Thanks for the card 
I reworked the card to look like an image of the original design. I added the color of the bulb in the icon and the brightness. Take it or not 
#cards
type: grid
cards:
- entity: light.salon_lampe_01
template:
- light_buttons_with_colors
type: custom:button-card
variables:
entity: light.salon_lampe_01
name: Salon
- entity: light.salon_lampe_01
template:
- light_buttons_with_colors_light
type: custom:button-card
variables:
entity: light.salon_lampe_01
name: Salon
columns: 2
square: false
#templates
button_card_templates:
list_items_light:
styles:
card:
- box-shadow: none
- padding: 0px
grid:
- grid-template-areas: '"item1 item2"'
- grid-template-columns: 2fr 1fr
- grid-template-rows: min-content
- column-gap: 7px
light_with_colors:
tap_action:
action: toggle
hold_action:
action: more-info
label: |-
[[[ if (entity.state !='unavailable'){
if (entity.state =='off'){
var bri = Math.round(entity.attributes.brightness / 2.55);
return 'Off';
}else{
var bri = Math.round(entity.attributes.brightness / 2.55);
return (bri ? bri + '%' : 'On') ;
}
}else{
return "Indisponible";
}
]]]
state:
- styles:
icon:
- filter: |-
[[[
var bri = entity.attributes.brightness / 2.55;
return ('brightness(' + (50+bri/2) + '%)') ;
]]]
- color: |-
[[[
var color = entity.attributes.rgb_color;
if (color){
return 'rgba(' + entity.attributes.rgb_color + ',1)'
}
else{
return 'rgba(var(--couleur-jaune),1)'
}
]]]
img_cell:
- background-color: |-
[[[
var color = entity.attributes.rgb_color;
if (color){
return 'rgba(' + entity.attributes.rgb_color + ',0.2)'
}
else{
return 'rgba(var(--couleur-jaune),0.2)'
}
]]]
value: 'on'
light_buttons_with_colors_light:
show_name: false
show_icon: false
variables:
entity: light.default
name: LumiĆØre
styles:
card:
- border-radius: 20px
- box-shadow: var(--box-shadow)
- padding: 12px
grid:
- grid-template-areas: '"item1" "item2"'
- grid-template-columns: 1fr
- grid-template-rows: min-content min-content
- row-gap: 12px
custom_fields:
item1:
card:
entity: '[[[ return variables.entity ]]]'
name: '[[[ return variables.name ]]]'
tap_action:
action: call-service
service: light.toggle
service_data:
entity_id: '[[[ return variables.entity ]]]'
template:
- icon_info
- light_with_colors
type: custom:button-card
item2:
card:
template: list_items_light
type: custom:button-card
custom_fields:
item1:
card:
type: custom:slider-card
entity: light.salon_lampe_01
radius: 12px
height: 42px
thumbColorOff: rgba(var(--couleur-theme),0.2)
mainSliderColorOff: rgb(var(--couleur-theme),0.2)
secondarySliderColorOff: var(--google-grey-500)
mainSliderColor: rgb(var(--couleur-gris-light))
thumbColor: rgb(var(--couleur-gris-light))
secondarySliderColor: var(--google-grey-500)
card_mod:
style: |
ha-card {
border-radius: 14px;
}
div {
border: 2px solid var(--google-grey-500);
border-radius: 14px !important;
box-sizing: border-box;
position: relative;
}
item2:
card:
icon: mdi:palette
tap_action:
action: more-info
type: custom:button-card
entity: '[[[ return variables.entity ]]]'
template: widget_icon
light_buttons_with_colors:
show_name: false
show_icon: false
variables:
entity: light.default
name: LumiĆØre
styles:
card:
- border-radius: 20px
- box-shadow: var(--box-shadow)
- padding: 12px
grid:
- grid-template-areas: '"item1" "item2"'
- grid-template-columns: 1fr
- grid-template-rows: min-content min-content
- row-gap: 12px
custom_fields:
item1:
card:
entity: '[[[ return variables.entity ]]]'
name: '[[[ return variables.name ]]]'
tap_action:
action: call-service
service: light.toggle
service_data:
entity_id: '[[[ return variables.entity ]]]'
template:
- icon_info
- light_with_colors
type: custom:button-card
item2:
card:
template: list_items_light
type: custom:button-card
custom_fields:
item1:
card:
type: custom:slider-card
entity: '[[[ return variables.entity ]]]'
radius: 14px
height: 42px
mainSliderColorOff: var(--google-grey-500)
secondarySliderColor: rgba(var(--couleur-theme),0.05)
secondarySliderColorOff: rgba(var(--couleur-theme),0.05)
thumbColorOff: white
item2:
card:
icon: mdi:palette
tap_action:
action: more-info
type: custom:button-card
entity: '[[[ return variables.entity ]]]'
template: widget_icon
The code is not optimized because I think we can lighten it by combining the templates