diff --git a/public/static/css/phone-image-templates.css b/public/static/css/phone-image-templates.css
index 8512105..fcb161a 100644
--- a/public/static/css/phone-image-templates.css
+++ b/public/static/css/phone-image-templates.css
@@ -61,6 +61,17 @@
     position: relative;
 }
 
+/* 水印 - 位于每页右下角的半透明文字 */
+.page-watermark {
+    position: absolute;
+    bottom: 60px;
+    right: 20px;
+    font-size: 12px;
+    color: rgba(0, 0, 0, 0.3);
+    pointer-events: none;
+    white-space: nowrap;
+}
+
 /* ============================================
    Size Variants
    两种主流手机图片尺寸
@@ -255,7 +266,7 @@
 }
 
 .page-content h4 {
-    font-size: var(--pi-font-size-base);
+    font-size: 14px;
     font-weight: bold;
     margin-top: var(--pi-spacing-sm);
     margin-bottom: 5px;
diff --git a/public/static/js/phone-image.js b/public/static/js/phone-image.js
index 50d1ab7..1df0b65 100644
--- a/public/static/js/phone-image.js
+++ b/public/static/js/phone-image.js
@@ -145,12 +145,23 @@ var PhoneImageEngine = (function () {
         var cleanHtml = preprocessContent(postData.content_html);
         var blocks = parseHtmlToBlocks(cleanHtml);
 
+        // 动态设置字号CSS变量，让fontSize滑块真正生效
+        var effectiveFontSize = parseInt(config.fontSize, 10) || 14;
+        document.documentElement.style.setProperty('--pi-font-size-base', effectiveFontSize + 'px');
+
         // 缓存清理：如果缓存条目过多则清空，防止内存膨胀
         var cacheKeys = Object.keys(convertedBlockCache);
         if (cacheKeys.length > blocks.length * 3) {
             convertedBlockCache = {};
         }
 
+        // 空内容检测：blocks 为空时直接提示，不进入渲染流程
+        if (blocks.length === 0) {
+            $('#paginated-preview').html('<div style="text-align:center;padding:60px 20px;color:#999;">文章正文内容为空</div>');
+            render._locked = false;
+            return deferred.resolve([]).promise();
+        }
+
         // 先渲染内容流(DOM) - 用于实测高度
         renderContentFlow(blocks);
 
@@ -681,6 +692,11 @@ var PhoneImageEngine = (function () {
             html += '<div class="cover-decor-line cover-decor-bottom"></div>';
         }
 
+        // 水印
+        if (config.watermark) {
+            html += '<div class="page-watermark">' + escapeHtml(config.watermark) + '</div>';
+        }
+
         html += '</div>';
 
         return { type: 'cover', html: html };
@@ -717,6 +733,11 @@ var PhoneImageEngine = (function () {
         html += '<span>' + pageNum + '</span>';
         html += '</div>';
 
+        // 水印
+        if (config.watermark) {
+            html += '<div class="page-watermark">' + escapeHtml(config.watermark) + '</div>';
+        }
+
         html += '</div>';
         return { type: 'content', html: html, pageNum: pageNum };
     }
@@ -740,6 +761,12 @@ var PhoneImageEngine = (function () {
             html += ' | ' + escapeHtml(postData.author_name);
         }
         html += '</div>';
+
+        // 水印
+        if (config.watermark) {
+            html += '<div class="page-watermark">' + escapeHtml(config.watermark) + '</div>';
+        }
+
         html += '</div>';
 
         return { type: 'summary', html: html };
@@ -944,6 +971,7 @@ var PhoneImageEngine = (function () {
             }
             onDone();
         }).catch(function (err) {
+            $staging.empty();
             $staging.css({ visibility: 'hidden' });
             deferred.reject('截图失败: ' + err);
         });
@@ -1297,6 +1325,19 @@ var PhoneImageEngine = (function () {
                 pagesData.push(canvases[i].toDataURL('image/jpeg', 0.92));
             }
 
+            // 检查数据总大小，防止超大文章导致请求失败
+            var totalSize = 0;
+            for (var i = 0; i < pagesData.length; i++) {
+                if (pagesData[i]) {
+                    totalSize += pagesData[i].length;
+                }
+            }
+            if (totalSize > 16 * 1024 * 1024) {
+                layer.msg('数据量过大（超过16MB），请减少内容或联系管理员');
+                deferred.reject('数据量过大（超过16MB）');
+                return;
+            }
+
             $.ajax({
                 url: '/index.php/admin/post/savePostOutput',
                 type: 'POST',