h1,h2,h3,h4,h5,h6 {
    clear: both;
}

h1,h2,h3,h4,h5,h6 {
    font-family: 'Georgia', serif;
    clear: both;
}

#site-title a {
    color: #111;
    font-size: 30px;
    font-weight: bold;
    line-height: 36px;
    text-decoration: none;
}

#site-title a {
    font-family: 'Verdana', sans-serif;
    color: #111;
    font-size: 30px;
    font-weight: bold;
    line-height: 36px;
    text-decoration: none;
}

.entry-title,
.entry-title a {
    color: #222;
    text-decoration: none;
}

Add in the font family you want to use. Example:

.entry-title,
.entry-title a {
    font-family: 'Georgia' , serif;
    color: #222;
    text-decoration: none;
}

CHANGE FONTS FOR NAVIGATION LINKS IN TWENTY ELEVEN THEME
The final place where one would like to have a different font would be the Navigation Menu. To change the fonts for the navigation links scroll down to find the comment, Menu

Under that find these codes:

#access a {
    color: #eee;
    display: block;
    line-height: 3.333em;
    padding: 0 1.2125em;
    text-decoration: none;
}

Add the font-family you want. Example:

#access a {
    font-family: 'Georgia', serif;
    color: #eee;
    display: block;
    line-height: 3.333em;
    padding: 0 1.2125em;
    text-decoration: none;
}

USING FANCY GOOGLE FONTS FOR TWENTY ELEVEN THEME
To take things a little bit further, you can use fancy fonts from Google Webfonts for the Twenty Eleven Theme. Follow these steps:

Go to Google Webfonts and choose the fonts you want.

Click “Add To Selection”.

Click “Use”

In the 3rd table, click the “@import” tab

Copy the string of codes provided. My example using the Meddon font, looks like this:

In the fourth table beneath, copy the font family name and paste it in Notepad for later use.
Go back to your Theme Editor – Stylesheet
At the top most portion of the stylesheet, you will find a long paragraph that includes the Theme credentials, License info and the theme tags. Immediately AFTER the closing comment of that paragraph, denoted by this symblol, */
Paste in the string of codes you copied from Google Webfonts.
Find the location where you want to use the Google Fonts. If you want it as the Site Title, just replace the font family with the name of the fonts. If you do not remember, check your Notepad where you copied and pasted the names from Google Webfonts. Example fancy fonts for the Site Title:

#site-title a {
    font-family: 'Meddon', cursive;
    color: #111;
    font-size: 30px;
    font-weight: bold;
    line-height: 36px;
    text-decoration: none;
}

CHANGE THE FONTS FOR THE CONTENT AREA IN TWENTY ELEVEN THEME
With the stylesheet open, scroll down till you see the comment, Global. Find these codes immediately below.

body, input, textarea {
    color: #373737;
    font: 15px "Helvetica Neue", Helvetica, Arial, sans-serif;
    font-weight: 300;
    line-height: 1.625;
}

Change the default font, Helvetica Neue to whatever you like. The 15px in front defines the size of the fonts. Increase or decrease the value if your font looks too bog or too small.

Since this is the global values, you will find that all the fonts have been changed to the one you specified. If you like it that way, you can keep it. Else, you can specify different fonts other areas individually.
Via:blogigs