/* ============================================================
   VAULT.CSS — COURSE → UNIT → PAPER HIERARCHY, SEARCH-FIRST MVP
   Level 1: course strip · Level 2: unit strip · Level 3: unit pack
   Loaded AFTER style.css. navbar.css untouched.
   ============================================================ */

:root {
  --ff-head: 'Bricolage Grotesque', system-ui, -apple-system, sans-serif;
  --ff-body: 'Plus Jakarta Sans', system-ui, -apple-system, sans-serif;
  --vault-nav-h: 68px; /* matches navbar.css */
  --vault-shadow-sm: 0 2px 8px rgba(14, 32, 64, 0.05);
  --vault-shadow-md: 0 8px 24px rgba(14, 32, 64, 0.08);
  --vault-shadow-lg: 0 16px 40px rgba(14, 32, 64, 0.15);
  --vault-radius: 16px;
}

.hidden { display: none !important; }
.hidden-file-input { display: none !important; }
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

.vault-page {
  background: var(--bg);
  color: var(--text);
  font-family: var(--ff-body);
  line-height: 1.5;
}

/* Room for the fixed mobile bottom nav (navbar.css) */
@media (max-width: 768px) {
  .vault-page { padding-bottom: calc(80px + env(safe-area-inset-bottom, 0px)); }
}

/* ────────────────────────────────────────────────────────────
   1. STICKY SEARCH BAR
   ──────────────────────────────────────────────────────────── */
.vault-sticky-search {
  position: sticky;
  top: var(--vault-nav-h);
  z-index: 900; /* below navbar (1000), above content */
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  box-shadow: var(--vault-shadow-sm);
  padding: 10px 0 8px;
}
.vault-search-outer { max-width: 1280px; margin: 0 auto; padding: 0 16px; }
.vault-search-container { position: relative; }

.vault-search-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  height: 48px;
  background: var(--surface);
  border: 2px solid rgba(14, 32, 64, 0.28);
  border-radius: 14px;
  padding: 0 6px 0 14px;
  transition: border-color 0.18s, box-shadow 0.18s;
}
.vault-search-bar:focus-within {
  border-color: var(--mnuc-navy);
  box-shadow: 0 0 0 4px rgba(201, 162, 39, 0.18);
}
.vs-icon { color: var(--mnuc-navy); display: flex; flex-shrink: 0; }
.vault-search-bar input {
  flex: 1; min-width: 0;
  border: none; background: transparent; outline: none;
  font: 600 1rem var(--ff-body);
  color: var(--text);
  padding: 0 4px;
}
.vault-search-bar input::placeholder { color: var(--text-muted); font-weight: 500; font-size: 0.92rem; }

.vs-clear {
  width: 28px; height: 28px; border-radius: 50%;
  border: none; background: var(--bg); color: var(--text-muted);
  cursor: pointer; flex-shrink: 0; display: grid; place-items: center;
  transition: background 0.15s, color 0.15s;
}
.vs-clear:hover { background: var(--border); color: var(--text); }

.search-kbd-badge {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 3px 8px;
  font-size: 0.72rem; font-weight: 700;
  color: var(--text-muted);
  flex-shrink: 0;
  font-family: monospace;
}

.vs-go {
  height: 38px; padding: 0 18px;
  border: none; border-radius: 10px;
  background: var(--mnuc-navy); color: var(--mnuc-gold);
  font: 800 0.85rem var(--ff-body);
  cursor: pointer; flex-shrink: 0;
  transition: background 0.18s;
}
.vs-go:hover { background: #182e56; }
.vs-go:active { transform: scale(0.97); }

/* Autocomplete dropdown (courses + units + search-all) */
.vault-autocomplete-results {
  position: absolute;
  top: calc(100% + 8px);
  left: 0; right: 0;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: 0 16px 48px rgba(14, 32, 64, 0.22);
  z-index: 20; /* inside the sticky search stacking context */
  max-height: 400px;
  overflow-y: auto;
  text-align: left;
  padding: 10px;
  display: none;
}
.vault-autocomplete-results.active { display: block; animation: dropdown-fade 0.2s ease; }

@keyframes dropdown-fade {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: translateY(0); }
}

.ac-section-label {
  font-size: 0.7rem; font-weight: 800;
  color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 0.08em;
  padding: 8px 12px 4px;
}
.ac-item {
  display: flex; align-items: center; gap: 12px;
  padding: 10px 12px; border-radius: 12px;
  cursor: pointer; transition: background 0.15s;
}
.ac-item:hover, .ac-item.highlighted { background: rgba(14, 32, 64, 0.05); }
.ac-icon {
  width: 32px; height: 32px; border-radius: 8px;
  background: rgba(0, 82, 255, 0.08); color: var(--mnuc-blue);
  display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.ac-icon-course { background: rgba(201, 162, 39, 0.14); color: #92400e; }
.ac-title { font-size: 0.9rem; font-weight: 800; color: var(--mnuc-navy); font-family: var(--ff-head); }
.ac-sub { font-size: 0.78rem; color: var(--text-muted); }
.ac-tag {
  margin-left: auto;
  font: 800 0.6rem var(--ff-body);
  text-transform: uppercase; letter-spacing: 0.06em;
  color: #92400e;
  background: rgba(201, 162, 39, 0.14);
  padding: 3px 8px; border-radius: 99px;
  flex-shrink: 0;
}
.ac-item-search .ac-title { color: var(--mnuc-blue); font-weight: 700; font-size: 0.85rem; }
.ac-none { padding: 14px 12px; font-size: 0.85rem; color: var(--text-muted); }

/* ────────────────────────────────────────────────────────────
   2. COMPACT FILTER ROW
   ──────────────────────────────────────────────────────────── */
.vault-filter-row { background: var(--surface); border-bottom: 1px solid var(--border); }
.vault-filter-inner {
  max-width: 1280px; margin: 0 auto;
  padding: 8px 16px;
  display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
}

.inst-chips { display: flex; gap: 6px; flex-wrap: wrap; }
.inst-chip {
  padding: 6px 14px; border-radius: 99px;
  border: 1px solid var(--border);
  background: var(--surface); color: var(--text-muted);
  font: 700 0.78rem var(--ff-body);
  cursor: pointer; transition: all 0.15s;
}
.inst-chip:hover { border-color: var(--mnuc-navy); color: var(--mnuc-navy); }
.inst-chip.active { background: var(--mnuc-navy); border-color: var(--mnuc-navy); color: var(--mnuc-gold); }

.vault-filter-right {
  margin-left: auto;
  display: flex; align-items: center; gap: 8px;
  position: relative; /* anchor for the desktop popover */
}

.clear-filters-link {
  background: none; border: none; cursor: pointer;
  color: var(--mnuc-blue);
  font: 700 0.78rem var(--ff-body);
  text-decoration: underline;
  padding: 4px 2px;
}

.filters-btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 14px; border-radius: 99px;
  border: 1px solid var(--border);
  background: var(--surface); color: var(--text);
  font: 700 0.8rem var(--ff-body);
  cursor: pointer; transition: all 0.15s;
}
.filters-btn:hover { border-color: var(--mnuc-navy); color: var(--mnuc-navy); }
.filters-btn.has-active { border-color: rgba(201, 162, 39, 0.6); background: rgba(201, 162, 39, 0.12); color: #92400e; }
.fb-count {
  background: var(--mnuc-navy); color: var(--mnuc-gold);
  min-width: 18px; height: 18px; padding: 0 5px;
  border-radius: 99px; display: inline-grid; place-items: center;
  font-size: 0.68rem; font-weight: 800;
}
.fb-caret { font-size: 0.7rem; }

.filter-select {
  padding: 7px 12px;
  border-radius: 99px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font: 700 0.78rem var(--ff-body);
  cursor: pointer; outline: none;
  transition: border 0.18s, box-shadow 0.18s;
}
.filter-select:focus { border-color: var(--mnuc-navy); box-shadow: 0 0 0 2px rgba(14, 32, 64, 0.1); }

/* ────────────────────────────────────────────────────────────
   3. FILTER PANEL — desktop popover / mobile bottom sheet
   ──────────────────────────────────────────────────────────── */
.filter-sheet-overlay { display: none; }

.filter-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: var(--vault-shadow-lg);
  z-index: 950; /* above sticky search (900) */
}

/* Desktop: dropdown anchored to the filter row */
@media (min-width: 768px) {
  .filter-panel {
    position: absolute;
    top: calc(100% + 8px);
    right: 0;
    width: 320px;
    padding: 16px;
  }
  .fp-grabber, .fp-foot { display: none; } /* no handle / no Apply — changes apply live */
}

/* Mobile: bottom sheet over a dark overlay, above the bottom nav (z 1000) */
@media (max-width: 767px) {
  .filter-sheet-overlay:not(.hidden) {
    display: block;
    position: fixed; inset: 0;
    background: rgba(10, 24, 50, 0.55);
    z-index: 1150;
    animation: fade-in 0.2s ease;
  }
  .filter-panel {
    position: fixed; left: 0; right: 0; bottom: 0;
    width: 100%;
    border-radius: 20px 20px 0 0;
    border-bottom: none;
    max-height: 84vh;
    overflow-y: auto;
    z-index: 1200;
    padding: 8px 16px calc(20px + env(safe-area-inset-bottom, 0px));
    animation: sheet-up 0.3s cubic-bezier(0.16, 1, 0.3, 1);
  }
  .fp-grabber {
    width: 44px; height: 5px; border-radius: 99px;
    background: var(--border); margin: 8px auto 4px;
  }
  .fp-pill { padding: 9px 16px; } /* bigger touch targets */
}

@keyframes sheet-up { from { transform: translateY(100%); } to { transform: translateY(0); } }
@keyframes fade-in { from { opacity: 0; } to { opacity: 1; } }

.fp-head { display: flex; align-items: center; justify-content: space-between; padding: 6px 0 10px; }
.fp-title { font: 800 0.95rem var(--ff-head); color: var(--mnuc-navy); }
.fp-section { margin-bottom: 14px; }
.fp-label {
  font: 800 0.68rem var(--ff-body);
  text-transform: uppercase; letter-spacing: 0.07em;
  color: var(--text-muted); margin-bottom: 8px;
}
.fp-pills { display: flex; flex-wrap: wrap; gap: 8px; }
.fp-pill {
  padding: 7px 14px; border-radius: 99px;
  border: 1px solid var(--border);
  background: var(--bg); color: var(--text);
  font: 700 0.8rem var(--ff-body);
  cursor: pointer; transition: all 0.15s;
}
.fp-pill:hover { border-color: var(--mnuc-navy); }
.fp-pill.active { background: var(--mnuc-navy); border-color: var(--mnuc-navy); color: var(--mnuc-gold); }
.fp-foot { padding-top: 6px; }

/* ────────────────────────────────────────────────────────────
   4. SLIM UPLOAD CTA STRIP (44px, dismissable)
   ──────────────────────────────────────────────────────────── */
.upload-cta-strip {
  background: rgba(201, 162, 39, 0.10);
  border-bottom: 1px solid rgba(201, 162, 39, 0.25);
}
.strip-inner {
  max-width: 1280px; margin: 0 auto;
  padding: 0 16px;
  height: 44px;
  display: flex; align-items: center; gap: 10px;
}
.strip-icon { display: flex; color: #92400e; flex-shrink: 0; }
.strip-text {
  flex: 1; min-width: 0;
  font: 600 0.8rem var(--ff-body); color: #6b5410;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.strip-text strong { color: #92400e; font-weight: 800; }
.strip-btn {
  flex-shrink: 0; height: 32px; padding: 0 16px;
  border: none; border-radius: 99px;
  background: var(--mnuc-navy); color: var(--mnuc-gold);
  font: 800 0.75rem var(--ff-body);
  cursor: pointer; transition: background 0.18s;
}
.strip-btn:hover { background: #182e56; }
.strip-close {
  flex-shrink: 0; width: 28px; height: 28px;
  border: none; border-radius: 50%;
  background: transparent; color: #92400e;
  cursor: pointer; display: grid; place-items: center;
  transition: background 0.15s;
}
.strip-close:hover { background: rgba(201, 162, 39, 0.2); }

/* ────────────────────────────────────────────────────────────
   5. HIERARCHY STRIPS — COURSES (L1) + UNITS (L2)
   ──────────────────────────────────────────────────────────── */
.course-strip, .unit-strip {
  max-width: 1280px; margin: 0 auto;
  padding: 14px 16px 2px;
}
.unit-strip { padding-top: 10px; }

.strip-head { display: flex; align-items: center; gap: 8px; margin-bottom: 8px; color: var(--mnuc-navy); }
.strip-label {
  font: 800 0.7rem var(--ff-body);
  text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--text-muted);
}

.chips-scroll {
  display: flex; gap: 10px;
  overflow-x: auto;
  padding: 2px 2px 8px;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.chips-scroll::-webkit-scrollbar { display: none; }

/* Level 1 — course chips (the primary browse path: slightly larger) */
.course-chip {
  flex-shrink: 0; scroll-snap-align: start;
  display: flex; flex-direction: column; gap: 2px;
  min-width: 160px; max-width: 210px;
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 14px;
  padding: 10px 14px;
  text-align: left; cursor: pointer;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
}
.course-chip:hover { border-color: var(--mnuc-navy); box-shadow: var(--vault-shadow-sm); transform: translateY(-1px); }
.course-chip.active {
  background: var(--mnuc-navy);
  border-color: var(--mnuc-navy);
  box-shadow: var(--vault-shadow-md);
}
.course-chip-name {
  font: 800 0.85rem var(--ff-head); color: var(--mnuc-navy);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.course-chip-meta { font: 600 0.68rem var(--ff-body); color: var(--text-muted); }
.course-chip.active .course-chip-name { color: var(--mnuc-gold); }
.course-chip.active .course-chip-meta { color: rgba(201, 162, 39, 0.85); }
.course-chip-skel { pointer-events: none; justify-content: center; gap: 6px; }

/* Level 2 — unit chips (contextual, inside the selected course) */
.unit-chip {
  flex-shrink: 0; scroll-snap-align: start;
  display: flex; flex-direction: column; gap: 1px;
  min-width: 118px; max-width: 172px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 8px 12px;
  text-align: left; cursor: pointer;
  transition: border-color 0.15s, box-shadow 0.15s, transform 0.15s;
}
.unit-chip:hover { border-color: var(--mnuc-navy); box-shadow: var(--vault-shadow-sm); transform: translateY(-1px); }
.unit-chip.active { border-color: var(--mnuc-blue); background: rgba(0, 82, 255, 0.05); }
.unit-chip-code { font: 800 0.85rem var(--ff-head); color: var(--mnuc-navy); white-space: nowrap; }
.unit-chip.active .unit-chip-code { color: var(--mnuc-blue); }
.unit-chip-name {
  font: 500 0.66rem var(--ff-body); color: var(--text-muted);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.unit-chip-count { font: 700 0.62rem var(--ff-body); color: var(--mnuc-blue); margin-top: 3px; }

/* ────────────────────────────────────────────────────────────
   6. RESULTS HEADER + GRID + COMPACT CARDS
   ──────────────────────────────────────────────────────────── */
.vault-main { max-width: 1280px; margin: 0 auto; padding: 14px 16px 8px; }

.results-header {
  display: flex; align-items: center; justify-content: space-between;
  gap: 10px; flex-wrap: wrap;
  margin-bottom: 12px;
  scroll-margin-top: 140px; /* clears sticky navbar + search */
}
.results-count-text { font-size: 0.85rem; color: var(--text-muted); }
.results-count-text strong { color: var(--mnuc-navy); font-weight: 800; }
.sort-select-m { display: none; }

.papers-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 12px;
}

/* Compact horizontal card: left = code+name+badges, right = actions */
.paper-card {
  display: flex; align-items: stretch; gap: 10px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
  min-height: 88px;
  box-shadow: var(--vault-shadow-sm);
  transition: border-color 0.18s, box-shadow 0.18s, transform 0.18s;
}
.paper-card:hover { border-color: var(--mnuc-navy); box-shadow: var(--vault-shadow-md); transform: translateY(-2px); }

.paper-card-left { flex: 1; min-width: 0; display: flex; flex-direction: column; gap: 3px; }
.paper-code {
  align-self: flex-start;
  background: none; border: none; padding: 0;
  cursor: pointer; text-align: left;
  font: 800 1rem var(--ff-head);
  color: var(--mnuc-navy); letter-spacing: -0.01em;
  transition: color 0.15s;
}
.paper-code:hover { color: var(--mnuc-blue); text-decoration: underline; }
.paper-unit-name {
  font: 700 0.82rem var(--ff-body); color: var(--text);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  margin-bottom: 1px;
}
.paper-name {
  font: 500 0.72rem var(--ff-body); color: var(--text-muted);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.paper-badges { display: flex; flex-wrap: wrap; gap: 4px; margin-top: auto; padding-top: 4px; }

.paper-card-actions {
  flex-shrink: 0;
  display: flex; flex-direction: column; gap: 6px; justify-content: center;
}
.btn-dl, .btn-pv {
  border-radius: 9px; cursor: pointer; white-space: nowrap;
  font: 800 0.72rem var(--ff-body);
  display: inline-flex; align-items: center; justify-content: center; gap: 5px;
  transition: all 0.15s;
}
.btn-dl { background: var(--mnuc-navy); color: var(--mnuc-gold); border: none; padding: 8px 14px; }
.btn-dl:hover { background: #182e56; }
.btn-dl:active { transform: scale(0.97); }
.btn-pv { background: transparent; color: var(--text); border: 1.5px solid var(--border); padding: 6.5px 14px; }
.btn-pv:hover { border-color: var(--mnuc-navy); color: var(--mnuc-navy); }

/* Badges */
.badge-inst {
  display: inline-flex; align-items: center;
  padding: 3px 9px; border-radius: 99px;
  font-size: 0.64rem; font-weight: 800; letter-spacing: 0.05em;
}
.badge-inst-mnuc { background: rgba(14, 32, 64, 0.08); color: var(--mnuc-navy); border: 1px solid rgba(14, 32, 64, 0.18); }
.badge-inst-ku { background: rgba(0, 82, 255, 0.08); color: var(--mnuc-blue); border: 1px solid rgba(0, 82, 255, 0.18); }
.badge-inst-other { background: rgba(100, 116, 139, 0.08); color: #64748b; border: 1px solid rgba(100, 116, 139, 0.18); }

.badge-year, .badge-sem {
  display: inline-flex; align-items: center;
  padding: 3px 8px; border-radius: 6px;
  font-size: 0.64rem; font-weight: 700;
}
.badge-year { background: rgba(0, 82, 255, 0.08); color: var(--mnuc-blue); }
.badge-sem { background: rgba(109, 40, 217, 0.08); color: #6d28d9; }

/* Skeletons */
.paper-skeleton {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 12px;
  min-height: 88px;
  display: flex; flex-direction: column; gap: 10px; justify-content: center;
}
.skel-shimmer {
  height: 14px;
  background: linear-gradient(90deg, var(--bg) 25%, var(--border) 50%, var(--bg) 75%);
  background-size: 400% 100%;
  animation: skel-shimmer-anim 1.3s infinite;
  border-radius: 6px;
}
.skel-shimmer.w-30 { width: 30%; }
.skel-shimmer.w-40 { width: 40%; }
.skel-shimmer.w-50 { width: 50%; }
.skel-shimmer.w-60 { width: 60%; }
.skel-shimmer.w-70 { width: 70%; }
.skel-shimmer.w-80 { width: 80%; }
.skel-shimmer.w-90 { width: 90%; }
.skel-shimmer.w-100 { width: 100%; }
.skel-shimmer.h-big { height: 22px; }
@keyframes skel-shimmer-anim {
  0% { background-position: 100% 0; }
  100% { background-position: -100% 0; }
}

/* Empty state */
.vault-empty-flex {
  grid-column: 1 / -1;
  text-align: center;
  padding: 56px 20px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--vault-radius);
}
.empty-icon-flex {
  display: inline-flex; align-items: center; justify-content: center;
  width: 76px; height: 76px;
  background: var(--bg); border-radius: 50%;
  color: var(--text-muted); margin-bottom: 16px;
}
.vault-empty-flex h3 { font: 800 1.2rem var(--ff-head); color: var(--mnuc-navy); margin-bottom: 6px; }
.vault-empty-flex p { font-size: 0.88rem; color: var(--text-muted); margin-bottom: 20px; }
.empty-actions-flex { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.load-more-wrap { text-align: center; margin: 24px 0 8px; }

/* ────────────────────────────────────────────────────────────
   7. FOOTER ZONE — STATS + LEADERBOARD
   ──────────────────────────────────────────────────────────── */
.vault-footer-zone {
  max-width: 1280px; margin: 0 auto;
  padding: 28px 16px 20px;
  border-top: 1px solid var(--border);
}
.vf-stats { display: flex; gap: 32px; flex-wrap: wrap; margin-bottom: 18px; }
.vf-stat strong { display: block; font: 800 1.3rem var(--ff-head); color: var(--mnuc-navy); }
.vf-stat span {
  font: 700 0.68rem var(--ff-body);
  text-transform: uppercase; letter-spacing: 0.06em;
  color: var(--text-muted);
}

.lb-toggle {
  display: inline-flex; align-items: center; gap: 8px;
  background: none; border: none; cursor: pointer; padding: 4px 0;
  font: 800 0.9rem var(--ff-head); color: var(--mnuc-navy);
}
.lb-toggle:hover { color: var(--mnuc-blue); }
.lb-caret { transition: transform 0.2s; }
.lb-toggle.open .lb-caret { transform: rotate(180deg); }

.lb-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 14px; }
.lb-item {
  flex: 1 1 160px; max-width: 230px;
  display: flex; align-items: center; gap: 8px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px 12px;
}
.lb-rank { font: 800 0.8rem var(--ff-head); color: var(--text-muted); width: 16px; flex-shrink: 0; }
.lb-rank.top { color: var(--mnuc-gold); }
.lb-avatar {
  width: 30px; height: 30px; border-radius: 50%;
  background: linear-gradient(135deg, var(--mnuc-navy), var(--mnuc-blue));
  color: var(--mnuc-gold);
  display: grid; place-items: center;
  font: 800 0.62rem var(--ff-body); flex-shrink: 0;
}
.lb-name {
  flex: 1; min-width: 0;
  font: 700 0.78rem var(--ff-body); color: var(--text);
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}
.lb-pts {
  font: 800 0.7rem var(--ff-body); color: var(--mnuc-navy);
  background: rgba(0, 82, 255, 0.08);
  padding: 3px 8px; border-radius: 99px; white-space: nowrap;
}
.lb-empty { font: 600 0.82rem var(--ff-body); color: var(--text-muted); padding: 8px 0; }

/* ────────────────────────────────────────────────────────────
   8. MODALS
   ──────────────────────────────────────────────────────────── */
.vault-page .modal-overlay {
  position: fixed; inset: 0;
  background: rgba(14, 32, 64, 0.75);
  backdrop-filter: blur(6px);
  z-index: 9000;
  display: none;
  place-items: center;
  padding: 16px;
}
.vault-page .modal-overlay:not(.hidden) { display: grid !important; }

.modal {
  background: var(--surface);
  border-radius: 24px;
  width: 100%;
  max-width: 620px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--vault-shadow-lg);
  animation: modal-pop 0.25s cubic-bezier(0.16, 1, 0.3, 1);
}
@keyframes modal-pop {
  from { opacity: 0; transform: scale(0.95) translateY(12px); }
  to { opacity: 1; transform: scale(1) translateY(0); }
}
.vault-modal-lg { max-width: 880px; }

.modal-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border);
}
.modal-title { font: 800 1.15rem var(--ff-head); color: var(--mnuc-navy); }
.modal-close {
  background: var(--bg); border: none; cursor: pointer;
  color: var(--text-muted);
  width: 34px; height: 34px; border-radius: 50%;
  display: grid; place-items: center;
  transition: all 0.15s; flex-shrink: 0;
}
.modal-close:hover { background: var(--border); color: var(--text); }
.vault-modal-body { padding: 24px; }

/* Upload form */
.upload-drop-zone {
  border: 2px dashed var(--border);
  border-radius: 16px;
  padding: 36px 20px;
  text-align: center; cursor: pointer;
  transition: all 0.2s;
  background: var(--bg);
  margin-bottom: 20px;
}
.upload-drop-zone:hover, .upload-drop-zone.drag-over {
  border-color: var(--mnuc-navy);
  background: rgba(14, 32, 64, 0.03);
}
.upload-drop-zone p { font-size: 0.9rem; font-weight: 600; color: var(--text); margin-bottom: 4px; }
.upload-drop-zone span { font-size: 0.75rem; color: var(--text-muted); }
.upload-drop-icon { color: var(--mnuc-navy); margin-bottom: 10px; display: flex; justify-content: center; }

.upload-form-grid-flex {
  display: flex; flex-wrap: wrap; gap: 16px;
  margin-bottom: 20px;
}
.form-group-flex { flex: 1 1 calc(50% - 8px); min-width: 220px; display: flex; flex-direction: column; }
.form-group-flex-full { flex: 1 1 100%; }
.form-group-flex label { font-size: 0.8rem; font-weight: 700; color: var(--text); margin-bottom: 6px; }

/* Live course hint under the Unit Code input */
.up-course-hint {
  margin-top: 6px;
  font: 600 0.72rem var(--ff-body);
  color: var(--text-muted);
}
.up-course-hint strong { color: var(--mnuc-navy); font-weight: 800; }

/* Safety nets (same intent as the global versions) */
.vault-page .upload-progress-bar {
  height: 6px; background: var(--bg); border-radius: 99px;
  overflow: hidden; margin-top: 10px;
}
.vault-page .upload-progress-fill {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--mnuc-navy), var(--mnuc-blue));
  border-radius: 99px; transition: width 0.25s ease;
}
.vault-page .wa-share-preview { white-space: pre-line; }

/* Detail modal */
.preview-meta-row {
  display: flex; align-items: center; gap: 10px;
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  flex-wrap: wrap;
}
.meta-dl {
  margin-left: auto;
  display: inline-flex; align-items: center; gap: 5px;
  font: 700 0.78rem var(--ff-body); color: var(--text-muted);
}
.paper-detail-grid-flex { display: flex; flex-wrap: wrap; gap: 16px; margin-bottom: 8px; }
.paper-detail-item-flex { flex: 1 1 calc(50% - 8px); min-width: 200px; }
.paper-detail-item-flex label {
  display: block; margin-bottom: 4px;
  font: 700 0.72rem var(--ff-body);
  color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 0.06em;
}
.paper-detail-item-flex span { font-size: 0.95rem; font-weight: 700; color: var(--mnuc-navy); }
.detail-actions {
  display: flex; gap: 10px; flex-wrap: wrap;
  padding: 0 24px 8px;
}

/* Unit pack modal */
.unit-pack-header {
  background: linear-gradient(135deg, var(--mnuc-navy), #172e5a);
  color: #ffffff;
  padding: 24px;
  border-radius: 24px 24px 0 0;
}
.unit-pack-head-row { display: flex; align-items: flex-start; justify-content: space-between; gap: 10px; }
.unit-pack-close { background: rgba(255, 255, 255, 0.2); color: #ffffff; }
.unit-pack-close:hover { background: rgba(255, 255, 255, 0.32); color: #ffffff; }
.unit-pack-code { font: 800 1.6rem var(--ff-head); color: var(--mnuc-gold); }
.unit-pack-name { font-size: 1rem; color: rgba(255, 255, 255, 0.85); margin: 4px 0 8px; }
.unit-pack-count { font-size: 0.8rem; opacity: 0.85; }
.unit-pack-list { display: flex; flex-direction: column; gap: 12px; padding: 20px 0; }
.unit-pack-card {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 12px;
}
.upc-meta { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; flex: 1; min-width: 0; }
.upc-sem {
  font: 700 0.72rem var(--ff-body); color: #6d28d9;
  background: rgba(109, 40, 217, 0.08);
  padding: 3px 9px; border-radius: 6px;
}
.pack-skel { flex: 1; display: flex; flex-direction: column; gap: 8px; }

/* ────────────────────────────────────────────────────────────
   9. RESPONSIVE
   ──────────────────────────────────────────────────────────── */
@media (max-width: 767px) {
  .search-kbd-badge { display: none; }
  .vs-go { padding: 0 14px; }
  #vault-sort { display: none; }        /* desktop sort hidden…   */
  .sort-select-m { display: block; }    /* …mobile sort in results header */
  .vault-filter-inner { padding: 8px 12px; }
  .inst-chip { padding: 8px 13px; font-size: 0.74rem; }
  .clear-filters-link { font-size: 0.74rem; }
  /* edge-to-edge strip scrolling */
  .course-strip .chips-scroll, .unit-strip .chips-scroll { margin: 0 -16px; padding: 2px 16px 8px; }
  .strip-text { font-size: 0.75rem; }
  .form-group-flex { flex: 1 1 100%; }
  .paper-detail-item-flex { flex: 1 1 100%; }
  .detail-actions { padding: 0 20px 8px; }
  .modal-header { padding: 16px 20px; }
  .vault-modal-body { padding: 20px; }
  .preview-meta-row { padding: 14px 20px; }
  .vf-stats { gap: 20px; }
}

@media (max-width: 600px) {
  /* 2-column compact grid */
  .papers-grid { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 10px; }
  .paper-card { min-height: 76px; padding: 10px; gap: 8px; }
  .paper-code { font-size: 0.92rem; }
  .paper-name { font-size: 0.7rem; }
  .btn-dl { padding: 7px 10px; font-size: 0.7rem; }
  .btn-pv { padding: 6px 10px; font-size: 0.7rem; }
  .badge-inst, .badge-year, .badge-sem { font-size: 0.58rem; padding: 2px 6px; }
  .course-chip { min-width: 140px; }
}

@media (max-width: 380px) {
  .vs-go { padding: 0 10px; font-size: 0.75rem; }
}

/* Keyboard focus + reduced motion */
.vault-page button:focus-visible,
.vault-page select:focus-visible,
.vault-page input:focus-visible {
  outline: 2px solid var(--mnuc-blue);
  outline-offset: 2px;
}
@media (prefers-reduced-motion: reduce) {
  .vault-page * { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
}