/* ===========================================================================
   Markdown Viewer — GitHub-like styling with light/dark themes.
   =========================================================================== */

:root {
  --sidebar-w: 300px;
  --toc-w: 240px;
  --header-h: 52px;
}

/* ---- Dark palette (default) ---- */
[data-theme="dark"] {
  --bg: #0d1117;
  --bg-elev: #161b22;
  --bg-inset: #010409;
  --border: #30363d;
  --border-muted: #21262d;
  --fg: #e6edf3;
  --fg-muted: #7d8590;
  --link: #2f81f7;
  --accent: #1f6feb;
  --hover: #1c2128;
  --selected: #1f6feb33;
  --code-bg: #161b22;
  --code-fg: #e6edf3;
  --table-alt: #161b22;
  --quote-border: #3b434b;
  --shadow: rgba(1, 4, 9, 0.6);
}

/* ---- Light palette ---- */
[data-theme="light"] {
  --bg: #ffffff;
  --bg-elev: #f6f8fa;
  --bg-inset: #f6f8fa;
  --border: #d0d7de;
  --border-muted: #d8dee4;
  --fg: #1f2328;
  --fg-muted: #656d76;
  --link: #0969da;
  --accent: #0969da;
  --hover: #eaeef2;
  --selected: #0969da1a;
  --code-bg: #f6f8fa;
  --code-fg: #1f2328;
  --table-alt: #f6f8fa;
  --quote-border: #d0d7de;
  --shadow: rgba(140, 149, 159, 0.2);
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
}

/* ---- Top bar ---- */
.topbar {
  flex: 0 0 var(--header-h);
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 0 12px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
  z-index: 50;
}
.topbar-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--fg);
  margin-left: 2px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.topbar-spacer { flex: 1 1 auto; }

.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--bg);
  color: var(--fg-muted);
  cursor: pointer;
  transition: background .15s, color .15s;
  flex: 0 0 auto;
}
.icon-btn:hover { background: var(--hover); color: var(--fg); }
.icon-btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

/* ---- Layout ---- */
.layout {
  display: grid;
  grid-template-columns: var(--col-sidebar, var(--sidebar-w)) minmax(0, 1fr) var(--col-toc, var(--toc-w));
  flex: 1 1 auto;
  min-height: 0;
}
html.is-sidebar-collapsed { --col-sidebar: 0px; }
html.is-toc-collapsed { --col-toc: 0px; }

.backdrop { display: none; }

/* ---- Sidebar ---- */
.sidebar {
  background: var(--bg-elev);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  min-height: 0;
  min-width: 0;
  overflow: hidden;
}

.sidebar-header {
  height: var(--header-h);
  flex: 0 0 var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 12px 0 16px;
  border-bottom: 1px solid var(--border);
}

.sidebar-title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--fg-muted);
}

[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

.tree-wrap {
  flex: 1 1 auto;
  overflow-y: auto;
  padding: 8px 8px 24px;
}

.tree-error, .tree-empty {
  color: var(--fg-muted);
  font-size: 13px;
  padding: 8px 12px;
}

/* ---- Tree ---- */
ul.tree { list-style: none; margin: 0; padding: 0; }
ul.tree ul.tree { padding-left: 14px; }

.folder > ul.tree { display: none; }
.folder.open > ul.tree { display: block; }

.folder-label, .file-link {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 14px;
  color: var(--fg);
  text-decoration: none;
  cursor: pointer;
  user-select: none;
  white-space: nowrap;
  overflow: hidden;
}
.folder-label:hover, .file-link:hover { background: var(--hover); }
.folder-label:focus-visible, .file-link:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

.folder-label .name, .file-link .name {
  overflow: hidden;
  text-overflow: ellipsis;
}

.chevron {
  flex: 0 0 12px;
  color: var(--fg-muted);
  transition: transform 0.15s ease;
}
.folder.open > .folder-label .chevron { transform: rotate(90deg); }

.icon-folder { color: #54aeff; flex: 0 0 16px; }
[data-theme="light"] .icon-folder { color: #54aeff; }
.icon-file { color: var(--fg-muted); flex: 0 0 16px; }

.file-link.active {
  background: var(--selected);
  color: var(--fg);
  font-weight: 500;
}
.file-link.active .icon-file { color: var(--accent); }

/* ---- Content ---- */
.content {
  overflow-y: auto;
  min-height: 0;
}

.markdown-body {
  max-width: 900px;
  margin: 0 auto;
  padding: 40px 48px 120px;
}

.welcome {
  color: var(--fg-muted);
  margin-top: 40px;
}
.welcome h1 { border: none; }

/* ---- TOC ---- */
.toc {
  border-left: 1px solid var(--border);
  overflow-y: auto;
  min-height: 0;
  min-width: 0;
  padding: 24px 16px;
  background: var(--bg);
}
.toc-header {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--fg-muted);
  margin-bottom: 10px;
}
.toc-list a {
  display: block;
  padding: 3px 8px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--fg-muted);
  text-decoration: none;
  border-left: 2px solid transparent;
  border-radius: 0 4px 4px 0;
}
.toc-list a:hover { color: var(--fg); background: var(--hover); }
.toc-list a.active {
  color: var(--fg);
  border-left-color: var(--accent);
  font-weight: 500;
}
.toc-list a.lvl-1 { padding-left: 8px; }
.toc-list a.lvl-2 { padding-left: 8px; }
.toc-list a.lvl-3 { padding-left: 20px; }
.toc-list a.lvl-4 { padding-left: 32px; }
.toc-list a.lvl-5 { padding-left: 44px; }
.toc-list a.lvl-6 { padding-left: 56px; }
.toc-empty { color: var(--fg-muted); font-size: 13px; }

/* ===========================================================================
   Markdown body typography (GitHub-like)
   =========================================================================== */
.markdown-body { word-wrap: break-word; }
.markdown-body > *:first-child { margin-top: 0 !important; }

.markdown-body h1, .markdown-body h2, .markdown-body h3,
.markdown-body h4, .markdown-body h5, .markdown-body h6 {
  margin: 24px 0 16px;
  font-weight: 600;
  line-height: 1.25;
  scroll-margin-top: 16px;
}
.markdown-body h1 { font-size: 2em; padding-bottom: .3em; border-bottom: 1px solid var(--border-muted); }
.markdown-body h2 { font-size: 1.5em; padding-bottom: .3em; border-bottom: 1px solid var(--border-muted); }
.markdown-body h3 { font-size: 1.25em; }
.markdown-body h4 { font-size: 1em; }
.markdown-body h5 { font-size: .875em; }
.markdown-body h6 { font-size: .85em; color: var(--fg-muted); }

.markdown-body p, .markdown-body ul, .markdown-body ol,
.markdown-body table, .markdown-body pre, .markdown-body blockquote {
  margin: 0 0 16px;
}

.markdown-body a { color: var(--link); text-decoration: none; }
.markdown-body a:hover { text-decoration: underline; }

.markdown-body ul, .markdown-body ol { padding-left: 2em; }
.markdown-body li + li { margin-top: .25em; }
.markdown-body li > ul, .markdown-body li > ol { margin: .25em 0 0; }

.markdown-body blockquote {
  padding: 0 1em;
  color: var(--fg-muted);
  border-left: .25em solid var(--quote-border);
}

.markdown-body img { max-width: 100%; box-sizing: content-box; }

.markdown-body hr {
  height: 1px;
  border: 0;
  background: var(--border);
  margin: 24px 0;
}

/* Code */
.markdown-body code {
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 85%;
  padding: .2em .4em;
  border-radius: 6px;
  background: var(--code-bg);
  color: var(--code-fg);
}
.markdown-body pre {
  padding: 16px;
  overflow: auto;
  border-radius: 6px;
  background: var(--code-bg);
  line-height: 1.45;
}
.markdown-body pre code {
  padding: 0;
  background: transparent;
  font-size: 100%;
  border: 0;
}

/* Tables */
.markdown-body table {
  border-collapse: collapse;
  display: block;
  width: max-content;
  max-width: 100%;
  overflow: auto;
}
.markdown-body table th, .markdown-body table td {
  padding: 6px 13px;
  border: 1px solid var(--border);
}
.markdown-body table th { font-weight: 600; background: var(--bg-elev); }
.markdown-body table tr:nth-child(2n) td { background: var(--table-alt); }

/* Task lists */
.markdown-body input[type="checkbox"] { margin-right: .5em; }

/* HTML comment callouts */
.md-comment {
  border: 1px solid var(--border);
  border-left: 3px solid var(--fg-muted);
  border-radius: 6px;
  margin: 16px 0;
  overflow: hidden;
}
.md-comment-header {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 6px 12px;
  background: var(--bg-elev);
  border-bottom: 1px solid var(--border);
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  font-size: 12px;
  font-weight: 500;
  color: var(--fg-muted);
}
.md-comment-body {
  margin: 0;
  padding: 10px 14px;
  background: var(--bg);
  line-height: 1.5;
  overflow-x: auto;
}
.md-comment-body code {
  background: transparent;
  padding: 0;
  font-size: 13px;
  color: var(--fg-muted);
}

/* Loading / error states */
.md-loading, .md-error {
  color: var(--fg-muted);
  margin-top: 40px;
}
.md-error { color: #f85149; }

/* Scrollbars */
.tree-wrap::-webkit-scrollbar, .content::-webkit-scrollbar, .toc::-webkit-scrollbar { width: 10px; }
.tree-wrap::-webkit-scrollbar-thumb, .content::-webkit-scrollbar-thumb, .toc::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 5px;
}

/* ---- Responsive ---- */

/* Desktop: clip panes while collapsed so 0-width tracks don't spill. */
@media (min-width: 821px) {
  html.is-sidebar-collapsed .sidebar,
  html.is-toc-collapsed .toc { overflow: hidden; }
}

/* Mobile / narrow: panes become off-canvas drawers over the content. */
@media (max-width: 820px) {
  .layout { grid-template-columns: 1fr; }

  .sidebar, .toc {
    position: fixed;
    top: var(--header-h);
    bottom: 0;
    z-index: 40;
    transition: transform .22s ease;
    box-shadow: 0 0 24px var(--shadow);
  }
  .sidebar {
    left: 0;
    width: 82%;
    max-width: 320px;
    transform: translateX(-100%);
  }
  .toc {
    right: 0;
    width: 78%;
    max-width: 280px;
    border-left: 1px solid var(--border);
    transform: translateX(100%);
  }
  .sidebar.open-mobile, .toc.open-mobile { transform: none; }

  .backdrop {
    position: fixed;
    inset: var(--header-h) 0 0 0;
    background: rgba(0, 0, 0, .45);
    z-index: 35;
  }
  .backdrop.show { display: block; }

  .markdown-body { padding: 24px 18px 80px; }
}