diff --git a/Controllers/VideoController.cs b/Controllers/VideoController.cs
index 9df3ede..dbc9db5 100644
--- a/Controllers/VideoController.cs
+++ b/Controllers/VideoController.cs
@@ -238,6 +238,75 @@ namespace dy.net.Controllers
             return new EmptyResult();
         }
 
+        /// <summary>
+        /// 获取视频封面图片
+        /// </summary>
+        /// <param name="id">视频ID</param>
+        [Authorize]
+        [HttpGet("cover/{id}")]
+        public async Task<IActionResult> GetVideoCover([FromRoute] string id)
+        {
+            try
+            {
+                var video = await douyinVideoService.GetById(id);
+                if (video == null)
+                {
+                    return GetDefaultCoverImage();
+                }
+
+                // 优先使用本地保存的封面
+                if (!string.IsNullOrWhiteSpace(video.VideoCoverSavePath) && System.IO.File.Exists(video.VideoCoverSavePath))
+                {
+                    var contentType = GetImageContentType(video.VideoCoverSavePath);
+                    var fileStream = System.IO.File.OpenRead(video.VideoCoverSavePath);
+                    return File(fileStream, contentType);
+                }
+
+                // 本地封面缺失时回落到默认占位图
+                return GetDefaultCoverImage();
+            }
+            catch (Exception ex)
+            {
+                Serilog.Log.Error(ex, $"获取视频封面失败: {id}");
+                return GetDefaultCoverImage();
+            }
+        }
+
+        /// <summary>
+        /// 默认封面占位图（SVG）
+        /// </summary>
+        private IActionResult GetDefaultCoverImage()
+        {
+            var svgContent = @"<svg width=""400"" height=""225"" xmlns=""http://www.w3.org/2000/svg"">
+  <rect width=""400"" height=""225"" fill=""#f0f0f0""/>
+  <text x=""50%"" y=""50%"" font-family=""Arial, sans-serif"" font-size=""16"" fill=""#999"" text-anchor=""middle"" dy="".3em"">暂无封面</text>
+</svg>";
+            var svgBytes = System.Text.Encoding.UTF8.GetBytes(svgContent);
+            return File(svgBytes, "image/svg+xml");
+        }
+
+        /// <summary>
+        /// 根据文件扩展名获取图片 Content-Type
+        /// </summary>
+        private string GetImageContentType(string fileName)
+        {
+            if (string.IsNullOrWhiteSpace(fileName))
+            {
+                return "image/jpeg";
+            }
+            var extension = Path.GetExtension(fileName).ToLowerInvariant();
+            return extension switch
+            {
+                ".jpg" or ".jpeg" => "image/jpeg",
+                ".png" => "image/png",
+                ".gif" => "image/gif",
+                ".webp" => "image/webp",
+                ".svg" => "image/svg+xml",
+                ".bmp" => "image/bmp",
+                _ => "image/jpeg"
+            };
+        }
+
         /// <summary>
         /// 播放视频
         /// </summary>
diff --git a/app/src/App.vue b/app/src/App.vue
index 200fbf1..7b80e14 100644
--- a/app/src/App.vue
+++ b/app/src/App.vue
@@ -179,15 +179,29 @@ body {
   }
 }
 
-// 抖音授权 Cookie 编辑用 full-modal（顶部对齐的宽 modal）
+// 抖音授权 Cookie 编辑用 full-modal（全屏抽屉式，高度 100vh、footer 常驻底部）
 .full-modal .ant-modal {
   top: 0 !important;
   padding-bottom: 0 !important;
-  margin-bottom: 0;
+  margin: 0 !important;
+  max-width: 100%;
+  height: 100vh;
+}
+.full-modal .ant-modal-content {
+  height: 100vh;
+  display: flex;
+  flex-direction: column;
+  border-radius: 0;
+}
+.full-modal .ant-modal-header,
+.full-modal .ant-modal-footer {
+  flex-shrink: 0;
 }
-// full-modal 没有 top 留白，body max-height 减去的常量更小
 .full-modal .ant-modal-body {
-  max-height: calc(100vh - 110px) !important;
+  flex: 1 1 auto;
+  min-height: 0;
+  max-height: none !important;
+  overflow-y: auto !important;
 }
 
 // 登录页整个界面本身就是一个 Modal（LoginModal.vue），必须恢复 antd 默认布局，不能被上面的全局规则改
diff --git a/app/src/pages/cok/CookieTable.vue b/app/src/pages/cok/CookieTable.vue
index 722ecde..dea74ad 100644
--- a/app/src/pages/cok/CookieTable.vue
+++ b/app/src/pages/cok/CookieTable.vue
@@ -713,26 +713,8 @@ const switchdownCollect = (e: any) => {
 
 <style scoped lang="less">
 .modal-scroll-body {
-  max-height: calc(100vh - 160px);
-  overflow-y: scroll;
-  overflow-x: hidden;
   padding-right: 4px;
 }
-.modal-scroll-body::-webkit-scrollbar {
-  -webkit-appearance: none;
-  width: 8px;
-}
-.modal-scroll-body::-webkit-scrollbar-track {
-  background: #f0f0f0;
-  border-radius: 4px;
-}
-.modal-scroll-body::-webkit-scrollbar-thumb {
-  background: #bbb;
-  border-radius: 4px;
-}
-.modal-scroll-body::-webkit-scrollbar-thumb:hover {
-  background: #888;
-}
 .ant-form-item {
   margin-bottom: 10px;
 }