Design guidelines from Espen Brunborg of primate.co.uk:

Colours:
Blue (main background): #41a9cc
Medium blue (button background): #00799c
Darkened medium blue (mainly used for hover states on buttons): #006f8f
Dark blue (for button dropshadows and text): #0d576d
Gray (for button): #e5e5e5
Darkened gray (for button hover state): #d9d9d9
medium gray (for button dropshadow): #a7a9ab
dark gray (for button text): #595959

// If any of the colours are inconsistent with the JS site, please feel free to use what you already have.

Typography:
Intro text: Alwyn new rounded, regular, 14px (or em equivalent), dark blue
Call-out text at the bottom: Alwyn new rounded, regular, 14px,white

Clear button:
Text: Alwyn new rounded, bold, 12px, dark gray, uppercase
Background: gray
Dimensions: try to keep it 30px tall, with a generous padding left/right
Dropshadow: medium gray, 2px vertical offset, no blur

Call-out button:
Text: Alwyn new rounded, bold, 14px, white, uppercase
Background: medium blue
Dimensions, try to keep it 35px tall, generous padding left/right (maybe even have a min-width of 175px)

404 page:
404 Text: Alwyn new rounded, bold, 220px, darkened medium blue
Strapline text: Same as intro text
Button: same as call-out button 
