:root {
    --bg-color: #ffffff;
    --text-color: #333;
    --header-bg: #4da6ff;
    --header-text: #fff;
    --nav-bg: #66b3ff;
    --nav-hover: #3399ff;
    --footer-bg: #4da6ff;
    --footer-text: #fff;
}
[data-theme="dark"] {
    --bg-color: #1e1e1e;
    --text-color: #ccc;
    --header-bg: #111;
    --header-text: #eee;
    --nav-bg: #222;
    --nav-hover: #333;
    --footer-bg: #000;
    --footer-text: #777;
}
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    scroll-behavior: smooth;
}
body {
    font-family: Arial, sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    transition: background 0.3s, color 0.3s;
    line-height: 1.6;
}
header {
    background: var(--header-bg);
    color: var(--header-text);
    padding: 20px;
    text-align: center;
}
nav {
    background: var(--nav-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    position: relative;
}
nav a, nav .dropdown > a {
    color: #fff;
    padding: 12px 18px;
    text-decoration: none;
    transition: background 0.3s;
    display: inline-block;
    font-weight: bold;
}
nav a{
	padding: 6px 12px;
}
nav a:hover, nav .dropdown > a:hover {
    background: var(--nav-hover);
}
nav .dropdown {
    position: relative;
}
nav .dropdown-content {
    display: none;
    position: absolute;
    background-color: var(--nav-bg);
    min-width: 160px;
    box-shadow: 0px 8px 16px rgba(0,0,0,0.2);
    z-index: 1;
}
nav .dropdown-content a {
    padding: 12px 16px;
    display: block;
    color: #fff;
}
nav .dropdown-content a:hover {
    background: var(--nav-hover);
}
nav .dropdown:hover .dropdown-content {
    display: block;
}

h2,h3,h4,h5,h6{
	padding-top:10px;
	padding-bottom:10px;
	font-size: 25px;
}
.menu-toggle {
    display: none;
    background: var(--nav-bg);
    color: #fff;
    padding: 10px 20px;
    cursor: pointer;
    text-align: center;
    font-weight: bold;
}
@media (max-width: 600px) {
    nav {
        flex-direction: column;
        display: none;
    }
    nav.active {
        display: flex;
    }
    nav a, nav .dropdown {
        flex: 1 0 100%;
        text-align: center;
    }
    .menu-toggle {
        display: block;
    }
}
.container {
    max-width: 1000px;
    margin: 30px auto;
    padding: 20px;
    background: #ffffff;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}
#toc {
    background: #e6f2ff;
    padding: 10px;
    margin-bottom: 10px;
    border-radius: 8px;
    text-align: center;
}
#toc ul {
    list-style: none;
    padding: 0;
    display: inline-block;
    text-align: left;
}
#toc li {
    margin: 5px 0;
}
#toc a {
    color: #3399ff;
    text-decoration: none;
    font-weight: bold;
}
#toc a:hover {
    text-decoration: underline;
}
footer {
    background: var(--footer-bg);
    color: var(--footer-text);
    text-align: center;
    padding: 15px;
    margin-top: 30px;
}