Code:
#start-focus,input.A,input.B{position:absolute;top:-1000px;left:-1000px}body{-webkit-animation:bugfix infinite 1s;font-family:"Courier New";font-size:20px;margin:3em 1em}@-webkit-keyframes bugfix{from,to{padding:0}}*,a,body,html,label{-webkit-touch-callout:none;-webkit-user-select:none;-khtml-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none}a,input.A,input.B{display:none}#start-focus:focus~input:checked+*+*+*+input:checked+*+*+*+input:not(:checked)+label+input.B:not(:checked),#start-focus:focus~input:checked+*+*+*+input:not(:checked)+*+*+*+input:checked+label+input.B:not(:checked),#start-focus:focus~input:not(:checked)+*+*+*+input:checked+*+*+*+input:checked+label+input.B:not(:checked),#start-focus:focus~input:not(:checked)+*+*+*+input:checked+*+*+*+input:not(:checked)+label+input.B:not(:checked),#start-focus:focus~input:not(:checked)+*+*+*+input:not(:checked)+*+*+*+input:checked+label+input.B:not(:checked),input:checked+*+*+*+input:checked+*+*+*+input:not(:checked)+label+.B:checked+a:focus,input:checked+*+*+*+input:checked+*+*+*+input:not(:checked)+label+.B:checked:focus+a,input:checked+*+*+*+input:checked+*+*+*+input:not(:checked)+label+input.B:focus,input:checked+*+*+*+input:not(:checked)+*+*+*+input:checked+label+.B:checked+a:focus,input:checked+*+*+*+input:not(:checked)+*+*+*+input:checked+label+.B:checked:focus+a,input:checked+*+*+*+input:not(:checked)+*+*+*+input:checked+label+input.B:focus,input:not(:checked)+*+*+*+input:checked+*+*+*+input:checked+label+.B:checked+a:focus,input:not(:checked)+*+*+*+input:checked+*+*+*+input:checked+label+.B:checked:focus+a,input:not(:checked)+*+*+*+input:checked+*+*+*+input:checked+label+input.B:focus,input:not(:checked)+*+*+*+input:checked+*+*+*+input:not(:checked)+label+.B:checked+a:focus,input:not(:checked)+*+*+*+input:checked+*+*+*+input:not(:checked)+label+.B:checked:focus+a,input:not(:checked)+*+*+*+input:checked+*+*+*+input:not(:checked)+label+input.B:focus,input:not(:checked)+*+*+*+input:not(:checked)+*+*+*+input:checked+label+.B:checked+a:focus,input:not(:checked)+*+*+*+input:not(:checked)+*+*+*+input:checked+label+.B:checked:focus+a,input:not(:checked)+*+*+*+input:not(:checked)+*+*+*+input:checked+label+input.B:focus,label{display:block}div{clear:both}#start-focus{width:1px;height:1px}a:before,input.A:target:not(:checked)+label{position:fixed;top:0;left:0;width:100%;height:100%}#start-focus:not(:focus)::after{position:fixed;top:0;left:0;font-size:40px;content:"[TAB]";background:#fff;padding:3px}label{float:left;padding:1px 5px;margin:2px;background:#ddd}label::before{content:"0"}input.A:checked+label::before{content:"1"}a:before,input.A:target:not(:checked)+label::before{font-size:40px;content:"[CLICK]"}input.A:checked+label{background:#afa!important}input:focus+label{background:#f0f!important}input.A:target:not(:checked)+label{display:block;z-index:1000}a:before{background:#fff;z-index:99;color:#000}#start-focus:focus~input.B:not(:checked)::before,input.B:not(:checked):focus::before{position:fixed;top:0;left:0;font-size:40px;background:#fff;height:50px;width:100%;padding:3px}#start-focus:focus~input.B:not(:checked)::before{content:"[TAB]"}input.B:not(:checked):focus::before{content:"[SPACE]"}