Add whitespace on all sides of the content section with padding and margin, as follows

.blog-content {
  padding: 15px;
  margin-bottom: 30px;
} 

Separate each blog post with some whitespace and borderline, as follows:

.post {
  margin-bottom: 60px;
  padding-bottom: 60px;
  border-bottom: 1px solid #ddd;
}

Align the title to the center, adjust the title font size a little, and change the color with the following style rules:

.post-title {
  font-size: 36px;
  text-align: center;
  margin-top: 0;
}
.post-title a {
  color: #333;
}
.post-title a:hover {
  color: #3498db;
}

Below the title, we have post-meta, which consists of the post author name and the post publishing date. Similar to the title, we also adjust the font size and the whitespace, and change the font color, as follows:

.post-meta {
  font-size: 18px;
  margin: 20px 0 0;
  text-align: center;
  color: #999;
}
.post...