• Problems

  This line enable URL Rewriting . It must be enabled via the RewriteEngine directive! and if your .htaccess file is going to use rewrite rules, you should always include this line. Otherwise, you can’t be sure if its enabled or not. The string “on” is case insensitive.

Bootstrap is a css library which is sleek , intutive ,
 and powerful mobile front end framework for faster and easier web development
In simple word " It is just like a external css stylesheet which consist of predefined class and it's style. Bootstrap cile consist of more than 700
line of css  code "


History
 Bootstrap was developed by Mark Otto and Jacob Thornton at Twitter.
 It was released as an open source product in August 2011 on GitHub.

Why use Bootstrap?
Mobile first approach:
Since Bootstrap 3, the framework consists of Mobile first styles throughout
the entire library instead of in separate files. ? Browser Support: It is supported by all popular browsers.
Easy to get started:
With just the knowledge of HTML and CSS anyone can get started with Bootstrap.
 Also the Bootstrap official site has a good documentation.
Responsive design:
 Bootstrap's responsive CSS adjusts to Desktops,Tablets and Mobiles.
 
Provides a clean and uniform solution for building an interface for developers.

It contains beautiful and functional built-in components which are easy to customize.

It also provides web based customization.

And best of all it is an open source.

What Bootstrap Package Includes?
Scaffolding:
 Bootstrap provides a basic structure with Grid System, link styles, background.
This is is covered in detail in the section Bootstrap Basic Structure

CSS: Bootstrap comes with feature of global CSS settings, fundamental HTML elements styled and enhanced
with extensible classes, and an advanced grid system. This is covered in detail in the section Bootstrap with CSS.

Components: Bootstrap contains over a dozen reusable components built to provide iconography, dropdowns,
 navigation, alerts, popovers, and much more. This is covered in detail in the section Layout Components.

JavaScript Plugins: Bootstrap contains over a dozen custom jQuery plugins. You can easily include them all,
 or one by one. This is covered in details in the section Bootstrap Plugins.

Customize: You can customize Bootstrap's components, LESS variables, and jQuery plugins to get your very own version.