diff --git a/server/src/main/resources/web/officeweb.ftl b/server/src/main/resources/web/officeweb.ftl
index 8f6c2b77..f174ad18 100644
--- a/server/src/main/resources/web/officeweb.ftl
+++ b/server/src/main/resources/web/officeweb.ftl
@@ -30,15 +30,15 @@
                 watermark_y: 0,
                 watermark_rows: 0,
                 watermark_cols: 0,
-                watermark_x_space: ${watermarkXSpace!10},
-                watermark_y_space: ${watermarkYSpace!10},
+                watermark_x_space: ${watermarkXSpace!'10'},
+                watermark_y_space: ${watermarkYSpace!'10'},
                 watermark_font: '${watermarkFont!'微软雅黑'}',
                 watermark_fontsize: '${watermarkFontsize!'18px'}',
                 watermark_color: '${watermarkColor!'black'}',
-                watermark_alpha: ${watermarkAlpha!0.2},
-                watermark_width: ${watermarkWidth!240},
-                watermark_height: ${watermarkHeight!80},
-                watermark_angle: ${watermarkAngle!10},
+                watermark_alpha: ${watermarkAlpha!'0.2'},
+                watermark_width: ${watermarkWidth!'240'},
+                watermark_height: ${watermarkHeight!'80'},
+                watermark_angle: ${watermarkAngle!'10'},
             });
         }
     }
diff --git a/server/src/test/java/cn/keking/web/OfficeWebWatermarkDefaultsTests.java b/server/src/test/java/cn/keking/web/OfficeWebWatermarkDefaultsTests.java
index b71b571b..70c4cb13 100644
--- a/server/src/test/java/cn/keking/web/OfficeWebWatermarkDefaultsTests.java
+++ b/server/src/test/java/cn/keking/web/OfficeWebWatermarkDefaultsTests.java
@@ -3,10 +3,12 @@ package cn.keking.web;
 import freemarker.template.Configuration;
 import freemarker.template.Template;
 import freemarker.template.TemplateExceptionHandler;
-import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 
 import java.io.StringWriter;
 import java.util.HashMap;
+import java.util.Locale;
 import java.util.Map;
 
 import static org.junit.jupiter.api.Assertions.assertTrue;
@@ -24,21 +26,36 @@ import static org.junit.jupiter.api.Assertions.assertTrue;
  *
  * The first test therefore renders with a model that carries no watermark* entry at all.
  * Do not add them "to make it realistic" - that is the condition under test.
+ *
+ * The template's defaults are string literals on purpose: a numeric default goes through
+ * FreeMarker's locale-aware number format, so under de_DE 0.2 renders as "0,2" and under
+ * ar_EG the digits become Arabic-Indic - either way the inline script no longer parses.
+ * The locale comes from the request's Accept-Language, which is why both tests run per
+ * locale and every numeric value is asserted, not just one.
  */
 class OfficeWebWatermarkDefaultsTests {
 
-    @Test
-    void shouldRenderXlsxPreviewPageWhenWatermarkAttributesAreMissing() throws Exception {
-        String html = render(baseModel());
+    @ParameterizedTest
+    @ValueSource(strings = {"zh-CN", "en-US", "de-DE", "fr-FR", "ar-EG"})
+    void shouldRenderXlsxPreviewPageWhenWatermarkAttributesAreMissing(String languageTag) throws Exception {
+        String html = render(baseModel(), Locale.forLanguageTag(languageTag));
 
         assertTrue(html.contains("</html>"), "page was truncated before </html>");
         assertTrue(html.contains("let watermarkTxt = '';"), "watermarkTxt did not fall back to an empty string");
-        assertTrue(html.contains("watermark_width: 240,"), "watermarkWidth did not fall back to its declared default");
-        assertTrue(html.contains("watermark_font: '\u5fae\u8f6f\u96c5\u9ed1',"), "watermarkFont did not fall back to its declared default");
+        assertRendered(html, "watermark_x_space: 10,");
+        assertRendered(html, "watermark_y_space: 10,");
+        assertRendered(html, "watermark_font: '微软雅黑',");
+        assertRendered(html, "watermark_fontsize: '18px',");
+        assertRendered(html, "watermark_color: 'black',");
+        assertRendered(html, "watermark_alpha: 0.2,");
+        assertRendered(html, "watermark_width: 240,");
+        assertRendered(html, "watermark_height: 80,");
+        assertRendered(html, "watermark_angle: 10,");
     }
 
-    @Test
-    void shouldKeepConfiguredWatermarkSettingsWhenAttributesArePresent() throws Exception {
+    @ParameterizedTest
+    @ValueSource(strings = {"zh-CN", "de-DE", "ar-EG"})
+    void shouldKeepConfiguredWatermarkSettingsWhenAttributesArePresent(String languageTag) throws Exception {
         Map<String, Object> model = baseModel();
         model.put("watermarkTxt", "kkFileView");
         model.put("watermarkXSpace", "20");
@@ -51,18 +68,26 @@ class OfficeWebWatermarkDefaultsTests {
         model.put("watermarkHeight", "120");
         model.put("watermarkAngle", "45");
 
-        String html = render(model);
+        String html = render(model, Locale.forLanguageTag(languageTag));
 
         assertTrue(html.contains("let watermarkTxt = 'kkFileView';"));
-        assertTrue(html.contains("watermark_x_space: 20,"));
-        assertTrue(html.contains("watermark_y_space: 30,"));
-        assertTrue(html.contains("watermark_font: 'Arial',"));
-        assertTrue(html.contains("watermark_fontsize: '24px',"));
-        assertTrue(html.contains("watermark_color: 'red',"));
-        assertTrue(html.contains("watermark_alpha: 0.5,"));
-        assertTrue(html.contains("watermark_width: 300,"));
-        assertTrue(html.contains("watermark_height: 120,"));
-        assertTrue(html.contains("watermark_angle: 45,"));
+        assertRendered(html, "watermark_x_space: 20,");
+        assertRendered(html, "watermark_y_space: 30,");
+        assertRendered(html, "watermark_font: 'Arial',");
+        assertRendered(html, "watermark_fontsize: '24px',");
+        assertRendered(html, "watermark_color: 'red',");
+        assertRendered(html, "watermark_alpha: 0.5,");
+        assertRendered(html, "watermark_width: 300,");
+        assertRendered(html, "watermark_height: 120,");
+        assertRendered(html, "watermark_angle: 45,");
+    }
+
+    /** On failure, show the line that was actually emitted for that key. */
+    private static void assertRendered(String html, String expected) {
+        String key = expected.substring(0, expected.indexOf(':') + 1);
+        int start = html.indexOf(key);
+        String actual = start < 0 ? "<missing>" : html.substring(start, html.indexOf('\n', start)).trim();
+        assertTrue(html.contains(expected), "expected \"" + expected + "\" but rendered \"" + actual + "\"");
     }
 
     /** Everything officeweb.ftl needs except the watermark attributes. */
@@ -78,13 +103,14 @@ class OfficeWebWatermarkDefaultsTests {
         return model;
     }
 
-    private String render(Map<String, Object> model) throws Exception {
+    /** Same lookup as Spring's FreeMarkerView: the template is resolved for the request locale. */
+    private String render(Map<String, Object> model, Locale locale) throws Exception {
         Configuration configuration = new Configuration(Configuration.VERSION_2_3_32);
         configuration.setClassLoaderForTemplateLoading(getClass().getClassLoader(), "web");
         configuration.setDefaultEncoding("UTF-8");
         configuration.setTemplateExceptionHandler(TemplateExceptionHandler.RETHROW_HANDLER);
 
-        Template template = configuration.getTemplate("officeweb.ftl");
+        Template template = configuration.getTemplate("officeweb.ftl", locale);
         StringWriter out = new StringWriter();
         template.process(model, out);
         return out.toString();