* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: #f3f4f6;
}

body { display: flex; flex-direction: column; }

.toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: #fff;
  border-bottom: 1px solid #e5e7eb;
}
.brand { margin-right: 8px; }
.spacer { flex: 1; }

.btn, select {
  font: inherit;
  font-size: 14px;
  padding: 6px 12px;
  border: 1px solid #d1d5db;
  border-radius: 6px;
  background: #fff;
  cursor: pointer;
}
.btn.primary { background: #2563eb; border-color: #2563eb; color: #fff; }
.btn.primary:hover { background: #1d4ed8; }

.workspace {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 0;
}

#editor {
  resize: none;
  border: 0;
  border-right: 1px solid #e5e7eb;
  padding: 20px;
  font: 14px/1.6 ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  outline: none;
}
#editor.dragover { background: #eff6ff; }

.preview-wrap { overflow: auto; padding: 24px; }

/* 预览区模拟一张纸 */
#preview {
  max-width: 210mm;
  margin: 0 auto;
  padding: 20mm;
  background: #fff;
  box-shadow: 0 1px 4px rgba(0, 0, 0, .12);
  min-height: 100%;
}

/* 公式与图表 */
.math-block { display: block; margin: 1em 0; overflow-x: auto; text-align: center; }
.markdown-body .mermaid { background: none; text-align: center; padding: 0; margin: 1em 0; }
.mermaid svg { max-width: 100%; height: auto; }
.render-error {
  color: #b91c1c;
  background: #fef2f2;
  border: 1px solid #fecaca;
  border-radius: 6px;
  padding: 8px 12px;
  font: 12px/1.5 ui-monospace, Menlo, monospace;
  white-space: pre-wrap;
  text-align: left;
}

@media (max-width: 800px) {
  .workspace { grid-template-columns: 1fr; grid-template-rows: 1fr 1fr; }
  #preview { padding: 16px; }
}

/* ---------- 打印（即导出 PDF）---------- */
@media print {
  html, body { height: auto; background: #fff; }
  .toolbar, #editor { display: none !important; }
  .workspace { display: block; }
  .preview-wrap { overflow: visible; padding: 0; }
  #preview { max-width: none; padding: 0; margin: 0; box-shadow: none; }

  /* 保留背景色（代码块、表格斑马纹等） */
  * { -webkit-print-color-adjust: exact; print-color-adjust: exact; }

  /* 分页控制 */
  h1, h2, h3, h4, h5, h6 { break-after: avoid; page-break-after: avoid; }
  pre, blockquote, table, figure, img, .math-block, .mermaid { break-inside: avoid; page-break-inside: avoid; }
  .math-block { overflow: visible; }
  tr { break-inside: avoid; }
  pre { white-space: pre-wrap; word-break: break-word; }
  img { max-width: 100% !important; }

  /* 手动分页：在 Markdown 中写 <div class="page-break"></div> */
  .page-break { break-after: page; page-break-after: always; }
}