro h2 {
    font-size: 1.5em;
    color: #666;
    margin-top: 0;
    font-weight: 400;
}

.intro p {
    font-size: 1.2em;
    line-height: 1.6;
    color: #666;
}

.intro a {
    color: #007acc;
    font-weight: 500;
}

.intro a:hover {
    color: #005fa3;
}

.main {
    flex: 3;
    padding: 20px;
    background: #fff;
    border-radius: 12px;
    border: 1px solid #ddd;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

.main h3 {
    margin-top: 0;
    color: #444;
    margin-bottom: 15px;
    font-weight: 600;
}

.summary, .preamble {
    margin-bottom: 20px;
}

.summary p, .preamble p {
    line-height: 1.8;
}

.summary a, .preamble a {
    color: #007acc;
}

.summary a:hover, .preamble a:hover {
    color: #005fa3;
}

.sidebar {
    flex: 1;
    padding: 20px;
    background: #333;
    color: #fff;
    border-radius: 12px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    margin-left: 20px;
    display: grid;
    grid-template-columns: 1fr;
}

.sidebar h3 {
    color: #fff;
    border-bottom: 2px solid #a5a5a5;
    margin-bottom: 15px;
    padding-bottom: 10px;
    margin-top: 0;
}

.sidebar a {
    color: #fff;
    transition: color 0.3s ease;
}

.sidebar a:hover {
    color: #007acc;
}

.sidebar ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.sidebar ul li {
    margin-bottom: 10px;
    transition: background 0.3s ease;
}

.sidebar ul li:hover {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 4px;
}

.logo {
    max-width: 150px;
    margin-bottom: 20px;
    display: block;
    margin-left: auto;
    margin-right: auto;
}

footer {
    display: flex;
    justify-content: center;
    padding: 20px;
    background: #333;
    color: #fff;
    margin-top: 20px;
    border-radius: 12px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

footer a {
    color: #fff;
    margin: 0 10px;
    transition: color 0.3s ease;
}

footer a:hover {
    color: #007acc;
}

@media (max-width: 768px) {
    .page-wrapper {
        flex-direction: column;
    }

    .sidebar {
        margin-left: 0;
        margin-top: 20px;
    }
    .intro {
        padding: 20px;
    }

    .intro h1 {
        font-size: 2em;
    }

    .intro p {
        font-size: 1em;
    }
}