:root {
    --bg-color: #fafafa;
    --text-color: #333;
    --header-bg: #4CAF50;
    --aside-bg: #f0f0f0;
    --footer-bg: #4CAF50;
    --tip-bg: #ffffff;
    --tip-border: #66bb6a;
    --code-bg: #2d2d2d;
    --code-text: #f8f8f2;
}
[data-theme="dark"] {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --header-bg: #1e1e1e;
    --aside-bg: #1b1b1b;
    --footer-bg: #1e1e1e;
    --tip-bg: #1e1e1e;
    --tip-border: #66bb6a;
    --code-bg: #2d2d2d;
    --code-text: #f8f8f2;
}
body {
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
header, footer {
    background-color: var(--header-bg);
    color: white;
    padding: 1em 2em;
    text-align: center;
}
.container { display: flex; }
aside {
    width: 250px;
    background: var(--aside-bg);
    padding: 1em;
    height: 100vh;
    overflow-y: auto;
    box-shadow: 2px 0 5px rgba(0,0,0,0.1);
}
aside ul { list-style: none; padding: 0; }
aside li { margin: 0.5em 0; }
aside a { text-decoration: none; color: var(--text-color); font-weight: bold; }
aside a:hover { color: #4CAF50; }
main { flex: 1; padding: 2em; }
nav {
    background: #eee;
    padding: 0.5em 2em;
    border-bottom: 1px solid #ddd;
    display: flex;
    align-items: center;
}
nav a { margin-right: 1em; color: #4CAF50; text-decoration: none; font-weight: 600; }
nav a:hover { text-decoration: underline; }
nav #theme-toggle {
    margin-left: auto;
    background: transparent;
    border: none;
    font-size: 1.2em;
    cursor: pointer;
}
pre {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 1em;
    border-radius: 4px;
    overflow-x: auto;
}
code { font-family: Consolas, monospace; background: #f4f4f4; padding: 2px 4px; border-radius: 3px; }
.tip {
    background: var(--tip-bg);
    border-left: 5px solid var(--tip-border);
    padding: 1em;
    margin: 1em 0;
    border-radius: 4px;
}
footer {
    background-color: var(--footer-bg);
}