.skipToContent{position:absolute;top:-1000px;left:-1000px;height:1px;width:1px;text-align:left;overflow:hidden}a.skipToContent:active,a.skipToContent:focus,a.skipToContent:hover{left:0;top:0;width:auto;height:auto;overflow:visible}.has-feedback label.sr-only~.form-control-feedback{top:0}.sr-only{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0,0,0,0);border:0}.sr-only-focusable:active,.sr-only-focusable:focus{position:static;width:auto;height:auto;margin:0;overflow:visible;clip:auto}@media screen and (min-width:808px){.display_wide_leaderboards{display:block!important}.display_short_leaderboards,.display_tiny_leaderboards{display:none!important}}@media screen and (min-width:548px) and (max-width:807px){.display_short_leaderboards{display:block!important}.display_tiny_leaderboards,.display_wide_leaderboards{display:none!important}}@media screen and (max-width:547px){.display_tiny_leaderboards{display:block!important}.display_short_leaderboards,.display_wide_leaderboards{display:none!important}}@media screen and (max-width:1024px){.sidebar_amazon,.sidebar_chegg{display:none!important}}@media screen and (max-width:600px){#WyzAntWidget,#contract_ad{max-width:180px;margin-right:15px}}.YT_mobile_submenu li{padding-left:15px}.text{font-family:Arial,Helvetica,sans-serif}.math{font-family:"Times New Roman",Times,serif;font-size:110%}.indent_prob{margin-left:20px;}.multiline{line-height:0.8em;}.question{font-weight:bold;color:green;line-height:1.7em}.answer{font-weight:bold;color:purple}.in-lesson-resp-ad-header{color:#898989;text-align:center;font-style:italic;font-size:.9em}.content a,.content a:link,.content a:visited{color:#00f;text-decoration:underline}.content a:visited{color:purple}.content a:active,.content a:hover{color:red;text-decoration:underline}.clearfix_table::after,.clearfix_table::before{content:"";display:table}.clearfix_table::after{clear:both}/*.clearfix_table{zoom:1}/*/.narrow::before{width:2em;}button{font:inherit;margin:0;overflow:visible;text-transform:none}optgroup{font-weight:700}[type=reset],[type=submit],button,html [type=button]{-webkit-appearance:button}[type=button]::-moz-focus-inner,[type=reset]::-moz-focus-inner,[type=submit]::-moz-focus-inner,button::-moz-focus-inner{border-style:none;padding:0}[type=button]:-moz-focusring,[type=reset]:-moz-focusring,[type=submit]:-moz-focusring,button:-moz-focusring{outline:1px dotted ButtonText}.w3-container:after{content:"";display:table;clear:both}.w3-container{padding:.01em 16px}.w3-btn,.w3-btn-block{border:none;display:inline-block;outline:0;padding:6px 16px;vertical-align:middle;overflow:hidden;text-decoration:none!important;color:#fff;background-color:#000;text-align:center;cursor:pointer;white-space:nowrap}.w3-btn-block:hover,.w3-btn:hover{box-shadow:0 8px 16px 0 rgba(0,0,0,.2),0 6px 20px 0 rgba(0,0,0,.19)}.w3-btn{-webkit-touch-callout:none;-webkit-user-select:none;-khtml-user-select:none;-moz-user-select:none;-ms-user-select:none;user-select:none}.w3-btn:disabled,.w3-disabled{cursor:not-allowed;opacity:.3}.w3-btn-block.w3-disabled,.w3-btn.w3-disabled *{pointer-events:none}.w3-btn-block.w3-disabled:hover,.w3-btn.w3-disabled:hover,.w3-btn:disabled:hover{box-shadow:none}.w3-btn-group .w3-btn{float:left}.w3-btn-block{width:100%}.w3-btn-bar .w3-btn{box-shadow:none;background-color:inherit;color:inherit;float:left}.w3-btn-bar .w3-btn:hover{background-color:#ccc}p:before {content:"";width:6em;display: block;overflow: hidden;}#gototop_button{display:none;position:fixed;bottom:20px;right:30px;z-index:99;font-size:18px;border:none;outline:none;background-color:#F8E7C8;cursor:pointer;padding:0px 15px 5px 15px;border-radius:4px;}#gototop_button:hover{background-color:#E7C8F8;}
