Get Site collection and sub site last modified date and size in a web application

gistfile1.ps1

#constructing table
                  $a = "<style>"
                  $a = $a + "BODY{background-color:#ffffff;}"
                  $a = $a + "TABLE{border-width: 1px;border-style: solid;border-color: ;border-collapse: collapse;}"
                  $a = $a + "TH{border-width: 1px;padding: 0px;border-style: solid;border-color: black;background-color:wheat}"
                  $a = $a + "TD{border-width: 1px;padding: 0px;border-style: solid;border-color: black;background-color:PaleGoldenrod}"
                  $a = $a + "</style>"

#Getting the list of site collection from the webapplication and stroing in an array
[array]$sites= get-spwebapplication http://sharepoint-journey.com| get-spsite -Limit All 

#Variables
$count=0
$webcount=0

#Looping through each sitecollection
foreach($site in $Sites)
{

		$count=$count + 1
		
		#Getting the site collection Title,Url,Last Modified Date and Size. Later adding that to the html file.
		$site | select @{label = "Title";Ex = {$_.rootweb.Title}} , url , @{label = "LastModifiedDate";Ex = {$_.lastcontentmodifieddate}} , @{label = "size";Ex = {$_.usage.storage/1MB}} | ConvertTo-HTML -head $a -body "<H4>Site Collection :$site</H4>" | Add-content C:\Sitecollectionandsubsites.html

		#Getting the list of sub sites in a sitecollection
		$Webs= get-spweb -site $site -Limit All
	   
	   #Looping through each sub site
		   foreach($web in $webs)
		   { 

		   #Getting the list details from the site
			$lists= $web.Lists
			$webcount= $webcount +1
			
			#Getting the sub site Url, Title, Template and appedning the details to the created html file.	
			$web | select Url , Title , Webtemplate| ConvertTo-HTML -head $a -body "<H4>Websites in the site collection  :$site</H4>" | Add-content C:\Sitecollectionandsubsites.html

			#Getting the List Name and Last Modified Date which are not hidden
			$lists | where{!($_.Hidden)} | select Title, @{label = "LastModifiedDate";Ex = {$_.LastItemModifiedDate}}    | sort -desc LastItemModifiedDate | ConvertTo-HTML -head $a -body "<H4>List details in this :$web</H4>" | Add-content C:\Sitecollectionandsubsites.html
			}
	   
		add-content C:\Sitecollectionandsubsites.html "<br>"
		add-content C:\Sitecollectionandsubsites.html "<b>"
		add-content C:\Sitecollectionandsubsites.html "<font color=black>"
		add-content C:\Sitecollectionandsubsites.html "Total Number of Webs in the site collection is $webcount"
		add-content C:\Sitecollectionandsubsites.html "</font>"
		add-content C:\Sitecollectionandsubsites.html "</b>"

		add-content C:\Sitecollectionandsubsites.html "<br>"
		add-content C:\Sitecollectionandsubsites.html "<b>"
		add-content C:\Sitecollectionandsubsites.html "<font color=black>"
		add-content C:\Sitecollectionandsubsites.html "----------------------------------------------------------------------------------------------------------------------------"
		add-content C:\Sitecollectionandsubsites.html "</font>"
		add-content C:\Sitecollectionandsubsites.html "</b>"   
	
}

add-content C:\Sitecollectionandsubsites.html "<br>"
add-content C:\Sitecollectionandsubsites.html "<b>"
add-content C:\Sitecollectionandsubsites.html "<font color=black>"
add-content C:\Sitecollectionandsubsites.html "Total Number of site collection is $count"
add-content C:\Sitecollectionandsubsites.html "</font>"
add-content C:\Sitecollectionandsubsites.html "</b>"