pressbooks aldine theme the theme used for the front page or default book
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:root{--font-family-sans-serif:"Karla",sans-serif;--font-family-monospace:"SFMono-Regular",Menlo,Monaco,Consolas,"Liberation Mono","Courier New",monospace;--brand:#b01109;--brand-hover:#770600;--brand-accent:#015d75;--body-bg:#fff;--body-bg-alt:#f9fdff;--body-bg-alt2:#ececec;--body-color:#000;--button-primary-color:#fff;--button-primary-hover-color:#770600;--button-secondary-color:#b01109;--button-secondary-hover-color:#770600;--header-bg:#000;--header-color:#fff;--footer-bg:#444;--footer-color:#fff;--book-bg:#fff;--brand-orig:#b01109;--brand-hover-orig:#770600;--brand-accent-orig:#015d75;--primary:#b01109;--accent:#015d75;--primary-fg:#fff;--accent-fg:#fff;--header-text:#000;--cover-header-bg:#000}*,:after,:before{-webkit-box-sizing:border-box;box-sizing:border-box}html{font-family:sans-serif;line-height:1.15;-webkit-text-size-adjust:100%;-ms-text-size-adjust:100%;-ms-overflow-style:scrollbar;-webkit-tap-highlight-color:transparent}@-ms-viewport{width:device-width}article,aside,dialog,figcaption,figure,footer,header,hgroup,main,nav,section{display:block}body{margin:0;font-family:Karla,sans-serif;font-size:1rem;font-weight:400;line-height:1.5;color:var(--body-color,#000);text-align:left;background-color:var(--body-bg,#fff)}[tabindex="-1"]:focus{outline:none!important}hr{-webkit-box-sizing:content-box;box-sizing:content-box;height:0;overflow:visible}h1,h2,h3,h4,h5,h6{margin-top:0;margin-bottom:.5rem}p{margin-top:0;margin-bottom:1rem}abbr[data-original-title],abbr[title]{text-decoration:underline;-webkit-text-decoration:underline 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a,.h1 a:active,.h1 a:hover,.h1 a:visited,.h2 a,.h2 a:active,.h2 a:hover,.h2 a:visited,.h3 a,.h3 a:active,.h3 a:hover,.h3 a:visited,.h4 a,.h4 a:active,.h4 a:hover,.h4 a:visited,.h5 a,.h5 a:active,.h5 a:hover,.h5 a:visited,.h6 a,.h6 a:active,.h6 a:hover,.h6 a:visited,h1 a,h1 a:active,h1 a:hover,h1 a:visited,h2 a,h2 a:active,h2 a:hover,h2 a:visited,h3 a,h3 a:active,h3 a:hover,h3 a:visited,h4 a,h4 a:active,h4 a:hover,h4 a:visited,h5 a,h5 a:active,h5 a:hover,h5 a:visited,h6 a,h6 a:active,h6 a:hover,h6 a:visited{color:inherit}.home .h1,.home .h2,.home .h3,.home .h4,.home .h5,.home .h6,.home h1,.home h2,.home h3,.home h4,.home h5,.home h6{color:var(--brand)}.h1,h1{font-size:3rem}.h2,h2{font-size:2.5rem}.h3,h3{font-size:2.25rem}.h4,h4{font-size:1.875rem}.h5,h5{font-size:1.5rem}.h6,h6{font-size:1.25rem}.dropdown,.dropup{position:relative}.dropdown-toggle:after{display:inline-block;width:0;height:0;margin-left:1rem;vertical-align:.255em;content:"";border-top:.3em solid;border-right:.3em solid 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(min-width:768px){.section__title{font-size:3rem}}.section__title:before{content:"";display:block;margin:0 auto 1rem;width:46px;height:5px;background:var(--brand-accent)}@media screen and (min-width:60em){.section__title:before{margin-bottom:2rem;width:75px}}.section__subtitle{font-size:1.5rem;margin-bottom:1rem;text-transform:uppercase}@media screen and (min-width:768px){.section__subtitle{margin-bottom:1.5rem}}.section-toggle__cta{position:relative;text-align:center}@media screen and (min-width:60em){.section-toggle__cta{display:none}.section-meta .section-toggle__cta{display:block}}.section-toggle__cta__blurb{font-size:.875rem;margin-bottom:0;padding-bottom:2.5rem}.section-toggle__cta__button{bottom:0;cursor:pointer;font-size:1.5rem;left:50%;margin:0;position:absolute;-webkit-transform:translate(-50%,50%);-o-transform:translate(-50%,50%);transform:translate(-50%,50%);z-index:10}.home .section.section-toggle{padding-bottom:0}@media screen and (max-width:59.975em){.home .section.section-toggle.section-toggle--visible .section-toggle__cta__blurb,.home .section.section-toggle:not(.section-toggle--visible) .section-toggle__content{display:none}}.home .section.section-toggle.section-meta:not(.section-toggle--visible) .section-toggle__content{display:none}@media screen and (min-width:60em){.home .section.section-toggle.section-meta:not(.section-toggle--visible) .section-toggle__cta{margin-top:-3.75rem}}.home .section.section-toggle.section-meta.section-toggle--visible .section-toggle__cta__blurb{display:none}.header{font-family:Karla,sans-serif;padding:3.5rem 1rem 1.5rem}@media screen and (min-width:60em){.header{padding:4rem 1rem 3rem}}.header a{color:var(--brand);text-decoration:none}.header a:hover{color:var(--brand-hover);text-decoration:underline}.header--home{--brand:var(--header-color);--brand-hover:var(--header-color);--brand-accent:var(--header-color);background-color:var(--header-bg);color:var(--header-color);padding:3.5rem 1rem 1.5rem}.header--root{--brand:var(--brand-color);--brand-hover:var(--brand-color);--brand-accent:var(--brand-color);background-color:var(--brand-bg);color:var(--brand-color);padding:3.5rem 1rem 1.5rem}.header__inner{display:-webkit-box;display:-ms-flexbox;display:flex;-webkit-box-pack:justify;-ms-flex-pack:justify;justify-content:space-between;max-width:1440px;margin:0 auto}.header__inner,.header__start-container{-webkit-box-align:center;-ms-flex-align:center;align-items:center}.header__start-container{display:none}@media screen and (min-width:60em){.header__start-container{display:-webkit-box;display:-ms-flexbox;display:flex}}.header__home{margin-right:4.5rem}.header__search{position:relative}.header:not(.header--home) .icon-search{font-size:1.5rem;cursor:pointer}.header__search__form{display:none;position:absolute;left:100%;top:0}.search--visible .header__search__form{display:block}.header__search__form label{height:0;overflow:hidden;position:absolute;width:0}.header__search__form input[type=text]{background-color:transparent;border:0 none;border-bottom:2px solid var(--body-color);color:var(--body-color)}.header__search__form input[type=text]:focus{border-color:var(--brand)}.header--home .header__search__form input[type=text]{color:var(--header-color);border-bottom:1px solid var(--header-color)}.header--home .header__search__form input[type=text]:focus{border-color:var(--brand-orig)}.header__search__form input[type=submit]{display:none}.header__brand{font-family:Karla,sans-serif;font-size:1.25rem;margin-bottom:0;max-width:100%;overflow:hidden}@media screen and (min-width:768px) and (max-width:60em){.header__brand{font-size:1.5rem}}@media screen and (min-width:60em){.header__brand{font-size:2.5rem}}.header__logo .icon--svg{display:inline-block;height:auto;margin-bottom:-1px;margin-right:2px;width:265px}.header--reading .header__logo .icon--svg{color:var(--brand)}.header__menu-icon{display:block;position:relative;width:25px;height:20px;z-index:99;text-indent:-9999em}@media screen and (min-width:60em){.header__menu-icon{display:none}}.header__menu-icon__icon{display:block;position:absolute;top:7px;width:25px;height:3px;background:var(--brand)}.header__menu-icon__icon:after,.header__menu-icon__icon:before{width:25px;height:3px;content:"";background:var(--brand)}.header__menu-icon__icon:before{position:absolute;top:-7px;right:0}.header__menu-icon__icon:after{position:absolute;top:7px;right:0}.\--active .header__menu-icon__icon,.\--active .header__menu-icon__icon:after,.\--active .header__menu-icon__icon:before{background:var(--header-color)}@media screen and (max-width:59.975em){.header__nav{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;left:0;margin:0 0 0 -100%;padding:0 17px;position:absolute;top:0;width:100%}.header__nav a{display:none;font-family:Karla,sans-serif;font-size:1.5rem;line-height:3.33333333;color:var(--header-color);letter-spacing:0}.header__nav .sep{display:none}.header__nav.\--visible{margin:0;padding:0 52px;z-index:1;background:var(--primary)}.header__nav.\--visible a{display:block;width:100%;border-bottom:solid 1px var(--header-color)}.header__nav.\--visible a:hover{color:var(--header-color)}.header__nav.\--visible a:last-child{border-bottom:0}}.book-header{--brand:var(--header-color);--brand-hover:var(--header-color);--brand-accent:var(--header-color);background-color:var(--header-bg);color:var(--header-color);padding:1.5rem 1rem 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