:root {
    --bg-color: #020618;
    --sidebar-bg: #1e293b;
    --text-main: #cad5e2;
    --accent-color: #38bdf8;
    --code-bg: #0f172a;
    --border-color: #334155;
    --content-color: #f1f5f9;
}

* {
    box-sizing: border-box;
}

body {
    font-family: Calibri, Roboto, Helvetica, Arial, sans-serif;
    margin: 0;
    display: flex;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.4;
    min-height: 100vh;
}

img {
    max-height: 320px;
}

nav {
    min-width: 230px;
    background: var(--sidebar-bg);
    border-right: 1px solid var(--border-color);
    height: 100vh;
    top: 0;
    position: sticky;
    padding: 1rem;
}

nav h2 {
    font-size: 1.2rem;
    color: var(--accent-color);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 1.2rem;
}

.nav-tree {
    list-style: none;
    padding: 0;
    margin: 0;
}

.nav-footer {
    position: absolute;
    bottom: 0.5rem;
    left: 0;
    width: 100%;
    text-align: center;
    font-size: 0.75rem;
    color: #475569;
    font-family: Consolas, monospace;
    font-size: 12px;
}

.category {
    margin-bottom: 0.25rem;
}

.category-toggle {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    width: 100%;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.45rem 0.5rem;
    border-radius: 4px;
    color: var(--accent-color);
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-family: inherit;
    transition: background 0.2s;
}

.category-toggle:hover {
    background: #27374d;
}

.category-icon {
    font-size: 0.7rem;
    opacity: 0.7;
}

.category-show {
    margin-left: auto;
    font-size: 0.65rem;
    transition: transform 0.25s ease;
    display: inline-block;
}

.category-toggle[aria-expanded="false"] .category-show {
    transform: rotate(-90deg);
}

.category-items {
    list-style: none;
    padding: 0 0 0 0.5rem;
    margin: 0 0 0.5rem 0;
    overflow: hidden;
    /* max-height: 500px; */
    /* open by default */
    opacity: 1;
    transition: max-height 0.3s ease, opacity 0.25s ease;
    border-left: 2px solid var(--border-color);
    /* margin-left: 0.6rem; */
}

.category-items li {
    margin-bottom: 3px;
}

.category-items a {
    color: #94a3b8;
    text-decoration: none;
    display: block;
    padding: 0.35rem 0.5rem;
    border-radius: 4px;
    transition: 0.2s;
    cursor: pointer;
    font-size: 0.9rem;
}

.category-items a:hover,
.category-items a.active {
    background: #334155;
    color: var(--accent-color);
}

nav h1,
nav h2,
nav h3 {
    color: var(--accent-color);
    margin-top: 2rem;
}

.repo {
    align-items: center;
    display: flex;
    text-decoration: none;
    color: var(--accent-color);
    gap: 0.25rem;
    font-size: 13px;
    width: fit-content;
    font-weight: bold;
    letter-spacing: 0.5px;
    padding: 2px;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    background: var(--sidebar-bg);
}

.repo span {
    color: var(--content-color);
    font-size: 13px;
    font-weight: bold;
    letter-spacing: 0.5px;
}

.repo:hover {
    background: #334155;
    color: var(--accent-color);
}

main {
    padding: 1rem 2rem;
    width: 100%;
    transition: opacity 0.3s ease;
    max-width: 1400px;
    margin-left: auto;
    margin-right: auto;
}

main h1,
main h2,
main h3 {
    color: var(--content-color);
}

h4 {
    color: #94a3b8;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

code {
    color: rgb(197, 200, 198);
    border-radius: 4px;
    font-family: Consolas, monospace;
    font-size: 12px;
}

pre {
    background: var(--code-bg);
    padding: 1rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    margin: 1.5rem 0;
    white-space: pre;
    overflow-x: auto;
    max-height: 300px;
    overflow-y: auto;
}

blockquote {
    margin: 1.5rem 0;
    padding: 1rem;
    background: #1e293b;
    border-left: 4px solid var(--accent-color);
    border-radius: 0 8px 8px 0;
}

blockquote p {
    margin: 0;
}

ul,
ol {
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0.5rem;
}

.fade-in {
    animation: fadeIn 0.4s ease forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(5px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@media (max-width: 780px) {
    body {
        flex-direction: column;
    }

    nav {
        width: 100%;
        height: auto;
        position: relative;
        padding: 1rem;
    }

    main {
        margin-left: 0;
        padding: 1.5rem;
    }

    img {
        max-width: 100%;
        height: auto;
    }
}