html - Google fonts not working on any browsers or tablets -

i having serious issue google fonts. working fine till last week , since have stopped working on browsers , tablets. if manually install fonts on pc show not accurately.

header code of api:

<link href='http://fonts.googleapis.com/css?family=open+sans:400,700,300' rel='stylesheet' type='text/css'> <link href='http://fonts.googleapis.com/css?family=open+sans+condensed:300,700' rel='stylesheet' type='text/css'> 

css:

body { font-family: 'open sans', arial, sans-serif; font-size: 16px; color: #4c4c4c; background: url('images/textures/header_bg1.png') no-repeat center top, url(images/textures/11.png) 0px 0px; }  h1, h2, h3, h4, h5, h6 { font-family: 'open sans', arial, sans-serif; padding-bottom: 6px; color: #474747; line-height: 1em; font-weight: 300; } h1 a, h2 a, h3 a, h4 a, h5 a, h6 { color: #2b2b2b; } h1 { font-size: 41px; font-weight: 300; color: #5a5a5a; margin-top: 25px;  margin-bottom:5px;} h2 { font-size: 30px; font-weight: 300; margin-top: 25px;  margin-bottom:5px;} h3 { font-size: 23px; font-weight: 300; margin-top: 25px;  margin-bottom:5px;} h4 { font-size: 18px; font-weight: lighter; margin-top: 25px;  margin-bottom:5px;} h5 { font-size: 16px; font-weight: lighter; margin-top: 25px;  margin-bottom:5px;} h6 { font-size: 14px; font-weight: lighter; margin-top: 25px;  margin-bottom:5px;}  p { font-family: 'open sans', arial, sans-serif; font-size: 12px; color: #4c4c4c; text-align: justify; margin-top: 10px; margin-bottom: 10px; line-height: 25px;} 

link site i'm working on: http://www.bpcdev.co.uk

bit late suppose issue google itself. changed google fonts url from

http 

to

https