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(max-width:900px){.shell{grid-template-columns:minmax(0,1fr)}.sidebar{left:0;top:var(--header-h);z-index:50;background:var(--bg-elev);width:min(300px,85vw);box-shadow:var(--shadow);transition:transform .2s;position:fixed;transform:translate(-100%)}.sidebar.open{transform:none}.backdrop.open{inset:var(--header-h) 0 0 0;z-index:45;background:#00000059;display:block;position:fixed}.menu-btn{display:inline-flex}.header-nav{display:none}.search-trigger{min-width:0}.search-trigger .label,.search-trigger kbd{display:none}.page,.doc-layout{padding:20px 16px 64px}.doc-nav{grid-template-columns:1fr}.doc-nav .next{grid-column:1}footer.site-footer{padding:20px 16px}}@media (max-width:520px){.problem-row{grid-template-columns:28px minmax(0,1fr)}.problem-right{grid-column:2}.viz{padding:14px}}.select{min-width:0;max-width:100%}.btn:disabled{opacity:.45;cursor:not-allowed;filter:none}