diff --git a/crates/model/src/style.rs b/crates/model/src/style.rs
index 126727eda..d3976876e 100644
--- a/crates/model/src/style.rs
+++ b/crates/model/src/style.rs
@@ -377,6 +377,12 @@ impl Default for StyleTable {
 }
 
 impl StyleTable {
+    /// A table whose default (Normal) style is `normal`, such as a file's own Normal font.
+    pub fn with_default(normal: Style) -> Self {
+        let mut index = HashMap::new();
+        index.insert(normal.clone(), StyleId::DEFAULT);
+        StyleTable { styles: vec![normal], index }
+    }
     pub fn get(&self, id: StyleId) -> &Style {
         self.styles.get(id.0 as usize).or_else(|| self.styles.first()).unwrap_or(&DEFAULT_STYLE)
     }
diff --git a/crates/xlsx/src/read.rs b/crates/xlsx/src/read.rs
index b379238c1..ed7996a6f 100644
--- a/crates/xlsx/src/read.rs
+++ b/crates/xlsx/src/read.rs
@@ -123,6 +123,10 @@ pub fn read_xlsx(bytes: &[u8]) -> Result<(Workbook, ReadReport), IoError> {
         if let Some(x) = cx.optional_xml(&r.target)? {
             let StylesIn { xfs, dxfs, palette, named, num_fmts } = read_styles(&x, &checkboxes);
             cx.num_fmts = num_fmts;
+            // Cell format 0 is the Normal style: its font is what every unformatted cell shows.
+            if let Some(normal) = xfs.first() {
+                cx.styles = StyleTable::with_default(Style { font: normal.font.clone(), ..Style::default() });
+            }
             cx.xf_map = xfs.into_iter().enumerate().map(|(i, s)| if i == 0 { StyleId::DEFAULT } else { cx.styles.intern(s) }).collect();
             cx.dxfs = dxfs;
             cx.palette = palette;
diff --git a/crates/xlsx/src/styles.rs b/crates/xlsx/src/styles.rs
index 1c98a544c..01f1fa632 100644
--- a/crates/xlsx/src/styles.rs
+++ b/crates/xlsx/src/styles.rs
@@ -396,7 +396,8 @@ pub fn color_attrs(c: &Color) -> String {
     }
 }
 
-fn font_xml(f: &Font, dxf: bool) -> String {
+/// `minor`: the font follows the theme's body font (`<scheme val="minor"/>`).
+fn font_xml(f: &Font, dxf: bool, minor: bool) -> String {
     let mut s = String::from("<font>");
     if f.bold {
         s.push_str("<b/>");
@@ -429,6 +430,9 @@ fn font_xml(f: &Font, dxf: bool) -> String {
     }
     if !dxf {
         let _ = write!(s, "<name val=\"{}\"/><family val=\"2\"/>", esc_attr(&f.name));
+        if minor {
+            s.push_str("<scheme val=\"minor\"/>");
+        }
     }
     s.push_str("</font>");
     s
@@ -667,7 +671,7 @@ pub fn write_styles(wb: &Workbook, dxfs: &[Style], extra_fmts: &[String]) -> (St
             || d.font.color != Color::Auto
             || d.font.vert != VertAlign::Baseline
         {
-            dx.push_str(&font_xml(&d.font, true));
+            dx.push_str(&font_xml(&d.font, true, false));
         }
         if d.num_fmt != def.num_fmt {
             let id = nf.id(d.num_fmt.as_str());
@@ -699,8 +703,9 @@ pub fn write_styles(wb: &Workbook, dxfs: &[Style], extra_fmts: &[String]) -> (St
         s.push_str("</numFmts>");
     }
     let _ = write!(s, "<fonts count=\"{}\">", fonts.len());
-    for f in &fonts {
-        s.push_str(&font_xml(f, false));
+    for (i, f) in fonts.iter().enumerate() {
+        // A Normal font in the theme's body face follows the theme, as Excel writes it (#805).
+        s.push_str(&font_xml(f, false, i == 0 && f.name == wb.theme.minor_font));
     }
     let _ = write!(s, "</fonts><fills count=\"{}\">", fills.len());
     for f in &fills {
diff --git a/crates/xlsx/src/tests/roundtrip.rs b/crates/xlsx/src/tests/roundtrip.rs
index 550c7a460..d214fd214 100644
--- a/crates/xlsx/src/tests/roundtrip.rs
+++ b/crates/xlsx/src/tests/roundtrip.rs
@@ -1051,6 +1051,51 @@ fn package_kind_sets_workbook_content_type() {
     assert_eq!(crate::XlsxKind::from_path("noext"), crate::XlsxKind::Workbook);
 }
 
+/// The workbook's default font (`fonts[0]`, the Normal style's) is what every default-formatted
+/// cell shows, typed or empty; saving keeps it instead of resetting it to Calibri 11 (#805).
+#[test]
+fn default_font_survives_a_round_trip() {
+    let styles = |font0: &str| {
+        format!(
+            r#"<styleSheet xmlns="http://schemas.openxmlformats.org/spreadsheetml/2006/main"><fonts count="2"><font>{font0}</font><font><b/><sz val="14"/><color theme="1"/><name val="Arial"/><family val="2"/></font></fonts>
+            <fills count="2"><fill><patternFill patternType="none"/></fill><fill><patternFill patternType="gray125"/></fill></fills><borders count="1"><border><left/><right/><top/><bottom/><diagonal/></border></borders>
+            <cellStyleXfs count="1"><xf numFmtId="0" fontId="0" fillId="0" borderId="0"/></cellStyleXfs>
+            <cellXfs count="2"><xf numFmtId="0" fontId="0" fillId="0" borderId="0" xfId="0"/><xf numFmtId="0" fontId="1" fillId="0" borderId="0" xfId="0" applyFont="1"/></cellXfs>
+            <cellStyles count="1"><cellStyle name="Normal" xfId="0" builtinId="0"/></cellStyles></styleSheet>"#
+        )
+    };
+    let rels = r#"<Relationship Id="rId2" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/styles" Target="styles.xml"/>"#;
+    let body = r#"<sheetData><row r="1"><c r="A1" t="inlineStr"><is><t>typed text</t></is></c><c r="B1" s="1"><v>1</v></c></row></sheetData>"#;
+    let font0 = |bytes: &[u8]| {
+        let mut pkg = Package::open(bytes).unwrap();
+        let st = pkg.read_xml("xl/styles.xml").unwrap().unwrap();
+        let f = st.child("fonts").unwrap().kids("font").next().unwrap().clone();
+        let val = |n: &str| f.child(n).and_then(|e| e.attr("val")).map(str::to_string);
+        (val("sz"), val("name"), val("family"), val("scheme"))
+    };
+
+    let file =
+        super::minimal(body, &[("xl/styles.xml", &styles(r#"<sz val="10"/><color theme="1"/><name val="Arial"/><family val="2"/>"#))], rels, "");
+    let (wb, _) = read_xlsx(&file).unwrap();
+    let saved = write_xlsx(&wb).unwrap();
+    assert_eq!(font0(&saved), (Some("10".into()), Some("Arial".into()), Some("2".into()), None));
+    let (back, _) = read_xlsx(&saved).unwrap();
+    let normal = &back.styles.get(StyleId::DEFAULT).font;
+    assert_eq!((normal.name.as_str(), normal.size), ("Arial", 10.0), "empty cells and new input take the Normal font");
+    let s = back.sheet(0).unwrap();
+    assert_eq!(s.cell(at("A1")).unwrap().style, StyleId::DEFAULT);
+    let b1 = &back.styles.get(s.cell(at("B1")).unwrap().style).font;
+    assert!(b1.bold && b1.size == 14.0, "an explicit font is still its own: {b1:?}");
+
+    // Excel's own Normal font follows the theme's body font; the scheme link survives too.
+    let file = super::minimal(
+        body,
+        &[("xl/styles.xml", &styles(r#"<name val="Calibri"/><family val="2"/><color theme="1"/><sz val="12"/><scheme val="minor"/>"#))],
+        rels,
+        "",
+    );
+    let saved = write_xlsx(&read_xlsx(&file).unwrap().0).unwrap();
+    assert_eq!(font0(&saved), (Some("12".into()), Some("Calibri".into()), Some("2".into()), Some("minor".into())));
 #[test]
 fn solid_data_bar_survives_with_sparklines_and_gradient_neighbours() {
     let mut wb = Workbook::new();