I created a theme based on this post: Why can’t we have UI like these? Quite inspiring!
Added: Dark Version
Preview
Install via HACS
The theme can now be installed via HACS. The background image will be added automatically
Install manually
Background
Save the background image to home-assistant/www/day.jpg
Theme
clear:
# Background image
lovelace-background: 'center / cover no-repeat url("/local/day.jpg") fixed'
# Colors
text-color: '#636B75' # Grey text
text-medium-color: '#8c96a5' # Medium grey text
text-light-color: '#BAC0C6' # Light grey text
accent-color: '#00a1ff' # Blue
background-color: '#F7F8F9' # Light grey background
background-color-2: '#F4F5F6' # Light grey background
background-card-color: 'rgba(255,255,255,1.0)' # White background
border-color: '#E8E8E8' # Light grey border
# Header
primary-color: 'var(--text-color)' # Background
text-primary-color: '#FFF' # Text
# Left Menu
paper-listbox-background-color: 'var(--background-color)' # Background
# TODO: Text and Icons
# UI
paper-card-header-color: 'var(--text-color)' # Title in settings
primary-background-color: 'var(--background-color)' # Background color (also title background in left menu)
# Card
paper-card-background-color: 'var(--background-card-color)' # Background
dark-primary-color: 'var(--text-color)'
primary-text-color: 'var(--text-color)'
paper-listbox-color: 'var(--text-color)'
light-primary-color: 'var(--text-light-color)'
secondary-text-color: 'var(--text-medium-color)'
disabled-text-color: 'var(--text-light-color)'
paper-dialog-button-color: 'var(--text-color)'
secondary-background-color: 'var(--background-color-2)' # Background more info title
# Icons
paper-item-icon-color: 'var(--text-light-color)' # Off
paper-item-icon-active-color: 'var(--accent-color)' # On
# Switches
switch-checked-button-color: '#FFF' # Knob On
switch-unchecked-button-color: '#FFF' # Knob Off
switch-checked-track-color: '#0077FF' # Background On
switch-unchecked-track-color: 'var(--disabled-text-color)' # Background Off
# Slider
paper-slider-active-color: 'var(--accent-color)' # Line On
paper-slider-container-color: '#e5e7ea' # Line Off
paper-slider-knob-color: 'var(--text-light-color)' # Knob On
paper-slider-knob-start-color: 'var(--text-light-color)' # Knob Off
# Shadows
ha-card-box-shadow: 'inset 0px 0px 0px 1px var(--border-color)'
Resources (optional)
Button Card: https://github.com/rodrigofragadf/lovelace-cards/tree/master/tiles-card
Animated Weather Card: https://github.com/bramkragten/custom-ui/tree/master/weather-card
Graph Card: https://github.com/kalkih/mini-graph-card
Slim Header: https://github.com/maykar/compact-custom-header/