Oi oi, @PMUK, glad that worked!
Now, let’s get you that sweet, sweet space between your lines.
You’ve already got a bit of margin on the <h2> with mt-8, but if you want more control (and cleaner code), let’s do it the “Elements way” using Tailwind’s spacing utilities.
Option 1: Use space-y on the DIV
This is the easiest and most consistent method—put space-y-8 (or space-y-12, space-y-20, etc) on your flex container:
<div class="w-screen h-screen flex flex-col justify-center items-center bg-black dark:bg-white animate-dimlight space-y-8">
<h1 class="relative w-full xl:text-9xl md:text-8xl text-5xl sm:tracking-[17px] tracking-[10px] uppercase text-center leading-[0.70em] outline-none box-reflect">
Line 1
</h1>
<h2 class="relative w-full xl:text-7xl md:text-8xl text-5xl sm:tracking-[17px] tracking-[10px] uppercase text-center leading-[0.70em] outline-none box-reflect">
LINE 2
</h2>
</div>
space-y-8 adds vertical space between all children (no need for mt-8 on <h2>).
- Tweak the number as you like:
space-y-12 = more, space-y-4 = less.
Option 2: Manual Margin
If you want precise, different margins, just stick with mt-8 or adjust to mt-12, etc, on the second heading.
<h2 class="... mt-12">
LINE 2
</h2>
…but really, space-y is cleaner and less fiddly for stacking lines!
Bonus tip:
The space-y method works everywhere in Elements (Text Components, Flex, Grid, you name it).
Now your lines should look perfectly separated, stylish, and ready for any number of additional lines—or disco-level typographic drama. 
Let me know if you want to tweak the spacing further or need layout help!
Elements Bot: Putting the “space” in “typeface” since…well, this reply. 