@charset "UTF-8";.header-optimize-mar.svelte-1elxaub{margin-right:13px}@keyframes svelte-1elxaub-pageFlyIn{0%{opacity:0;transform:translateY(100px)}to{opacity:1;transform:translateY(0)}}.site-header.svelte-1elxaub{z-index:100000;background-color:#fff}@media(min-width:1025px){.site-header.svelte-1elxaub{position:fixed;width:100%}}.site-header__inner.svelte-1elxaub{height:76px;padding:0 25px;display:flex;align-items:center;justify-content:center}@media(min-width:1025px){.site-header__inner.svelte-1elxaub{width:1280px;margin:0 auto}}.site-header.svelte-1elxaub .branding:where(.svelte-1elxaub){display:flex;align-items:center;text-decoration:none;color:#000}@media(min-width:1025px){.site-header.svelte-1elxaub .branding:where(.svelte-1elxaub){padding-right:35px;border-right:1px solid #c5c5c5}}.site-header.svelte-1elxaub .branding:where(.svelte-1elxaub) p:where(.svelte-1elxaub){font-size:10px;line-height:12px;letter-spacing:.24em;font-weight:700;text-transform:uppercase;margin:0}.site-header.svelte-1elxaub .branding:where(.svelte-1elxaub) p:where(.svelte-1elxaub) small:where(.svelte-1elxaub){display:block;font-size:9px;line-height:12px;font-weight:400;text-transform:none;letter-spacing:0;color:#8d8d8d}.site-header__menu.svelte-1elxaub{display:none}@media(min-width:1025px){.site-header__menu.svelte-1elxaub{flex:1;display:block}}.site-header__menu.svelte-1elxaub .navbar-nav:where(.svelte-1elxaub){width:100%;display:flex;justify-content:space-around;counter-reset:step-counter}.site-header__menu.svelte-1elxaub .navbar-nav__item:where(.svelte-1elxaub){text-align:center;position:relative;margin:0 1px;list-style:none;width:100%}.site-header__menu.svelte-1elxaub .navbar-nav__item:where(.svelte-1elxaub):hover a:where(.svelte-1elxaub){color:#575757}.site-header__menu.svelte-1elxaub .navbar-nav__item.is-active:where(.svelte-1elxaub) a:where(.svelte-1elxaub){color:#575757;border-bottom-color:#db592c;font-weight:800}.site-header__menu.svelte-1elxaub .navbar-nav:where(.svelte-1elxaub) a:where(.svelte-1elxaub){font-size:8px;font-weight:700;color:#c5c5c5;text-transform:uppercase;transition:all .15s ease;text-decoration:none;letter-spacing:.05em;display:block;padding-bottom:10px;border-bottom:2px solid #c5c5c5}.site-header__menu.svelte-1elxaub .navbar-nav:where(.svelte-1elxaub) a:where(.svelte-1elxaub):before{font-family:Coda-n8,Coda,sans-serif;content:counter(step-counter) ".";counter-increment:step-counter;display:block;font-size:10px;margin-bottom:2px;font-weight:800}@font-face{font-family:Coda;src:url(../../../fonts/Coda-Regular.woff2) format("woff2"),url(../../../fonts/Coda-Regular.woff) format("woff");font-weight:400;font-style:normal;font-display:swap}@font-face{font-family:Open Sans;src:url(../../../fonts/OpenSans-ExtraBold.woff2) format("woff2"),url(../../../fonts/Coda-ExtraBold.woff) format("woff");font-weight:800;font-style:normal;font-display:swap}@font-face{font-family:Coda;src:url(../../../fonts/Coda-ExtraBold.woff2) format("woff2"),url(../../../fonts/Coda-ExtraBold.woff) format("woff");font-weight:800;font-style:normal;font-display:swap}.fixed{position:fixed;top:0;left:0;right:0;z-index:9999}.img-responsive.hero{display:block;width:100%;height:auto}.text-center{text-align:center!important}html{line-height:1.15;-ms-text-size-adjust:100%;-webkit-text-size-adjust:100%}body{margin:0}article,aside,footer,header,nav,section{display:block}h1{font-size:2em;margin:.67em 0}figcaption,figure{display:block}figure{margin:1em 40px}hr{-webkit-box-sizing:content-box;box-sizing:content-box;height:0;overflow:visible}main{display:block}pre{font-family:monospace,monospace;font-size:1em}a{background-color:transparent;-webkit-text-decoration-skip:objects}abbr[title]{border-bottom:none;text-decoration:underline;-webkit-text-decoration:underline dotted;text-decoration:underline dotted}b,strong{font-weight:inherit}b,strong{font-weight:bolder}code,kbd,samp{font-family:monospace,monospace;font-size:1em}dfn{font-style:italic}mark{background-color:#ff0;color:#000}small{font-size:80%}sub,sup{font-size:75%;line-height:0;position:relative;vertical-align:baseline}sub{bottom:-.25em}sup{top:-.5em}audio,video{display:inline-block}audio:not([controls]){display:none;height:0}img{border-style:none}svg:not(:root){overflow:hidden}button,input,optgroup,select,textarea{font-family:sans-serif;font-size:100%;line-height:1.15;margin:0}button{overflow:visible}button,select{text-transform:none}button,html [type=button],[type=reset],[type=submit]{-webkit-appearance:button}button::-moz-focus-inner,[type=button]::-moz-focus-inner,[type=reset]::-moz-focus-inner,[type=submit]::-moz-focus-inner{border-style:none;padding:0}button:-moz-focusring,[type=button]:-moz-focusring,[type=reset]:-moz-focusring,[type=submit]:-moz-focusring{outline:1px dotted ButtonText}input{overflow:visible}[type=checkbox],[type=radio]{-webkit-box-sizing:border-box;box-sizing:border-box;padding:0}[type=number]::-webkit-inner-spin-button,[type=number]::-webkit-outer-spin-button{height:auto}[type=search]{-webkit-appearance:textfield;outline-offset:-2px}[type=search]::-webkit-search-cancel-button,[type=search]::-webkit-search-decoration{-webkit-appearance:none}::-webkit-file-upload-button{-webkit-appearance:button;font:inherit}fieldset{padding:.35em .75em .625em}legend{-webkit-box-sizing:border-box;box-sizing:border-box;display:table;max-width:100%;padding:0;color:inherit;white-space:normal}progress{display:inline-block;vertical-align:baseline}textarea{overflow:auto}details{display:block}summary{display:list-item}menu{display:block}canvas{display:inline-block}template{display:none}[hidden]{display:none}@-moz-document url-prefix(){select:-moz-focusring,select::-moz-focus-inner{color:transparent!important;text-shadow:0 0 0 #ffffff!important;background-image:none!important;border:0}}select::-ms-expand{display:none}.hide{display:none}.alignleft{float:left;margin-right:10px}.alignright{float:right;margin-left:10px}.aligncenter{display:block;margin-left:auto;margin-right:auto}.align-text-left{text-align:left}.align-text-right{text-align:right}.align-text-center{text-align:center}.no-margin-botom{margin-bottom:0}@media(max-width:320px){.mobile-text-center{text-align:center!important}}@media(max-width:768px){.mobile-text-left{text-align:left!important}}@media(max-width:991px){.tablet-text-center{text-align:center!important}}@media(max-width:767px){.mobile-hide{display:none!important;visibility:collapse}}.inner-container{position:relative;display:block;margin:0 auto;max-width:1440px}.inner-container:after{content:"";display:table;clear:both}.text-center{text-align:center}button{background:transparent}img{max-width:100%;height:auto}img:focus{outline:0px}.no-padding-bottom{padding-bottom:0}.no-gutter>[class*=col-]{padding-right:0;padding-left:0}.row{margin-right:0;margin-left:0}.row .text-center{text-align:center}.padding-extra{padding-right:30px;padding-left:30px}.container-fluid{padding-right:0;padding-left:0}form label{font-family:Open Sans,sans-serif!important}form .col-md-6{margin-bottom:10px}.left{float:left}.right{float:right}input,textarea{font-size:24px;padding:10px}video{width:100%!important;height:auto!important}figure{display:block;padding:10px}.background-image{background-size:cover;background-position:center center;background-repeat:no-repeat;padding-bottom:50%}@-webkit-keyframes uil-ring-anim{0%{-webkit-transform:rotate(0deg);transform:rotate(0)}to{-webkit-transform:rotate(360deg);transform:rotate(360deg)}}@keyframes uil-ring-anim{0%{-webkit-transform:rotate(0deg);transform:rotate(0)}to{-webkit-transform:rotate(360deg);transform:rotate(360deg)}}.uil-ring-css{background:none;position:relative;width:200px;height:200px}.uil-ring-css>div{position:absolute;display:block;width:160px;height:160px;top:20px;left:20px;border-radius:80px;-webkit-box-shadow:0 6px 0 0 #0F2749;box-shadow:0 6px #0f2749;-webkit-animation:uil-ring-anim 1s linear infinite;animation:uil-ring-anim 1s linear infinite}@font-face{font-family:fontello;src:url(../../../fonts/fontello.woff2) format("woff2"),url(../../../fonts/fontello.woff) format("woff"),url(../../../fonts/fontello.ttf) format("truetype");font-weight:400;font-style:normal}.icon-volume-up:before{content:"";display:inline-block;width:14px;height:14px;background-image:url(../../../icons/Icon_Audio.svg);background-size:contain;background-repeat:no-repeat;background-position:center}.icon-attention:before{content:""}.icon-cancel:before,.question__choice.wrong:before{content:""}.icon-pause-circled:before{content:"";display:inline-block;width:14px;height:14px;background-image:url(../../../icons/Icon_Pause.svg);background-size:contain;background-repeat:no-repeat;background-position:center}.icon-three-arrows:before,.rangeslider__handle:before{content:"›››"}.icon-circle-empty:before,.question__choice.correct:before{content:""}.hiker a{color:#fff;font-size:8px;font-weight:700;text-transform:uppercase;letter-spacing:.3em}.hiker svg{width:27px}.hiker svg .bg{fill:#fff}.hiker svg .letter{fill:#000}*,*:before,*:after{-webkit-box-sizing:border-box;box-sizing:border-box}*{-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}html{font-family:Lucida Grande,Open Sans-n4,Open Sans,Tahoma,Verdana,Arial,sans-serif;font-style:normal;font-weight:400}body{background-color:#000}.container{width:1280px;min-width:1280px;max-width:1280px;margin:0 auto;padding:0 40px}.row{display:-webkit-box;display:-ms-flexbox;display:flex}.col-half{width:50%}a{text-decoration:none}.site-content{display:none}@media(min-width:1025px){.site-content{position:relative;display:block;overflow:hidden;height:calc(100vh - 76px);top:76px}}.page-footer{position:relative;padding:10px 0 20px}.page-footer .hiker a{display:inline-flex;-webkit-box-align:center;-ms-flex-align:center;align-items:center}.page-footer .hiker svg{margin-right:8px}.page-footer--dark .hiker a{color:#00000073}.page-footer--dark .hiker svg .cls-1{fill:#00000073}.page-footer--dark .hiker svg .letter{fill:#fff}.move-to-next{position:absolute;top:0;left:50%;margin-left:-24px;display:inline-block;background:#0006;border:0;width:48px;height:48px;padding:0;border-radius:50%;cursor:pointer;-webkit-animation:bounce 2s infinite ease-in-out;animation:bounce 2s infinite ease-in-out}@-webkit-keyframes bounce{0%,20%,60%,to{-webkit-transform:translateY(0);transform:translateY(0)}40%{-webkit-transform:translateY(-20px);transform:translateY(-20px)}80%{-webkit-transform:translateY(-10px);transform:translateY(-10px)}}@keyframes bounce{0%,20%,60%,to{-webkit-transform:translateY(0);transform:translateY(0)}40%{-webkit-transform:translateY(-20px);transform:translateY(-20px)}80%{-webkit-transform:translateY(-10px);transform:translateY(-10px)}}.textblock h1,.textblock h2,.textblock h3,.textblock h4,.textblock h5,.textblock h6{font-family:Open Sans,sans-serif;font-weight:500;margin:0}.dark .textblock h1,.dark .textblock h2,.dark .textblock h3,.dark .textblock h4,.dark .textblock h5,.dark .textblock h6{color:#fff}.textblock h1,.textblock .h1{font-size:3.75em;line-height:1.08333em;font-weight:700}@media(max-width:767px){.textblock h1,.textblock .h1{font-size:2.25em;line-height:1em}}.textblock h2,.textblock .h2{font-size:3.4375em;font-weight:300}p+.textblock h2,p+.textblock .h2{margin-bottom:10px}@media(max-width:768px){.textblock h2,.textblock .h2{font-size:1.5em;margin-bottom:10px}}.textblock h3,.textblock .h3{font-size:1.125em;font-weight:700}.textblock h4,.textblock .h4{font-size:1em;font-weight:700}.textblock p,.textblock .p{font-family:Open Sans,sans-serif;font-size:1.25em;font-weight:400;margin-bottom:2em;line-height:1.5em;color:#000}@media(max-width:767px){.textblock p,.textblock .p{font-size:1em}}.textblock strong{font-weight:700}.textblock ul,.textblock ol,.textblock dl{margin:0 0 0 18px;padding:0}.textblock ul li,.textblock ul dt,.textblock ul dd,.textblock ol li,.textblock ol dt,.textblock ol dd,.textblock dl li,.textblock dl dt,.textblock dl dd{margin:0 0 10px;padding:0;font-size:1.125em}.textblock blockquote{border:0px;padding:0 40px;font-size:1em}.textblock blockquote p{font-size:1em;font-style:italic;font-weight:700}.textblock blockquote p cite{position:relative;display:block;clear:both;text-align:right;font-style:italic;font-weight:400}figure.image{padding:0;margin:0}figure.image .image__caption{color:#fff;font-size:14px;line-height:20px;max-width:60%;margin:26px auto 0;text-align:center}.notice{text-align:center;display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;height:calc(100vh - 76px)}@media(min-width:1025px){.notice{display:none}}.notice__content{-webkit-box-flex:1;-ms-flex:1;flex:1;width:100%;display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center}.notice__icon{margin-bottom:17px}.notice__icon img{max-width:124px}.notice__message{font-size:20px;line-height:27px;color:#fff;font-weight:700;margin-bottom:20px}.notice__action .btn{background-color:#ff931e;color:#fff;-webkit-transition:all .15s ease;transition:all .15s ease;border:2px solid transparent;cursor:pointer;font-size:10px;font-weight:700;text-transform:uppercase;line-height:1;display:inline-block;border-radius:50px;padding:8px 50px}.notice__action .btn i{margin-right:2px;color:#fff}.notice__action .btn span.arrow{font-size:15px;top:1px;position:relative;margin-left:6px;line-height:0;color:#fff}.notice__action .btn:hover{color:#000;text-decoration:none}.notice__action .btn:hover i,.notice__action .btn:hover .span.arrow{color:#fff}.notice__bottom{padding-bottom:24px}.notice .hiker a{display:block}.notice .hiker svg{display:block;margin:0 auto 10px}@media(min-width:769px){.notice .hiker svg{display:inline-block;margin-bottom:0;margin-right:8px;vertical-align:middle}}.page{-webkit-transition:.5s all ease;transition:.5s all ease;background-size:cover;background-position:top center;background-repeat:no-repeat;background-color:transparent;margin:0;padding:0;width:100%;position:absolute;top:100vh;overflow:auto;overflow-y:scroll;height:100%;background:#000}.page-inner{min-height:100%;display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center;-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;margin:0 auto;background-size:cover;background-position:top center;background-repeat:no-repeat}.page-1{top:auto}.page-content{-webkit-box-flex:1;-ms-flex:1;flex:1;display:-webkit-box;display:-ms-flexbox;display:flex;position:relative}.page.current,.page.prev{display:block;top:0}.page.light{background:#fff;color:#000}.page .header-block{position:relative;display:block;width:100%;height:auto;margin:0 auto}.page .header-block__white h2,.page .header-block__white p{color:#000}.page .header-block .inner{position:relative;display:block;height:auto;margin-left:-100%;margin-right:-100%}.page .image-wrapper{position:relative;display:block;background-repeat:no-repeat;background-position:top center;background-size:100%;width:100%}.page .copy.center{text-align:center}.page .copy.dark h1{color:#000}.page .copy.dark p,.page .copy.dark small{color:#fff}.page .header{margin-bottom:24px}.page .header .header-title{display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center;-webkit-box-align:end;-ms-flex-align:end;align-items:flex-end;border-right:1px solid #C5C5C5}.page .header .header-title h2{font-size:2em;font-family:Open Sans,sans-serif;font-weight:700;margin-bottom:0}.page .header .header-title p{margin-bottom:0}.page .header .header-blurb{display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center;-webkit-box-align:center;-ms-flex-align:center;align-items:center}.page .header .header-blurb p{margin-bottom:0}#introduction .container{padding:95px 60px}#introduction .page-content{-webkit-box-align:end;-ms-flex-align:end;align-items:flex-end}#introduction h1{font-size:40px;line-height:1;letter-spacing:.1em;margin:0 0 -12px;color:#fff;font-weight:800;text-transform:uppercase}#introduction .subheading{font-size:16px;margin-bottom:23px;display:block;width:100%;font-weight:700}#introduction p{font-size:16px;line-height:20px;font-weight:600;color:#fff}.pagnation-blk{text-align:center;padding:10px 10px 50px}.pagnation-blk .button{display:inline-block;color:#fff;-webkit-appearance:none;-moz-appearance:none;appearance:none;border:0;background-color:transparent;-webkit-box-shadow:none;box-shadow:none;font-weight:700;font-size:15px;cursor:pointer;vertical-align:middle}.pagnation-blk .button i{margin-right:5px;border:1px solid #ffffff;border-radius:50%;line-height:11px;font-size:12px;text-align:center;width:15px;height:15px;display:inline-block;vertical-align:middle}.pagnation-blk .button span{display:inline-block;vertical-align:middle}#review .page-content{-webkit-box-orient:vertical;-webkit-box-direction:normal;-ms-flex-direction:column;flex-direction:column;-webkit-box-pack:center;-ms-flex-pack:center;justify-content:center}.content-wrap p a{font-weight:600;text-decoration:underline;color:#000}.site-content{z-index:1001}.bg-color-gold{background-color:#ffe385}.bg-color-gold-dark{background-color:#edbb3e}.bg-color-gold-orange{background-color:#ff931e}.bg-color-orange{background-color:#d8400b}.bg-color-orange-dark{background-color:#db592c}.bg-color-blue{background-color:#2970c0}.bg-color-green{background-color:#509917}.bg-color-white{background-color:#fff}.color-gold,#introduction .subheading,#physics-of-sound .section-header--gold .section-header__title,#physics-of-sound .title-line__title,#physics-of-sound .keyword__word,#physics-of-sound .keyword__callout__content .special{color:#ffe385}.color-gold-dark{color:#edbb3e}.color-gold-orange,#physics-of-sound .section-header--orange .section-header__title{color:#ff931e}.color-orange{color:#d8400b}.color-orange-dark{color:#db592c}.color-blue{color:#2970c0}.color-green{color:#509917}.color-purple,#physics-of-sound .section-header--purple .section-header__title{color:#8e6c93}.parent{position:relative;display:block;width:100%;height:100%;background:#00f}.fade-enter-active,.fade-leave-active{-webkit-transition-property:opacity;transition-property:opacity;-webkit-transition-duration:.25s;transition-duration:.25s}.fade-enter-active{-webkit-transition-delay:.25s;transition-delay:.25s}.fade-enter,.fade-leave-active{opacity:0}.hideTheIntro-enter-active,.hideTheIntro-leave-active{-webkit-transition:top .5s ease;transition:top .5s ease}.hideTheIntro-enter,.hideTheIntro-leave-to{top:-100px}#app{position:relative;display:block;width:100%;height:100%}.page-1{z-index:110}.page-2{z-index:120}.page-3{z-index:130}.page-4{z-index:140}.page-5{z-index:150}.page-6{z-index:160}.page-7{z-index:170}.page-8{z-index:180}.page-9{z-index:190}.page-10{z-index:200}.copy.dark h1,.copy.dark p{color:#fff}.copy.dark p.subheading{color:#ffe385}main.svelte-12qhfyh{padding-top:75px;position:relative;overflow-x:hidden}.page-container.svelte-12qhfyh{width:100%;min-height:calc(100vh - 75px)}body{overflow-x:hidden}