/**
 * 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=window.document,e=[];o.prototype.THROTTLE_TIMEOUT=100,o.prototype.POLL_INTERVAL=null,o.prototype.USE_MUTATION_OBSERVER=!0,o.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(),this._checkForIntersections()}},o.prototype.unobserve=function(t){this._observationTargets=this._observationTargets.filter(function(e){return e.element!=t}),this._observationTargets.length||(this._unmonitorIntersections(),this._unregisterInstance())},o.prototype.disconnect=function(){this._observationTargets=[],this._unmonitorIntersections(),this._unregisterInstance()},o.prototype.takeRecords=function(){var t=this._queuedEntries.slice();return this._queuedEntries=[],t},o.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]})},o.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},o.prototype._monitorIntersections=function(){this._monitoringIntersections||(this._monitoringIntersections=!0,this.POLL_INTERVAL?this._monitoringInterval=setInterval(this._checkForIntersections,this.POLL_INTERVAL):(i(window,"resize",this._checkForIntersections,!0),i(t,"scroll",this._checkForIntersections,!0),this.USE_MUTATION_OBSERVER&&"MutationObserver"in window&&(this._domObserver=new MutationObserver(this._checkForIntersections),this._domObserver.observe(t,{attributes:!0,childList:!0,characterData:!0,subtree:!0}))))},o.prototype._unmonitorIntersections=function(){this._monitoringIntersections&&(this._monitoringIntersections=!1,clearInterval(this._monitoringInterval),this._monitoringInterval=null,r(window,"resize",this._checkForIntersections,!0),r(t,"scroll",this._checkForIntersections,!0),this._domObserver&&(this._domObserver.disconnect(),this._domObserver=null))},o.prototype._checkForIntersections=function(){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,r=s(i),h=this._rootContainsTarget(i),c=o.entry,a=t&&h&&this._computeTargetAndRootIntersection(i,e),u=o.entry=new n({time:window.performance&&performance.now&&performance.now(),target:i,boundingClientRect:r,rootBounds:e,intersectionRect:a});c?t&&h?this._hasCrossedThreshold(c,u)&&this._queuedEntries.push(u):c&&c.isIntersecting&&this._queuedEntries.push(u):this._queuedEntries.push(u)},this),this._queuedEntries.length&&this._callback(this.takeRecords(),this)},o.prototype._computeTargetAndRootIntersection=function(e,n){if("none"!=window.getComputedStyle(e).display){for(var o,i,r,h,a,u,d,l,p=s(e),f=c(e),g=!1;!g;){var _=null,v=1==f.nodeType?window.getComputedStyle(f):{};if("none"==v.display)return;if(f==this.root||f==t?(g=!0,_=n):f!=t.body&&f!=t.documentElement&&"visible"!=v.overflow&&(_=s(f)),_&&(o=_,i=p,r=void 0,h=void 0,a=void 0,u=void 0,d=void 0,l=void 0,r=Math.max(o.top,i.top),h=Math.min(o.bottom,i.bottom),a=Math.max(o.left,i.left),u=Math.min(o.right,i.right),l=h-r,!(p=(d=u-a)>=0&&l>=0&&{top:r,bottom:h,left:a,right:u,width:d,height:l})))break;f=c(f)}return p}},o.prototype._getRootRect=function(){var e;if(this.root)e=s(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)},o.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},o.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}},o.prototype._rootIsInDom=function(){return!this.root||h(t,this.root)},o.prototype._rootContainsTarget=function(e){return h(this.root||t,e)},o.prototype._registerInstance=function(){e.indexOf(this)<0&&e.push(this)},o.prototype._unregisterInstance=function(){var t=e.indexOf(this);-1!=t&&e.splice(t,1)},window.IntersectionObserver=o,window.IntersectionObserverEntry=n}function n(t){this.time=t.time,this.target=t.target,this.rootBounds=t.rootBounds,this.boundingClientRect=t.boundingClientRect,this.intersectionRect=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 o(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(" ")}function i(t,e,n,o){"function"==typeof t.addEventListener?t.addEventListener(e,n,o||!1):"function"==typeof t.attachEvent&&t.attachEvent("on"+e,n)}function r(t,e,n,o){"function"==typeof t.removeEventListener?t.removeEventListener(e,n,o||!1):"function"==typeof t.detatchEvent&&t.detatchEvent("on"+e,n)}function s(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 h(t,e){for(var n=e;n;){if(n==t)return!0;n=c(n)}return!1}function c(t){var e=t.parentNode;return e&&11==e.nodeType&&e.host?e.host:e&&e.assignedSlot?e.assignedSlot.parentNode:e}}();