diff --git a/A00_Common/spreadsheet/spreadsheet_clipboard.ts b/A00_Common/spreadsheet/spreadsheet_clipboard.ts
index 4cad6c73..5b5e0093 100644
--- a/A00_Common/spreadsheet/spreadsheet_clipboard.ts
+++ b/A00_Common/spreadsheet/spreadsheet_clipboard.ts
@@ -20,6 +20,7 @@ import { moveFormula, r1c1ToA1 } from "./spreadsheet_refshift";
 import { st } from "./spreadsheet_text";
 import type {
   BorderLine,
+  BorderSide,
   Cell,
   CellAddress,
   CellInput,
@@ -48,7 +49,12 @@ const BORDER_CSS: Record<BorderLine, string> = {
 
 function styleAt(book: Workbook, sheet: Sheet, r: number, c: number): CellStyle {
   const cell = sheet.칸[toA1(r, c)];
-  const idx = cell?.서식 ?? sheet.열?.[colName(c)]?.서식 ?? sheet.행?.[String(r + 1)]?.서식 ?? 0;
+  const idx =
+    cell?.서식 ??
+    sheet.열?.[colName(c)]?.서식 ??
+    sheet.행?.[String(r + 1)]?.서식 ??
+    sheet.기본?.서식 ??
+    0;
   return book.서식[idx] ?? {};
 }
 
@@ -213,12 +219,108 @@ function walkTable(table: HTMLTableElement): TableWalk {
   return { rows: rows.length, cols, owner, merges };
 }
 
+/** 엑셀 · 구글이 `td style="..."` 에 싣는 인라인 서식 → `CellStyle`(읽을 것 없으면 undefined). */
+function parseStyleAttr(styleAttr: string): Record<string, string> {
+  const out: Record<string, string> = {};
+  for (const decl of styleAttr.split(";")) {
+    const i = decl.indexOf(":");
+    if (i < 0) continue;
+    const key = decl.slice(0, i).trim().toLowerCase();
+    const value = decl.slice(i + 1).trim();
+    if (key) out[key] = value;
+  }
+  return out;
+}
+
+function cssColorToHex(v: string | undefined): string | undefined {
+  if (!v) return undefined;
+  const s = v.trim().toLowerCase();
+  if (!s || s === "windowtext" || s === "transparent" || s === "none" || s === "auto")
+    return undefined;
+  if (/^#[0-9a-f]{3}$/.test(s)) return `#${s[1]}${s[1]}${s[2]}${s[2]}${s[3]}${s[3]}`;
+  if (/^#[0-9a-f]{6}$/.test(s)) return s;
+  const rgb = /^rgba?\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)/.exec(s);
+  if (rgb) {
+    const hex = (n: string) => Number(n).toString(16).padStart(2, "0");
+    return `#${hex(rgb[1])}${hex(rgb[2])}${hex(rgb[3])}`;
+  }
+  return undefined;
+}
+
+/** 엑셀 `mso-number-format:"\#\,\#\#0\.00"` — 따옴표 떼고 `\x` 이스케이프 풀기. */
+function unescapeMsoNumFmt(v: string): string {
+  return v.replace(/^"|"$/g, "").replace(/\\(.)/g, "$1");
+}
+
+const BORDER_STYLE_MAP: Record<string, BorderLine> = {
+  solid: "thin",
+  dashed: "dashed",
+  dotted: "dotted",
+  double: "double",
+};
+
+function parseBorderShorthand(v: string): BorderSide | undefined {
+  const m = /([\d.]+)\s*(?:pt|px)\s+(solid|dashed|dotted|double)\s*([^;]*)/i.exec(v);
+  if (!m) return undefined;
+  const 선 = BORDER_STYLE_MAP[m[2].toLowerCase()] ?? "thin";
+  const 색 = cssColorToHex(m[3]);
+  return 색 ? { 선, 색 } : { 선 };
+}
+
+/** `<style>...</style>` 안 `.xl65 {...}` 짜임(엑셀이 인라인 대신 클래스로 서식을 실을 때) → 클래스별 선언. */
+function parseClassRules(doc: Document): Record<string, Record<string, string>> {
+  const css = Array.from(doc.querySelectorAll("style"))
+    .map((s) => s.textContent ?? "")
+    .join("\n");
+  const rules: Record<string, Record<string, string>> = {};
+  for (const m of css.matchAll(/\.([a-zA-Z0-9_-]+)\s*\{([^}]*)\}/g)) {
+    rules[m[1]] = parseStyleAttr(m[2]);
+  }
+  return rules;
+}
+
+function styleFromTd(
+  cellEl: HTMLTableCellElement,
+  classRules: Record<string, Record<string, string>>,
+): CellStyle | undefined {
+  const decls: Record<string, string> = {};
+  for (const cls of cellEl.classList) Object.assign(decls, classRules[cls]);
+  const raw = cellEl.getAttribute("style");
+  if (raw) Object.assign(decls, parseStyleAttr(raw));
+  if (!Object.keys(decls).length) return undefined;
+  const style: CellStyle = {};
+  const weight = decls["font-weight"];
+  if (weight === "bold" || Number(weight) >= 700) style.굵게 = true;
+  if (decls["font-style"] === "italic") style.기울임 = true;
+  const color = cssColorToHex(decls["color"]);
+  if (color) style.글자색 = color;
+  const bg = cssColorToHex(decls["background-color"] ?? decls["background"]);
+  if (bg) style.채움 = bg;
+  const align = decls["text-align"];
+  if (align === "left" || align === "center" || align === "right") style.가로 = align;
+  if (decls["mso-number-format"]) style.형식 = unescapeMsoNumFmt(decls["mso-number-format"]);
+  const 테두리: NonNullable<CellStyle["테두리"]> = {};
+  const sideMap: [string, "위" | "아래" | "왼" | "오른"][] = [
+    ["border-top", "위"],
+    ["border-bottom", "아래"],
+    ["border-left", "왼"],
+    ["border-right", "오른"],
+  ];
+  for (const [prop, side] of sideMap) {
+    const b = parseBorderShorthand(decls[prop] ?? decls["border"] ?? "");
+    if (b) 테두리[side] = b;
+  }
+  if (Object.keys(테두리).length) style.테두리 = 테두리;
+  return Object.keys(style).length ? style : undefined;
+}
+
 function parseHtmlTable(html: string, at: CellAddress): ClipBlock | null {
   const doc = new DOMParser().parseFromString(html, "text/html");
   const table = doc.querySelector("table");
   if (!table) return null;
   const walk = walkTable(table);
   const sheetsMode = /data-sheets-formula/.test(html);
+  const classRules = parseClassRules(doc);
   const 칸: Record<string, ClipCell> = {};
   for (const [key, cellEl] of walk.owner) {
     const [r, c] = key.split(",").map(Number);
@@ -229,8 +331,14 @@ function parseHtmlTable(html: string, at: CellAddress): ClipBlock | null {
       칸[key] = { 식: r1c1ToA1(formula.replace(/^=/, ""), target) };
       continue;
     }
-    if (!text) continue;
-    칸[key] = cellFromText(text);
+    const style = styleFromTd(cellEl, classRules);
+    if (!text) {
+      if (style) 칸[key] = { 서식: style };
+      continue;
+    }
+    const clip = cellFromText(text);
+    if (style) clip.서식 = style;
+    칸[key] = clip;
   }
   return {
     rows: walk.rows,
@@ -286,7 +394,48 @@ function activeRange(ctx: SpreadsheetContext): CellRange {
   );
 }
 
+function rangesOverlap(a: CellRange, b: CellRange): boolean {
+  return a.r0 <= b.r1 && a.r1 >= b.r0 && a.c0 <= b.c1 && a.c1 >= b.c0;
+}
+
+function rangeContains(outer: CellRange, inner: CellRange): boolean {
+  return (
+    outer.r0 <= inner.r0 && outer.r1 >= inner.r1 && outer.c0 <= inner.c0 && outer.c1 >= inner.c1
+  );
+}
+
+/** 붙일 자리가 기존 병합의 일부만 걸치면 막음(엑셀 「병합된 셀의 일부를 바꿀 수 없습니다」) — 병합을
+ * 통째로 덮거나(허용) · 병합 한 칸에 값 하나만 얹는 것(허용)은 됨. */
+function findBlockingMerge(sheet: Sheet, target: CellRange): boolean {
+  const isSingleCell = target.r0 === target.r1 && target.c0 === target.c1;
+  for (const m of sheet.병합 ?? []) {
+    const mr = parseRange(m);
+    if (!mr || !rangesOverlap(target, mr)) continue;
+    if (rangeContains(target, mr)) continue;
+    if (isSingleCell && rangeContains(mr, target)) continue;
+    return true;
+  }
+  return false;
+}
+
 function pasteBlock(ctx: SpreadsheetContext, block: ClipBlock, at: CellAddress): void {
+  const target: CellRange = {
+    r0: at.r,
+    c0: at.c,
+    r1: at.r + block.rows - 1,
+    c1: at.c + block.cols - 1,
+  };
+  const sheet = ctx.sheet();
+  if (findBlockingMerge(sheet, target)) {
+    showToast(st("ClipboardMergeBlocked"), "error");
+    return;
+  }
+  // 붙일 자리가 기존 병합을 통째로 덮으면 먼저 풂(엑셀도 큰 덩어리를 얹으면 병합이 풀리고 칸마다 값이 옴) —
+  // 안 풀면 A `applyCommand` 가 병합 속 왼위 아닌 칸에 값을 넣으려 할 때 막음.
+  const unmergeCmds: Command[] = (sheet.병합 ?? [])
+    .map((m) => parseRange(m))
+    .filter((m): m is CellRange => !!m && rangeContains(target, m))
+    .map((범위) => ({ 종류: "병합풀기", 시트: ctx.selection.시트, 범위 }));
   const shift = block.원점 ? { dr: at.r - block.원점.r, dc: at.c - block.원점.c } : null;
   const 칸: Record<string, Cell | null> = {};
   const styleCmds: Command[] = [];
@@ -307,7 +456,11 @@ function pasteBlock(ctx: SpreadsheetContext, block: ClipBlock, at: CellAddress):
       });
     }
   }
-  const commands: Command[] = [{ 종류: "칸", 시트: ctx.selection.시트, 칸 }, ...styleCmds];
+  const commands: Command[] = [
+    ...unmergeCmds,
+    { 종류: "칸", 시트: ctx.selection.시트, 칸 },
+    ...styleCmds,
+  ];
   for (const m of block.병합) {
     commands.push({
       종류: "병합",
diff --git a/A00_Common/spreadsheet/spreadsheet_text.ts b/A00_Common/spreadsheet/spreadsheet_text.ts
index 65c96852..df33f3d5 100644
--- a/A00_Common/spreadsheet/spreadsheet_text.ts
+++ b/A00_Common/spreadsheet/spreadsheet_text.ts
@@ -91,6 +91,10 @@ const TEXT = {
   MenuCommentEdit: ["메모 편집", "Edit comment"],
   MenuCommentDelete: ["메모 삭제", "Delete comment"],
   ClipboardPasteFailed: ["붙여넣기를 읽지 못함", "Could not read paste content"],
+  ClipboardMergeBlocked: [
+    "병합된 셀의 일부를 바꿀 수 없습니다",
+    "Can't change part of a merged cell",
+  ],
 } as const;
 
 export function st(key: keyof typeof TEXT): string {
diff --git a/A00_Common/spreadsheet/spreadsheet_toolbar.ts b/A00_Common/spreadsheet/spreadsheet_toolbar.ts
index 30846b46..21d20b15 100644
--- a/A00_Common/spreadsheet/spreadsheet_toolbar.ts
+++ b/A00_Common/spreadsheet/spreadsheet_toolbar.ts
@@ -53,11 +53,16 @@ const BORDER_LINES: BorderLine[] = [
   "dashed",
 ];
 
-/** 활성 칸에 지금 걸린 서식 — 칸 자기 것 없으면 열 · 행 · 그다음 기본(0). */
+/** 활성 칸에 지금 걸린 서식 — 칸 자기 것 없으면 열 · 행 · 시트 기본(`Sheet.기본.서식`) · 그다음 0. */
 function styleAt(ctx: SpreadsheetContext, r: number, c: number): CellStyle {
   const sheet = ctx.sheet();
   const cell = sheet.칸[toA1(r, c)];
-  const idx = cell?.서식 ?? sheet.열?.[colName(c)]?.서식 ?? sheet.행?.[String(r + 1)]?.서식 ?? 0;
+  const idx =
+    cell?.서식 ??
+    sheet.열?.[colName(c)]?.서식 ??
+    sheet.행?.[String(r + 1)]?.서식 ??
+    sheet.기본?.서식 ??
+    0;
   return ctx.book.서식[idx] ?? {};
 }