:root {
    --primary: #1e88e5;
    --secondary: #26a69a;
    --dark: #263238;
    --light: #eceff1;
    --accent: #ff8f00;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    color: var(--dark);
    line-height: 1.6;
    background-color: #f5f5f5;
}

.container {
    max-width: 1000px;
    margin: 120px auto 50px;
    padding: 40px;
    background: white;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

header {
    background-color: var(--light);
    padding: 20px 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
    height: 44px;
}

.logo img {
    height: 100%;
}

nav ul {
    display: flex;
    list-style: none;
}

nav ul li {
    margin-left: 30px;
}

nav ul li a {
    text-decoration: none;
    color: var(--dark);
    font-weight: 500;
    transition: color 0.3s;
}

nav ul li a:hover {
    color: var(--primary);
}

h1 {
    font-size: 32px;
    margin-bottom: 30px;
    color: var(--primary);
    text-align: center;
}

h2 {
    font-size: 24px;
    margin-top: 40px;
    margin-bottom: 15px;
    color: var(--dark);
    border-bottom: 2px solid var(--light);
    padding-bottom: 10px;
}

h3 {
    font-size: 20px;
    margin-top: 25px;
    margin-bottom: 10px;
    color: var(--dark);
}

p {
    margin-bottom: 15px;
}

ul, ol {
    margin-left: 20px;
    margin-bottom: 20px;
}

li {
    margin-bottom: 8px;
}

.last-updated {
    text-align: center;
    font-style: italic;
    color: #78909c;
    margin-bottom: 30px;
}

a {
    color: var(--primary);
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--primary);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    text-decoration: none;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    transition: background-color 0.3s;
}

.back-to-top:hover {
    background-color: #1565c0;
    text-decoration: none;
}

footer {
    background-color: var(--dark);
    color: white;
    padding: 30px 0;
    text-align: center;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.copyright {
    color: #b0bec5;
    font-size: 14px;
}

.toc {
    background-color: var(--light);
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 30px;
}

.toc h3 {
    margin-top: 0;
}

.toc ul {
    margin-bottom: 0;
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        text-align: center;
    }

    nav ul {
        margin-top: 15px;
        justify-content: center;
    }

    nav ul li {
        margin: 0 10px;
    }

    .container {
        margin: 100px 15px 30px;
        padding: 20px;
    }

    h1 {
        font-size: 26px;
    }

    h2 {
        font-size: 22px;
    }
}