.yfe-site{--ink:#142e2e;--teal:#00796f;--accent:#00baa4;--mint:#e8fefb;--line:#d0e7e2;--serif:Georgia,'Times New Roman',serif;margin:0;color:var(--ink);background:white;font-family:Arial,Helvetica,sans-serif;font-size:17px;line-height:1.65}
.yfe-site *{box-sizing:border-box}.yfe-site h1,.yfe-site h2,.yfe-site h3,.yfe-site p{margin:0;color:inherit;padding:0}.yfe-site h1,.yfe-site h2,.yfe-site h3{font-family:var(--serif);font-weight:400;line-height:1.12;letter-spacing:-.025em}.yfe-site a{color:inherit;text-decoration:none}.yfe-site img,.yfe-site video{max-width:100%;display:block}.yfe-site button,.yfe-site summary{font:inherit}.yfe-site a:focus-visible,.yfe-site button:focus-visible,.yfe-site summary:focus-visible{outline:3px solid #ea873d;outline-offset:5px}.yfe-site .skip{position:fixed;top:8px;left:8px;z-index:1000;padding:12px 20px;background:white;color:var(--ink);transform:translateY(-180%)}.yfe-site .skip:focus{transform:none}
.yfe-header{display:flex;align-items:center;justify-content:space-between;gap:26px;padding:26px 4%;border-bottom:1px solid var(--line);background:white;position:relative;z-index:20}.yfe-site .yfe-brand{font-family:var(--serif);font-size:25px;line-height:1.2;letter-spacing:-1px;flex-shrink:0}.yfe-brand strong{display:block;color:var(--teal);font-weight:400}.yfe-navigation{display:flex;align-items:center;gap:25px;font-size:14px;font-weight:600}.yfe-navigation>a{padding:12px 0}.yfe-navigation details{position:relative}.yfe-navigation summary{cursor:pointer;padding:12px 0;list-style:none;display:flex;gap:10px;align-items:center}.yfe-navigation summary::-webkit-details-marker{display:none}.yfe-dropdown{position:absolute;top:100%;left:-30px;width:310px;padding:20px;background:white;box-shadow:0 15px 45px #142e2e20;border-top:3px solid var(--accent)}.yfe-dropdown a{display:flex;justify-content:space-between;gap:16px;padding:11px 10px;border-bottom:1px solid var(--line);font-weight:400}.yfe-dropdown a:hover{background:var(--mint)}.yfe-header-tools{display:flex;gap:12px;align-items:center}.yfe-languages{display:flex;gap:3px;font-size:11px}.yfe-languages a{padding:12px 8px}.yfe-mobile-nav{display:none}
.yfe-main{padding:20px 20px 0}.yfe-hero{min-height:680px;height:min(78vh,960px);position:relative;display:flex;align-items:center;overflow:hidden;background:#173e3b}.yfe-hero>img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;object-position:70% 35%}.yfe-hero:after{content:'';position:absolute;inset:0;background:linear-gradient(90deg,rgba(10,32,32,.9),rgba(10,32,32,.6) 50%,rgba(10,32,32,.1))}.yfe-hero-copy{position:relative;z-index:1;max-width:870px;padding:7% 7.5%;color:white}.yfe-kicker{text-transform:uppercase;font-size:11px;font-weight:600;letter-spacing:.17em;margin-bottom:24px!important}.yfe-hero h1{font-size:clamp(54px,5.8vw,90px);line-height:1.13}.yfe-hero h1 em{color:#c8fff2;font-weight:400}.yfe-hero-copy>p:not(.yfe-kicker){margin-top:25px;max-width:490px;font-size:17px;line-height:1.65}.yfe-actions{display:flex;gap:18px;align-items:center;flex-wrap:wrap;margin-top:32px}.yfe-btn{display:inline-flex;align-items:center;justify-content:space-between;gap:36px;padding:17px 26px;background:var(--accent);color:#082e29!important;font-size:13px;font-weight:600;min-height:52px;transition:background .2s}.yfe-btn:hover{background:#c8fff2}.yfe-link{display:inline-flex;align-items:center;gap:24px;border-bottom:1px solid currentColor;padding:10px 0;font-size:13px}.yfe-hero-note{font-size:11px!important;opacity:.9}
.yfe-chapters{display:grid;grid-template-columns:repeat(3,1fr);background:var(--mint);border-bottom:1px solid var(--line)}.yfe-chapters>a{padding:30px 8%;border-right:1px solid var(--line);display:flex;flex-direction:column;gap:8px}.yfe-chapters span{font-size:10px;letter-spacing:.13em;text-transform:uppercase;color:var(--teal)}.yfe-chapters strong{font:italic 28px var(--serif);font-weight:400}.yfe-section{padding:95px 6%;max-width:1440px;margin:auto}.yfe-section h2{font-size:clamp(35px,4vw,57px)}.yfe-intro{display:grid;grid-template-columns:1.05fr 1fr;gap:8%;align-items:start}.yfe-intro h2{max-width:570px}.yfe-intro p{margin-bottom:20px}.yfe-intro .yfe-kicker{color:var(--teal)}
.yfe-features{display:grid;grid-template-columns:repeat(2,1fr);gap:30px;padding-top:0}.yfe-feature{background:#f4faf8}.yfe-feature img{width:100%;aspect-ratio:1.7;object-fit:cover}.yfe-feature>div{padding:32px}.yfe-feature h3{font-size:33px;margin-bottom:20px}.yfe-feature p{margin-bottom:22px;max-width:500px}.yfe-section-heading{display:flex;align-items:end;justify-content:space-between;gap:50px;margin-bottom:35px}.yfe-section-heading p{max-width:410px;font-size:15px}.yfe-topics{padding:0 0 70px}.yfe-topics .yfe-section-heading{padding:0 6%}.yfe-topic-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}.yfe-topic{position:relative;overflow:hidden;min-height:480px;background:#284f4e;display:flex;align-items:end}.yfe-topic>img{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;transition:transform .6s}.yfe-topic:hover>img{transform:scale(1.025)}.yfe-topic:after{content:'';position:absolute;inset:0;background:linear-gradient(transparent 20%,rgba(8,29,29,.8))}.yfe-topic>div{position:relative;z-index:1;color:white;padding:28px;width:100%}.yfe-topic .yfe-kicker{margin-bottom:14px!important;color:#cafff3}.yfe-topic h3{font-size:35px}.yfe-topic p:not(.yfe-kicker){font-size:13px;margin-top:14px;color:white}.yfe-topic a{display:inline-block;margin-top:18px;font-size:12px;border-bottom:1px solid #ffffff90;padding-bottom:5px}
.yfe-film{display:grid;grid-template-columns:.8fr 1.2fr;gap:8%;align-items:center;background:var(--mint);max-width:none}.yfe-film-copy p:not(.yfe-kicker){margin-top:22px;max-width:450px}.yfe-film figure{margin:0}.yfe-film video{width:100%;background:#142e2e;aspect-ratio:16/9;object-fit:contain}.yfe-film figcaption{font-size:11px;line-height:1.5;margin-top:12px}.yfe-about{display:grid;grid-template-columns:.85fr 1.15fr;gap:8%;align-items:start}.yfe-about h2{margin-bottom:25px}.yfe-about details{border-bottom:1px solid var(--line);padding:20px 0}.yfe-about summary{cursor:pointer;list-style:none;font:23px/1.3 var(--serif);display:flex;justify-content:space-between;gap:24px}.yfe-about summary:after{content:'+';color:var(--teal);font:22px Arial}.yfe-about details[open] summary:after{content:'−'}.yfe-about details p{font-size:15px;margin-top:17px;max-width:680px}.yfe-about summary::-webkit-details-marker{display:none}.yfe-contributors{border-top:1px solid var(--line);display:grid;grid-template-columns:1fr 1fr;gap:9%;align-items:center}.yfe-contributors p:not(.yfe-kicker){margin-top:20px}.yfe-contributor-note{border-left:3px solid var(--accent);padding:20px 25px;background:var(--mint)}.yfe-contributor-note strong{font:25px/1.3 var(--serif)}.yfe-contributor-note p{font-size:14px}
.yfe-boundary{padding:40px 8%;background:#f3f7f6;border-top:1px solid var(--line)}.yfe-boundary strong{font-size:15px}.yfe-boundary p{font-size:12px;max-width:1120px;margin-top:12px}.yfe-footer{padding:55px 8% 28px;background:#113a37;color:white;display:grid;grid-template-columns:1fr 1fr;gap:35px}.yfe-footer .yfe-brand strong{color:#a9f4e6}.yfe-footer p{font-size:13px;margin-top:16px}.yfe-footer nav{display:grid;grid-template-columns:1fr 1fr;align-content:start;gap:16px;font-size:13px}.yfe-footer .yfe-small{grid-column:1/-1;border-top:1px solid #ffffff30;padding-top:20px;font-size:11px}.yfe-reading{max-width:920px;margin:auto;padding:75px 28px 100px}.yfe-reading h1{font-size:clamp(36px,5vw,60px);margin-bottom:35px}.yfe-content h2{font-size:30px;margin:40px 0 20px}.yfe-content h3{font-size:24px;margin:25px 0 15px}.yfe-content p{margin-bottom:20px}.yfe-content ul,.yfe-content ol{padding-left:25px}.yfe-content a{color:var(--teal);text-decoration:underline}
@media(max-width:1150px){.yfe-navigation{gap:18px;font-size:12px}.yfe-header{gap:18px;padding:23px 3%}.yfe-topic{min-height:400px}.yfe-topic>div{padding:20px}.yfe-topic h3{font-size:30px}}
@media(max-width:980px){.yfe-navigation{display:none}.yfe-mobile-nav{display:block}.yfe-mobile-nav>summary{list-style:none;cursor:pointer;width:46px;height:46px;display:flex;align-items:center;justify-content:center;flex-direction:column;gap:5px;border:1px solid var(--teal);border-radius:50%;padding:0}.yfe-mobile-nav>summary::-webkit-details-marker{display:none}.yfe-mobile-nav>summary span{width:18px;height:1px;background:var(--ink)}.yfe-mobile-nav nav{position:absolute;top:100%;left:0;right:0;padding:20px 6%;background:white;box-shadow:0 15px 30px #142e2e20;max-height:70vh;overflow:auto}.yfe-mobile-nav nav a{display:block;padding:13px 0;border-bottom:1px solid var(--line)}.yfe-topic-grid{grid-template-columns:repeat(2,1fr)}.yfe-topic{min-height:460px}.yfe-section{padding:70px 6%}.yfe-topics{padding:10px 0 65px}.yfe-hero{height:auto;min-height:660px}.yfe-hero-copy{padding:75px 8%;max-width:760px}.yfe-film{gap:5%;grid-template-columns:1fr 1.2fr}.yfe-film h2{font-size:35px}}
@media(max-width:600px){.yfe-header{padding:18px 5%;min-height:89px}.yfe-site .yfe-brand{font-size:20px;letter-spacing:-.5px}.yfe-main{padding:10px 10px 0}.yfe-header-tools{gap:8px}.yfe-languages{gap:0}.yfe-languages a{padding:10px 5px;font-size:10px}.yfe-hero{min-height:680px;align-items:end}.yfe-hero-copy{padding:65px 7% 50px}.yfe-hero h1{font-size:52px;line-height:1.07}.yfe-hero-copy>p:not(.yfe-kicker){font-size:15px;max-width:310px}.yfe-hero>img{object-position:67% center}.yfe-hero:after{background:linear-gradient(0deg,rgba(7,29,29,.94),rgba(7,29,29,.68) 50%,rgba(7,29,29,.12))}.yfe-kicker{font-size:10px}.yfe-actions{gap:20px}.yfe-btn{padding:15px 22px}.yfe-hero-note{font-size:10px!important}.yfe-chapters{grid-template-columns:1fr}.yfe-chapters>a{padding:20px 7%;border-right:none;border-bottom:1px solid var(--line);flex-direction:row;align-items:center;justify-content:space-between;gap:20px}.yfe-chapters strong{font-size:24px}.yfe-intro,.yfe-features,.yfe-about,.yfe-contributors,.yfe-film{grid-template-columns:1fr;gap:30px}.yfe-section{padding:55px 7%}.yfe-features{padding-top:0}.yfe-feature>div{padding:25px}.yfe-feature h3{font-size:30px}.yfe-section-heading{display:block;padding:0 7%!important}.yfe-section-heading p{margin-top:22px}.yfe-topic-grid{grid-template-columns:1fr;gap:10px}.yfe-topic{min-height:480px}.yfe-topic>div{padding:28px}.yfe-topic h3{font-size:38px}.yfe-topic>img{object-position:center 35%}.yfe-topics{padding:10px 0 40px}.yfe-about summary{font-size:21px}.yfe-boundary{padding:30px 8%}.yfe-footer{grid-template-columns:1fr;padding:40px 8% 25px;gap:28px}.yfe-reading{padding:50px 7% 70px}.yfe-content h2{font-size:27px}}
@media(prefers-reduced-motion:reduce){.yfe-site *{scroll-behavior:auto!important;transition:none!important;animation:none!important}.yfe-topic:hover>img{transform:none}}
.yfe-content .yfe-lead{font-size:21px;line-height:1.7;color:#365755}.yfe-toc{padding:25px 30px;margin:35px 0 45px;background:var(--mint);border-left:3px solid var(--accent)}.yfe-toc strong{font-size:11px;text-transform:uppercase;letter-spacing:.13em}.yfe-content .yfe-toc ul{list-style:none;padding:0;margin:15px 0 0;display:grid;grid-template-columns:1fr 1fr;gap:6px 28px}.yfe-toc a{display:block;padding:7px 0;font-size:14px;line-height:1.5}.yfe-content section{scroll-margin-top:25px}.yfe-questions details{border-bottom:1px solid var(--line);padding:20px 0}.yfe-questions summary{cursor:pointer;display:flex;justify-content:space-between;gap:24px;list-style:none;font:22px/1.4 var(--serif)}.yfe-questions summary::-webkit-details-marker{display:none}.yfe-questions summary:after{content:'+';font:24px Arial;color:var(--teal)}.yfe-questions details[open] summary:after{content:'−'}.yfe-questions p{margin:20px 0 0}.yfe-source-note{padding:25px 30px;margin-top:45px;background:#f4f8f7;border-top:1px solid var(--line);font-size:13px}.yfe-content .yfe-source-note h2{font:24px var(--serif);margin:0 0 15px}.yfe-source-note p{margin-bottom:10px}.yfe-source-note ul{margin-bottom:0}.yfe-related{margin-top:45px;border-top:1px solid var(--line)}.yfe-related ul{list-style:none;padding:0!important;display:grid;grid-template-columns:1fr 1fr;gap:10px 25px}.yfe-related a{display:block;padding:12px 0;border-bottom:1px solid var(--line);font-size:15px}.yfe-date-tool{padding:30px;margin-top:40px;background:var(--mint);border:1px solid var(--line)}.yfe-date-tool label{display:block;font-size:14px;font-weight:600;margin:20px 0 8px}.yfe-date-tool input{display:block;width:100%;max-width:360px;min-height:52px;padding:12px 15px;border:1px solid #6e9991;border-radius:0;background:#fff;color:var(--ink);font:17px Arial}.yfe-date-tool input:focus-visible{outline:3px solid #ea873d;outline-offset:3px}.yfe-date-tool button{min-height:52px;cursor:pointer;border:0;padding:15px 24px;background:var(--teal);color:#fff;margin:20px 12px 20px 0;font-size:14px}.yfe-date-tool button:hover{background:#005b53}.yfe-date-tool #yfe-reset{background:white;color:var(--teal);border:1px solid var(--teal)}.yfe-date-tool #yfe-date-result{padding:18px 20px;margin:0;background:#fff;min-height:65px;font-size:15px;line-height:1.6;border-left:3px solid var(--accent)}
@media(max-width:600px){.yfe-content .yfe-lead{font-size:18px}.yfe-toc,.yfe-source-note,.yfe-date-tool{padding:22px}.yfe-content .yfe-toc ul,.yfe-related ul{grid-template-columns:1fr}.yfe-toc a{padding:10px 0}.yfe-questions summary{font-size:21px}.yfe-date-tool input{min-width:0;max-width:100%}}
.yfe-calculator{padding:30px;margin-top:40px;background:var(--mint);border:1px solid var(--line)}.yfe-calculator fieldset{border:0;padding:0;margin:25px 0 0;min-width:0}.yfe-calculator legend{font-size:12px;font-weight:600;letter-spacing:.06em}.yfe-calculator label{display:block;font-size:14px;font-weight:600;margin:20px 0 8px}.yfe-calculator input{display:block;width:100%;max-width:360px;min-width:0;min-height:52px;padding:12px 15px;border:1px solid #6e9991;border-radius:0;background:#fff;color:var(--ink);font:17px Arial}.yfe-calculator input:focus-visible{outline:3px solid #ea873d;outline-offset:3px}.yfe-calculator button{min-height:52px;cursor:pointer;border:0;padding:15px 24px;background:var(--teal);color:#fff;margin:20px 12px 20px 0;font-size:14px}.yfe-calculator button:hover{background:#005b53}.yfe-calculator #yfe-reset{background:white;color:var(--teal);border:1px solid var(--teal)}.yfe-calculator #yfe-date-result{padding:18px 20px;margin:0;background:#fff;min-height:65px;font-size:15px;line-height:1.6;border-left:3px solid var(--accent)}
@media(max-width:600px){.yfe-calculator{padding:22px}.yfe-calculator input{max-width:100%}}