Update header layout and theme transition

[victor-duarte]

Closes #163

Note

Style fix adjustment vs a logic update.

Updates

• Update CSS animation to only address elements properties required to be affected by theme avoiding the all value
• Apply cosmetic updates on header layout
  • Remove unneeded styles
  • Follow mobile first approach
  • Adjust layout in some viewports
  • Update border on some elements (e.g: tags) to avoid shifting between themes
• Enables search bar in header for small viewports
• Moves "scroll for dev news..." into view on small viewports
• Fix Cards internal scroll on small viewports

[medyo]

Can you fix the search bar width, it looks too small in the DND mode

[medyo]

Can you also check this

[victor-duarte]

@medyo, new updates have pushed that handle the header overlap and search input size in DND mode, plus other minor tweaks to improve layout.