For who likes it, this is the code. Not all things are themed properly as some elements just don’t popup in my configuration. So I made them bright green so they stand out and you can fix them if needed.
midnight:
# Main colors
primary-color: '#5294E2' # Header
accent-color: '#E45E65' # Accent color
dark-primary-color: 'var(--accent-color)' # Hyperlinks
light-primary-color: 'var(--accent-color)' # Horizontal line in about
# Text colors
primary-text-color: '#FFFFFF' # Primary text colour, here is referencing dark-primary-color
text-primary-color: 'var(--primary-text-color)' # Primary text colour
secondary-text-color: '#5294E2' # For secondary titles in more info boxes etc.
disabled-text-color: '#7F848E' # Disabled text colour
label-badge-border-color: 'green' # Label badge border, just a reference value
# Background colors
primary-background-color: '#383C45' # Settings background
secondary-background-color: '#383C45' # Main card UI background
divider-color: 'rgba(0, 0, 0, .12)' # Divider
# Table rows
table-row-background-color: '#353840' # Table row
table-row-alternative-background-color: '#3E424B' # Table row alternative
# Nav Menu
paper-listbox-color: 'var(--primary-color)' # Navigation menu selection hoover
paper-listbox-background-color: '#2E333A' # Navigation menu background
paper-grey-50: 'var(--primary-text-color)'
paper-grey-200: '#414A59' # Navigation menu selection
# Paper card
paper-card-header-color: 'var(--accent-color)' # Card header text colour
paper-card-background-color: '#434954' # Card background colour
paper-dialog-background-color: '#434954' # Card dialog background colour
paper-item-icon-color: 'var(--primary-text-color)' # Icon color
paper-item-icon-active-color: '#F9C536' # Icon color active
paper-item-icon_-_color: 'green'
paper-item-selected_-_background-color: '#434954' # Popup item select
paper-tabs-selection-bar-color: 'green'
# Labels
label-badge-red: 'var(--accent-color)' # References the brand colour label badge border
label-badge-text-color: 'var(--primary-text-color)' # Now same as label badge border but that's a matter of taste
label-badge-background-color: '#2E333A' # Same, but can also be set to transparent here
# Switches
paper-toggle-button-checked-button-color: 'var(--accent-color)'
paper-toggle-button-checked-bar-color: 'var(--accent-color)'
paper-toggle-button-checked-ink-color: 'var(--accent-color)'
paper-toggle-button-unchecked-button-color: 'var(--disabled-text-color)'
paper-toggle-button-unchecked-bar-color: 'var(--disabled-text-color)'
paper-toggle-button-unchecked-ink-color: 'var(--disabled-text-color)'
# Sliders
paper-slider-knob-color: 'var(--accent-color)'
paper-slider-knob-start-color: 'var(--accent-color)'
paper-slider-pin-color: 'var(--accent-color)'
paper-slider-active-color: 'var(--accent-color)'
paper-slider-container-color: 'linear-gradient(var(--primary-background-color), var(--secondary-background-color)) no-repeat'
paper-slider-secondary-color: 'var(--secondary-background-color)'
paper-slider-disabled-active-color: 'var(--disabled-text-color)'
paper-slider-disabled-secondary-color: 'var(--disabled-text-color)'
# Google colors
google-red-500: '#E45E65'
google-green-500: '#39E949'