We’re currently working on a number of pull request changes to add more flexibility with colours for theming. Please see here: https://github.com/home-assistant/home-assistant-polymer/pull/361
Here’s two screenshots of where we currently stand – night and day themes:
Über like !
Do you reckon these will make 0.50.0?
Dark themes are now possible as of HA 0.51. 
Personally I like teal with dark colours.
https://community.home-assistant.io/t/dark-theme-or-night-mode-theme/446/37
I love the teal one - would you be willing to share it?
(Like the title of the thread implies…)
same here, nice work!
I have to make some changes and then I will post the code right here… 
In this topic you can find the codes for the darkcyan theme: "Dark" theme, or "night" mode/theme - #88
And here you can find the darkred theme: "Dark" theme, or "night" mode/theme - #53
Enjoy 
Thanks; as soon as I saw the notification I grabbed it!
Theme loosely based off of the Solarized palette. Probably doesn’t meet criteria for Solarized but I really like the palette.
solarized:
primary-color: "#2aa198"
disabled-text-color: "#859900"
divider-color: "#586e75" #"rgba(255, 255, 255, 0.12)"
paper-card-background-color: "#002b36"
paper-grey-200: "#586e75"
paper-item-icon-color: "#b58900"
paper-listbox-background-color: "#002b36"
paper-listbox-color: "#b58900"
primary-background-color: "#073642"
primary-text-color: "#839496"
secondary-background-color: "#073642"
secondary-text-color: "#859900"
text-primary-color: "#839496"
label-badge-background-color: "var(--secondary-background-color)"
label-badge-text-color: "var(--text-primary-color)"
paper-card-header-color: "#cb4b16"
paper-grey-50: "#b58900"
paper-item-icon-active-color: "#dc322f"
paper-item-icon_-_color: "#FF00FF" # no clue
paper-slider-active-color: "#dc322f"
paper-slider-knob-color: "#dc322f"
paper-slider-knob-start-color: "#b58900"
paper-slider-pin-color: "#FF00FF" # no clue
paper-slider-secondary-color: "#dc322f"
paper-toggle-button-checked-ink-color: "#dc322f"
paper-toggle-button-checked-button-color: "#dc322f"
paper-toggle-button-checked-bar-color: "#cb4b16"
paper-toggle-button-unchecked-bar-color: "#b58900"
table-row-background-color: "#002b36"
table-row-alternative-background-color: "#073642"
google-red: "#dc322f"
google-green: "#859900"
google-blue: "#268bd2"
google-yellow: "#b58900"
accent-color: "#cb4b16"
paper-green: "#859900"
paper-blue: "#268bd2"
paper-orange: "#cb4b16"
Oh wow! Themes!
Thats great, gotta update 
One of the themes I recently made. Kind of a variant of the default theme. It’s still a WIP though, so there might be some issues with colours.
PmxDefault:
# Primary Color
primary-color: 'hsl(192, 96%, 48%)'
# Backgrounds
primary-background-color: 'hsl(0, 0%, 98%)'
secondary-background-color: 'hsl(0, 0%, 95%)'
paper-listbox-background-color: 'var(--primary-background-color)'
paper-card-background-color: 'var(--primary-background-color)'
paper-dialog-background-color: 'var(--primary-background-color)'
table-row-background-color: 'hsl(0, 0%, 96%)'
table-row-alternative-background-color: 'var(--primary-background-color)'
# Divider
divider-color: 'hsla(0, 0%, 0%, 0)'
dark-divider-opacity: '0'
light-divider-opacity: '0'
# Text colors
primary-text-color: 'hsl(0, 0%, 50%)'
text-primary-color: 'hsl(0, 0%, 60%)'
secondary-text-color: 'hsl(0, 0%, 60%)'
disabled-text-color: 'hsl(0, 0%, 70%)'
label-badge-border-color: 'hsl(0, 0%, 100%)'
sidebar-text_-_color: 'hsl(0, 0%, 90%)'
sidebar-text-color: 'hsl(0, 0%, 90%)'
# Text Adjustments
paper-font-headline_-_letter-spacing: '-0.5px'
paper-font-headline_-_font-weight: '500'
paper-font-body1_-_font-weight: '500'
# Nav Menu
paper-listbox-color: 'hsl(0, 0%, 85%)'
paper-grey-50: 'hsl(0, 0%, 85%)'
paper-grey-200: 'hsl(0, 0%, 95%)'
# Paper card
paper-card-header-color: 'hsla(0, 0%, 0%, 0.5)'
paper-item-icon-color: 'hsl(0, 0%, 80%)'
paper-item-icon-active-color: 'var(--paper-item-icon-color)'
paper-item-icon_-_color: 'var(--paper-item-icon-color)'
paper-item-selected_-_background-color: 'hsla(0, 0%, 0%, 0.2)'
paper-tabs-selection-bar-color: 'hsla(0, 0%, 0%, 0.2)'
ha-slider-background-color: 'var(--primary-background-color)'
paper-slider-bar-color: 'var(--primary-background-color)'
# Labels
label-badge-red: 'var(--primary-color)'
label-badge-background-color: 'var(--paper-card-background-color)'
label-badge-text-color: 'hsl(0, 0%, 60%)'
# Shadows
shadow-elevation-2dp_-_box-shadow: 'inset 0px 0px 0px 3px hsl(0, 0%, 88%)'
shadow-elevation-4dp_-_box-shadow: 'var(--shadow-elevation-2dp_-_box-shadow)'
shadow-elevation-6dp_-_box-shadow: 'var(--shadow-elevation-2dp_-_box-shadow)'
shadow-elevation-8dp_-_box-shadow: 'var(--shadow-elevation-2dp_-_box-shadow)'
shadow-elevation-10dp_-_box-shadow: 'var(--shadow-elevation-2dp_-_box-shadow)'
shadow-elevation-12dp_-_box-shadow: 'var(--shadow-elevation-2dp_-_box-shadow)'
shadow-elevation-14dp_-_box-shadow: 'var(--shadow-elevation-2dp_-_box-shadow)'
shadow-elevation-16dp_-_box-shadow: '0px 0px 0px 4px var(--primary-color)'
# Switches
paper-toggle-button-checked-button-color: 'hsl(192, 0%, 98%)'
paper-toggle-button-checked-bar-color: 'hsl(192, 0%, 50%)'
paper-toggle-button-unchecked-button-color: 'hsl(192, 0%, 98%)'
paper-toggle-button-unchecked-bar-color: 'hsl(192, 0%, 85%)'
# Sliders
paper-slider-knob-color: 'var(--primary-color)'
paper-slider-knob-start-color: 'hsl(0, 0%, 60%)'
paper-slider-pin-color: 'var(--primary-color)'
paper-slider-active-color: 'var(--primary-color)'
paper-slider-container-color: 'hsl(0, 0%, 90%)'
paper-slider-secondary-color: 'hsl(0, 0%, 90%)'
paper-slider-disabled-active-color: 'hsl(0, 0%, 90%)'
paper-slider-disabled-secondary-color: 'hsl(0, 0%, 90%)'
paper-dialog-color: 'hsl(0, 0%, 50%)'Anyone interested in a ‘way-too-early’ christmas theme?
I’ve got my homeassistant set-up to show this theme around the christmas period (nice theme + automation practice)
It still needs some touch-ups (e.g. slider & icon color on pop-ups for which I can 't seem to find the correct variables), but if people are interested I’ll post the code once I finish.
Hi! Just made a theme in wood colours.
wood:
primary-color: "#6B3A1F"
disabled-text-color: "#A58456"
divider-color: "#EDE4D8" #"rgba(255, 255, 255, 0.15)"
dark-primary-color: "#592A13"
primary-background-color: "#C4AD92"
primary-text-color: "#FFFFFF"
secondary-background-color: "#675335"
secondary-text-color: "#6B3A1F"
text-primary-color: "#693A23"
label-badge-background-color: "var(--primary-background-color)"
label-badge-text-color: "var(--text-primary-color)"
paper-card-background-color: "#A58456"
paper-grey-50: "#6B3A1F"
paper-grey-200: "#DDD4C8"
paper-item-icon-color: "#6B3A1F"
paper-listbox-background-color: "#A58456"
paper-listbox-color: "#6B3A1F"
paper-card-header-color: "#EDE4D8"
paper-item-icon-active-color: "#F7C02A"
paper-item-icon_-_color: "#FF00FF"
paper-slider-active-color: "#A56521"
paper-slider-knob-color: "#A56521"
paper-slider-knob-start-color: "#6B3A1F"
paper-slider-pin-color: "#FF00FF"
paper-slider-secondary-color: "#A06020"
paper-toggle-button-checked-ink-color: "#A56521"
paper-toggle-button-checked-button-color: "#A56521"
paper-toggle-button-checked-bar-color: "#EDE4D8"
paper-toggle-button-unchecked-bar-color: "#EDE4D8"
table-row-background-color: "#A58456"
table-row-alternative-background-color: "#C67A2E"
google-red: "#A56521"
google-green: "#A58456"
google-blue: "#268BD2"
google-yellow: "#6B3A1F"
accent-color: "#EDE4D8"
paper-green: "#A58456"
paper-blue: "#268BD2"
paper-orange: "#EDE4D8"
Screenshots:
update: fixed accidentally duplicate paper-grey-50
Absolute awesome! I added this to my setup THANKS!!!
Another WIP theme, which isn’t perfect yet due to some limitations we/I still have with themes (some things not able to theme properly, because things not set to a variable), but I thought maybe someone would like it already anyway. This time is created as a dark monochromatic theme which allows people to adjust how saturated the theme should be, and what the base hue of the theme should be (to make it totally grey, or greyish-blue/brown or whatever you like). I’ve made 3 examples (see screenshots) by only changing the first 2 variables to show the possibilities. Again, it’s not perfect yet, but I feel like some might enjoy it.
PmxMononight:
# MyVariables
base-hue: '220' #Controls the base (and accent) color hue (0-360) | 0=Red 60=Yellow 120=Green 180=Cyan 240=Blue 300=Magenta 360=Red
base-sat: '16%' #Controls the saturation of the theme (0%-100%) | 0%=Grey 100%=Full Saturation
# MyVar
huesat: 'var(--base-hue), var(--base-sat),'
# Primary Color
primary-color: 'hsl(var(--huesat) 20%)'
# Backgrounds
primary-background-color: 'var(--primary-color)'
secondary-background-color: 'hsl(var(--huesat) 16%)'
paper-listbox-background-color: 'var(--primary-color)'
paper-card-background-color: 'hsl(var(--huesat) 12%)'
paper-dialog-background-color: 'var(--paper-card-background-color)'
table-row-background-color: 'hsl(var(--huesat) 12%)'
table-row-alternative-background-color: 'hsl(var(--huesat) 10%)'
# Devider
divider-color: 'hsla(0, 0%, 0%, 0)'
dark-divider-opacity: '0'
light-divider-opacity: '0'
# Text colors
primary-text-color: 'hsl(var(--huesat) 60%)'
text-primary-color: 'hsl(var(--huesat) 60%)'
secondary-text-color: 'hsl(var(--huesat) 60%)'
disabled-text-color: 'hsl(var(--huesat) 70%)'
sidebar-text_-_color: 'hsl(var(--huesat) 90%)'
sidebar-text-color: 'hsl(var(--huesat) 90%)'
paper-card-header-color: 'hsl(var(--base-hue), 90%, 50%)'
# Text Adjustments
paper-font-headline_-_letter-spacing: '-0.5px'
paper-font-headline_-_font-weight: '500'
paper-font-body1_-_font-weight: '500'
# Nav Menu
paper-listbox-color: 'hsl(var(--huesat) 50%)'
paper-grey-50: 'hsl(var(--huesat) 50%)'
paper-grey-200: 'hsla(var(--huesat) 26%)'
# Paper card
paper-item-icon-color: 'hsl(var(--huesat) 30%)'
paper-item-icon-active-color: 'var(--paper-item-icon-color)'
paper-item-icon_-_color: 'var(--paper-item-icon-color)'
paper-item-selected_-_background-color: 'hsla(0, 0%, 0%, 0.2)'
paper-tabs-selection-bar-color: 'hsla(0, 0%, 0%, 0.2)'
# Labels
label-badge-red: 'hsla(0, 0%, 0%, 0)'
label-badge-border-color: 'var(--label-badge-red)'
label-badge-background-color: 'var(--paper-card-background-color)'
label-badge-text-color: 'var(--primary-text-color)'
# Shadows
shadow-elevation-2dp_-_box-shadow: 'inset 0px 0px 0px 4px hsl(var(--huesat) 18%)'
shadow-elevation-16dp_-_box-shadow: 'inset 0px 0px 0px 4px hsl(var(--huesat) 28%)'
# Switches
paper-toggle-button-checked-button-color: 'hsl(var(--base-hue), 90%, 50%)'
paper-toggle-button-checked-bar-color: 'hsl(var(--huesat) 25%)'
paper-toggle-button-unchecked-button-color: 'hsl(var(--huesat) 25%)'
paper-toggle-button-unchecked-bar-color: 'hsl(var(--huesat) 5%)'
# Sliders
paper-slider-knob-color: 'hsl(var(--base-hue), 90%, 50%)'
paper-slider-knob-start-color: 'hsl(var(--base-hue), 80%, 25%)'
paper-slider-pin-color: 'hsl(var(--base-hue), 90%, 50%)'
paper-slider-active-color: 'hsl(var(--base-hue), 90%, 50%)'
paper-slider-container-color: 'hsl(var(--huesat) 28%)'
paper-slider-secondary-color: 'hsl(var(--huesat) 90%)'
paper-slider-disabled-active-color: 'hsl(var(--base-hue), 80%, 25%)'
paper-slider-disabled-secondary-color: 'hsl(var(--base-hue), 80%, 25%)'
paper-dialog-color: 'hsl(var(--base-hue), 20%, 80%)'Hot damn, you know what you’re doing! Excited to see what themes you come up with.
Wow! Nice work! Will add this to my setup of course even if I use dashboard to control my stuff