how can I make the first letter of each word capitalized when each word is capitalized?( :first-letter is not working )

I am trying to assign a style to an element where its attribute index=0
The selector :first-letter is not working.

How can do it the selector by attribute (in this case [index='0'] )?

My desired output for the first element is:
Text 0 Paragraph (red text)

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-css -->

p[index='0']{
  color:red;
}

p[index='0']{
  text-transform: lowercase;
}

p[index='0']:first-letter {
  text-transform: uppercase;
}

<!-- language: lang-html -->

<p index="0">TEXT 0 PARAGRAPH</p>
<p index="1">TEXT 1 PARAGRAPH</p>
<p index="2">TEXT 2 PARAGRAPH</p>
<p index="3">TEXT 3 PARAGRAPH</p>

<!-- end snippet -->

:first-letter only work on the first word. If your text is short you can use :first-line. Otherwise you need to use js to transform it

p[index='0']{
  color:red;
  text-transform: lowercase;
}

p[index='0']:first-line{
  text-transform: capitalize;
}