Github centered, sticky header by kyoukisu

/* ==UserStyle==
@name         GitHub Sticky Header
@version      1
@namespace    userstyles.world/user/kyoukisu
@description  Make the GitHub header sticky
@author       kyoukisu
@license      MIT
==/UserStyle== */

@-moz-document domain("github.com") {
  @media (min-width: 1012px) {
    .Layout {
      --Layout-sidebar-width: 175px;
      margin-left: 175px;  /* Shifts main block to the right */
    }
  }
    
    .AppHeader .AppHeader-globalBar {
        display: flex;
        padding: 8px 275px;  /* Increased left and right padding */
        gap: var(--base-size-12, 12px);
    }

    .UnderlineNav {

        justify-content: center;
    }
    
    #repository-container-header {
        padding-left: 260px;
        padding-right:285px;
    }


  
  /* Existing Styles */
  .AppHeader {
    position: fixed;
    width: 100%;
    z-index: 1000;
    top: 0;
  }

  body {
    padding-top: 115px;
  }
}