Shadows on buttons

Change made: Eliminate drop shadow from buttons or make it much softer & spread

Motivation:

Especially when shadows are NOT soft, they tend to clutter the UI, at the same time dating the overall design.

With no shadows on buttons, we would get more into the modern flat design. The only problem with flat design is that sometimes elements (buttons, especially) don't feel clickable to some users.

If we feel like our users would have trouble differentiating clickable elements from non-clickable, we can keep the shadow but make it blurrier (softer and more spread) or add a hoover effect that adds this blurry shadow.