diff --git a/src/components/Resizable.tsx b/src/components/Resizable.tsx
index b44fc68..39133fb 100644
--- a/src/components/Resizable.tsx
+++ b/src/components/Resizable.tsx
@@ -4,6 +4,7 @@ import cx from 'utils/cx'
 import { useWindowSize, useMediaStyleSheet } from 'utils/hooks'
 import { bodySpacingClassName } from 'utils/DOMHelper'
 import configHelper, { configKeys } from 'utils/configHelper'
+import * as features from 'utils/features'
 
 export type Size = number
 type Props = {
@@ -53,12 +54,14 @@ export default function Resizable({
   return (
     <div className={cx('gitako-position-wrapper', className)}>
       <div className={'gitako-position-content'}>{children}</div>
-      <HorizontalResizeHandler
-        onResize={size => {
-          if (size < window.innerWidth - MINIMAL_CONTENT_VIEWPORT_WIDTH) setSize(size)
-        }}
-        size={size}
-      />
+      {features.resize && (
+        <HorizontalResizeHandler
+          onResize={size => {
+            if (size < window.innerWidth - MINIMAL_CONTENT_VIEWPORT_WIDTH) setSize(size)
+          }}
+          size={size}
+        />
+      )}
     </div>
   )
 }
diff --git a/src/components/SizeObserver.tsx b/src/components/SizeObserver.tsx
index 7e63657..d7a633d 100644
--- a/src/components/SizeObserver.tsx
+++ b/src/components/SizeObserver.tsx
@@ -1,4 +1,5 @@
 import * as React from 'react'
+import * as features from 'utils/features'
 
 type Size = {
   width: number
@@ -23,24 +24,37 @@ export default function SizeObserver({
   })
 
   React.useEffect(() => {
-    const observer = new window.ResizeObserver(entries => {
-      const entry = entries[0]
-      if (!entry) return
-      const rect = entry.contentRect
-      // requestAnimationFrame fixes "ResizeObserver loop limit exceeded" error
-      requestAnimationFrame(() =>
-        setSize({
-          width: rect.width,
-          height: rect.height,
-        }),
-      )
-    })
+    if (features.resize) {
+      const observer = new window.ResizeObserver(entries => {
+        const entry = entries[0]
+        if (!entry) return
+        const rect = entry.contentRect
+        safeSetSize(rect)
+      })
 
-    if (ref.current) observer.observe(ref.current)
-    return () => observer.disconnect()
+      if (ref.current) observer.observe(ref.current)
+      return () => observer.disconnect()
+    } else {
+      if (ref.current) {
+        if ('getBoundingClientRect' in ref.current) {
+          const rect = ref.current.getBoundingClientRect()
+          setSize(rect)
+        }
+      }
+    }
   }, [])
 
   const props: any = { ...rest, ref } // :)
 
   return React.createElement(type, props, children(size))
+
+  function safeSetSize(rect: DOMRectReadOnly) {
+    // requestAnimationFrame fixes "ResizeObserver loop limit exceeded" error
+    requestAnimationFrame(() =>
+      setSize({
+        width: rect.width,
+        height: rect.height,
+      }),
+    )
+  }
 }
diff --git a/src/utils/features.ts b/src/utils/features.ts
new file mode 100644
index 0000000..fb1df66
--- /dev/null
+++ b/src/utils/features.ts
@@ -0,0 +1 @@
+export const resize = Boolean(window.ResizeObserver)