@import url('https://fonts.googleapis.com/css2?family=JetBrains+Mono:wght@400;500;600;700&family=Inter:wght@400;500;600&display=swap');

:root {
  --bg: #0d1310;
  --surface: #10201a1a;
  --surface-solid: #131e19;
  --surface-raised: #1a2721;
  --border: #2a3c34;
  --border-bright: #435d4e;
  --text: #eaf1ec;
  --text-muted: #a3b6ab;
  --text-dim: #7c8f83;
  --accent: #9df05a;
  --accent-dim: #6a9c45;
  --accent-glow: #9df05a33;
  --amber: #e8cc7a;
  --mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --radius: 3px;
  --max-w: 920px;
}

* { box-sizing: border-box; }

html { color-scheme: dark; }

body {
  margin: 0;
  background: var(--bg);
  background-image:
    linear-gradient(var(--border) 1px, transparent 1px);
  background-size: 100% 3px;
  background-attachment: fixed;
  color: var(--text);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.55;
}

@media (prefers-reduced-motion: no-preference) {
  .fade-in { animation: fadeIn 0.4s ease-out; }
}
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
a:focus-visible, button:focus-visible, [tabindex]:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

h1, h2, h3, h4 {
  font-family: var(--mono);
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 0.5em;
  color: #fff;
}
p { margin: 0 0 1em; max-width: 70ch; color: var(--text); }
code, pre { font-family: var(--mono); }

.wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Header ---------- */
.site-header {
  border-bottom: 1px solid var(--border);
  background: rgba(10, 15, 12, 0.92);
  backdrop-filter: blur(6px);
  position: sticky;
  top: 0;
  z-index: 50;
}
.site-header__inner {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 14px 20px;
  max-width: 1080px;
  margin: 0 auto;
}
.site-header__path {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--text-muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.site-header__path .seg { color: var(--text); }
.site-header__path .seg:last-child { color: var(--accent); }
.site-header__spacer { flex: 1; }
.site-header__back {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 6px 10px;
  white-space: nowrap;
}
.site-header__back:hover { color: var(--accent); border-color: var(--accent-dim); text-decoration: none; }

/* ---------- Search ---------- */
.search-box {
  position: relative;
  min-width: 0;
  flex: 0 1 320px;
}
.search-box input {
  width: 100%;
  background: var(--surface-solid);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: var(--mono);
  font-size: 13px;
  padding: 7px 10px 7px 26px;
  border-radius: var(--radius);
}
.search-box input:focus {
  outline: none;
  border-color: var(--accent-dim);
}
.search-box::before {
  content: '$';
  position: absolute;
  left: 9px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--accent-dim);
  font-family: var(--mono);
  font-size: 13px;
  pointer-events: none;
}
.search-results {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  right: 0;
  background: var(--surface-solid);
  border: 1px solid var(--border-bright);
  border-radius: var(--radius);
  max-height: 340px;
  overflow-y: auto;
  display: none;
  z-index: 60;
}
.search-results.open { display: block; }
.search-results a {
  display: block;
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  font-size: 13.5px;
}
.search-results a:last-child { border-bottom: none; }
.search-results a:hover { background: var(--surface-raised); text-decoration: none; }
.search-results .r-cat {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent);
}
.search-results .r-empty {
  padding: 14px 12px;
  color: var(--text-dim);
  font-size: 13px;
  font-family: var(--mono);
}

/* ---------- Hero / terminal panel ---------- */
.terminal {
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface-solid);
  overflow: hidden;
  margin: 32px 0;
}
.terminal__bar {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
  background: #0d1512;
}
.terminal__dot { width: 9px; height: 9px; border-radius: 50%; background: var(--border-bright); }
.terminal__title {
  margin-left: 8px;
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-dim);
}
.terminal__body { padding: 20px 22px; font-family: var(--mono); font-size: 14px; }
.terminal__body .prompt { color: var(--accent); }
.terminal__body .line { margin-bottom: 4px; color: var(--text-muted); }
.terminal__body p { font-family: var(--sans); color: var(--text); margin-top: 10px; max-width: 62ch; }

.hero-lead {
  padding: 8px 0 28px;
}
.hero-lead h1 { font-size: clamp(28px, 4vw, 40px); }
.hero-lead p { font-size: 17px; color: var(--text-muted); }

/* ---------- Directory listing (categories / workshops) ---------- */
.listing { border: 1px solid var(--border); border-radius: 6px; overflow: hidden; }
.listing-row {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  padding: 16px 18px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  transition: background 0.12s ease;
}
.listing-row:last-child { border-bottom: none; }
.listing-row:hover { background: var(--surface-raised); text-decoration: none; }
.listing-row__icon {
  font-family: var(--mono);
  color: var(--accent-dim);
  width: 20px;
  flex: none;
  padding-top: 2px;
}
.listing-row__main { flex: 1; min-width: 0; }
.listing-row__title {
  font-family: var(--mono);
  font-size: 15.5px;
  color: #fff;
  margin-bottom: 3px;
}
.listing-row__desc { font-size: 14.5px; color: var(--text-muted); margin: 0; line-height: 1.5; }
.listing-row__badges {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  flex: none;
  max-width: 220px;
  justify-content: flex-end;
}
.badge {
  font-family: var(--mono);
  font-size: 11px;
  padding: 3px 7px;
  border-radius: var(--radius);
  border: 1px solid var(--border-bright);
  color: var(--text-muted);
  white-space: nowrap;
}
.listing-row__count {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-dim);
  flex: none;
  padding-top: 3px;
}
.empty-state {
  padding: 40px 20px;
  text-align: center;
  color: var(--text-dim);
  font-family: var(--mono);
  font-size: 14px;
}

/* ---------- Category grid (landing page) ---------- */
.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 12px;
  margin: 24px 0 40px;
}
.cat-card {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 16px 18px;
  color: var(--text);
  background: var(--surface-solid);
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.cat-card:hover {
  border-color: var(--accent-dim);
  text-decoration: none;
  transform: translateY(-1px);
}
.cat-card__icon {
  font-size: 26px;
  margin-bottom: 8px;
  line-height: 1;
}
.cat-card__name {
  font-family: var(--mono);
  font-size: 16px;
  color: var(--accent);
  margin-bottom: 6px;
}
.cat-card__name::after { content: '/'; color: var(--text-dim); }
.cat-card__tagline { font-size: 13.5px; color: var(--text-muted); margin-bottom: 10px; }
.cat-card__count { font-family: var(--mono); font-size: 12px; color: var(--text-dim); }

/* ---------- Pin panel (Robotics persistent reference) ---------- */
.pin-panel {
  border: 1px solid var(--border-bright);
  border-radius: 6px;
  background: var(--surface-solid);
  margin-bottom: 20px;
  overflow: hidden;
}
.pin-panel__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  cursor: pointer;
  user-select: none;
}
.pin-panel__header h3 {
  font-size: 13px;
  margin: 0;
  color: var(--amber);
}
.pin-panel__toggle {
  font-family: var(--mono);
  font-size: 12px;
  color: var(--text-dim);
}
.pin-panel__body {
  padding: 0 14px 14px;
  display: flex;
  align-items: center;
  gap: 14px;
}
.pin-panel__body img {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
  border: 1px solid var(--border);
}
.pin-panel__body p { font-size: 13px; color: var(--text-muted); margin: 0; }
.pin-panel.collapsed .pin-panel__body { display: none; }

/* ---------- Workshop page ---------- */
.workshop-header { padding: 28px 0 8px; }
.workshop-header h1 { font-size: 28px; }
.workshop-header p { color: var(--text-muted); font-size: 15.5px; }
.workshop-badges { display: flex; gap: 6px; margin: 10px 0 0; flex-wrap: wrap; }

.recording-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 14px 0 4px;
  padding: 8px 14px;
  border: 1px solid var(--border-bright);
  border-radius: var(--radius);
  font-family: var(--mono);
  font-size: 13px;
  color: var(--accent);
}
.recording-link:hover { border-color: var(--accent); text-decoration: none; }

.resource-list { display: flex; flex-direction: column; gap: 14px; margin: 24px 0 48px; }

.resource {
  border: 1px solid var(--border);
  border-radius: 6px;
  background: var(--surface-solid);
  overflow: hidden;
}
.resource__head {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
}
.resource__type {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent-dim);
  border: 1px solid var(--border-bright);
  border-radius: 3px;
  padding: 2px 6px;
  flex: none;
}
.resource__name {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--text);
  flex: 1;
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.resource__actions { display: flex; gap: 8px; flex: none; }
.btn {
  font-family: var(--mono);
  font-size: 12.5px;
  padding: 6px 11px;
  border-radius: var(--radius);
  border: 1px solid var(--border-bright);
  color: var(--text);
  background: transparent;
  cursor: pointer;
  white-space: nowrap;
}
.btn:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.btn--accent { border-color: var(--accent-dim); color: var(--accent); }
.btn--accent:hover { background: var(--accent-glow); }

.resource__body { padding: 0; }
.resource__placeholder {
  padding: 40px 16px;
  text-align: center;
  color: var(--text-dim);
  font-family: var(--mono);
  font-size: 13px;
  cursor: pointer;
}
.resource__placeholder:hover { color: var(--accent); }
.resource__pdf-frame { width: 100%; height: 640px; border: none; display: block; background: #1a1a1a; }
.resource__markdown { padding: 20px 24px; }
.resource__markdown h1, .resource__markdown h2, .resource__markdown h3 { font-family: var(--sans); color: #fff; }
.resource__markdown h1 { font-size: 22px; } .resource__markdown h2 { font-size: 19px; } .resource__markdown h3 { font-size: 16px; }
.resource__markdown pre {
  background: #0d1512; border: 1px solid var(--border); border-radius: 4px;
  padding: 12px 14px; overflow-x: auto; font-size: 13px;
}
.resource__markdown code { background: #0d1512; padding: 1px 5px; border-radius: 3px; font-size: 0.9em; }
.resource__markdown pre code { background: none; padding: 0; }
.resource__markdown ul, .resource__markdown ol { padding-left: 22px; }
.resource__markdown a { color: var(--accent); }

.resource__code { position: relative; }
.resource__code pre {
  margin: 0; padding: 16px 20px; overflow-x: auto; font-size: 13px; line-height: 1.6;
  background: #0d1512; max-height: 480px;
}

.resource__sb3, .resource__generic {
  display: flex; align-items: center; gap: 12px; padding: 16px;
}
.resource__file-icon { font-family: var(--mono); font-size: 20px; color: var(--text-dim); flex: none; }
.resource__file-meta { flex: 1; }
.resource__file-meta .fname { font-family: var(--mono); font-size: 13.5px; color: var(--text); }
.resource__file-meta .fdesc { font-size: 12.5px; color: var(--text-dim); }

/* ---------- Archive / exam-paper tree ---------- */
.archive-tree { border: 1px solid var(--border); border-radius: 6px; overflow: hidden; margin: 20px 0 48px; }
.archive-group summary {
  padding: 12px 16px; cursor: pointer; font-family: var(--mono); font-size: 14px;
  color: var(--text); list-style: none; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 8px;
}
.archive-group summary::-webkit-details-marker { display: none; }
.archive-group summary::before { content: '▸'; color: var(--accent-dim); font-size: 11px; }
.archive-group[open] > summary::before { content: '▾'; }
.archive-group { border-bottom: 1px solid var(--border); }
.archive-group:last-child { border-bottom: none; }
.archive-files { padding: 4px 16px 12px 34px; display: flex; flex-direction: column; }
.archive-file {
  display: flex; align-items: center; justify-content: space-between; gap: 10px;
  padding: 6px 0; font-family: var(--mono); font-size: 13px; color: var(--text-muted);
  border-bottom: 1px dashed var(--border);
}
.archive-file:last-child { border-bottom: none; }
.archive-file a.dl { color: var(--accent); font-size: 12px; }
.archive-nested { padding-left: 16px; }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 20px 40px;
  margin-top: 40px;
  text-align: center;
  color: var(--text-dim);
  font-family: var(--mono);
  font-size: 12.5px;
}
.site-footer a { color: var(--text-muted); }

@media (max-width: 640px) {
  .site-header__inner { flex-wrap: wrap; }
  .search-box { flex: 1 1 100%; order: 3; }
  .listing-row { flex-wrap: wrap; }
  .listing-row__badges { max-width: none; justify-content: flex-start; }
  .resource__pdf-frame { height: 420px; }
}