博客地址：http://blog.csdn.net/FoxDave
SharePoint现代化用户接口处理品牌风格的方式跟经典SharePoint不同；特别地，它忽略了自定义母版页或外部CSS配置，这些在现代化网站并不可用。我们可以选择继续保留这些内容，它们仍然能够对经典的用户接口页面起作用，但是切换回默认母版页并移除外部样式显然是更干净整洁的方式。
除了自定义母版页和外部样式设置之外，我们可能还使用了经典的自定义主题。这些经典的自定义主题在现代化用户接口下仍然能工作，但是面向未来更好的方式是新的租户控制的SharePoint主题，同样也能在新旧两种模式下工作。

检测使用了自定义母版页和外部样式的网站

进行检测推荐使用之前介绍的扫描工具：SharePoint "Modern" user interface experience scanner。它会在我们的租户范围内对所有网站进行深度的分析，创建相应的报告告知我们关于不兼容母版页和外部样式的具体细节，我们可以基于报告去修复这些网站。

复原到默认设置
下面是PnP(Patterns and Practices)的PowerShell脚本用来复原到默认设置：

$minimumVersion = New-Object System.Version("2.24.1803.0")
if (-not (Get-InstalledModule -Name SharePointPnPPowerShellOnline -MinimumVersion $minimumVersion -ErrorAction Ignore))
{
    Install-Module SharePointPnPPowerShellOnline -MinimumVersion $minimumVersion -Scope CurrentUser
}
Import-Module SharePointPnPPowerShellOnline -DisableNameChecking -MinimumVersion $minimumVersion

Connect-PnPOnline -Url "<your site url>"

# Set out-of-the-box master page
Set-PnPMasterPage -MasterPageSiteRelativeUrl _catalogs/masterpage/seattle.master -CustomMasterPageSiteRelativeUrl _catalogs/masterpage/seattle.master

# Remove the alternate CSS setting
$web = Get-PnPWeb -Includes AlternateCssUrl
$web.AlternateCssUrl = ""
$web.Context.ExecuteQuery()

使用租户控制的SharePoint主题

SharePoint提供了一些列拆箱即用的默认主题供我们使用，但是如果我们想要推广我们的公司品牌，我们应该创建自己的公司主题并隐藏默认的主题。配置完成后，用户只能从我们配置的主题中进行选择，我们可以通过编程的方式将这种主题设置作为网站现代化的一部分。

添加一个SharePoint公司主题
下面是PnP的PowerShell脚本用来演示如何添加一个SharePoint公司主题：

$minimumVersion = New-Object System.Version("2.24.1803.0")
if (-not (Get-InstalledModule -Name SharePointPnPPowerShellOnline -MinimumVersion $minimumVersion -ErrorAction Ignore))
{
    Install-Module SharePointPnPPowerShellOnline -MinimumVersion $minimumVersion -Scope CurrentUser
}
Import-Module SharePointPnPPowerShellOnline -DisableNameChecking -MinimumVersion $minimumVersion

Connect-PnPOnline -Url "<your tenant admin url>"

# Define your company theme colors
$themepalette = @{
      "themePrimary" = "#00ffff";
      "themeLighterAlt" = "#f3fcfc";
      "themeLighter" = "#daffff";
      "themeLight" = "#affefe";
      "themeTertiary" = "#76ffff";
      "themeSecondary" = "#39ffff";
      "themeDarkAlt" = "#00c4c4";
      "themeDark" = "#009090";
      "themeDarker" = "#005252";
      "neutralLighterAlt" = "#f8f8f8";
      "neutralLighter" = "#f4f4f4";
      "neutralLight" = "#eaeaea";
      "neutralQuaternaryAlt" = "#dadada";
      "neutralQuaternary" = "#d0d0d0";
      "neutralTertiaryAlt" = "#c8c8c8";
      "neutralTertiary" = "#a6a6a6";
      "neutralSecondaryAlt" = "#767676";
      "neutralSecondary" = "#666666";
      "neutralPrimary" = "#333";
      "neutralPrimaryAlt" = "#3c3c3c";
      "neutralDark" = "#212121";
      "black" = "#000000";
      "white" = "#fff";
      "primaryBackground" = "#fff";
      "primaryText" = "#333"
     }

# Add the company theme
Add-PnPTenantTheme -Identity "CustomCompanyTheme" -Palette $themepalette -IsInverted:$false

使用我们的SharePoint公司主题
我们可以通过下面的脚本来设置使用我们的公司主题：

$minimumVersion = New-Object System.Version("2.24.1803.0")
if (-not (Get-InstalledModule -Name SharePointPnPPowerShellOnline -MinimumVersion $minimumVersion -ErrorAction Ignore))
{
    Install-Module SharePointPnPPowerShellOnline -MinimumVersion $minimumVersion -Scope CurrentUser
}
Import-Module SharePointPnPPowerShellOnline -DisableNameChecking -MinimumVersion $minimumVersion

Connect-PnPOnline -Url "<your site url>"

# Set the company theme
Set-PnPWebTheme -Theme "CustomCompanyTheme"