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

:root {
  --bg: #faf8f5;
  --bg-sidebar: #f0ede8;
  --text: #2c2c2c;
  --text-muted: #777;
  --accent: #8b4513;
  --accent-hover: #a0522d;
  --border: #ddd;
  --header-bg: #1a1a2e;
  --header-text: #eee;
  --reader-bg: #fffff8;
  --highlight: #fff3cd;
  --shadow: rgba(0,0,0,0.1);
}

html { font-size: 16px; }

body {
  font-family: "Noto Serif SC", "Source Han Serif CN", "Songti SC", STSong, serif;
  background: var(--bg);
  color: var(--text);
  height: 100vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

/* Header */
#header {
  background: var(--header-bg);
  color: var(--header-text);
  display: flex;
  align-items: center;
  padding: 0 1rem;
  height: 52px;
  flex-shrink: 0;
  gap: 1rem;
  z-index: 100;
}

#menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--header-text);
  font-size: 1.4rem;
  cursor: pointer;
  padding: 0.25rem;
}

#site-title {
  font-size: 1.1rem;
  font-weight: 600;
  white-space: nowrap;
}

#search-box {
  position: relative;
  flex: 1;
  max-width: 400px;
  margin-left: auto;
}

#search-input {
  width: 100%;
  padding: 0.4rem 0.75rem;
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 6px;
  background: rgba(255,255,255,0.1);
  color: #fff;
  font-size: 0.9rem;
  outline: none;
  font-family: inherit;
}

#search-input::placeholder { color: rgba(255,255,255,0.5); }
#search-input:focus { border-color: rgba(255,255,255,0.5); background: rgba(255,255,255,0.15); }

#search-results {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 0 0 6px 6px;
  max-height: 400px;
  overflow-y: auto;
  display: none;
  z-index: 200;
  box-shadow: 0 4px 12px var(--shadow);
}

#search-results.active { display: block; }

.search-item {
  padding: 0.5rem 0.75rem;
  cursor: pointer;
  color: var(--text);
  font-size: 0.85rem;
  border-bottom: 1px solid #f0f0f0;
}

.search-item:hover, .search-item.active { background: var(--highlight); }
.search-item .search-path { color: var(--text-muted); font-size: 0.75rem; display: block; }

/* Layout */
#app {
  display: flex;
  flex: 1;
  overflow: hidden;
}

/* Sidebar */
#sidebar {
  width: 300px;
  flex-shrink: 0;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

#sidebar-header {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}

#tree {
  flex: 1;
  overflow-y: auto;
  padding: 0.5rem 0;
}

.tree-category, .tree-work {
  cursor: pointer;
  user-select: none;
}

.tree-category > .tree-label,
.tree-work > .tree-label {
  display: flex;
  align-items: center;
  padding: 0.4rem 0.75rem;
  font-size: 0.9rem;
  gap: 0.4rem;
  transition: background 0.15s;
}

.tree-category > .tree-label:hover,
.tree-work > .tree-label:hover { background: rgba(0,0,0,0.05); }

.tree-label .arrow {
  font-size: 0.65rem;
  transition: transform 0.2s;
  color: var(--text-muted);
  width: 1em;
  text-align: center;
}

.tree-label .arrow.open { transform: rotate(90deg); }

.tree-category > .tree-label { font-weight: 600; color: var(--accent); }
.tree-work > .tree-label { padding-left: 1.5rem; }

.tree-children { display: none; }
.tree-children.open { display: block; }

.tree-file {
  display: block;
  padding: 0.3rem 0.75rem 0.3rem 3rem;
  font-size: 0.82rem;
  color: var(--text);
  cursor: pointer;
  text-decoration: none;
  transition: background 0.15s;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.tree-file:hover { background: rgba(0,0,0,0.05); }
.tree-file.active { background: var(--highlight); font-weight: 600; }

/* Badge for file count */
.tree-label .badge {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-left: auto;
  font-weight: normal;
}

/* Main content */
#content {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

#welcome {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  flex: 1;
  text-align: center;
  color: var(--text-muted);
  padding: 2rem;
}

#welcome h2 { font-size: 1.5rem; margin-bottom: 0.5rem; color: var(--text); }
#stats { margin-top: 1rem; font-size: 0.85rem; }

/* Reader */
#reader { display: flex; flex-direction: column; flex: 1; }

#reader-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.5rem 1rem;
  background: var(--bg-sidebar);
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
  gap: 0.5rem;
}

#reader-title {
  font-weight: 600;
  font-size: 0.95rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
}

#reader-actions {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  flex-shrink: 0;
}

#reader-actions button, #download-link {
  padding: 0.3rem 0.6rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: #fff;
  cursor: pointer;
  font-size: 0.8rem;
  color: var(--text);
  text-decoration: none;
  font-family: inherit;
}

#reader-actions button:hover, #download-link:hover { background: #f0f0f0; }

#reader-loading {
  text-align: center;
  padding: 3rem;
  color: var(--text-muted);
}

#reader-text {
  flex: 1;
  padding: 1.5rem 2rem;
  background: var(--reader-bg);
  font-family: "Noto Serif SC", "Source Han Serif CN", "Songti SC", STSong, serif;
  font-size: 1rem;
  line-height: 1.9;
  white-space: pre-wrap;
  word-wrap: break-word;
  overflow-y: auto;
  tab-size: 4;
}

/* Overlay for mobile sidebar */
#overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.4);
  z-index: 49;
}

/* Responsive */
@media (max-width: 768px) {
  #menu-toggle { display: block; }

  #sidebar {
    position: fixed;
    top: 52px;
    left: 0;
    bottom: 0;
    z-index: 50;
    transform: translateX(-100%);
    transition: transform 0.25s ease;
    width: 280px;
  }

  #sidebar.open { transform: translateX(0); }

  #site-title { font-size: 1rem; }

  #reader-text { padding: 1rem; }
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: #ccc; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: #aaa; }