[SPARK-42853][DOC] Updating the Style for the Spark Docs based on the Webpage

docs/building-spark.md

@@ -47,7 +47,7 @@ You can fix these problems by setting the `MAVEN_OPTS` variable as discussed bef
 **Note:**
 
 * If using `build/mvn` with no `MAVEN_OPTS` set, the script will automatically add the above options to the `MAVEN_OPTS` environment variable.
-* The `test` phase of the Spark build will automatically add these options to `MAVEN_OPTS`, even when not using `build/mvn`.    
+* The `test` phase of the Spark build will automatically add these options to `MAVEN_OPTS`, even when not using `build/mvn`.
 
 ### build/mvn
 
@@ -290,8 +290,8 @@ If use an individual repository or a repository on GitHub Enterprise, export bel
 
 ### Related environment variables
 
-<table class="table">
-<tr><th>Variable Name</th><th>Default</th><th>Meaning</th></tr>
+<table class="table table-striped">
+<thead><tr><th>Variable Name</th><th>Default</th><th>Meaning</th></tr></thead>
 <tr>
   <td><code>SPARK_PROJECT_URL</code></td>
   <td>https://github.com/apache/spark</td>

docs/cluster-overview.md

@@ -8,9 +8,9 @@ license: |
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at
- 
+
      http://www.apache.org/licenses/LICENSE-2.0
- 
+
   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -91,7 +91,7 @@ The [job scheduling overview](job-scheduling.html) describes this in more detail
 
 The following table summarizes terms you'll see used to refer to cluster concepts:
 
-<table class="table">
+<table class="table table-striped">
   <thead>
     <tr><th style="width: 130px;">Term</th><th>Meaning</th></tr>
   </thead>