Esta é uma referência antiga, mas boa, para as propriedades básicas do CSS: link
Eu faria
BEGIN {
print "<html><head>"
print "<title> Set the page title here </title>"
print "<style type=\"text/css\">"
print ".error {
print " color: red,"
print " font-size: larger,"
print " // other properties... take care, no trailing comma allowed"
print "}"
print "</style></head>"
print "<body>"
# use P tags, not BR line breaks -- easier to apply styling.
print "<p>The report provides overall Percentage Secured in the given subjects.</p>"
print "<table border=1 bgcolor=\"LemonChiffon\" cellspacing=1 cellpadding=1>"
}
NR == 1 {...} # I would use TH tags for the headers
NR > 1 {
# Data rows
print "<tr>"
for ( i = 1; i <= NF; i++ ) {
class = $i < 100 ? "class=\"error\"" : ""
printf "<td %s>%s</td>\n", class, $i
}
print "</tr>"
}
Colocar estilos em um lugar ajudará se