Hello ,dear readers, today bootstrap css will be discussed, though many references quoted from this book , examples and demos will be added in later blogs.

1.        Typography

       Starting with typography, Bootstrap uses Helvetica Neue, Helvetica, Arial, and sansserif in its default font stack.here,we can know the types of defalut fonts in Bootstrap.

if these fonts above are not installed in your computer and broswer, and  sansserif  will be used as its default font and showed to you.  All body copy has the font-size set at 14

pixels, with the line-height set at 20 pixels. The

tag has a margin-bottom of 10 pixels, or half the line-height(5 pixels).

       1.1     headings

       All six standard heading levels have been styled in Bootstrap range from

to

  with the

at 36 pixels tall

, and the

down to 12 pixels

(for reference,

default body text is 14 pixels tall). in order  to add an inline subheading to any of the headings ,you can add a tag  around to create a subheading and make its color

lighter than the  parent heading.

      1.2    lead body copy

       To add some emphasis to a paragraph, add class="lead" 。This will give you larger font size, lighter weight, and a taller line height. This is generally used for

the first few paragraphs in a section, but it can really be used anywhere.

     1.3    Emphasis

     In addition to using the tag within headings, as discussed above, you can also use it with body copy. When is applied to body text, the font shrinks to

85% of  its original size.

      1.4    Bold

    To add emphasis to text, simply wrap it in a tag. This will add fontweight:bold; to the selected text.

      1.5   Italics

      For italics, wrap your content in the tag. The term “em” derives from the word “emphasis” and is meant to add stress to your text.

      HERE ,A NEW QUESTATION WILL BE ASKED,AND THEN I WILL FIND AN ANSWER FOR IT.

1.why not just use the or tags instead of or ?

      1.6   Emphasis Classes

     Along with and , Bootstrap offers a few other classes that can be used toprovide emphasisThese could be applied to paragraphs or spans:
   

This content is muted

     1.6.1 Abbreviations（中文:缩略词）

     The HTML element provides markup for abbreviations or acronyms, like WWW or HTTP.By marking up abbreviations, you can give useful
information to browsers, spell checkers, translation systems, or search engines. Bootstrap styles elements with a light dotted border along the bottom and reveals
the full text on hover (as long as you add that text to the title attribute): RSS.

    1.6.2 Addresses

    Adding

tag :


  

Favorite Outdoor Activities


    

      
• Backpacking in Yosemite

      
• Hiking in Arches
            
  
               
  • Delicate Arch
  
                
  • Park Avenue
  
            
  
        

      
• Biking the Flintstones Trail

   

    1.7.2 Ordered list


    An ordered list is a list that falls in some sort of sequential order and is prefaced by numbers rather than bullets (see Figure 2-10). This is handy when you want to build a
list of numbered items like a task list, guide items, or even a list of comments on a blog post:


    

Self-Referential Task List


    

       
1. Turn off the internet.

       
2. Write the book.

       
3. ... Profit?

    

      1.7.3 Definition list

      The third type of list you get with Bootstrap is the definition list. The definition list  differs from the ordered and unordered list in that instead of just having a block-level

and then styling the

and

as you would the heading and the text .That being said, Bootstrap offers some clean default styles and an option for a side-by-side layout of each definition:

 

Common Electronics Parts

   

    

LED

   

A light-emitting diode (LED) is a semiconductor light source.

    

Servo

   

Servos are small, cheap, mass-produced actuators used for radio control and small robotics.

   

  To change the

to a horizontal layout, with the

on the left side and the

on the right, simply add class="dl-horizontal" to the opening tag