A few tweaks for Ubuntu 18.04 LTS to make it a bit less horrible-looking. Ubuntu makes life easy, but the default colour scheme is gross.

Gnome

The orange, the dirty brown-grey. Gross.

Gross.

First, install the default Gnome shell to do away with the Ubuntu colour scheme:

# apt install gnome-session

Log out, select a “Gnome” session, and log back in to see this (also includes Dash to Panel gnome extension):

Nice.

Much better.

GDM

The default log-in screen is also a gross purple-orange mixture:

Gross.

This repository contains a modified version of the default Ubuntu gdm3.css, which has been modified to match the colour scheme of the standard, non-Ubuntued Gnome shell. Copy the modified .css file to the relevant location:

# cp gdm3.css /usr/share/gnome-shell/theme/gdm3.css

The result (with a profile picture added):

Nice.

Plymouth

The default Plymouth theme also includes the ghastly purple colour scheme:

Gross.

It can be changed by modifying the ubuntu-logo Plymouth theme to get rid of the horrible purple colour (lines 174, 175 of /usr/share/plymouth/themes/ubuntu-logo/ubuntu-logo.script):

Window.SetBackgroundTopColor (0.00, 0.00, 0.00)
Window.SetBackgroundBottomColor (0.00, 0.00, 0.00);

Then update the initramfs:

# update-initramfs -u

Much better:

Nice.

If using an encrypted root partition, which forces the password prompt to be shown on the splash screen, copy password-field.png from the repository to the Plymouth theme folder:

# cp password-field.png /usr/share/plymouth/themes/ubuntu-logo/password-field.png

GRUB

And to get rid of the awful purple background on GRUB, modify /usr/share/plymouth/theme/default.grub to read:

if background_color 0,0,0; then
  clear
fi

And update GRUB:

# update-grub

Result

I also like to use the Flat Remix GTK theme. End result:

Super nice.