diff --git a/gui/index.html b/gui/index.html
index 802ebb9..ca5c21b 100644
--- a/gui/index.html
+++ b/gui/index.html
@@ -11,6 +11,8 @@
             body {
                 /* same background color as the Slint app */
                 background: #1b1b1b;
+                /* make it seamless */
+                margin: 0;
             }
             #canvas {
                 /* Force Slint to occupy the entire viewport */