This line should be the culprit:
<link href="{{STATIC_URL}}/style.css" rel="stylesheet" type="text/css" />
Remove the trailing slash after {{STATIC_URL}}
You should say
<link href="{{STATIC_URL}}style.css" rel="stylesheet" type="text/css" />
Can you make sure STATICFILES_DIRS refer to your static
directory.
from django.conf import settings
print settings.STATICFILES_DIRS