Fixes #9358 - Add article about using light themes

reference/docs-conceptual/learn/shell/using-light-theme.md

@@ -0,0 +1,139 @@
+---
+description: >
+  This article shows how to configure PSReadLine color settings for a light themed terminal.
+ms.date: 12/07/2022
+title: Configuring a light colored theme
+---
+# Configuring a light colored theme
+
+The default colors for both PowerShell and **PSReadLine** are selected for a dark background
+terminal. However, some users may choose to use a light background with dark text. Since most of the
+default colors don't set the background, using light foreground colors on a light background
+produces unreadable text.
+
+**PSReadLine** allows you to define colors for 18 different syntax elements. You can view the
+current settings using the `Get-PSReadLineOption` cmdlet.
+
+```Output
+EditMode                               : Windows
+AddToHistoryHandler                    : System.Func`2[System.String,System.Object]
+HistoryNoDuplicates                    : True
+HistorySavePath                        : C:\Users\user1\AppData\Roaming\Microsoft\Wind...
+HistorySaveStyle                       : SaveIncrementally
+HistorySearchCaseSensitive             : False
+HistorySearchCursorMovesToEnd          : False
+MaximumHistoryCount                    : 4096
+ContinuationPrompt                     : >>
+ExtraPromptLineCount                   : 0
+PromptText                             : {> }
+BellStyle                              : Audible
+DingDuration                           : 50
+DingTone                               : 1221
+CommandsToValidateScriptBlockArguments : {ForEach-Object, %, Invoke-Command, icm...}
+CommandValidationHandler               :
+CompletionQueryItems                   : 100
+MaximumKillRingCount                   : 10
+ShowToolTips                           : True
+ViModeIndicator                        : None
+WordDelimiters                         : ;:,.[]{}()/\|^&*-=+'"-—―
+AnsiEscapeTimeout                      : 100
+PredictionSource                       : HistoryAndPlugin
+PredictionViewStyle                    : InlineView
+CommandColor                           : "`e[93m"
+CommentColor                           : "`e[32m"
+ContinuationPromptColor                : "`e[37m"
+DefaultTokenColor                      : "`e[37m"
+EmphasisColor                          : "`e[96m"
+ErrorColor                             : "`e[91m"
+InlinePredictionColor                  : "`e[38;5;238m"
+KeywordColor                           : "`e[92m"
+ListPredictionColor                    : "`e[33m"
+ListPredictionSelectedColor            : "`e[48;5;238m"
+MemberColor                            : "`e[97m"
+NumberColor                            : "`e[97m"
+OperatorColor                          : "`e[90m"
+ParameterColor                         : "`e[90m"
+SelectionColor                         : "`e[30;47m"
+StringColor                            : "`e[36m"
+TypeColor                              : "`e[37m"
+VariableColor                          : "`e[92m"
+```
+
+The color settings are stored as strings containing ANSI escape sequences that change the color in
+your terminal. Using the `Set-PSReadLineOption` cmdlet you can change the colors to values that work
+better for a light-colored background.
+
+## Defining colors for a light theme
+
+The PowerShell ISE can be configured to use a light theme for both the editor and console panes. You
+can also view and change the colors that the ISE uses for various syntax and output types. You can
+use these color choices to define a similar theme for **PSReadLine**.
+
+The following hashtable defines colors for **PSReadLine** that mimic the colors in the PowerShell
+ISE.
+
+```powershell
+$ISETheme = @{
+    Command                  = $PSStyle.Foreground.FromRGB(0x0000FF)
+    Comment                  = $PSStyle.Foreground.FromRGB(0x006400)
+    ContinuationPrompt       = $PSStyle.Foreground.FromRGB(0x0000FF)
+    Default                  = $PSStyle.Foreground.FromRGB(0x0000FF)
+    Emphasis                 = $PSStyle.Foreground.FromRGB(0x287BF0)
+    Error                    = $PSStyle.Foreground.FromRGB(0xE50000)
+    InlinePrediction         = $PSStyle.Foreground.FromRGB(0x93A1A1)
+    Keyword                  = $PSStyle.Foreground.FromRGB(0x00008b)
+    ListPrediction           = $PSStyle.Foreground.FromRGB(0x06DE00)
+    Member                   = $PSStyle.Foreground.FromRGB(0x000000)
+    Number                   = $PSStyle.Foreground.FromRGB(0x800080)
+    Operator                 = $PSStyle.Foreground.FromRGB(0x757575)
+    Parameter                = $PSStyle.Foreground.FromRGB(0x000080)
+    String                   = $PSStyle.Foreground.FromRGB(0x8b0000)
+    Type                     = $PSStyle.Foreground.FromRGB(0x008080)
+    Variable                 = $PSStyle.Foreground.FromRGB(0xff4500)
+    ListPredictionSelected   = $PSStyle.Background.FromRGB(0x93A1A1)
+    Selection                = $PSStyle.Background.FromRGB(0x00BFFF)
+}
+```
+
+> [!NOTE]
+> In PowerShell 7.2 and higher you can use the `FromRGB()` method of `$PSStyle` to create the ANSI
+> escape sequences for the colors you want.
+>
+> For more information about `PSStyle`, see [about_ANSI_Terminals][01].
+>
+> For more information about ANSI escape sequences, see the [ANSI escape code][04] article in
+> Wikipedia.
+
+## Setting the color theme in your profile
+
+To have the color settings you want in every PowerShell session, you must add the configuration
+settings to your PowerShell profile script. For an example, see
+[Customizing your shell environment][02]
+
+Add the `$ISETheme` variable and the following `Set-PSReadLineOption` command to your profile.
+
+```powershell
+Set-PSReadLineOption -Colors $ISETheme
+```
+
+## Choosing colors for accessibility
+
+The ISE color theme may not work for users with color-blindness or other conditions that limit their
+ability to see colors.
+
+The [World Wide Web Consortium (W3C)][05] has recommendations for using colors for accessibility.
+The Web Content Accessibility Guidelines (WCAG) 2.1 recommends that "visual presentation of text and
+images of text has a contrast ratio of at least 4.5:1." For more information, see
+[Success Criterion 1.4.3 Contrast (Minimum)][06].
+
+The [Contrast Ratio][03] website provides a tool that lets you pick foreground and background
+colors and measure the contrast. You can use this tool to find color combinations that work best for
+you.
+
+<!-- link references -->
+[01]: /powershell/module/Microsoft.PowerShell.Core/About/about_ANSI_Terminals
+[02]: creating-profiles.md
+[03]: https://contrast-ratio.com/
+[04]: https://en.wikipedia.org/wiki/ANSI_escape_code
+[05]: https://www.w3.org/
+[06]: https://www.w3.org/TR/WCAG/#contrast-minimum

reference/docs-conceptual/toc.yml

@@ -86,6 +86,8 @@ items:
             href: learn/shell/using-aliases.md
           - name: Customizing your shell environment
             href: learn/shell/creating-profiles.md
+          - name: Configuring a light colored theme
+            href: learn/shell/using-light-theme.md
       - name: Deep dives
         items:
           - name: Overview