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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  flex-direction: column;
  height: 100vh;
  overflow: hidden;
  background: #fff;
  font-size: 14px;
  color: #1e1e1e;
}

/* ── Top Bar ────────────────────────────── */
.top-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 16px;
  height: 44px;
  background: #5646F5;
  color: #fff;
  flex-shrink: 0;
  z-index: 20;
}
.top-bar-left {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}
.top-bar-back {
  color: rgba(255,255,255,0.85);
  text-decoration: none;
  font-size: 1.1rem;
  line-height: 1;
}
.top-bar-back:hover { color: #fff; }
.top-bar-title {
  font-size: 0.95rem;
  font-weight: 600;
  white-space: nowrap;
}
.top-bar-right {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-left: auto;
}
.top-btn {
  background: rgba(255,255,255,0.18);
  border: 1px solid rgba(255,255,255,0.25);
  color: #fff;
  width: 32px;
  height: 32px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}
.top-btn:hover { background: rgba(255,255,255,0.3); }

/* ── Menu bar ──────────────────────────────── */
.menubar {
  display: flex;
  background: #f0f0f0;
  border-bottom: 1px solid #d4d4d4;
  padding: 2px 4px;
  user-select: none;
  flex-shrink: 0;
  position: relative;
  z-index: 500;
}

.menu-item {
  position: relative;
  padding: 4px 10px;
  cursor: pointer;
  border-radius: 4px;
  font-size: 13px;
}

.menu-item:hover,
.menu-item.open {
  background: #d4d4d4;
}

.menu-item .dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  background: #fff;
  border: 1px solid #c8c8c8;
  border-radius: 4px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.18);
  z-index: 1000;
  min-width: 190px;
  padding: 4px 0;
}

.menu-item.open .dropdown {
  display: block;
}

.dropdown button {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 6px 16px;
  background: none;
  border: none;
  cursor: pointer;
  font-size: 13px;
  text-align: left;
  white-space: nowrap;
  color: #1e1e1e;
  gap: 12px;
}

.dropdown button:hover {
  background: #5646F5;
  color: #fff;
}

.dropdown hr {
  border: none;
  border-top: 1px solid #e4e4e4;
  margin: 3px 0;
}

.kbd {
  font-size: 11px;
  opacity: 0.65;
  flex-shrink: 0;
}

/* ── Toolbar ───────────────────────────────── */
.toolbar {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 4px 8px;
  background: #f8f8f8;
  border-bottom: 1px solid #e0e0e0;
  flex-shrink: 0;
  flex-wrap: wrap;
}

.tb-group {
  display: flex;
  align-items: center;
  gap: 4px;
}

.tb-sep {
  width: 1px;
  height: 20px;
  background: #c8c8c8;
  margin: 0 4px;
}

.toolbar button {
  padding: 4px 10px;
  border: 1px solid #c8c8c8;
  background: #fff;
  border-radius: 3px;
  cursor: pointer;
  font-size: 12px;
  line-height: 1.4;
}

.toolbar button:hover {
  background: #e5f0fb;
  border-color: #5646F5;
}

.toolbar label {
  font-size: 12px;
  color: #555;
}

.toolbar select {
  padding: 3px 4px;
  border: 1px solid #c8c8c8;
  border-radius: 3px;
  font-size: 12px;
  background: #fff;
  cursor: pointer;
}

/* ── Editor area ───────────────────────────── */
.editor-wrap {
  flex: 1;
  display: flex;
  overflow: hidden;
  background: #fff;
}

.line-nums {
  display: none;
  width: 52px;
  background: #f5f5f5;
  border-right: 1px solid #e0e0e0;
  padding: 8px 6px 8px 0;
  text-align: right;
  color: #aaa;
  font-size: 12px;
  font-family: Consolas, 'Courier New', monospace;
  line-height: 1.5;
  overflow: hidden;
  user-select: none;
  flex-shrink: 0;
}

.editor-wrap.show-ln .line-nums {
  display: block;
}

#editor {
  flex: 1;
  border: none;
  outline: none;
  resize: none;
  padding: 8px 10px;
  font-family: Consolas, 'Courier New', monospace;
  font-size: 12px;
  line-height: 1.5;
  tab-size: 4;
  white-space: pre-wrap;
  overflow-y: auto;
  overflow-x: hidden;
  background: #fff;
  color: #1e1e1e;
  caret-color: #5646F5;
}

/* ── Markdown preview pane ─────────────────── */
#preview-pane {
  display: none;
  flex: 1;
  padding: 16px 24px;
  overflow-y: auto;
  background: #fff;
  font-family: 'Segoe UI', Tahoma, Georgia, serif;
  font-size: 15px;
  line-height: 1.75;
  color: #1e1e1e;
}

.editor-wrap.preview-mode #editor       { display: none; }
.editor-wrap.preview-mode .line-nums    { display: none !important; }
.editor-wrap.preview-mode #preview-pane { display: block; }

#preview-pane h1, #preview-pane h2, #preview-pane h3,
#preview-pane h4, #preview-pane h5, #preview-pane h6 {
  margin: 1.1em 0 0.4em;
  line-height: 1.3;
  font-weight: 700;
}
#preview-pane h1 { font-size: 2em;   border-bottom: 2px solid #e0e0e0; padding-bottom: 6px; }
#preview-pane h2 { font-size: 1.5em; border-bottom: 1px solid #e8e8e8; padding-bottom: 4px; }
#preview-pane h3 { font-size: 1.2em; }
#preview-pane p  { margin: 0.6em 0; }
#preview-pane ul, #preview-pane ol { padding-left: 1.8em; margin: 0.5em 0; }
#preview-pane li { margin: 0.2em 0; }
#preview-pane blockquote {
  border-left: 4px solid #5646F5;
  margin: 0.8em 0;
  padding: 4px 12px;
  background: #f0f6ff;
  color: #444;
}
#preview-pane code {
  background: #f4f4f4;
  border: 1px solid #e0e0e0;
  border-radius: 3px;
  padding: 1px 5px;
  font-family: Consolas, 'Courier New', monospace;
  font-size: 0.9em;
}
#preview-pane pre {
  background: #1e1e1e;
  color: #d4d4d4;
  padding: 14px 16px;
  border-radius: 6px;
  overflow-x: auto;
  margin: 0.8em 0;
}
#preview-pane pre code {
  background: none;
  border: none;
  padding: 0;
  color: inherit;
  font-size: 13px;
}
#preview-pane table {
  border-collapse: collapse;
  margin: 0.8em 0;
  width: 100%;
}
#preview-pane th, #preview-pane td {
  border: 1px solid #ccc;
  padding: 6px 12px;
  text-align: left;
}
#preview-pane th { background: #f0f0f0; font-weight: 600; }
#preview-pane a  { color: #5646F5; }
#preview-pane hr { border: none; border-top: 1px solid #ddd; margin: 1em 0; }
#preview-pane img { max-width: 100%; }

/* KaTeX display-mode block centering */
#preview-pane .katex-display { margin: 0.8em 0; overflow-x: auto; }

/* Preview active button state */
#btn-preview.active {
  background: #5646F5;
  color: #fff;
  border-color: #4535e0;
}

/* ── Status bar ────────────────────────────── */
.statusbar {
  display: flex;
  align-items: center;
  gap: 0;
  background: #5646F5;
  color: #fff;
  font-size: 12px;
  flex-shrink: 0;
  border-top: 1px solid #4535e0;
  overflow: hidden;
}

.statusbar span {
  padding: 3px 12px;
  border-right: 1px solid rgba(255,255,255,0.25);
  white-space: nowrap;
  opacity: 0.92;
}

.statusbar span:empty {
  display: none;
}

.sb-file {
  margin-left: auto;
  border-right: none !important;
  border-left: 1px solid rgba(255,255,255,0.25);
  font-weight: 600;
}
.sb-save {
  color: var(--accent);
  font-size: 11px;
  opacity: 0;
  transition: opacity 0.3s;
}
.sb-save.flash { opacity: 1; }

/* ── Dialog overlays ───────────────────────── */
.dlg-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.28);
  z-index: 2000;
  align-items: flex-start;
  justify-content: center;
  padding-top: 80px;
}

.dlg-overlay.visible {
  display: flex;
}

.dlg {
  background: #fff;
  border: 1px solid #c8c8c8;
  border-radius: 6px;
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.22);
  width: 420px;
  max-width: 95vw;
}

.dlg-hdr {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 14px;
  background: #f0f0f0;
  border-bottom: 1px solid #d8d8d8;
  border-radius: 6px 6px 0 0;
  font-weight: 600;
  font-size: 13px;
}

.dlg-x {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 14px;
  color: #666;
  padding: 0 4px;
  line-height: 1;
}

.dlg-x:hover { color: #c00; }

.dlg-body {
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

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

.frow label {
  font-size: 13px;
  white-space: nowrap;
  min-width: 62px;
}

.frow-opts {
  gap: 16px;
}

.frow-opts label {
  min-width: 0;
  font-size: 12px;
  display: flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
}

.frow input[type="text"] {
  flex: 1;
  padding: 5px 8px;
  border: 1px solid #bbb;
  border-radius: 3px;
  font-size: 13px;
  outline: none;
}

.frow input[type="text"]:focus {
  border-color: #5646F5;
  box-shadow: 0 0 0 2px rgba(86,70,245,0.2);
}

.dlg-btns {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.dlg-btns button {
  padding: 5px 14px;
  border: 1px solid #bbb;
  background: #f0f0f0;
  border-radius: 3px;
  cursor: pointer;
  font-size: 13px;
}

.dlg-btns button:hover {
  background: #5646F5;
  color: #fff;
  border-color: #5646F5;
}

.dlg-msg {
  font-size: 12px;
  min-height: 16px;
  padding: 2px 0;
}

.dlg-msg.err { color: #c00; }
.dlg-msg.ok  { color: #090; }

/* ── Split-pane preview ────────────────────── */
.pane-splitter {
  display: none;
  width: 5px;
  cursor: col-resize;
  background: #d4d4d4;
  flex-shrink: 0;
  transition: background 0.15s;
}
.pane-splitter:hover,
.pane-splitter.dragging { background: #5646F5; }

.preview-panel {
  display: none;
  flex-direction: column;
  width: 45%;
  min-width: 160px;
  max-width: 75%;
  border-left: none;
  overflow: hidden;
}

.preview-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 10px;
  background: #f0f0f0;
  border-bottom: 1px solid #d4d4d4;
  font-size: 12px;
  font-weight: 600;
  color: #444;
  flex-shrink: 0;
}

.prev-close-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 13px;
  color: #666;
  padding: 0 2px;
  line-height: 1;
}
.prev-close-btn:hover { color: #c00; }

.prev-expand-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 14px;
  color: #666;
  padding: 0 4px;
  line-height: 1;
  margin-right: auto;
}
.prev-expand-btn:hover { color: #5646F5; }

/* In split mode the preview-panel and splitter appear */
.editor-wrap.split-mode .pane-splitter    { display: block; }
.editor-wrap.split-mode .preview-panel    { display: flex; }
.editor-wrap.split-mode #preview-pane     { display: block; flex: 1; overflow-y: auto; padding: 16px 20px; }

/* Expanded preview: hide editor, fill full width */
.editor-wrap.preview-expanded .pane-splitter { display: none !important; }
.editor-wrap.preview-expanded #editor        { display: none !important; }
.editor-wrap.preview-expanded .line-nums     { display: none !important; }
.editor-wrap.preview-expanded .preview-panel { width: 100% !important; max-width: 100% !important; }

/* Preview pane inside split-mode uses panel bg */
.editor-wrap.split-mode #preview-pane { background: var(--np-bg, #fff); }

/* Active state for split button */
#btn-split.active {
  background: #5646F5;
  color: #fff;
  border-color: #4535e0;
}

/* ── Status-bar zoom group ─────────────────── */
.sb-zoom-group {
  display: flex;
  align-items: center;
  gap: 2px;
  padding: 0 6px !important;
  border-right: 1px solid rgba(255,255,255,0.25) !important;
}

.sb-btn {
  background: none;
  border: none;
  color: #fff;
  cursor: pointer;
  font-size: 11px;
  padding: 1px 4px;
  border-radius: 3px;
  line-height: 1;
}
.sb-btn:hover { background: rgba(255,255,255,0.2); }

#sb-zoom { min-width: 34px; text-align: center; }

/* ── Case Converter dialog ─────────────────── */
.case-hint {
  font-size: 12px;
  color: var(--np-text2, #555);
  padding: 2px 0;
}

.case-btns {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.case-btns button {
  padding: 6px 14px;
  border: 1px solid #bbb;
  background: #f0f0f0;
  border-radius: 3px;
  cursor: pointer;
  font-size: 13px;
  font-family: Consolas, 'Courier New', monospace;
}

.case-btns button:hover {
  background: #5646F5;
  color: #fff;
  border-color: #5646F5;
}

[data-theme="dark"] .case-hint { color: var(--np-text2); }
[data-theme="dark"] .case-btns button {
  background: var(--np-bg3);
  border-color: var(--np-border);
  color: var(--np-text);
}
[data-theme="dark"] .case-btns button:hover {
  background: var(--np-accent);
  border-color: var(--np-accent);
  color: #1e1e1e;
}

/* ── Dark mode overrides ───────────────────── */
:root {
  --np-bg: #ffffff;
  --np-bg2: #f0f0f0;
  --np-bg3: #f8f8f8;
  --np-border: #d4d4d4;
  --np-text: #1e1e1e;
  --np-text2: #555555;
  --np-accent: #5646F5;
  --np-header-bg: #5646F5;
  --np-header-text: #ffffff;
}

[data-theme="dark"] {
  --np-bg: #1e1e1e;
  --np-bg2: #252526;
  --np-bg3: #2d2d30;
  --np-border: #3e3e42;
  --np-text: #cccccc;
  --np-text2: #888888;
  --np-accent: #8b83f7;
  --np-header-bg: #3c2fd4;
  --np-header-text: #ffffff;
}

[data-theme="dark"] body {
  background: var(--np-bg);
  color: var(--np-text);
}
[data-theme="dark"] .menubar {
  background: var(--np-bg2);
  border-bottom-color: var(--np-border);
}
[data-theme="dark"] .menu-item { color: var(--np-text); }
[data-theme="dark"] .menu-item:hover,
[data-theme="dark"] .menu-item.open { background: var(--np-bg3); }
[data-theme="dark"] .menu-item .dropdown {
  background: var(--np-bg2);
  border-color: var(--np-border);
  box-shadow: 0 4px 14px rgba(0,0,0,0.5);
}
[data-theme="dark"] .menu-item .dropdown button {
  color: var(--np-text);
}
[data-theme="dark"] .menu-item .dropdown button:hover {
  background: var(--np-bg3);
}
[data-theme="dark"] .menu-item .dropdown hr { border-color: var(--np-border); }
[data-theme="dark"] .toolbar {
  background: var(--np-bg2);
  border-bottom-color: var(--np-border);
}
[data-theme="dark"] .toolbar label { color: var(--np-text2); }
[data-theme="dark"] .toolbar button,
[data-theme="dark"] .toolbar select {
  background: var(--np-bg3);
  border-color: var(--np-border);
  color: var(--np-text);
}
[data-theme="dark"] .toolbar button:hover { background: var(--np-bg); }
[data-theme="dark"] .tb-sep { background: var(--np-border); }
[data-theme="dark"] .editor-wrap { background: var(--np-bg); }
[data-theme="dark"] .line-nums {
  background: var(--np-bg2);
  border-right-color: var(--np-border);
  color: var(--np-text2);
}
[data-theme="dark"] #editor {
  background: var(--np-bg);
  color: var(--np-text);
}
[data-theme="dark"] #preview-pane {
  background: var(--np-bg);
  color: var(--np-text);
}
[data-theme="dark"] #preview-pane h1 { border-bottom-color: var(--np-border); }
[data-theme="dark"] #preview-pane h2 { border-bottom-color: var(--np-border); }
[data-theme="dark"] #preview-pane blockquote {
  background: #1a2a3a;
  border-left-color: var(--np-accent);
  color: var(--np-text2);
}
[data-theme="dark"] #preview-pane code {
  background: var(--np-bg2);
  border-color: var(--np-border);
  color: #ce9178;
}
[data-theme="dark"] #preview-pane th { background: var(--np-bg2); }
[data-theme="dark"] #preview-pane th,
[data-theme="dark"] #preview-pane td { border-color: var(--np-border); }
[data-theme="dark"] #preview-pane a  { color: var(--np-accent); }
[data-theme="dark"] #preview-pane hr { border-top-color: var(--np-border); }
[data-theme="dark"] .preview-header {
  background: var(--np-bg2);
  border-bottom-color: var(--np-border);
  color: var(--np-text);
}
[data-theme="dark"] .prev-close-btn { color: var(--np-text2); }
[data-theme="dark"] .prev-expand-btn { color: var(--np-text2); }
[data-theme="dark"] .prev-expand-btn:hover { color: var(--np-accent); }
[data-theme="dark"] .pane-splitter  { background: var(--np-border); }
[data-theme="dark"] .pane-splitter:hover,
[data-theme="dark"] .pane-splitter.dragging { background: var(--np-accent); }
[data-theme="dark"] .dlg {
  background: var(--np-bg2);
  border-color: var(--np-border);
}
[data-theme="dark"] .dlg-hdr {
  background: var(--np-bg3);
  border-bottom-color: var(--np-border);
  color: var(--np-text);
}
[data-theme="dark"] .dlg-x { color: var(--np-text2); }
[data-theme="dark"] .dlg-body { color: var(--np-text); }
[data-theme="dark"] .frow label { color: var(--np-text); }
[data-theme="dark"] .frow input[type="text"] {
  background: var(--np-bg);
  border-color: var(--np-border);
  color: var(--np-text);
}
[data-theme="dark"] .frow input[type="text"]:focus { border-color: var(--np-accent); }
[data-theme="dark"] .dlg-btns button {
  background: var(--np-bg3);
  border-color: var(--np-border);
  color: var(--np-text);
}
[data-theme="dark"] .dlg-btns button:hover {
  background: var(--np-accent);
  border-color: var(--np-accent);
  color: #fff;
}

/* ═══════════════════════════════════════════
   RESPONSIVE
═══════════════════════════════════════════ */
@media (max-width: 768px) {
  .menubar { font-size: 12px; flex-wrap: wrap; }
  .menu-item { padding: 4px 8px; }
  .toolbar { flex-wrap: wrap; gap: 4px; padding: 4px 8px; }
  .toolbar button, .toolbar select { padding: 3px 6px; font-size: 11px; }
  .split-preview { min-width: 200px; }
  .dialog-box { width: 90vw; max-width: 400px; }
}

@media (max-width: 480px) {
  .top-bar-title { font-size: 0.85rem; }
  .top-bar { padding: 0 8px; height: 38px; }
  .menubar { font-size: 11px; }
  .menu-item { padding: 3px 6px; }
  .toolbar { padding: 3px 6px; }
  .toolbar button, .toolbar select { padding: 2px 4px; font-size: 10px; }
  #editor { font-size: 13px; padding: 6px 8px; }
  .line-numbers { display: none; }
  .dialog-box { width: 95vw; padding: 12px; }
}