/* ── CSS 變數（深色編輯器 / 亮色預覽，預設） ── */
:root {
  --bg: #0f1419;
  --surface: #1a2332;
  --border: #2d3a4d;
  --text: #e6edf3;
  --muted: #8b9cb3;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --editor-bg: #0d1117;
  --editor-text: #e6edf3;
  --preview-bg: #ffffff;
  --preview-text: #24292f;
  --preview-border: #d0d7de;
  --preview-header-bg: #f6f8fa;
  --preview-title: #57606a;
  --preview-code-bg: #f6f8fa;
  --preview-blockquote-color: #57606a;
  --preview-blockquote-border: #d0d7de;
  --preview-blockquote-bg: #f8f9fa;
  --preview-table-th-bg: #f6f8fa;
  --preview-h-border: #d0d7de;
  --preview-hr: #d0d7de;
  --preview-link: #0969da;
  --preview-inline-code-bg: #f6f8fa;
  --preview-inline-code-color: #c9241d;
  --preview-inline-code-border: #d0d7de;
  --transition: background-color 0.22s ease, color 0.22s ease, border-color 0.22s ease;
}

/* ── 亮色編輯器主題 ── */
html[data-editor-dark="false"] {
  --bg: #f6f8fa;
  --surface: #ffffff;
  --border: #d0d7de;
  --text: #1f2328;
  --muted: #57606a;
  --editor-bg: #ffffff;
  --editor-text: #1f2328;
}

html[data-editor-dark="false"] .btn:hover {
  background: #e7eaf0;
  border-color: #b8c0cc;
}

html[data-editor-dark="false"] .btn-primary:hover {
  background: var(--accent-hover);
  border-color: var(--accent-hover);
}

html[data-editor-dark="false"] .resizer {
  background: #d0d7de;
}

/* ── GitHub Dark 預覽主題 ── */
html[data-preview-dark="true"] {
  --preview-bg: #0d1117;
  --preview-text: #e6edf3;
  --preview-border: #30363d;
  --preview-header-bg: #161b22;
  --preview-title: #8b949e;
  --preview-code-bg: #161b22;
  --preview-blockquote-color: #8b949e;
  --preview-blockquote-border: #3d444d;
  --preview-blockquote-bg: #161b22;
  --preview-table-th-bg: #161b22;
  --preview-h-border: #30363d;
  --preview-hr: #30363d;
  --preview-link: #4493f8;
  --preview-inline-code-bg: #1c2128;
  --preview-inline-code-color: #f78166;
  --preview-inline-code-border: #30363d;
}

html[data-preview-dark="true"] .markdown-body tr:nth-child(even) td {
  background: #161b22;
}

html[data-preview-dark="true"] .markdown-body th {
  color: #e6edf3;
}

html[data-preview-dark="true"] .markdown-body td {
  border-color: #30363d;
}

html[data-preview-dark="true"] .markdown-body th {
  border-color: #30363d;
}

/* ── 基本重置 ── */
*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
  margin: 0;
}

body {
  font-family: "Noto Sans TC", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  transition: var(--transition);
}

/* ── 工具列 ── */
.toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.625rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  flex-shrink: 0;
  gap: 1rem;
  transition: var(--transition);
}

.logo {
  margin: 0;
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.toolbar-center {
  flex: 1;
  display: flex;
  justify-content: center;
}

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

.toolbar-sep {
  width: 1px;
  height: 20px;
  background: var(--border);
  margin: 0 0.25rem;
  flex-shrink: 0;
}

/* ── 按鈕 ── */
.btn {
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 500;
  padding: 0.4375rem 0.875rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  line-height: 1;
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  white-space: nowrap;
  text-decoration: none;
}

.btn:hover {
  background: #243044;
}

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

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

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* 圖示按鈕 */
.btn-icon {
  padding: 0.4375rem 0.625rem;
  color: var(--muted);
  border-color: transparent;
  background: transparent;
}

.btn-icon:hover {
  background: rgba(255, 255, 255, 0.08);
  color: var(--text);
  border-color: var(--border);
}

html[data-editor-dark="false"] .btn-icon:hover {
  background: rgba(0, 0, 0, 0.06);
  color: var(--text);
}

.btn-icon.is-active {
  background: rgba(59, 130, 246, 0.12);
  color: var(--accent);
  border-color: rgba(59, 130, 246, 0.35);
}

.btn-icon.sync-on {
  background: rgba(59, 130, 246, 0.12);
  color: var(--accent);
  border-color: rgba(59, 130, 246, 0.35);
}

.btn-theme-icon {
  gap: 0.3rem;
  padding: 0.4375rem 0.75rem;
  border: 1px solid var(--border);
  background: transparent;
}

.theme-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--muted);
  font-family: "JetBrains Mono", monospace;
}

.btn-theme-icon:hover .theme-label {
  color: var(--text);
}

.btn-lang {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.4375rem 0.625rem;
  border: 1px solid var(--border);
  font-family: "JetBrains Mono", monospace;
  min-width: 2.25rem;
  justify-content: center;
}

/* 按鈕群組 */
.btn-group {
  display: inline-flex;
  border-radius: 8px;
  border: 1px solid var(--border);
  overflow: hidden;
}

.btn-group .btn {
  border-radius: 0;
  border: none;
  border-right: 1px solid var(--border);
}

.btn-group .btn:last-child {
  border-right: none;
}

.btn-group .btn.is-active {
  border-color: transparent;
}

/* hint */
.hint {
  font-size: 0.8rem;
  color: var(--muted);
  min-width: 7rem;
  text-align: right;
}

/* ── 版面 ── */
.layout {
  display: flex;
  flex: 1;
  min-height: 0;
  overflow: hidden;
}

.pane {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  transition: var(--transition);
}

.pane-editor {
  flex: 1 1 50%;
}

.pane-preview {
  flex: 1 1 50%;
  background: var(--preview-bg);
  transition: var(--transition);
}

/* ── 版面切換（editor-only / preview-only） ── */
html[data-layout="editor"] .resizer,
html[data-layout="editor"] #pane-preview {
  display: none;
}

html[data-layout="editor"] .pane-editor {
  flex: 1 1 100%;
}

html[data-layout="preview"] .resizer,
html[data-layout="preview"] #pane-editor {
  display: none;
}

html[data-layout="preview"] .pane-preview {
  flex: 1 1 100%;
}

/* ── Pane Header ── */
.pane-header {
  padding: 0.4375rem 1rem;
  border-bottom: 1px solid var(--border);
  background: var(--surface);
  flex-shrink: 0;
  transition: var(--transition);
}

.pane-preview .pane-header {
  background: var(--preview-header-bg);
  border-color: var(--preview-border);
}

.pane-title {
  font-size: 0.6875rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--muted);
}

.pane-preview .pane-title {
  color: var(--preview-title);
}

/* ── 編輯器 ── */
.md-input {
  flex: 1;
  width: 100%;
  min-height: 0;
  padding: 1rem 1.25rem;
  border: none;
  resize: none;
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 0.875rem;
  line-height: 1.65;
  background: var(--editor-bg);
  color: var(--editor-text);
  outline: none;
  transition: var(--transition);
}

.md-input::placeholder {
  color: #6e7681;
}

/* 拖曳匯入高亮 */
.pane-editor.drag-over .md-input {
  outline: 3px dashed var(--accent);
  outline-offset: -3px;
  background: rgba(59, 130, 246, 0.06);
}

html[data-editor-dark="false"] .pane-editor.drag-over .md-input {
  background: rgba(59, 130, 246, 0.04);
}

/* ── 預覽 ── */
.preview {
  flex: 1;
  overflow: auto;
  padding: 1.25rem 1.75rem;
  color: var(--preview-text);
  font-size: 0.9375rem;
  line-height: 1.7;
  transition: var(--transition);
}

/* ── Markdown Body ── */
.markdown-body h1,
.markdown-body h2,
.markdown-body h3,
.markdown-body h4,
.markdown-body h5,
.markdown-body h6 {
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
  font-weight: 600;
  line-height: 1.25;
  color: var(--preview-text);
}

.markdown-body h1,
.markdown-body h2 {
  border-bottom: 1px solid var(--preview-h-border);
  padding-bottom: 0.3em;
}

.markdown-body h1 { font-size: 1.75rem; }
.markdown-body h2 { font-size: 1.375rem; }
.markdown-body h3 { font-size: 1.125rem; }
.markdown-body h4 { font-size: 1rem; }

.markdown-body h1:first-child,
.markdown-body h2:first-child,
.markdown-body h3:first-child {
  margin-top: 0;
}

.markdown-body p {
  margin: 0 0 1rem;
}

.markdown-body ul,
.markdown-body ol {
  margin: 0 0 1rem;
  padding-left: 1.5rem;
}

.markdown-body li {
  margin: 0.25rem 0;
}

.markdown-body blockquote {
  margin: 0 0 1rem;
  padding: 0.5em 1em;
  color: var(--preview-blockquote-color);
  border-left: 4px solid var(--preview-blockquote-border);
  background: var(--preview-blockquote-bg);
  border-radius: 0 4px 4px 0;
}

.markdown-body pre {
  margin: 0 0 1rem;
  padding: 1rem;
  overflow: auto;
  font-size: 0.8125rem;
  line-height: 1.5;
  background: var(--preview-code-bg);
  border-radius: 8px;
  border: 1px solid var(--preview-border);
}

.markdown-body pre code {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  background: none;
  padding: 0;
  border: none;
  color: inherit;
}

.markdown-body code:not(pre code) {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 0.875em;
  padding: 0.2em 0.4em;
  background: var(--preview-inline-code-bg);
  border: 1px solid var(--preview-inline-code-border);
  border-radius: 4px;
  color: var(--preview-inline-code-color);
}

.markdown-body a {
  color: var(--preview-link);
  text-decoration: none;
}

.markdown-body a:hover {
  text-decoration: underline;
}

.markdown-body table {
  border-collapse: collapse;
  width: 100%;
  margin: 0 0 1rem;
  font-size: 0.875rem;
}

.markdown-body th,
.markdown-body td {
  border: 1px solid var(--preview-border);
  padding: 0.5rem 0.75rem;
}

.markdown-body th {
  background: var(--preview-table-th-bg);
  font-weight: 600;
}

.markdown-body img {
  max-width: 100%;
  height: auto;
}

.markdown-body hr {
  border: none;
  border-top: 1px solid var(--preview-hr);
  margin: 1.5rem 0;
}

/* ── 分隔條 ── */
.resizer {
  width: 5px;
  flex-shrink: 0;
  background: var(--border);
  cursor: col-resize;
  transition: background 0.15s;
}

.resizer:hover,
.resizer.is-dragging {
  background: var(--accent);
}

/* ── 列印樣式 ── */
@media print {
  body { background: #fff; }

  .toolbar,
  .pane-editor,
  .resizer { display: none !important; }

  .layout { display: block; }

  .pane-preview { flex: none; min-height: auto; }

  .pane-preview .pane-header { display: none; }

  .preview { overflow: visible; padding: 0; }
}

/* ── 行動裝置 ── */
@media (max-width: 768px) {
  .toolbar-center { display: none; }

  .layout { flex-direction: column; }

  .resizer { width: 100%; height: 5px; cursor: row-resize; }

  .pane-editor,
  .pane-preview { flex: 1 1 auto; min-height: 40vh; }
}