Improve spacing between titles

README.md

@@ -172,45 +172,6 @@ This is the summary of my book.
 
 Files that are not included in `SUMMARY.md` will not be processed by `gitbook`.
 
-#### Exercises
-
-A book can contain interactive exercises (currently only in Javascript but Python and Ruby are coming soon ;) ). An exercise is a code challenge provided to the reader, who is given a code editor to write a solution which is checked against the book author's validation code.
-
-An exercise is defined by 4 simple parts:
-
-* Exercise **Message**/Goals (in markdown/text)
-* **Initial** code to show to the user, providing a starting point
-* **Solution** code, being a correct solution to the exercise
-* **Validation** code that tests the correctness of the user's input
-
-Exercises need to start and finish with a separation bar (```---``` or ```***```). It should contain 3 code elements (**base**, **solution** and **validation**). It can contain a 4th element that provides **context** code (functions, imports of libraries, etc which shouldn't be displayed to the user).
-
-    ---
-
-    Define a variable `x` equal to 10.
-
-    ```js
-    var x =
-    ```
-
-    ```js
-    var x = 10;
-    ```
-
-    ```js
-    assert(x == 10);
-    ```
-
-    ```js
-    // This is context code available everywhere
-    // The user will be able to call magicFunc in his code
-    function magicFunc() {
-        return 3;
-    }
-    ```
-
-    ---
-
 #### Multi-Languages
 
 GitBook supports building books written in multiple languages. Each language should be a sub-directory following the normal GitBook format, and a file named `LANGS.md` should be present at the root of the repository with the following format:

theme/stylesheets/website/markdown.less

@@ -198,13 +198,13 @@
     h6 {
         position: relative;
         margin-top: 1em;
+        margin-bottom: 16px;
         font-weight: bold;
         line-height: 1.4;
     }
 
     h1 {
         padding-bottom: 0.3em;
-        margin-bottom: 16px;
         font-size: 2.25em;
         line-height: 1.2;
         border-bottom: 1px solid #eee;
@@ -212,30 +212,25 @@
 
     h2 {
         padding-bottom: 0.3em;
-        margin-bottom: 16px;
         font-size: 1.75em;
         line-height: 1.225;
         border-bottom: 1px solid #eee;
     }
 
     h3 {
-        margin-bottom: 0;
         font-size: 1.5em;
         line-height: 1.43;
     }
 
     h4 {
-        margin-bottom: 0.1em;
         font-size: 1.25em;
     }
 
     h5 {
-        margin-bottom: 0.2em;
         font-size: 1em;
     }
 
     h6 {
-        margin-bottom: 0.2em;
         font-size: 1em;
         color: #777;
     }