:root {
  --bg-main: #0f172a;
  --bg-card: #1e293b;
  --bg-sidebar: #111827;
  --bg-header: #0f172a;
  --bg-hover: #334155;
  --bg-active: rgba(99, 102, 241, 0.15);
  
  --border-color: #334155;
  --accent: #6366f1;
  --accent-hover: #4f46e5;
  --accent-light: rgba(99, 102, 241, 0.2);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  
  --font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-heading: 'Outfit', sans-serif;
}

[data-theme="light"] {
  --bg-main: #f8fafc;
  --bg-card: #ffffff;
  --bg-sidebar: #f1f5f9;
  --bg-header: #ffffff;
  --bg-hover: #e2e8f0;
  --bg-active: rgba(99, 102, 241, 0.12);
  
  --border-color: #cbd5e1;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-light: rgba(79, 70, 229, 0.1);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #94a3b8;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
  line-height: 1.5;
  transition: background-color 0.3s ease, color 0.3s ease;
}

.app-layout {
  display: flex;
  flex-direction: column;
  height: 100vh;
}

/* Header */
.app-header {
  height: 64px;
  background-color: var(--bg-header);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  z-index: 10;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-logo {
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--accent), #a855f7);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.4);
}

.brand-info {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-info h1 {
  font-family: var(--font-heading);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.badge {
  background-color: var(--accent-light);
  color: var(--accent);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

.stats-pill {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  padding: 6px 14px;
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.stats-pill #docCount {
  color: var(--accent);
  font-weight: 700;
}

.btn-icon {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  width: 38px;
  height: 38px;
  border-radius: var(--radius-md);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.btn-icon:hover {
  background-color: var(--bg-hover);
}

[data-theme="light"] .moon-icon { display: block; }
[data-theme="light"] .sun-icon { display: none; }
.moon-icon { display: none; }
.sun-icon { display: block; }

/* Body Grid */
.app-body {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* Sidebar */
.sidebar {
  width: 360px;
  background-color: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 16px;
  gap: 16px;
}

.search-box {
  position: relative;
  display: flex;
  align-items: center;
}

.search-box svg {
  position: absolute;
  left: 12px;
  color: var(--text-muted);
}

.search-box input {
  width: 100%;
  padding: 10px 36px 10px 38px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.9rem;
  outline: none;
  transition: border-color 0.2s;
}

.search-box input:focus {
  border-color: var(--accent);
}

.btn-clear {
  position: absolute;
  right: 10px;
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.2rem;
  cursor: pointer;
}

.filter-chips {
  display: flex;
  gap: 8px;
}

.chip {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 6px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.chip:hover {
  background: var(--bg-hover);
}

.chip.active {
  background: var(--accent);
  color: white;
  border-color: var(--accent);
}

/* Document List */
.doc-list {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding-right: 4px;
}

.doc-list::-webkit-scrollbar {
  width: 6px;
}
.doc-list::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}

.doc-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  cursor: pointer;
  transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
}

.doc-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  box-shadow: var(--shadow-md);
}

.doc-card.active {
  background-color: var(--bg-active);
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.doc-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background-color: var(--accent-light);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.doc-info {
  flex: 1;
  min-width: 0;
}

.doc-title {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
  line-height: 1.3;
  word-wrap: break-word;
}

.doc-sub {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.doc-tag {
  background: var(--bg-main);
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 500;
}

/* Viewer Container */
.viewer-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-main);
}

.viewer-toolbar {
  height: 64px;
  background-color: var(--bg-card);
  border-bottom: 1px solid var(--border-color);
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.doc-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.doc-meta h2 {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 600;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.doc-size-badge {
  font-size: 0.75rem;
  color: var(--text-muted);
  background: var(--bg-main);
  padding: 2px 8px;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.toolbar-btns {
  display: flex;
  align-items: center;
  gap: 10px;
}

.btn-primary, .btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
}

.btn-primary {
  background-color: var(--accent);
  color: white;
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-secondary {
  background-color: var(--bg-main);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-hover);
}

/* iframe area */
.iframe-wrapper {
  flex: 1;
  position: relative;
  background-color: #525659;
}

.iframe-wrapper iframe {
  width: 100%;
  height: 100%;
  border: none;
  display: block;
}

.empty-state {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 12px;
  color: var(--text-muted);
  padding: 20px;
}

.empty-state svg {
  color: var(--text-muted);
  opacity: 0.6;
}

.empty-state h3 {
  color: var(--text-primary);
  font-size: 1.1rem;
}

.empty-state p {
  font-size: 0.9rem;
  max-width: 320px;
}

/* Toast */
.toast {
  position: fixed;
  bottom: 24px;
  right: 24px;
  background: #10b981;
  color: white;
  padding: 12px 20px;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  transform: translateY(100px);
  opacity: 0;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 100;
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

/* Responsive */
@media (max-width: 840px) {
  .app-body {
    flex-direction: column;
  }
  
  .sidebar {
    width: 100%;
    height: 40%;
    border-right: none;
    border-bottom: 1px solid var(--border-color);
  }
  
  .viewer-container {
    height: 60%;
  }
  
  .brand-info h1 {
    font-size: 1rem;
  }
  
  .toolbar-btns span {
    display: none;
  }
}