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

:root {
  --accent-sel:  #0063D1;
  --text-1:      #1C1C1E;
  --text-2:      #636366;
  --text-3:      #AEAEB2;
  --text-4:      #C7C7CC;
  --sep:         rgba(0,0,0,0.10);
  --sep-strong:  rgba(0,0,0,0.16);
  --sidebar-bg:  rgba(242,242,247,0.92);
  --titlebar-bg: rgba(235,235,235,0.97);
  --content-bg:  #FFFFFF;
  --row-hover:   rgba(0,0,0,0.045);
  --shadow:      0 24px 80px rgba(0,0,0,0.22), 0 6px 18px rgba(0,0,0,0.12),
                 inset 0 0 0 0.5px rgba(255,255,255,0.5);
}

html, body {
  height: 100%;
  overflow: hidden;
  font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Text', 'Helvetica Neue', sans-serif;
  -webkit-font-smoothing: antialiased;
}

body {
  background: #D4D4D4;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

/* ─── Window ──────────────────────────────────────────────── */
.window {
  /* size set by JS on init */
  display: flex;
  flex-direction: column;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 0.5px solid rgba(0,0,0,0.22);
  position: relative;
}

/* ─── Resize handles ──────────────────────────────────────── */
.rh { position: absolute; z-index: 500; }
.rh-e  { right: 0;  top: 8px;  bottom: 8px; width: 5px;   cursor: ew-resize; }
.rh-s  { bottom: 0; left: 8px; right: 8px;  height: 5px;  cursor: ns-resize; }
.rh-se { right: 0;  bottom: 0; width: 16px; height: 16px; cursor: nwse-resize; }

/* ─── Title bar ───────────────────────────────────────────── */
.titlebar {
  height: 48px;
  background: var(--titlebar-bg);
  display: flex;
  align-items: center;
  padding: 0 10px;
  border-bottom: 0.5px solid var(--sep-strong);
  flex-shrink: 0;
  position: relative;
  -webkit-user-select: none;
  user-select: none;
  cursor: grab;
}

.titlebar:active { cursor: grabbing; }

.titlebar-btns {
  display: flex;
  align-items: center;
  gap: 2px;
  flex-shrink: 0;
  z-index: 1;
}

.tb-btn {
  width: 28px;
  height: 24px;
  background: none;
  border: none;
  border-radius: 6px;
  cursor: default;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-3);
  transition: background 0.08s, color 0.08s;
  flex-shrink: 0;
}

.tb-btn:hover {
  background: rgba(0,0,0,0.07);
  color: var(--text-1);
}

.tb-btn svg {
  width: 13px;
  height: 13px;
  stroke: currentColor;
  fill: none;
  stroke-width: 1.6;
  stroke-linecap: round;
  stroke-linejoin: round;
  display: block;
}

.titlebar-center {
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  align-items: center;
  gap: 6px;
  pointer-events: none;
}

.titlebar-icon {
  width: 15px;
  height: 15px;
  opacity: 0.45;
  flex-shrink: 0;
}

.titlebar-title {
  font-size: 13px;
  font-weight: 600;
  color: var(--text-1);
  letter-spacing: -0.15px;
  max-width: 460px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ─── Tab bar ─────────────────────────────────────────────── */
.tabbar {
  height: 32px;
  flex-shrink: 0;
  background: #E4E4E4;
  border-bottom: 0.5px solid var(--sep-strong);
  display: flex;
  align-items: stretch;
  overflow: hidden;
}

.tab {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 0 8px 0 12px;
  max-width: 180px;
  min-width: 80px;
  border-right: 0.5px solid var(--sep-strong);
  cursor: default;
  flex-shrink: 1;
  position: relative;
  background: transparent;
  transition: background 0.08s;
}

.tab:hover { background: rgba(255,255,255,0.45); }

.tab.active {
  background: var(--content-bg);
  border-bottom: 0.5px solid var(--content-bg); /* erase bottom border */
  margin-bottom: -0.5px;
}

.tab-name {
  font-size: 11.5px;
  color: var(--text-2);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  flex: 1;
  min-width: 0;
}

.tab.active .tab-name { color: var(--text-1); }

.tab-close {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  border: none;
  background: none;
  border-radius: 4px;
  font-size: 13px;
  line-height: 1;
  color: var(--text-4);
  cursor: default;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  transition: opacity 0.1s, background 0.08s, color 0.08s;
  padding: 0;
}

.tab:hover .tab-close,
.tab.active .tab-close { opacity: 1; }

.tab-close:hover {
  background: rgba(0,0,0,0.09);
  color: var(--text-1);
}

/* ─── Panes ───────────────────────────────────────────────── */
.panes {
  display: flex;
  flex: 1;
  min-height: 0;
}

/* ─── Sidebar ─────────────────────────────────────────────── */
.sidebar {
  width: 218px;
  flex-shrink: 0;
  background: var(--sidebar-bg);
  border-right: 0.5px solid var(--sep-strong);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  overflow-x: hidden;
  transition: width 0.2s cubic-bezier(0.4,0,0.2,1),
              border-right-width 0.2s;
}

.sidebar.collapsed {
  width: 0;
  border-right-width: 0;
}

.sidebar::-webkit-scrollbar { width: 0; }

.sidebar-section { padding: 16px 0 8px; }

.section-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-3);
  padding: 0 18px 5px;
  white-space: nowrap;
}

/* ─── File rows ───────────────────────────────────────────── */
.row {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 3px 10px 3px 14px;
  margin: 0 5px;
  border-radius: 7px;
  cursor: default;
  min-height: 27px;
  transition: background 0.08s;
  white-space: nowrap;
}

.row:hover           { background: var(--row-hover); }
.row.active          { background: var(--accent-sel); }
.row.active .row-name,
.row.active .row-icon { color: #fff; }

.row-icon {
  font-size: 14px;
  line-height: 1;
  width: 17px;
  text-align: center;
  flex-shrink: 0;
  color: var(--text-2);
}

.row-name {
  font-size: 12.5px;
  color: var(--text-1);
  overflow: hidden;
  text-overflow: ellipsis;
  line-height: 1;
}

/* ─── Folder ──────────────────────────────────────────────── */
.folder-header {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 3px 10px;
  margin: 0 5px;
  border-radius: 7px;
  cursor: default;
  min-height: 27px;
  transition: background 0.08s;
}

.folder-header:hover { background: var(--row-hover); }

.chevron {
  width: 13px;
  height: 13px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: transform 0.14s ease;
}

.chevron svg {
  width: 8px;
  height: 8px;
  fill: none;
  stroke: var(--text-3);
  stroke-width: 2.2;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.chevron.open { transform: rotate(90deg); }

.folder-children {
  overflow: hidden;
  max-height: 0;
  transition: max-height 0.22s cubic-bezier(0.4,0,0.2,1);
}

.folder-children .row { padding-left: 30px; }

/* ─── Viewer ──────────────────────────────────────────────── */
.viewer {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  background: var(--content-bg);
  min-width: 0;
}

.viewer-topbar {
  height: 36px;
  flex-shrink: 0;
  border-bottom: 0.5px solid var(--sep);
  display: flex;
  align-items: center;
  padding: 0 20px;
  justify-content: space-between;
  background: #FAFAFA;
}

.viewer-topbar-left {
  display: flex;
  align-items: center;
  gap: 6px;
  min-width: 0;
}

.viewer-filename {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-1);
  letter-spacing: -0.1px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.viewer-ext {
  font-size: 10.5px;
  color: var(--text-3);
  font-weight: 500;
  background: #EFEFEF;
  padding: 1px 5px;
  border-radius: 4px;
  flex-shrink: 0;
}

.viewer-meta {
  font-size: 11px;
  color: var(--text-3);
  flex-shrink: 0;
}

#js-content {
  flex: 1;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  min-height: 0;
}

/* ─── Empty state ─────────────────────────────────────────── */
.empty-state {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  -webkit-user-select: none;
  user-select: none;
}

.empty-icon      { font-size: 40px; opacity: 0.28; line-height: 1; }
.empty-primary   { font-size: 13px; font-weight: 600; color: var(--text-3); }
.empty-secondary { font-size: 11.5px; color: var(--text-4); }

/* ─── Story content ───────────────────────────────────────── */
.viewer-scroll {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 36px 48px 48px;
}

.viewer-scroll::-webkit-scrollbar { width: 7px; }
.viewer-scroll::-webkit-scrollbar-track { background: transparent; }
.viewer-scroll::-webkit-scrollbar-thumb {
  background: rgba(0,0,0,0.10);
  border-radius: 4px;
}
.viewer-scroll::-webkit-scrollbar-thumb:hover { background: rgba(0,0,0,0.18); }

.story-text {
  font-family: 'Menlo', 'Monaco', 'Courier New', monospace;
  font-size: 12.5px;
  line-height: 1.82;
  color: #2C2C2E;
  white-space: pre-wrap;
  word-break: break-word;
  tab-size: 4;
}

@keyframes fadeUp {
  from { opacity: 0; transform: translateY(5px); }
  to   { opacity: 1; transform: translateY(0); }
}

.story-text  { animation: fadeUp 0.16s ease; }

/* ─── Status bar ──────────────────────────────────────────── */
.statusbar {
  height: 22px;
  background: var(--titlebar-bg);
  border-top: 0.5px solid var(--sep-strong);
  flex-shrink: 0;
  display: flex;
  align-items: center;
  padding: 0 16px;
  gap: 12px;
  -webkit-user-select: none;
  user-select: none;
}

.status-item { font-size: 11px; color: var(--text-3); }
.status-item a {
  color: var(--text-3);
  text-decoration: none;
  transition: color 0.08s;
}
.status-item a:hover { color: var(--text-1); }
.status-dot  { color: var(--text-4); }

.loading-msg {
  font-family: 'Menlo', 'Monaco', monospace;
  font-size: 12px;
  color: var(--text-3);
  padding: 48px;
  animation: fadeUp 0.2s ease;
}

.error-msg {
  font-family: 'Menlo', 'Monaco', monospace;
  font-size: 12px;
  color: #FF3B30;
  padding: 48px;
  line-height: 1.8;
  white-space: pre;
}