What theme are you using? Where did you download it from?
Sorry? That is the name of your theme? If so, where did you download it from?
I download it form styletheme.com and the name of the theme is encounters
Ah! You will probably need to start customising your theme’s CSS – possibly via a child theme or a custom CSS plugin. You could try using Firefox with the Firebug add-on for this kind of CSS troubleshooting. Or use whatever developer tool is available in your web browser.
I’m sorry but as you are using a non-WPORG theme, you need to seek theme-specific support from the theme’s developers – paid or otherwise. We only support themes downloaded from wordpress.org here.