/*!
 * copyright 2016 google inc. all rights reserved.
 * licensed under the w3c software and document notice and license.
 *  https://www.w3.org/consortium/legal/2015/copyright-software-and-document
 */
!function(){'use strict';if('object'==typeof window)if('intersectionobserver'in window&&'intersectionobserverentry'in window&&'intersectionratio'in window.intersectionobserverentry.prototype)'isintersecting'in window.intersectionobserverentry.prototype||object.defineproperty(window.intersectionobserverentry.prototype,'isintersecting',{get:function(){return this.intersectionratio>0}});else{var t=function(t){for(var e=window.document,n=i(e);n;)n=i(e=n.ownerdocument);return e}(),e=[],n=null,o=null;s.prototype.throttle_timeout=100,s.prototype.poll_interval=null,s.prototype.use_mutation_observer=!0,s._setupcrossoriginupdater=function(){return n||(n=function(t,n){o=t&&n?l(t,n):{top:0,bottom:0,left:0,right:0,width:0,height:0},e.foreach(function(t){t._checkforintersections()})}),n},s._resetcrossoriginupdater=function(){n=null,o=null},s.prototype.observe=function(t){if(!this._observationtargets.some(function(e){return e.element==t})){if(!t||1!=t.nodetype)throw new error('target must be an element');this._registerinstance(),this._observationtargets.push({element:t,entry:null}),this._monitorintersections(t.ownerdocument),this._checkforintersections()}},s.prototype.unobserve=function(t){this._observationtargets=this._observationtargets.filter(function(e){return e.element!=t}),this._unmonitorintersections(t.ownerdocument),0==this._observationtargets.length&&this._unregisterinstance()},s.prototype.disconnect=function(){this._observationtargets=[],this._unmonitorallintersections(),this._unregisterinstance()},s.prototype.takerecords=function(){var t=this._queuedentries.slice();return this._queuedentries=[],t},s.prototype._initthresholds=function(t){var e=t||[0];return array.isarray(e)||(e=[e]),e.sort().filter(function(t,e,n){if('number'!=typeof t||isnan(t)||t<0||t>1)throw new error('threshold must be a number between 0 and 1 inclusively');return t!==n[e-1]})},s.prototype._parserootmargin=function(t){var e=(t||'0px').split(/\s+/).map(function(t){var e=/^(-?\d*\.?\d+)(px|%)$/.exec(t);if(!e)throw new error('rootmargin must be specified in pixels or percent');return{value:parsefloat(e[1]),unit:e[2]}});return e[1]=e[1]||e[0],e[2]=e[2]||e[0],e[3]=e[3]||e[1],e},s.prototype._monitorintersections=function(e){var n=e.defaultview;if(n&&-1==this._monitoringdocuments.indexof(e)){var o=this._checkforintersections,r=null,s=null;if(this.poll_interval?r=n.setinterval(o,this.poll_interval):(h(n,'resize',o,!0),h(e,'scroll',o,!0),this.use_mutation_observer&&'mutationobserver'in n&&(s=new n.mutationobserver(o)).observe(e,{attributes:!0,childlist:!0,characterdata:!0,subtree:!0})),this._monitoringdocuments.push(e),this._monitoringunsubscribes.push(function(){var t=e.defaultview;t&&(r&&t.clearinterval(r),c(t,'resize',o,!0)),c(e,'scroll',o,!0),s&&s.disconnect()}),e!=(this.root&&this.root.ownerdocument||t)){var u=i(e);u&&this._monitorintersections(u.ownerdocument)}}},s.prototype._unmonitorintersections=function(e){var n=this._monitoringdocuments.indexof(e);if(-1!=n){var o=this.root&&this.root.ownerdocument||t;if(!this._observationtargets.some(function(t){var n=t.element.ownerdocument;if(n==e)return!0;for(;n&&n!=o;){var r=i(n);if((n=r&&r.ownerdocument)==e)return!0}return!1})){var r=this._monitoringunsubscribes[n];if(this._monitoringdocuments.splice(n,1),this._monitoringunsubscribes.splice(n,1),r(),e!=o){var s=i(e);s&&this._unmonitorintersections(s.ownerdocument)}}}},s.prototype._unmonitorallintersections=function(){var t=this._monitoringunsubscribes.slice(0);this._monitoringdocuments.length=0,this._monitoringunsubscribes.length=0;for(var e=0;e<t.length;e++)t[e]()},s.prototype._checkforintersections=function(){if(this.root||!n||o){var t=this._rootisindom(),e=t?this._getrootrect():{top:0,bottom:0,left:0,right:0,width:0,height:0};this._observationtargets.foreach(function(o){var i=o.element,s=u(i),h=this._rootcontainstarget(i),c=o.entry,a=t&&h&&this._computetargetandrootintersection(i,s,e),l=o.entry=new r({time:window.performance&&performance.now&&performance.now(),target:i,boundingclientrect:s,rootbounds:n&&!this.root?null:e,intersectionrect:a});c?t&&h?this._hascrossedthreshold(c,l)&&this._queuedentries.push(l):c&&c.isintersecting&&this._queuedentries.push(l):this._queuedentries.push(l)},this),this._queuedentries.length&&this._callback(this.takerecords(),this)}},s.prototype._computetargetandrootintersection=function(e,i,r){if('none'!=window.getcomputedstyle(e).display){for(var s,h,c,a,f,d,g,m,v=i,_=p(e),b=!1;!b&&_;){var w=null,y=1==_.nodetype?window.getcomputedstyle(_):{};if('none'==y.display)return null;if(_==this.root||9==_.nodetype)if(b=!0,_==this.root||_==t)n&&!this.root?!o||0==o.width&&0==o.height?(_=null,w=null,v=null):w=o:w=r;else{var i=p(_),e=i&&u(i),t=i&&this._computetargetandrootintersection(i,e,r);e&&t?(_=i,w=l(e,t)):(_=null,v=null)}else{var r=_.ownerdocument;_!=r.body&&_!=r.documentelement&&'visible'!=y.overflow&&(w=u(_))}if(w&&(s=w,h=v,c=void 0,a=void 0,f=void 0,d=void 0,g=void 0,m=void 0,c=math.max(s.top,h.top),a=math.min(s.bottom,h.bottom),f=math.max(s.left,h.left),d=math.min(s.right,h.right),m=a-c,v=(g=d-f)>=0&&m>=0&&{top:c,bottom:a,left:f,right:d,width:g,height:m}||null),!v)break;_=_&&p(_)}return v}},s.prototype._getrootrect=function(){var e;if(this.root)e=u(this.root);else{var n=t.documentelement,o=t.body;e={top:0,left:0,right:n.clientwidth||o.clientwidth,width:n.clientwidth||o.clientwidth,bottom:n.clientheight||o.clientheight,height:n.clientheight||o.clientheight}}return this._expandrectbyrootmargin(e)},s.prototype._expandrectbyrootmargin=function(t){var e=this._rootmarginvalues.map(function(e,n){return'px'==e.unit?e.value:e.value*(n%2?t.width:t.height)/100}),n={top:t.top-e[0],right:t.right+e[1],bottom:t.bottom+e[2],left:t.left-e[3]};return n.width=n.right-n.left,n.height=n.bottom-n.top,n},s.prototype._hascrossedthreshold=function(t,e){var n=t&&t.isintersecting?t.intersectionratio||0:-1,o=e.isintersecting?e.intersectionratio||0:-1;if(n!==o)for(var i=0;i<this.thresholds.length;i++){var r=this.thresholds[i];if(r==n||r==o||r<n!=r<o)return!0}},s.prototype._rootisindom=function(){return!this.root||f(t,this.root)},s.prototype._rootcontainstarget=function(e){return f(this.root||t,e)&&(!this.root||this.root.ownerdocument==e.ownerdocument)},s.prototype._registerinstance=function(){e.indexof(this)<0&&e.push(this)},s.prototype._unregisterinstance=function(){var t=e.indexof(this);-1!=t&&e.splice(t,1)},window.intersectionobserver=s,window.intersectionobserverentry=r}function i(t){try{return t.defaultview&&t.defaultview.frameelement||null}catch(t){return null}}function r(t){this.time=t.time,this.target=t.target,this.rootbounds=a(t.rootbounds),this.boundingclientrect=a(t.boundingclientrect),this.intersectionrect=a(t.intersectionrect||{top:0,bottom:0,left:0,right:0,width:0,height:0}),this.isintersecting=!!t.intersectionrect;var e=this.boundingclientrect,n=e.width*e.height,o=this.intersectionrect,i=o.width*o.height;this.intersectionratio=n?number((i/n).tofixed(4)):this.isintersecting?1:0}function s(t,e){var n,o,i,r=e||{};if('function'!=typeof t)throw new error('callback must be a function');if(r.root&&1!=r.root.nodetype)throw new error('root must be an element');this._checkforintersections=(n=this._checkforintersections.bind(this),o=this.throttle_timeout,i=null,function(){i||(i=settimeout(function(){n(),i=null},o))}),this._callback=t,this._observationtargets=[],this._queuedentries=[],this._rootmarginvalues=this._parserootmargin(r.rootmargin),this.thresholds=this._initthresholds(r.threshold),this.root=r.root||null,this.rootmargin=this._rootmarginvalues.map(function(t){return t.value+t.unit}).join(' '),this._monitoringdocuments=[],this._monitoringunsubscribes=[]}function h(t,e,n,o){'function'==typeof t.addeventlistener?t.addeventlistener(e,n,o||!1):'function'==typeof t.attachevent&&t.attachevent('on'+e,n)}function c(t,e,n,o){'function'==typeof t.removeeventlistener?t.removeeventlistener(e,n,o||!1):'function'==typeof t.detatchevent&&t.detatchevent('on'+e,n)}function u(t){var e;try{e=t.getboundingclientrect()}catch(t){}return e?(e.width&&e.height||(e={top:e.top,right:e.right,bottom:e.bottom,left:e.left,width:e.right-e.left,height:e.bottom-e.top}),e):{top:0,bottom:0,left:0,right:0,width:0,height:0}}function a(t){return!t||'x'in t?t:{top:t.top,y:t.top,bottom:t.bottom,left:t.left,x:t.left,right:t.right,width:t.width,height:t.height}}function l(t,e){var n=e.top-t.top,o=e.left-t.left;return{top:n,left:o,height:e.height,width:e.width,bottom:n+e.height,right:o+e.width}}function f(t,e){for(var n=e;n;){if(n==t)return!0;n=p(n)}return!1}function p(e){var n=e.parentnode;return 9==e.nodetype&&e!=t?i(e):n&&11==n.nodetype&&n.host?n.host:n&&n.assignedslot?n.assignedslot.parentnode:n}}();