:root {
  --bg: #0b0f14;
  --panel: #121821;
  --panel-2: #18212c;
  --panel-3: #0f141b;
  --text: #ebf2f8;
  --muted: #98a6b5;
  --accent: #6ab0ff;
  --border: #273241;
  --chip: #223041;
  --shadow: 0 12px 32px rgba(0, 0, 0, 0.28);
  --radius: 16px;
  --thumb-width: 320px;
  --toolbar-height: 72px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Arial, Helvetica, sans-serif;
}

a { color: var(--accent); }
button, input { font: inherit; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  border: 0;
}

.app {
  display: grid;
  grid-template-columns: var(--thumb-width) 1fr;
  min-height: 100vh;
}

.sidebar {
  background: var(--panel);
  border-right: 1px solid var(--border);
  min-width: 0;
  display: flex;
  flex-direction: column;
  max-height: 100vh;
}

.sidebar-top {
  position: sticky;
  top: 0;
  z-index: 20;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 16px;
}

.crumb {
  display: inline-block;
  margin-bottom: 10px;
  text-decoration: none;
  font-size: 0.92rem;
}

.title {
  margin: 0 0 10px;
  font-size: 1.2rem;
  line-height: 1.35;
}

.desc {
  margin: 0 0 12px;
  color: var(--muted);
  line-height: 1.45;
  font-size: 0.92rem;
}

.chips {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.chip {
  padding: 5px 10px;
  border-radius: 999px;
  background: var(--chip);
  border: 1px solid var(--border);
  font-size: 0.78rem;
}

.search-wrap {
  display: grid;
  gap: 8px;
}

.search {
  width: 100%;
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--panel-3);
  color: var(--text);
  outline: none;
}

.search-status {
  min-height: 18px;
  color: var(--muted);
  font-size: 0.82rem;
}

.thumbs {
  overflow: auto;
  padding: 12px;
  display: grid;
  gap: 10px;
}

.thumb {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 10px;
  width: 100%;
  text-align: left;
  padding: 10px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
}

.thumb.active {
  outline: 2px solid var(--accent);
}

.thumb img {
  width: 72px;
  height: 96px;
  object-fit: cover;
  border-radius: 8px;
  background: var(--panel-3);
}

.thumb-meta { min-width: 0; }

.thumb-page {
  font-size: 0.86rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.thumb-title {
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.3;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
}

.main {
  min-width: 0;
  display: flex;
  flex-direction: column;
  max-height: 100vh;
}

.toolbar {
  position: sticky;
  top: 0;
  z-index: 30;
  min-height: var(--toolbar-height);
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  padding: 14px 18px;
  background: rgba(11, 15, 20, 0.94);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.toolbar-group-end {
  margin-left: auto;
}

button,
.btn-link {
  padding: 10px 12px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
  text-decoration: none;
  font-size: 0.92rem;
}

button.active {
  border-color: var(--accent);
  color: #fff;
}

.page-display {
  min-width: 120px;
  color: var(--muted);
  font-size: 0.92rem;
}

.viewer-scroll {
  flex: 1;
  min-height: 0;
  overflow: auto;
  padding: 18px;
  background: var(--bg);
  scroll-behavior: smooth;
}

.pdf-single {
  width: 100%;
  min-height: calc(100vh - 130px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  background: #fff;
  box-shadow: var(--shadow);
}

.pdf-frame {
  width: 100%;
  min-height: calc(100vh - 130px);
  border: 0;
  display: block;
  background: #fff;
}

.doc-stack {
  display: grid;
  gap: 18px;
  max-width: 1100px;
  margin: 0 auto;
}

.page-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow);
  overflow: hidden;
  scroll-margin-top: calc(var(--toolbar-height) + 20px);
}

.page-card.active {
  outline: 2px solid var(--accent);
}

.page-head {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--panel-2);
}

.page-head-left { min-width: 0; }

.page-number {
  font-size: 0.9rem;
  font-weight: 700;
}

.page-scope {
  color: var(--muted);
  font-size: 0.82rem;
  line-height: 1.3;
  margin-top: 2px;
}

.page-keywords {
  color: var(--muted);
  font-size: 0.75rem;
  text-align: right;
  max-width: 40%;
  line-height: 1.35;
}

.page-image-wrap {
  background: #fff;
  padding: 12px;
}

.page-image {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 10px;
}

.page-text-wrap {
  padding: 16px 18px;
}

.page-text {
  white-space: pre-wrap;
  line-height: 1.7;
  color: #dbe7f2;
  font-size: 0.98rem;
}

mark {
  background: #ffe082;
  color: #111;
  padding: 0 0.08em;
  border-radius: 3px;
}

.empty-state {
  max-width: 900px;
  margin: 0 auto;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--panel);
  padding: 24px;
  box-shadow: var(--shadow);
}

@media (max-width: 980px) {
  .app { grid-template-columns: 1fr; }

  .sidebar {
    max-height: 42vh;
    border-right: 0;
    border-bottom: 1px solid var(--border);
  }

  .viewer-scroll { padding: 12px; }

  .page-head {
    flex-direction: column;
    align-items: flex-start;
  }

  .page-keywords {
    max-width: none;
    text-align: left;
  }
}