:root {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  
  --bg-primary: #0e1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --border-color: #30363d;
  
  --text-main: #f0f6fc;
  --text-muted: #8b949e;
  --text-dim: #484f58;
  
  --accent: #58a6ff;
  --accent-hover: #79b8ff;
  --accent-dim: rgba(88, 166, 255, 0.15);
  
  --success: #3fb950;
  --warning: #d29922;
  --danger: #f85149;
  
  --header-height: 54px;
  --sidebar-width: 280px;
}

body.theme-light {
  --bg-primary: #ffffff;
  --bg-secondary: #f6f8fa;
  --bg-tertiary: #eaeef2;
  --border-color: #d0d7de;
  
  --text-main: #1f2328;
  --text-muted: #656d76;
  --text-dim: #8c959f;
  
  --accent: #0969da;
  --accent-hover: #0860ca;
  --accent-dim: rgba(9, 105, 218, 0.1);
}

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

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-main);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

/* Header */
.app-header {
  height: var(--header-height);
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  z-index: 100;
}

.header-left, .header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 6px;
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

.logo-glyph {
  color: var(--accent);
}

.session-badge {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--bg-tertiary);
  padding: 3px 8px;
  border-radius: 12px;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.session-badge .dot {
  width: 6px;
  height: 6px;
  background: var(--accent);
  border-radius: 50%;
}

.header-center {
  flex: 1;
  max-width: 440px;
  margin: 0 20px;
}

.search-box {
  display: flex;
  align-items: center;
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 4px 10px;
  font-size: 0.85rem;
  transition: border-color 0.15s ease;
}

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

.search-icon {
  font-size: 0.85rem;
  margin-right: 6px;
  opacity: 0.7;
}

.search-box input {
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-main);
  width: 100%;
  font-size: 0.85rem;
}

.shortcut-hint {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  background: var(--bg-tertiary);
  padding: 2px 4px;
  border-radius: 3px;
  color: var(--text-muted);
}

.expiry-timer, .p2p-status {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.status-indicator {
  width: 8px;
  height: 8px;
  border-radius: 50%;
}

.status-connecting {
  background: var(--warning);
  animation: pulse 1.5s infinite;
}

.status-connected {
  background: var(--success);
}

.status-failed {
  background: var(--danger);
}

@keyframes pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.9); }
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 6px;
  border-radius: 6px;
  font-size: 1rem;
  transition: color 0.15s, background 0.15s;
}

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

/* Banner */
.banner {
  padding: 8px 16px;
  font-size: 0.85rem;
  text-align: center;
  border-bottom: 1px solid transparent;
}

.banner-hidden {
  display: none;
}

.banner-warning {
  background: rgba(210, 153, 34, 0.15);
  color: var(--warning);
  border-color: rgba(210, 153, 34, 0.3);
}

.banner-danger {
  background: rgba(248, 81, 73, 0.15);
  color: var(--danger);
  border-color: rgba(248, 81, 73, 0.3);
}

/* Layout */
.app-layout {
  display: flex;
  flex: 1;
  overflow: hidden;
}

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

.sidebar-header {
  padding: 10px 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-dim);
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--border-color);
}

.tree-container {
  flex: 1;
  overflow-y: auto;
  padding: 8px 4px;
}

.tree-item {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 4px 8px;
  border-radius: 4px;
  cursor: pointer;
  font-size: 0.82rem;
  color: var(--text-muted);
  user-select: none;
  transition: background 0.1s, color 0.1s;
}

.tree-item:hover {
  background: var(--bg-tertiary);
  color: var(--text-main);
}

.tree-item.active {
  background: var(--accent-dim);
  color: var(--accent);
  font-weight: 500;
}

.tree-icon {
  font-size: 0.9rem;
}

/* Main Content */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--bg-primary);
}

.breadcrumb-nav {
  height: 40px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px;
  background: var(--bg-secondary);
}

.breadcrumbs {
  display: flex;
  align-items: center;
  gap: 4px;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.crumb {
  cursor: pointer;
}

.crumb:hover {
  color: var(--accent);
}

.crumb.active {
  color: var(--text-main);
  font-weight: 500;
}

.crumb-sep {
  color: var(--text-dim);
}

.file-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.btn {
  border: 1px solid var(--border-color);
  background: var(--bg-tertiary);
  color: var(--text-main);
  padding: 4px 10px;
  border-radius: 5px;
  font-size: 0.8rem;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}

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

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #ffffff;
}

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

/* Views */
.view-panel {
  flex: 1;
  overflow: auto;
  position: relative;
}

/* Table */
.file-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.file-table th {
  text-align: left;
  padding: 8px 16px;
  color: var(--text-dim);
  font-weight: 500;
  border-bottom: 1px solid var(--border-color);
}

.file-table td {
  padding: 8px 16px;
  border-bottom: 1px solid rgba(48, 54, 61, 0.4);
}

.file-row {
  cursor: pointer;
  transition: background 0.1s;
}

.file-row:hover {
  background: var(--bg-secondary);
}

.file-name-cell {
  display: flex;
  align-items: center;
  gap: 8px;
}

.td-size, .td-date {
  color: var(--text-muted);
  font-size: 0.8rem;
}

/* File Viewer */
.file-view {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.file-viewer-header {
  padding: 8px 16px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
}

.file-name {
  font-weight: 600;
}

.file-meta {
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.75rem;
}

.code-container {
  display: flex;
  flex: 1;
  overflow: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.5;
}

.line-numbers {
  padding: 12px 10px;
  text-align: right;
  color: var(--text-dim);
  user-select: none;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  min-width: 48px;
}

.code-body {
  padding: 12px 16px;
  flex: 1;
  overflow-x: auto;
  background: var(--bg-primary);
  color: var(--text-main);
}

.markdown-preview {
  padding: 24px 32px;
  max-width: 860px;
  margin: 0 auto;
  line-height: 1.6;
}

.markdown-preview h1, .markdown-preview h2, .markdown-preview h3 {
  margin-top: 1.2em;
  margin-bottom: 0.6em;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 0.3em;
}

.markdown-preview p {
  margin-bottom: 1em;
}

.markdown-preview pre {
  background: var(--bg-secondary);
  padding: 12px;
  border-radius: 6px;
  overflow-x: auto;
  margin-bottom: 1em;
}

.media-preview {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 32px;
  height: 100%;
}

.media-preview img, .media-preview video {
  max-width: 100%;
  max-height: 80vh;
  border-radius: 6px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.binary-notice {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  gap: 16px;
  color: var(--text-muted);
}

.binary-icon {
  font-size: 3rem;
}

/* Search results view */
.search-view {
  padding: 16px;
}

.search-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 8px;
}

.search-match-item {
  padding: 10px 14px;
  border-radius: 6px;
  background: var(--bg-secondary);
  margin-bottom: 8px;
  cursor: pointer;
  transition: background 0.1s;
}

.search-match-item:hover {
  background: var(--bg-tertiary);
}

.search-match-path {
  font-weight: 600;
  font-size: 0.85rem;
  color: var(--accent);
  margin-bottom: 4px;
}

.search-match-line {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--text-muted);
  white-space: pre-wrap;
}

/* Responsive */
@media (max-width: 768px) {
  :root {
    --sidebar-width: 0px;
  }
  .sidebar {
    display: none;
  }
  .header-center {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}