It looks so modern
Modern Elements
For this new theme we decided to go flat. Flat design is characterized by a minimalistic look with bright but muted colors. Gradients, bevels, embossing, shadows or any other artificial textures are minimized or dropped. 
Sleek Font
We are using Roboto as the font for the London theme. Roboto has a dual nature. It has a mechanical skeleton and the forms are largely geometric. At the same time, the font features friendly and open curves. While some grotesks distort their letterforms to force a rigid rhythm, Roboto doesn’t compromise, allowing letters to be settled into their natural width. This makes for a more natural reading rhythm more commonly found in humanist and serif types.
The London theme was designed to be Monochromatic - one base color - apart from  the scale of grays  in use. The base color is a red/orange shade (#E83E26) which is used in all actions, links and buttons. Being Monochromatic means that you can easily customize it for your application color(s) without much effort.
Feedback messages
The London theme also customizes the default OutSystems feedback messages. They are now bigger and more visible.
Awesome Icons
We have included an icon library as part of the London theme which is free to use in your projects. These are not normal icons, but a font library - Font Awesome. Font Awesome gives you scalable vector icons that can instantly be customized — size, color, drop shadow, and anything that can be done with the power of CSS.
How to use the icons
In the RichWidgets eSpace , you will find a new WebBlock called Icon. Just drag the WebBlock into your screens and choose the icon you want to use. For a complete list of icons, please refer to the Awesome Icons documentation. Here you can find an example of some of the icons included in the collection:
Click here to see your activities