[www] Prevent image twitching in Chrome when hovering a blog index card (#5396)

Author: fk

www/src/components/blog-post-preview-item.js

@@ -34,6 +34,8 @@ class BlogPostPreviewItem extends React.Component {
               marginRight: rhythm(1 / 2),
               marginBottom: 0,
               verticalAlign: `top`,
+              // prevents image twitch in Chrome when hovering the card
+              transform: `translateZ(0)`,
             }}
           />
           <div