/* ===========================================================
   Workbook — index shell.
   Palette + spacing tokens loosely match the tutorial so the two
   apps don't feel disjoint when you cross from one to the other.
============================================================ */

:root {
  --bg-0: #0b0f1a;
  --bg-1: #121826;
  --bg-2: #1a2236;
  --bg-3: #232d45;
  --bg-elev: #1c2438;
  --border: #2a3550;
  --border-soft: #1f2840;
  --text: #e6ecf7;
  --text-dim: #a4b0c8;
  --text-mute: #6a7693;

  --accent: #7c5cff;
  --accent-2: #4cc9f0;
  --accent-soft: rgba(124, 92, 255, 0.12);
  --accent-glow: rgba(124, 92, 255, 0.28);

  --good: #4ade80;
  --bad: #f87171;
  --warn: #facc15;

  --sidebar-w: 280px;
  --topbar-h: 52px;
  --radius: 12px;
  --radius-sm: 8px;
  --radius-xs: 6px;

  --code-bg: #0e1322;
  --code-border: #1c2543;
  --code-text: #d6dcea;

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto,
               Helvetica, Arial, sans-serif;
  background: var(--bg-0);
  color: var(--text);
  line-height: 1.55;
}
a { color: var(--accent-2); text-decoration: none; }
a:hover { color: var(--accent); }

#app {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr;
  min-height: 100vh;
}
#app.loading #main > #view { opacity: 0; }

/* ===================== SIDEBAR ===================== */

#sidebar {
  background: var(--bg-1);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  padding: 18px 14px;
}
.brand {
  display: flex; gap: 12px; align-items: center;
  padding: 6px 8px 18px;
  border-bottom: 1px solid var(--border-soft);
  margin-bottom: 12px;
  color: var(--text);
}
.brand-mark {
  width: 38px; height: 38px;
  border-radius: var(--radius-sm);
  display: grid; place-items: center;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: white; font-weight: 700;
  letter-spacing: 0.5px;
  box-shadow: 0 6px 18px -10px var(--accent-glow);
}
.brand-title { font-weight: 600; font-size: 15px; }
.brand-sub { color: var(--text-mute); font-size: 11.5px; letter-spacing: 1px;
             text-transform: uppercase; }

#nav { display: flex; flex-direction: column; gap: 2px; flex: 1; }
.nav-item {
  display: flex; align-items: center; gap: 10px;
  padding: 9px 10px;
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-size: 13.5px;
  cursor: pointer;
  border: 1px solid transparent;
  transition: background-color 160ms var(--ease-out),
              color 160ms var(--ease-out),
              border-color 160ms var(--ease-out);
}
.nav-item:hover {
  background: var(--bg-2);
  color: var(--text);
}
.nav-item.active {
  background: var(--accent-soft);
  border-color: color-mix(in srgb, var(--accent) 38%, transparent);
  color: var(--text);
}
.nav-item.home { font-weight: 500; }
.nav-item .ni-icon {
  width: 28px; height: 22px;
  display: grid; place-items: center;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 10.5px;
  letter-spacing: 0.5px;
  font-weight: 600;
  background: var(--bg-2);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-xs);
  color: var(--text-mute);
}
.nav-item.kind-tutorial .ni-icon { color: var(--accent); border-color: var(--accent-soft); }
.nav-item.kind-markdown .ni-icon { color: var(--accent-2); }
.nav-item.kind-code     .ni-icon { color: var(--good); }
.nav-item.kind-mixed    .ni-icon { color: var(--warn); }
.nav-item.kind-pdf      .ni-icon { color: var(--bad); }
.nav-item .ni-name { flex: 1; }
.nav-item .ni-count {
  font-size: 11px;
  color: var(--text-mute);
  background: var(--bg-2);
  padding: 1px 7px;
  border-radius: 999px;
}

.data-source-tag {
  margin-top: 12px;
  padding: 6px 10px;
  border-radius: var(--radius-xs);
  font-size: 11px;
  letter-spacing: 0.6px;
  text-transform: uppercase;
  text-align: center;
  background: var(--bg-2);
  color: var(--text-mute);
  border: 1px dashed var(--border-soft);
}
.data-source-tag.dynamic {
  color: var(--good);
  border-color: color-mix(in srgb, var(--good) 35%, transparent);
}

/* ===================== TOPBAR ===================== */

#topbar {
  position: sticky; top: 0; z-index: 10;
  height: var(--topbar-h);
  display: flex; align-items: center; gap: 14px;
  padding: 0 22px;
  background: color-mix(in srgb, var(--bg-0) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-soft);
}
#menu-toggle {
  background: transparent; border: 0;
  color: var(--text-dim);
  font-size: 18px; cursor: pointer;
  display: none;
}
#back-btn {
  background: var(--bg-2);
  border: 1px solid var(--border-soft);
  color: var(--text-dim);
  padding: 5px 11px;
  border-radius: var(--radius-xs);
  font-size: 12.5px;
  cursor: pointer;
  transition: color 140ms var(--ease-out), border-color 140ms var(--ease-out);
}
#back-btn:hover { color: var(--text); border-color: var(--accent); }
#back-btn.hidden { display: none; }
#crumbs { color: var(--text-dim); font-size: 13.5px; }
#crumbs strong { color: var(--text); }
#crumbs .crumb-link { color: var(--text-dim); }
#crumbs .crumb-link:hover { color: var(--accent-2); }

/* ===================== VIEW ===================== */

#view {
  padding: 24px 28px 80px;
  max-width: 1100px;
  margin: 0 auto;
  transition: opacity 200ms var(--ease-out);
}

.card {
  background: var(--bg-1);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius);
  padding: 22px 26px;
  margin-bottom: 18px;
}
.card.hero {
  background: linear-gradient(135deg,
    color-mix(in srgb, var(--accent) 16%, var(--bg-1)),
    var(--bg-1));
  border-color: var(--border);
}
.card h1 { margin: 0 0 8px; font-size: 26px; }
.card h2 { margin: 0 0 8px; font-size: 19px; }
.card p { margin: 0; color: var(--text-dim); }
.card.error {
  border-color: color-mix(in srgb, var(--bad) 50%, transparent);
  background: color-mix(in srgb, var(--bad) 8%, var(--bg-1));
}

/* ----- Home tiles ----- */

.folder-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 14px;
}
.tile {
  display: flex; flex-direction: column; gap: 6px;
  padding: 18px 18px 16px;
  background: var(--bg-1);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  color: var(--text);
  transition: border-color 160ms var(--ease-out),
              transform 160ms var(--ease-out),
              box-shadow 200ms var(--ease-out);
}
.tile:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 12px 28px -16px var(--accent-glow);
  color: var(--text);
}
.tile-icon {
  width: 40px; height: 30px;
  display: grid; place-items: center;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 12px;
  font-weight: 700;
  background: var(--bg-2);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-xs);
  color: var(--text-mute);
}
.tile.kind-tutorial .tile-icon { color: var(--accent); }
.tile.kind-markdown .tile-icon { color: var(--accent-2); }
.tile.kind-code     .tile-icon { color: var(--good); }
.tile.kind-mixed    .tile-icon { color: var(--warn); }
.tile.kind-pdf      .tile-icon { color: var(--bad); }
.tile-name { font-weight: 600; font-size: 14.5px; }
.tile-sub { color: var(--text-mute); font-size: 12px; }

/* ----- Folder view: file accordion ----- */

.file-list { display: flex; flex-direction: column; gap: 10px; }

.file-item {
  background: var(--bg-1);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-sm);
  overflow: hidden;
  transition: border-color 160ms var(--ease-out);
}
.file-item[open] { border-color: var(--border); }
.file-item summary {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px;
  cursor: pointer;
  list-style: none;
  font-size: 14px;
  transition: background-color 140ms var(--ease-out);
}
.file-item summary::-webkit-details-marker { display: none; }
.file-item summary::before {
  content: "▸";
  color: var(--text-mute);
  width: 14px;
  font-size: 11px;
  transition: transform 180ms var(--ease-out);
}
.file-item[open] summary::before { transform: rotate(90deg); }
.file-item summary:hover { background: var(--bg-2); }

.file-item .f-kind {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 10.5px;
  font-weight: 700;
  letter-spacing: 0.6px;
  padding: 2px 8px;
  background: var(--bg-2);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-xs);
  color: var(--text-mute);
}
.file-item.kind-markdown .f-kind { color: var(--accent-2); }
.file-item.kind-code     .f-kind { color: var(--good); }
.file-item.kind-pdf      .f-kind { color: var(--bad); }
.file-item .f-name { flex: 1; color: var(--text); font-weight: 500; }
.file-item .f-meta { color: var(--text-mute); font-size: 11.5px; }

.file-body {
  border-top: 1px solid var(--border-soft);
  background: var(--bg-0);
}
.loading-tile {
  padding: 20px;
  text-align: center;
  color: var(--text-mute);
  font-style: italic;
}
.error {
  padding: 14px 16px;
  color: var(--bad);
  font-size: 13.5px;
}

/* Markdown render */
.markdown-body {
  padding: 22px 28px;
  font-size: 14.5px;
  color: var(--text);
}
.markdown-body h1, .markdown-body h2, .markdown-body h3, .markdown-body h4 {
  margin: 22px 0 10px;
  line-height: 1.3;
}
.markdown-body h1 { font-size: 22px; padding-bottom: 6px; border-bottom: 1px solid var(--border-soft); }
.markdown-body h2 { font-size: 18px; color: var(--accent); }
.markdown-body h3 { font-size: 16px; color: var(--accent-2); }
.markdown-body p, .markdown-body ul, .markdown-body ol { margin: 8px 0; color: var(--text-dim); }
.markdown-body code {
  background: var(--bg-2);
  color: var(--text);
  padding: 1px 6px;
  border-radius: var(--radius-xs);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
}
.markdown-body pre {
  background: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
  overflow-x: auto;
  margin: 12px 0;
}
.markdown-body pre code {
  background: transparent;
  padding: 0;
  color: var(--code-text);
  font-size: 13px;
}
.markdown-body table {
  border-collapse: collapse;
  margin: 12px 0;
  width: 100%;
}
.markdown-body th, .markdown-body td {
  padding: 8px 12px;
  border: 1px solid var(--border-soft);
  text-align: left;
}
.markdown-body th { background: var(--bg-2); }
.markdown-body blockquote {
  border-left: 3px solid var(--accent);
  padding: 6px 14px;
  margin: 10px 0;
  background: color-mix(in srgb, var(--accent) 6%, transparent);
  color: var(--text-dim);
}
.markdown-body a { color: var(--accent-2); }
.markdown-body a:hover { color: var(--accent); }
.markdown-body hr {
  border: 0;
  height: 1px;
  background: var(--border-soft);
  margin: 18px 0;
}

/* Code render */
.file-body pre {
  margin: 0;
  padding: 18px 22px;
  background: var(--code-bg);
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.55;
}
.file-body pre code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

/* PDF render */
.pdf-frame { padding: 14px 16px; }
.pdf-frame iframe {
  width: 100%;
  height: 70vh;
  border: 1px solid var(--code-border);
  border-radius: var(--radius-sm);
  background: white;
}
.pdf-fallback {
  margin-top: 8px;
  font-size: 12.5px;
  color: var(--text-mute);
  text-align: right;
}

/* ===================== TUTORIAL VIEW ===================== */
/* Hide sidebar and fill the viewport when the tutorial is embedded. */

body.tutorial-mode #sidebar { display: none; }
body.tutorial-mode #app { grid-template-columns: 1fr; }
body.tutorial-mode #view {
  max-width: none;
  padding: 0;
  height: calc(100vh - var(--topbar-h));
}
body.tutorial-mode #topbar {
  background: var(--bg-0);
  border-bottom: 1px solid var(--border-soft);
}
.tutorial-iframe {
  width: 100%;
  height: 100%;
  border: 0;
  display: block;
  background: var(--bg-0);
}

/* ===================== RESPONSIVE ===================== */

@media (max-width: 800px) {
  #app { grid-template-columns: 1fr; }
  #sidebar {
    position: fixed; inset: 0 auto 0 0;
    z-index: 30;
    width: 78%;
    max-width: 320px;
    transform: translateX(-100%);
    transition: transform 240ms var(--ease-out);
    box-shadow: 18px 0 40px -10px rgba(0,0,0,0.5);
  }
  body.menu-open #sidebar { transform: none; }
  #menu-toggle { display: inline-block; }
  body.menu-open::after {
    content: "";
    position: fixed; inset: 0;
    background: rgba(0,0,0,0.4);
    z-index: 25;
  }
}