diff --git a/lib/hterm.js b/lib/hterm.js
index 647ce440..3d69d05e 100644
--- a/lib/hterm.js
+++ b/lib/hterm.js
@@ -146,6 +146,7 @@ hterm.Terminal.prototype.setFontSize = function (px) {
   unicodeNodeStyle.innerHTML = `
     .unicode-node {
       display: inline-block;
+      vertical-align: top;
       width: ${this.scrollPort_.characterSize.width}px;
     }
   `;