body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background: #f4f4f4;
    color: #333;
}

.container {
    width: 80%;
    margin: auto;
    overflow: hidden;
    padding: 0 20px;
}

header {
    background: #333;
    color: #fff;
    padding-top: 30px;
    min-height: 70px;
    border-bottom: #0779e4 3px solid;
    text-align: center;
}

header h1 {
    margin: 0;
    font-size: 2.5em;
}

header p {
    font-size: 1.2em;
}

main {
    padding: 20px 0;
}

section {
    background: #fff;
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 5px;
}

.content-page {
    background: #fff;
    padding: 30px;
    border-radius: 5px;
}

.content-page h2 {
    border-bottom: 2px solid #0779e4;
    padding-bottom: 10px;
    margin-top: 40px;
}

.content-page h3 {
    margin-top: 30px;
}

.toc {
    background: #eef;
    border-left: 5px solid #0779e4;
    padding: 15px;
    margin: 20px 0;
}

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

.toc ul li {
    margin-bottom: 5px;
}

.toc a {
    text-decoration: none;
    color: #333;
}

.toc a:hover {
    color: #0779e4;
}

footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 30px 0;
    margin-top: 30px;
}

footer a {
    color: #fff;
    text-decoration: none;
}

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

a {
    color: #0779e4;
}