main.css

.markdown-body {
    font-family: -apple-system, system-ui, BlinkMacSystemFont, "Segoe UI";
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
    color: #24292e;
}

.markdown-body h1, .markdown-body h2 {
    border-bottom: 1px solid #eaecef;
    padding-bottom: .3em;
}

.markdown-body pre {
    padding: 16px;
    overflow: auto;
    background-color: #f6f8fa;
    border-radius: 3px;
}

.markdown-body table {
    border-collapse: collapse;
    width: 100%;
}

.markdown-body table th, 
.markdown-body table td {
    padding: 6px 13px;
    border: 1px solid #dfe2e5;
}