/* back_to_top */
.back-to-top-button{position:fixed;right:max(20px,calc((100vw - 1100px)/2 - 48px));bottom:calc(20px + env(safe-area-inset-bottom));z-index:30;display:grid;width:36px;min-width:36px;height:36px;min-height:36px;padding:0;place-items:center;border:1px solid var(--line);border-radius:50%;background:var(--panel);color:var(--text-muted);box-shadow:0 4px 14px var(--shadow-medium);transition:background var(--transition-normal),border-color var(--transition-normal),color var(--transition-normal),transform var(--transition-normal)}.back-to-top-button:hover{border-color:var(--brand);background:var(--brand-soft);color:var(--brand)}.back-to-top-button:focus-visible{outline:0;border-color:var(--brand);box-shadow:0 0 0 3px var(--focus-ring)}.back-to-top-button:active{transform:translateY(1px)}.back-to-top-button[hidden]{display:none}body:has([data-back-to-top-layout][data-top-fixed="1"]) .top{position:sticky;top:0;z-index:35;box-shadow:0 3px 10px var(--shadow-base)}body:has([data-back-to-top-layout][data-top-fixed="1"]) .forum-more-region{position:sticky;top:var(--btt-top-h,48px);z-index:34}@media(min-width:721px){body:has([data-back-to-top-layout][data-sidebar-fixed="1"]) .sidebar{position:sticky;top:calc(var(--btt-top-h,0px) + 12px)}html.back-to-top-sidebar-tall body:has([data-back-to-top-layout][data-sidebar-fixed="1"]) .sidebar{position:static;top:auto}}@media(max-width:720px){.back-to-top-button{right:12px;bottom:calc(12px + env(safe-area-inset-bottom))}}