Trying to split configuration file

I try to understand how it works and I prepared to split my themes into a directory.
In the configuration.yaml I wrote

frontend:
  themes: !include_dir_named themes

But they aren’t available.
this is on of them

Dark Yellow:
    ### Main Interface Colors ###
    primary-color: "#FCB800"
    light-primary-color: "#FFCD44"
    primary-background-color: "#141414"
    secondary-background-color: var(--primary-background-color)
    divider-color: "#262626"
    ### Text ###
    primary-text-color: "#EBEBEB"
    secondary-text-color: "#FCB800"
    text-primary-color: "#141414"
    disabled-text-color: "#5D5D5D"
    ### Sidebar Menu ###
    sidebar-icon-color: "#8E8E8E"
    sidebar-text-color: "#EBEBEB"
    sidebar-selected-background-color: var(--primary-background-color)
    sidebar-selected-icon-color: "#FCB800"
    sidebar-selected-text-color: var(--sidebar-selected-icon-color)
    ### States and Badges ###
    state-icon-color: "#FCB800"
    state-icon-active-color: "#FDEAB0"
    state-icon-unavailable-color: var(--disabled-text-color)
    ### Sliders ###
    paper-slider-knob-color: "#FCB800"
    paper-slider-knob-start-color: var(--paper-slider-knob-color)
    paper-slider-pin-color: var(--paper-slider-knob-color)
    paper-slider-active-color: var(--paper-slider-knob-color)
    paper-slider-secondary-color: var(--light-primary-color)
    ### Labels ###
    label-badge-background-color: "#515151"
    label-badge-text-color: "#EBEBEB"
    label-badge-red: "#515151"
    ### Cards ###
    paper-card-background-color: "#1A1A1A"
    paper-listbox-background-color: var(--primary-background-color)
    ### Toggles ###
    paper-toggle-button-checked-button-color: "#FCB800"
    paper-toggle-button-checked-bar-color: "#FFD45D"
    paper-toggle-button-unchecked-button-color: "#8E8E8E"
    paper-toggle-button-unchecked-bar-color: "#515151"
    ### Table row ###
    table-row-background-color: var(--primary-background-color)
    table-row-alternative-background-color: var(--secondary-background-color)

If I use to join the list in one file, then they appear on my profile when I point to a file.

EDIT
Here’s the errors

019-06-30 23:51:54 ERROR (MainThread) [homeassistant.config] Invalid config for [frontend]: value should be a string for dictionary value @ data['frontend']['themes']['Dark-green']['Dark Green']. Got OrderedDict([('primary-color', '#03B14B'), ('light-primary-color', '#47FC92'), ('primary-background-color', '#1F1F28'), ('secondary-background-color', 'var(--primary-background-color)'), ('divider-color', '#2F2F3D'), ('primary-text-color', '#FFFFFF'), ('secondary-text-color', '#47FC92'), ('text-primary-color', '#FFFFFF'), ('disabled-text-color', '#464653'), ('sidebar-icon-color', '#B6B6C1'), ('sidebar-text-color', '#F1F1F1'), ('sidebar-selected-background-color', 'var(--primary-background-col...
value should be a string for dictionary value @ data['frontend']['themes']['Dark-yellow']['Dark Yellow']. Got OrderedDict([('primary-color', '#FCB800'), ('light-primary-color', '#FFCD44'), ('primary-background-color', '#141414'), ('secondary-background-color', 'var(--primary-background-color)'), ('divider-color', '#262626'), ('primary-text-color', '#EBEBEB'), ('secondary-text-color', '#FCB800'), ('text-primary-color', '#141414'), ('disabled-text-color', '#5D5D5D'), ('sidebar-icon-color', '#8E8E8E'), ('sidebar-text-color', '#EBEBEB'), ('sidebar-selected-background-color', 'var(--primary-background-col.... (See /config/configuration.yaml, line 17). Please check the docs at https://home-assistant.io/components/frontend/
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Setup failed for frontend: Invalid config.
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Unable to set up dependencies of logbook. Setup failed for dependencies: frontend
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Setup failed for logbook: Could not set up all dependencies.
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Unable to set up dependencies of panel_custom. Setup failed for dependencies: frontend
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Setup failed for panel_custom: Could not set up all dependencies.
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Unable to set up dependencies of map. Setup failed for dependencies: frontend
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Setup failed for map: Could not set up all dependencies.
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Unable to set up dependencies of hassio. Setup failed for dependencies: panel_custom
2019-06-30 23:51:54 ERROR (MainThread) [homeassistant.setup] Setup failed for hassio: Could not set up all dependencies.
2019-06-30 23:51:55 ERROR (MainThread) [homeassistant.setup] Unable to set up dependencies of default_config. Setup failed for dependencies: frontend, logbook, map
2019-06-30 23:51:55 ERROR (MainThread) [homeassistant.setup] Setup failed for default_config: Could not set up all dependencies.

You need to remove the first line, as shown in the example. This is because it’ll be named to match the filename.

For example

Dark Yellow:
    ### Main Interface Colors ###
    primary-color: "#FCB800"
    light-primary-color: "#FFCD44"

becomes

### Main Interface Colors ###
primary-color: "#FCB800"
light-primary-color: "#FFCD44"

I did such trial, but I don’t know what could cause the failure.
I tried once more and I succeeded. Probably some wrong typo.
Thank you!