:root {
    --primary-color: #3f51b5;
    --accent-color: #7c4dff;
    --text-color: #212121;
    --bg-color: #ffffff;
    --sidebar-bg: #f5f5f5;
    --border-color: #e0e0e0;
    --code-bg: #f5f5f5;
    --header-height: 60px;
    --sidebar-width: 280px;
    --tab-active-border: #3f51b5;
}

[data-theme="dark"] {
    --primary-color: #5c6bc0;
    --accent-color: #b388ff;
    --text-color: #e0e0e0;
    --bg-color: #121212;
    --sidebar-bg: #1e1e1e;
    --border-color: #333333;
    --code-bg: #2d2d2d;
    --tab-active-border: #5c6bc0;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body {
    font-family: 'Roboto', -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    color: var(--text-color);
    background-color: var(--bg-color);
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    padding: 0 20px;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.header-content {
    display: flex;
    justify-content: space-between;
    width: 100%;
    align-items: center;
}

.logo { font-size: 1.2rem; font-weight: 700; text-decoration: none; color: white; }
.theme-toggle { background: none; border: none; color: white; cursor: pointer; font-size: 1.2rem; }

.container {
    display: flex;
    margin-top: var(--header-height);
    min-height: calc(100vh - var(--header-height));
}

.sidebar {
    width: var(--sidebar-width);
    background-color: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    padding: 20px 0;
    position: fixed;
    height: 100%;
    overflow-y: auto;
    transition: transform 0.3s;
}

.nav-item { display: block; padding: 10px 20px; color: var(--text-color); text-decoration: none; font-size: 0.95rem; }
.nav-item:hover { background-color: rgba(0,0,0,0.05); color: var(--primary-color); }
.nav-item.active { background-color: rgba(63, 81, 181, 0.1); color: var(--primary-color); font-weight: 500; border-right: 3px solid var(--primary-color); }
.nav-group { padding: 10px 20px; font-weight: 700; color: var(--text-color); opacity: 0.7; font-size: 0.85rem; text-transform: uppercase; margin-top: 15px; }

.main-content {
    margin-left: var(--sidebar-width);
    padding: 40px;
    max-width: 900px;
    width: 100%;
}

h1 { font-size: 2.5rem; margin-bottom: 1rem; color: var(--primary-color); }
h2 { font-size: 1.8rem; margin-top: 2.5rem; margin-bottom: 1rem; border-bottom: 1px solid var(--border-color); padding-bottom: 0.5rem; }
h3 { font-size: 1.4rem; margin-top: 2rem; margin-bottom: 0.8rem; }
p { margin-bottom: 1rem; }
a { color: var(--primary-color); text-decoration: none; }
a:hover { text-decoration: underline; }

pre {
    background-color: var(--code-bg);
    padding: 15px;
    border-radius: 4px;
    overflow-x: auto;
    margin: 1.5rem 0;
    border: 1px solid var(--border-color);
}
code { font-family: 'Fira Code', 'Consolas', monospace; font-size: 0.9em; }
p code { background-color: var(--code-bg); padding: 2px 5px; border-radius: 3px; }

table { width: 100%; border-collapse: collapse; margin: 1.5rem 0; }
th, td { padding: 12px; border: 1px solid var(--border-color); text-align: left; }
th { background-color: var(--sidebar-bg); }

blockquote {
    border-left: 4px solid var(--primary-color);
    padding-left: 1rem;
    margin: 1.5rem 0;
    color: var(--text-color);
    background-color: rgba(63, 81, 181, 0.05);
    padding: 1rem;
    border-radius: 0 4px 4px 0;
}

@media (max-width: 768px) {
    .sidebar { transform: translateX(-100%); z-index: 999; }
    .sidebar.open { transform: translateX(0); }
    .main-content { margin-left: 0; padding: 20px; }
    .menu-toggle { display: block; }
}
.menu-toggle { display: none; background: none; border: none; color: white; font-size: 1.5rem; cursor: pointer; margin-right: 15px; }