<!DOCTYPE html>
<
html
>
<
head
>
<
style
>
.main {
border:2px solid green;
}
.1st {
color:green;
font-size:30px;
background-color:#9400D3;
}
._st {
color:green;
font-size:30px;
background-color:#4B0082;
}
.-st {
color:green;
font-size:30px;
background-color:#0000FF;
}
.st {
color:green;
font-size:30px;
background-color:##00FF00;
}
.St {
color:green;
font-size:30px;
background-color:#FFFF00;
}
.--1st {
color:green;
font-size:30px;
background-color:#FF7F00;
}
.s {
color:green;
font-size:30px;
background-color:#FF0000;
}
._1 {
color:green;
font-size:30px;
background-color:#9400D3;
}
.- {
color:green;
font-size:30px;
background-color:#4B0082;
}
.-- {
color:green;
font-size:30px;
background-color:#0000FF;
}
._ {
color:green;
font-size:30px;
background-color:##00FF00;
}
.__{
color:green;
font-size:30px;
background-color:#FFFF00;
}
</
style
>
</
head
>
<
body
>
<
div
class
=
"main"
>
<
h1
style
=
"color:green; text-align:center;"
>
GeeksforGeeks
</
h1
>
<
hr
>
<
div
class
=
"1st"
>Starting with digit </
div
>
<
div
class
=
"_st"
>Starting with underscore</
div
>
<
div
class
=
"-st"
>Starting with hyphen</
div
>
<
div
class
=
"st"
>Starting with lower case alphabet</
div
>
<
div
class
=
"St"
>Starting with upper case alphabet</
div
>
<
div
class
=
"--1st"
>Starting with double hyphen</
div
>
<
div
class
=
"s"
>only one alphabet</
div
>
<
div
class
=
"_1"
>underscore before digit</
div
>
<
div
class
=
"-"
>only hyphen</
div
>
<
div
class
=
"--"
>double hyphen</
div
>
<
div
class
=
"_"
>only underscore</
div
>
<
div
class
=
"__"
>double underscore</
div
>
</
div
>
</
body
>
</
html
>