Just removing the font-weight: 300 helps tremendously. Personally, I'm becoming less of a fan of external fonts. I've noticed lately that they're often the slowest thing to load on sites that use them (especially Google fonts).

The weight works great on a high DPI display, but on older displays, it just doesn't work. Open on a rMBP or iPad, and it's beautiful. I'm guessing the designers are working on a high DPI Mac.

Edit: should be sorted.

Original: working on a standard DPI Mac, but it still looks fine - see http://imgur.com/WRWYzBx. Trying to figure it out now...

Do you mean "fine" as in "very fine lines", or "looks fine" as in "looks good"?

Cause that looks like a printer that ran out of ink.

I'm guessing OS X's font smoothing is more aggressive and makes it look better than Windows'. It also depends on how the font was hinted for Windows, whereas on OS X, the system "knows best" and has its own font smoothing technique.

I am on a rMBP and I wouldn't call it beautiful.

It's painfully thin, and the eyestrain factor is pretty high.

I downloaded all of Google’s font library and installed it locally, means I can read the fonts without having to load them from Google. Still doesn’t help against fonts with 0.5px thin lines.

Back in the day, running a massive library of fonts slowed down many apps. Is this still the case? I'm running Mac OS X 10.10.

I’m on linux, and yes, it does. Opening the font selection menu can take for me, with 7000 installed fonts, about half an hour sometimes. I just don’t do that, instead select fonts by name (I know most of them now).

But you don’t notice it until you open a font selection menu.

That's insane! Guessing you don't use Photoshop. At least, the last version I used (I think CS5), the font selection was weird and, no matter what, required that you open the drop down. Bleh. Haha

Photoshop on linux, that’s funny ;P

But seriously, I had to use Gtk3's font selection menu today, and it was impossible to work with it.

Also on Ubuntu. I (only) have 671 fonts, no delay at all for me.

Edit:

I've made some changes to Typekit to thicken things up. Is it better? If not, can you provide details of your OS?

Original:

I'll investigate and fix that now. What OS are you on so I can reproduce it?

It looks this this here in Firefox (http://imgur.com/WRWYzBx) and this in Chrome (http://imgur.com/6dFeQhG) on OS X, testing across multiple Macs here. I'd really like to fix it though! Thanks for the heads up!

We moved from Google Fonts to TypeKit recently, so I suspect it may have happened then.

On the updated version, want to give some actionable feedback:

Not just the weight, the size combined with the weight: 12px in a thin font is too light for a screen, especially done in grey. Going to 16px could really make a difference.

Going with a bigger size gives the scope to use a different, contrasting (perhaps thicker, perhaps thicker and smaller for double-contrast?) font for the headings currently in green.

* Getting older happens to different people at different ages, one of the effects of this means eyes get more temperamental, and this doesn't happen 50+, it happens a lot earlier for a lot of people.

Thanks - I'm really grateful for the feedback - and would like it if you have any more.

I'll be changing the base font to 14px and darkening the grey to #222 quite soon.

I'll also look at 16px but this needs some additional design work.

As I said above, the Firefox screenshot looks like a printer that ran out of ink, the Chrome version is slightly better, but look at the letter 'T', that's still wrong, a hairline that falls between pixels. That's only acceptable for text that is not actually intended to be read (thumbnails, mockups, zoomed out stuff, etc).

In Chrome is better but still terrible :/