separate main colors into variables

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
added styling for package details

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
improvement: move loading icon into the header line of a node when it is clicked

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
make the loading indicator a bit smaller (24px -> 16px)

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
add minor hierarchy styling into node and package details

Signed-off-by: Dominik Richter <dominik.richter@gmail.com>
Merge pull request #9 from TelekomCloud/improvement/ui-styling

improve the ui styling