GitHub Fixed Header for better accessibility.

stylish.css

/**
1. Install the Stylish(https://chrome.google.com/webstore/detail/stylish/fjnbnpbmkenffdnngjfgmeleoegfcffe?hl=en) extension for Chrome.
2. Open up extension options and paste the whole CSS mentioned below.
3. Specify the domain name to be `github.com`.
4. Add a title and save.
*/

.header {
    padding-top: 10px;
    padding-bottom: 10px;
    background-color: #f5f5f5;
    border-bottom: 1px solid #e5e5e5;
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 99999;
}

div[role="main"] {
	padding-top: 50px !important;
}