/* ─── Navigation panel (preview): papers + exercise jump links ─────────── */
.overview-panel {
  display: none;
}

.preview-mode.preview-mode--settled .overview-panel:not(.hidden) {
  display: block;
  border-color: rgba(56, 189, 248, 0.22);
  box-shadow:
    0 0 0 1px rgba(56, 189, 248, 0.08) inset,
    0 18px 40px -16px rgba(0, 0, 0, 0.5),
    0 0 48px -14px rgba(56, 189, 248, 0.12);
}

.preview-mode #result-panel:not(.hidden) {
  border-color: rgba(34, 211, 238, 0.2);
  box-shadow:
    0 0 0 1px rgba(34, 211, 238, 0.06) inset,
    0 18px 40px -16px rgba(0, 0, 0, 0.5),
    0 0 44px -12px rgba(34, 211, 238, 0.1);
}

.overview-body {
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.overview-paper-block {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.overview-paper-btn {
  width: 100%;
  text-align: left;
  border-radius: 0.65rem;
  border: 1px solid rgba(56, 189, 248, 0.22);
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.14) 0%, rgba(99, 102, 241, 0.08) 50%, rgba(8, 14, 30, 0.35) 100%);
  padding: 0.45rem 0.6rem;
  font-size: 0.72rem;
  font-weight: 600;
  color: rgb(224 242 254);
  cursor: pointer;
  transition: all 0.18s ease;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.06),
    0 0 20px -8px rgba(56, 189, 248, 0.2);
}

.overview-paper-btn:hover {
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.24) 0%, rgba(99, 102, 241, 0.14) 50%, rgba(8, 14, 30, 0.4) 100%);
  border-color: rgba(125, 211, 252, 0.38);
  color: rgb(240 249 255);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.1),
    0 0 22px -6px rgba(56, 189, 248, 0.32);
}

.overview-q-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  padding-left: 0.15rem;
}

.overview-q-btn {
  min-width: 1.9rem;
  padding: 0.22rem 0.4rem;
  border-radius: 0.45rem;
  border: 1px solid rgba(34, 211, 238, 0.32);
  background: linear-gradient(180deg, rgba(34, 211, 238, 0.18) 0%, rgba(56, 189, 248, 0.08) 100%);
  font-size: 0.68rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  color: rgb(207 250 254);
  cursor: pointer;
  transition: all 0.18s ease;
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.08),
    0 0 10px -3px rgba(34, 211, 238, 0.22);
}

.overview-q-btn:hover {
  background: linear-gradient(180deg, rgba(34, 211, 238, 0.3) 0%, rgba(56, 189, 248, 0.16) 100%);
  border-color: rgba(103, 232, 249, 0.48);
  color: rgb(236 254 255);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.12),
    0 0 16px -3px rgba(34, 211, 238, 0.38);
}

.overview-q-btn:focus-visible {
  outline: 2px solid rgba(56, 189, 248, 0.55);
  outline-offset: 2px;
}

.overview-q-btn-mcq {
  border-color: rgba(167, 139, 250, 0.38);
  background: linear-gradient(180deg, rgba(139, 92, 246, 0.22) 0%, rgba(167, 139, 250, 0.1) 100%);
  color: rgb(237 233 254);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.08),
    0 0 10px -3px rgba(167, 139, 250, 0.25);
}

.overview-q-btn-mcq:hover {
  background: linear-gradient(180deg, rgba(139, 92, 246, 0.34) 0%, rgba(167, 139, 250, 0.18) 100%);
  border-color: rgba(196, 181, 253, 0.52);
  color: rgb(245 243 255);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.12),
    0 0 16px -3px rgba(167, 139, 250, 0.38);
}

.overview-q-btn-mcq:focus-visible {
  outline-color: rgba(167, 139, 250, 0.65);
}

.pdf-viewport-scroll:focus {
  outline: none;
}

.pdf-viewport-scroll:focus-visible {
  box-shadow: inset 0 0 0 2px rgba(34, 211, 238, 0.35);
}

.pdf-page-wrap {
  position: relative;
  flex-shrink: 0;
  max-width: 100%;
  border-radius: 1rem;
  overflow: hidden;
}

.pdf-page-wrap .textLayer {
  position: absolute;
  left: 0;
  top: 0;
  right: 0;
  bottom: 0;
  overflow: hidden;
  opacity: 1;
  line-height: 1;
  z-index: 1;
  pointer-events: auto;
}

.pdf-page-wrap .textLayer span {
  color: transparent;
  position: absolute;
  white-space: pre;
  cursor: text;
  transform-origin: 0 0;
  user-select: text;
  -webkit-user-select: text;
}

.pdf-page-wrap .textLayer br {
  color: transparent;
  position: absolute;
  user-select: none;
  -webkit-user-select: none;
}

.pdf-page-wrap .textLayer ::selection {
  background: rgba(56, 189, 248, 0.38);
  color: transparent;
}

.pdf-page-wrap .textLayer ::-moz-selection {
  background: rgba(56, 189, 248, 0.38);
  color: transparent;
}

.pdf-canvas,
.pdf-canvas-page {
  display: block;
  position: relative;
  z-index: 0;
  background: #ffffff;
  border-radius: 1rem;
  box-shadow: 0 2px 14px rgba(0, 0, 0, 0.38);
}

.pdf-canvas-page {
  flex-shrink: 0;
}

.pdf-loading-overlay {
  position: absolute;
  inset: 0;
  z-index: 2;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(8, 14, 30, 0.65);
  backdrop-filter: blur(4px);
}

.pdf-loading-overlay.hidden {
  display: none;
}

.pdf-empty-state {
  position: absolute;
  inset: 0;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 1.5rem;
  text-align: center;
  color: rgb(148 163 184);
  font-size: 0.8rem;
  background: rgba(8, 14, 30, 0.35);
}

.pdf-empty-state.hidden {
  display: none;
}

body.preview-mode-active {
  --preview-sticky-top: 5.25rem;
}

@media (max-width: 1023px) {
  body.preview-mode-active:has(#pdf-tab-bar-wrap:not([hidden])) {
    --preview-sticky-top: 6.75rem;
  }
}

body.preview-mode-active #site-main {
  max-width: none;
  width: 100%;
  padding-left: 1rem;
  padding-right: 1rem;
  padding-top: 0.75rem;
  padding-bottom: 1rem;
  box-sizing: border-box;
}

body.preview-mode-active .site-header-inner.max-w-5xl {
  max-width: none;
}