Watermark opacity (#76)

src/main/resources/templates/compress-pdf.html

@@ -33,7 +33,7 @@
 					            <input type="checkbox" name="jbig2Lossy" id="jbig2Lossy">
 					            <label for="jbig2Lossy" th:text="#{compress.selectText.7}"></label>
 					        </div>
-					        <button type="submit" th:text="#{compress.submit}"></button>
+					        <button type="submit" class="btn btn-primary" th:text="#{compress.submit}"></button>
 					    </form>
              			<p class="mt-3" th:text="#{compress.credit}"></p>