{%- comment -%}
    # Whether the page is a post.
{%- endcomment -%}
{%- if page.layout == "post" -%}
  {%- assign is_post = true -%}
{%- endif -%}

{%- assign default_lang          = "en" -%}
{%- assign default_charset       = "utf-8" -%}
{%- assign default_color_scheme  = "light dark" -%}
{%- assign default_viewport      = "width=device-width, initial-scale=1" -%}
{%- assign default_title         = "" -%}
{%- assign default_canonical_url = page.url | absolute_url -%}
{%- assign default_license_url   = false -%}
{%- assign default_stylesheets   = "" | split: ", " -%}

{%- comment -%}
    # Lang.
{%- endcomment -%}
{%- assign lang = page.lang -%}
{%- if lang == nil -%}{%- assign lang = site.lang -%}
{%- if lang == nil -%}{%- assign lang = default_lang -%}{%- endif -%}{%- endif -%}

{%- comment -%}
    # Charset.
{%- endcomment -%}
{%- assign charset = page.charset -%}
{%- if charset == nil -%}{%- assign charset = site.charset -%}
{%- if charset == nil -%}{%- assign charset = default_charset -%}{%- endif -%}{%- endif -%}

{%- comment -%}
    # Color scheme.
{%- endcomment -%}
{%- assign color_scheme = page.color_scheme -%}
{%- if color_scheme == nil -%}{%- assign color_scheme = site.color_scheme -%}
{%- if color_scheme == nil -%}{%- assign color_scheme = default_color_scheme -%}{%- endif -%}{%- endif -%}

{%- comment -%}
    # Viewport.
{%- endcomment -%}
{%- assign viewport = page.viewport -%}
{%- if viewport == nil -%}{%- assign viewport = site.viewport -%}
{%- if viewport == nil -%}{%- assign viewport = default_viewport -%}{%- endif -%}{%- endif -%}

{%- comment -%}
    # Canonical url.
{%- endcomment -%}
{%- assign canonical_url = page.canonical_url -%}
{%- if canonical_url == nil -%}{%- assign canonical_url = site.canonical_url -%}
{%- if canonical_url == nil -%}{%- assign canonical_url = default_canonical_url -%}{%- endif -%}{%- endif -%}

{%- comment -%}
    # Title.
{%- endcomment -%}
{%- if is_post -%}
  {%-
      assign title =
        canonical_url
        | remove_first: "https://www."
        | remove_first: "http://www."
        | remove_first: "https://"
        | remove_first: "http://"
  -%}
{%- else -%}
  {%- assign title = page.title -%}
  {%- if title == nil -%}{%- assign title = site.title -%}
  {%- if title == nil -%}{%- assign title = default_title -%}{%- endif -%}{%- endif -%}
{%- endif -%}

{%- comment -%}
    # License url.
{%- endcomment -%}
{%- assign license_url = page.license_url -%}
{%- if license_url == nil -%}{%- assign license_url = site.license_url -%}
{%- if license_url == nil -%}{%- assign license_url = default_license_url -%}{%- endif -%}{%- endif -%}

{%- comment -%}
    # Stylesheets.
{%- endcomment -%}
{%- assign stylesheets = page.stylesheets -%}
{%- if stylesheets == nil -%}{%- assign stylesheets = site.stylesheets -%}
{%- if stylesheets == nil -%}{%- assign stylesheets = default_stylesheets -%}{%- endif -%}{%- endif -%}