Why do you want to add a accent in second A instead of a straight A?
In uppercase words we never use the
tonos sign in the middle of the word (in modern Greek mono-tonic system). We use the tonos sign only in the first letter if this is a vowel and use a tonos in accent.
Like
Anagki, the tonos sign is on the second A.
In uppercase is written as:
ΑΝΑΓΚΗ (without any tonos)
In lowercase is written as:
Ανάγκη (tonos in second lowercase A)
Another example, is the word άλλος (other)
Uppercase:
ΆΛΛΟΣ (tonos in first uppercase A) and
άλλος in lowercase.
The poly-tonic system and ancient Greek the things is a little confusing... As mentioned already, we have dasia (δασεία) oksia (οξεία) perispomeni (περισπωμένη) and psili (ψηλή).
Like my name:
In modern Greek is: Αντώνης - ΑΝΤΩΝΗΣ.
In polytonic is: Ἁντῶνης - ἉΝΤΩΝΗΣ.
If you want a program to write in greek polytonic system and past it in a css code, then you can use this tool:
https://drive.google.com/file/d/0B6s...lMdXBqczA/view
You must use a greek unicode character set for your system keyboard, I think.