headspace | Next generation web header UX

Start with using webpack-dev-server.

It has an option for 'hot reloading', where only changed elements of your app will be rebuilt. It aims to adjust in browser without refreshing but depending on your app, that functionality doesn't always work.

npm install webpack-dev-server --save-dev

TL;DR: Don't.

First, let's see what Googler and Flutter engineer Matt Sullivan has to say about this topic:

With Flutter creating and destroying objects with great frequency, should developers take steps to limit this behavior? It’s not uncommon to see new Flutter developers create references to widgets they know will not change over time, and place them in state so that they won’t be destroyed and rebuilt.

Don’t do this.

In order to understand why this is a bad idea, you first of all need to understand that Widgets do very little. Because they usually just compose other Widgets or instantiate RenderObjects, they don't do the actual rendering; all the heavy lifting is done by RenderObjects. You can think of the Widgets as super-lightweight "blueprints" for RenderObjects.
Also note that RenderObjects get heavily cached by the Flutter framework itself, so if you create some similar Widget in consecutive builds, the underlying RenderObject is automatically reused. By caching your UI, you are effectively re-creating a functionality which Flutter's rendering pipeline provides out of the box. Solely because of that, many people would argue the added complexity to your code isn't worth it.

"Okay then," you might think, "The performance benefit may be very very small, but it does exist, right?"

Actually, no. That's because the underlying Dart runtime uses two types of garbage collectors: the Young Space Scavenger garbage collector for short-lived objects and the mark-sweep garbage collector for long-lived objects. For a more detailed explanation about how they work, check out this article fittingly named "Don't Fear the Garbage Collector".
Basically, it says that the Young Space Scavenger is much faster than the mark-sweep collector and if an app doesn't adhere to the "weak generational hypothesis" which states that most objects die young, then the mark-sweeping will occur more often. Put short, performance might actually get worse.

To sum it up, re-implementing a built-in Flutter feature while making your code less readable and your app slower is probably not the right way to go.

Partition management in Cosmos DB is automatic - that is if your partition exceeds its space we will double it. Keep in mind that it is better for query performance to have proper partition key (which should probably not contain just 1 component like in this case) that allows for even distribution than simply rely on Cosmos DB to grow your partitions.

This should make it a bit better. You are practically repeating the outer query in the inner queries, but not anymore:

Something like this. This allows you to feed in the dataset and the variable names and assuming your constants really are constants, it's fine to hardcode them.

Did you try using the viewport http://www.w3schools.com/css/css_rwd_viewport.asp

This will basically make your app react based on the size of the screen.

One tip to make this behavior tested will be using the Google Chrome console as it allows you to change the viewport size based on device type.

position:absolute is relative to the nearest positioned parent, or the entire page. Therefore, here you are setting the images to be at the exact same location.

What you need is for .imgB1 to set position: relative and then move it to place with the top and others. E.g something like so: