Fleux is a free modern Tumblr theme which gives you the freedom to display detailed contents on your blog. This theme comes with quick customization options such as changing the colors, fonts etc. This theme even features a responsive grid layout with a sidebar displaying the navigation. Fleux theme comes with infinite scrolling features which can be used by clicking the load more posts button. This theme even features Twitter and Instagram widgets, menu popups, customizable tags list popup etc. Not to mention, you can easily customize the text options as well. This theme has been built with user engagement in mind.