:root {
    --bg-body: #1b1e2b;
    --bg-panel: #262a3b;
    --bg-panel-alt: #2f3349;
    --bg-header: #363b52;
    --border-color: #3f4459;
    --accent: #5b7fdb;
    --accent-dark: #4a68b8;
    --text-main: #e8e9ee;
    --text-muted: #a9adc1;
    --danger: #e57373;
    --success: #6fcf97;
    --radius: 6px;
}

* { box-sizing: border-box; }

body {
    margin: 0;
    background: var(--bg-body);
    color: var(--text-main);
    font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
    line-height: 1.6;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

.site-header {
    background: var(--bg-header);
    text-align: center;
    padding: 2.5rem 1rem 1.5rem;
}

.site-header h1 { margin: 0; letter-spacing: 0.04em; }
.site-header h1 a { color: #fff; }
.site-header .tagline { margin: 0.5rem 0 0; color: var(--text-muted); }

.accent-line {
    height: 3px;
    background: var(--accent);
}

.site-nav {
    background: var(--bg-panel-alt);
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    padding: 1rem;
}

.nav-btn {
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.5rem 1rem;
    color: var(--text-main);
    font-weight: 500;
}

.nav-btn:hover {
    border-color: var(--accent);
    text-decoration: none;
    background: rgba(91, 127, 219, 0.12);
}

.layout {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.25rem;
    display: flex;
    align-items: flex-start;
    gap: 2rem;
}

.sidebar {
    width: 260px;
    flex-shrink: 0;
    position: sticky;
    top: 1.5rem;
    background: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.1rem;
    margin-top: 2rem;
}

.sidebar-title {
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.sidebar-empty { color: var(--text-muted); font-size: 0.9rem; }

.tree-category { margin-bottom: 0.4rem; }
.tree-category summary {
    cursor: pointer;
    font-weight: 600;
    padding: 0.35rem 0.25rem;
    border-radius: 4px;
    list-style: none;
}
.tree-category summary::-webkit-details-marker { display: none; }
.tree-category summary::before { content: '▸ '; color: var(--text-muted); }
.tree-category[open] summary::before { content: '▾ '; }
.tree-category summary:hover { background: rgba(91, 127, 219, 0.12); }

.tree-pages {
    list-style: none;
    margin: 0.2rem 0 0.6rem;
    padding-left: 1.1rem;
    display: grid;
    gap: 0.15rem;
}

.tree-pages a {
    display: block;
    color: var(--text-muted);
    padding: 0.3rem 0.5rem;
    border-radius: 4px;
    font-size: 0.92rem;
}
.tree-pages a:hover { color: var(--text-main); background: rgba(91, 127, 219, 0.12); text-decoration: none; }
.tree-pages a.active { color: #fff; background: var(--accent); }

.tree-subcategories {
    padding-left: 0.9rem;
    margin: 0.2rem 0 0.4rem;
    border-left: 1px solid var(--border-color);
}

.container {
    flex: 1;
    min-width: 0;
    max-width: 800px;
    margin: 0;
    padding: 2rem 0 4rem;
}

@media (max-width: 760px) {
    .layout { flex-direction: column; }
    .sidebar { position: static; width: 100%; margin-top: 1.5rem; }
    .container { max-width: none; padding: 1.5rem 0 3rem; }
}

.section-heading {
    display: inline-block;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.75rem 1.25rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    margin-bottom: 1.25rem;
}

.panel {
    background: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.category-group { margin-bottom: 2rem; }
.category-group h2 { text-transform: uppercase; font-size: 1rem; letter-spacing: 0.04em; color: var(--text-muted); }

.page-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 0.75rem; }
.page-list li {
    background: var(--bg-panel);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 0.9rem 1.1rem;
}
.page-list .meta { color: var(--text-muted); font-size: 0.85rem; }

form { display: flex; flex-direction: column; gap: 1rem; max-width: 520px; }
form.wide { max-width: none; }

label { font-weight: 600; font-size: 0.9rem; }

input[type=text], input[type=password], input[type=search], select, textarea {
    background: var(--bg-panel-alt);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    color: var(--text-main);
    padding: 0.65rem 0.8rem;
    font-family: inherit;
    font-size: 1rem;
}

textarea { min-height: 400px; font-family: 'JetBrains Mono', ui-monospace, monospace; resize: vertical; }

input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--accent);
}

button, .btn {
    background: var(--accent);
    border: 1px solid var(--accent-dark);
    color: #fff;
    border-radius: var(--radius);
    padding: 0.65rem 1.2rem;
    font-weight: 600;
    cursor: pointer;
    font-size: 1rem;
    display: inline-block;
    width: fit-content;
}

button:hover, .btn:hover { background: var(--accent-dark); text-decoration: none; }

.btn-danger { background: transparent; border-color: var(--danger); color: var(--danger); }
.btn-danger:hover { background: var(--danger); color: #fff; }

.btn-secondary { background: transparent; border-color: var(--border-color); color: var(--text-main); }
.btn-secondary:hover { background: var(--bg-panel-alt); }

.actions { display: flex; gap: 0.75rem; flex-wrap: wrap; margin-top: 1rem; }

.flash {
    border-radius: var(--radius);
    padding: 0.85rem 1.1rem;
    margin-bottom: 1.25rem;
    border: 1px solid;
}
.flash-success { background: rgba(111, 207, 151, 0.12); border-color: var(--success); color: var(--success); }
.flash-error { background: rgba(229, 115, 115, 0.12); border-color: var(--danger); color: var(--danger); }

.markdown-body h1, .markdown-body h2, .markdown-body h3 { color: #fff; }
.markdown-body pre {
    background: #14161f;
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1rem;
    overflow-x: auto;
}
.markdown-body code {
    background: #14161f;
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.9em;
}
.markdown-body pre code { background: none; padding: 0; }
.markdown-body blockquote {
    border-left: 3px solid var(--accent);
    margin-left: 0;
    padding-left: 1rem;
    color: var(--text-muted);
}
.markdown-body table { border-collapse: collapse; width: 100%; }
.markdown-body th, .markdown-body td { border: 1px solid var(--border-color); padding: 0.5rem 0.75rem; }
.markdown-body img { max-width: 100%; border-radius: var(--radius); cursor: zoom-in; }

.page-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1.5rem;
}
.page-header .meta { color: var(--text-muted); font-size: 0.9rem; }

.site-footer {
    text-align: center;
    color: var(--text-muted);
    padding: 2rem 1rem;
    border-top: 1px solid var(--border-color);
}

.lightbox-overlay {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 1.5rem 7rem;
    background: rgba(10, 12, 20, 0.9);
    cursor: zoom-out;
}
.lightbox-overlay[hidden] { display: none; }
.lightbox-overlay #lightbox-image {
    max-width: 100%;
    max-height: calc(100vh - 9rem);
    border-radius: var(--radius);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
    cursor: zoom-out;
}

.lightbox-nav {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid var(--border-color);
    color: #fff;
    font-size: 1.1rem;
    line-height: 1;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
}
.lightbox-nav:hover { background: rgba(255, 255, 255, 0.18); }
.lightbox-nav[hidden] { display: none; }
.lightbox-prev { left: 1rem; }
.lightbox-next { right: 1rem; }

.lightbox-strip {
    position: absolute;
    left: 50%;
    bottom: 1.5rem;
    transform: translateX(-50%);
    display: flex;
    gap: 0.5rem;
    max-width: calc(100% - 3rem);
    padding: 0.5rem;
    overflow-x: auto;
    cursor: default;
}
.lightbox-strip img {
    width: 4rem;
    height: 4rem;
    object-fit: cover;
    border-radius: 4px;
    border: 2px solid transparent;
    opacity: 0.55;
    cursor: pointer;
    flex-shrink: 0;
}
.lightbox-strip img:hover { opacity: 0.85; }
.lightbox-strip img.active { opacity: 1; border-color: var(--accent); }

.empty-state { color: var(--text-muted); text-align: center; padding: 2rem; }