/* Shared frame, banner and five-column footer, based on OpenAI's site structure. */
:root{--shell-gutter:32px;scroll-padding-top:96px}
.header{height:64px;padding:0 var(--shell-gutter);gap:34px;position:sticky;top:0;z-index:60;background:rgba(var(--header),.97);backdrop-filter:blur(14px)}
.header .wordmark{font-size:26px}.header-actions{gap:10px}.header .contact-nav{min-height:38px;padding:9px 21px;font-size:13px}.desktop-nav{gap:22px;align-items:center}.mobile-nav{top:64px;max-height:calc(100dvh - 64px);overflow:auto}.mobile-nav-group{display:grid;gap:6px}.mobile-nav-group>span{font-size:13px;color:var(--muted);margin:18px 0 6px}.mobile-contact{border-top:1px solid var(--line);margin-top:20px}
.home-page .hero{width:calc(100% - var(--shell-gutter)*2);height:560px;min-height:540px;max-width:1600px;margin:46px auto 0;border-radius:6px;background:var(--bg);overflow:hidden}
:root[data-theme=light] .home-page .hero{background:var(--bg)}
.hero-content{padding:48px 24px 45px}.home-page .hero h1{font-size:96px;line-height:1.04}.home-page .identity{font-size:23px;margin-top:15px}.home-page .hero-description{font-size:17px;margin-top:23px;line-height:1.65}.home-page .hero-actions{margin-top:26px}.home-page .hero-actions .button{font-size:13px;min-height:43px;padding:11px 22px}
.hero-toolbar{position:absolute;left:22px;right:14px;top:12px;z-index:5}.featured-note{display:flex;justify-content:space-between;gap:20px;align-items:center;min-height:38px}.featured-note[hidden],.featured-restore[hidden]{display:none}.featured-note>a{font-size:12px;display:flex;gap:20px;align-items:center;line-height:1.5;color:var(--muted)}.featured-note-link{white-space:nowrap;color:var(--ink);text-decoration:underline;text-underline-offset:4px}.featured-note .icon-button{width:34px;height:34px;flex-shrink:0}.featured-note .icon-button svg{width:16px;height:16px}.featured-restore{background:var(--surface);border-radius:999px;padding:9px 14px;font-size:12px}.banner-shortcuts{display:flex;justify-content:center;gap:10px;flex-wrap:wrap;padding:30px 24px 6px}.banner-shortcuts a{font-size:14px;padding:10px 20px;border-radius:999px;background:var(--surface);transition:background .15s}.banner-shortcuts a:hover{background:var(--line)}
.home-page .closing.wrap{max-width:1600px;width:calc(100% - var(--shell-gutter)*2);margin:110px auto 0;padding:72px 24px;min-height:380px;border-radius:6px;background:var(--surface);display:flex;flex-direction:column;justify-content:center;align-items:center;text-align:center;gap:0}.closing .closing-logo{width:62px;height:54px;margin-bottom:20px}.closing h2{font-size:48px;line-height:1.08}.closing p{font-size:16px;margin-top:18px}.closing-actions{display:flex;justify-content:center;gap:12px;flex-wrap:wrap;margin-top:30px}.closing-actions .button{margin:0;font-size:14px}.closing-back{font-size:12px;color:var(--muted);margin-top:25px;text-decoration:underline;text-underline-offset:4px}
footer.site-footer{display:block;max-width:1664px;margin:0 auto;padding:100px var(--shell-gutter) 24px;background:var(--bg);font-size:14px}
.site-footer>.footer-columns{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:38px;margin:0;color:var(--ink);font-size:14px}.footer-column{min-width:0;display:grid;align-content:start;gap:38px}.footer-group{display:flex;flex-direction:column;gap:15px}.footer-group h2{font-size:14px;font-weight:400;letter-spacing:normal;line-height:1.4;color:var(--muted);margin:0 0 4px}.footer-group a{font-size:14px;line-height:1.5;width:fit-content;max-width:100%;overflow-wrap:anywhere;text-decoration:none}.footer-group a:hover{text-decoration:underline;text-underline-offset:4px}
.site-footer>.footer-utility{display:grid;grid-template-columns:1fr auto 1fr;gap:24px;align-items:center;margin:95px 0 0;font-size:12px;color:var(--ink)}.footer-icons{display:flex;gap:20px;align-items:center}.footer-icons a{display:grid;place-items:center;width:22px;height:30px}.footer-icons svg{width:18px;height:18px}.footer-identity{display:flex;gap:12px;align-items:center;flex-wrap:wrap;justify-content:center}.footer-identity a{font-weight:500}.footer-identity>span:last-child{color:var(--muted)}.footer-preferences{display:flex;gap:16px;align-items:center;justify-content:flex-end;flex-wrap:wrap}.footer-theme{background:transparent;padding:8px 0;font-size:12px}.footer-theme:hover{text-decoration:underline;text-underline-offset:4px}.footer-language{display:flex;gap:8px;align-items:center;white-space:nowrap;background:var(--surface);padding:10px 14px;border-radius:999px;font-size:12px}.footer-language svg{width:14px;height:14px}
.site-search{width:min(720px,calc(100% - 32px));max-height:82dvh;padding:28px;margin:8vh auto auto;border:1px solid var(--line);border-radius:12px;background:var(--bg);color:var(--ink);box-shadow:0 24px 80px rgba(0,0,0,.35);overflow:auto}.site-search::backdrop{background:rgba(0,0,0,.55);backdrop-filter:blur(6px)}.search-top{display:flex;justify-content:space-between;align-items:center;margin-bottom:22px;gap:20px}.search-top h2{font-size:24px;letter-spacing:-.02em}.search-field{display:flex;gap:14px;align-items:center;border:1px solid var(--line);padding:15px;border-radius:8px;background:var(--surface)}.search-field svg{flex:0 0 20px;color:var(--muted)}.search-field input{font:16px/1.5 SiteSans,Arial,sans-serif;width:100%;border:0;outline:0;background:none;color:var(--ink);min-width:0}.search-field:focus-within{outline:2px solid #8ebff0;outline-offset:3px}.search-status{font-size:12px;color:var(--muted);margin:18px 0}.search-results{display:grid}.search-result{padding:17px 8px;border-top:1px solid var(--line);display:grid;gap:7px}.search-result[hidden]{display:none}.search-result strong{font-size:17px;font-weight:400;line-height:1.4;letter-spacing:-.01em}.search-result span{font-size:13px;line-height:1.55;color:var(--muted)}.search-result:hover{background:var(--surface);border-radius:6px}
.closing-actions .button-soft{background:var(--bg);color:var(--ink)}
@media(min-width:1600px){.header{padding-left:48px;padding-right:48px}}
@media(max-width:1050px){.header{gap:24px}.desktop-nav{gap:15px}.header-actions{gap:6px}.site-footer>.footer-utility{grid-template-columns:1fr auto}.footer-identity{grid-column:1/-1;grid-row:2;justify-content:flex-start}.site-footer>.footer-columns{gap:25px}.footer-group a{font-size:13px}}
@media(max-width:900px){.header .desktop-nav{display:none}.header .menu-toggle{display:grid}.header .mobile-nav{position:absolute;left:0;right:0;top:64px;background:var(--bg);box-shadow:0 15px 25px rgba(0,0,0,.15);padding:15px 24px 24px;display:grid;grid-template-columns:1fr 1fr;gap:10px 30px}.header .mobile-nav[hidden]{display:none}.mobile-nav a{font-size:15px;padding:9px 0}.mobile-contact{grid-column:1/-1}.site-footer>.footer-columns{grid-template-columns:repeat(3,minmax(0,1fr));gap:48px 32px}}
@media(max-width:620px){:root{--shell-gutter:16px}.header{padding:0 20px;gap:16px}.header .wordmark{font-size:25px}.home-page .hero{margin-top:22px;min-height:590px;height:590px}.hero-toolbar{left:16px;right:10px;top:10px}.featured-note{align-items:flex-start;gap:10px}.featured-note>a{display:block;font-size:12px;max-width:250px;padding-top:7px}.featured-note-link{display:block;margin-top:5px}.hero-content{padding:70px 20px 60px}.home-page .hero h1{font-size:82px}.home-page .identity{font-size:18px}.home-page .hero-description{font-size:15px;margin-top:24px}.home-page .hero-actions{gap:8px}.home-page .hero-actions .button{padding:12px 16px;font-size:12px}.banner-shortcuts{padding-top:23px;gap:7px}.banner-shortcuts a{font-size:12px;padding:9px 14px}.home-page .closing.wrap{margin-top:75px;padding:58px 22px;min-height:360px}.closing h2{font-size:39px}.closing p{font-size:15px}.closing-actions{gap:9px}.closing-actions .button{font-size:13px;padding:12px 20px}.closing .closing-logo{width:52px;height:45px}
footer.site-footer{padding:65px 24px 24px}.site-footer>.footer-columns{grid-template-columns:1fr 1fr;gap:36px 26px}.footer-column{gap:30px}.footer-group{gap:14px}.footer-group h2,.footer-group a{font-size:13px}.site-footer>.footer-utility{margin-top:55px;grid-template-columns:1fr;gap:23px}.footer-icons{justify-content:center}.footer-identity{grid-column:auto;grid-row:auto;justify-content:center;gap:8px 12px}.footer-preferences{justify-content:center;grid-row:2}.footer-identity>span:last-child{width:100%;text-align:center}.site-search{padding:20px;max-height:88dvh;margin-top:4vh}.search-top h2{font-size:23px}.search-field{padding:12px;gap:10px}.search-field input{font-size:16px}.search-result strong{font-size:16px}}

/* Full-viewport home scene. Shared article navigation and footer stay in flow. */
.home-page .header{margin-bottom:-64px;background:rgba(var(--header),.78)}
.home-page .hero{width:100%;max-width:none;height:100vh;height:100dvh;min-height:100svh;max-height:none;margin:0;border-radius:0}
.home-page .hero-content{padding:120px 24px 112px}
.home-page .hero-toolbar{top:84px;left:var(--shell-gutter);right:var(--shell-gutter)}
.home-page .hero canvas{opacity:.68}
:root[data-theme=light] .home-page .hero canvas{opacity:.72}
@media(max-width:620px){.home-page .hero-content{padding:145px 20px 112px}.home-page .hero-toolbar{left:20px;right:14px;top:80px}.site-footer .footer-identity>span:last-child{width:auto}}
@media(max-height:620px){.home-page .hero-content{padding-top:100px;padding-bottom:76px}.home-page .hero h1{font-size:64px}.home-page .hero-description{margin-top:16px;font-size:14px;line-height:1.5}.home-page .hero-actions{margin-top:19px}.home-page .hero-toolbar{top:72px}}
@media(max-height:520px){.home-page .hero-content{padding:112px 20px 32px}.home-page .hero h1{font-size:48px}.home-page .hero-description{font-size:13px;line-height:1.35;margin-top:10px}.home-page .hero-actions{margin-top:10px}.home-page .hero-actions .button{min-height:32px;padding:7px 14px}.home-page .hero-toolbar{top:70px}.featured-note>a{display:flex;max-width:none;gap:12px;padding-top:0}.featured-note>a>span:first-child{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.featured-note-link{display:inline!important;margin-top:0!important}}
@media(max-height:360px){.home-page .hero-content{padding-bottom:48px}}

/* The reference's lower edge disappears into the page, without a panel seam. */
:root[data-theme=light]{--bg:#fcfcfc;--header:252,252,252}
:root[data-theme] .home-page .hero{background:var(--bg)}
.home-page .header{background:var(--bg)}
.home-page .hero canvas{mask-image:linear-gradient(to bottom,#000 0%,#000 44%,rgba(0,0,0,.88) 55%,rgba(0,0,0,.45) 67%,rgba(0,0,0,.12) 77%,transparent 88%,transparent 100%);-webkit-mask-image:linear-gradient(to bottom,#000 0%,#000 44%,rgba(0,0,0,.88) 55%,rgba(0,0,0,.45) 67%,rgba(0,0,0,.12) 77%,transparent 88%,transparent 100%)}
.banner-shortcuts{border:0;background:var(--bg)}

/* One continuous navigation surface unfolds beneath the header. */
:root{scrollbar-gutter:stable}
:root.mobile-menu-open{overflow:hidden}
:root.mega-open .header{background:var(--bg)}
.header .nav-trigger{display:flex;align-items:center;gap:5px;min-height:44px;padding:10px 0;background:none;color:var(--ink);font:14px/1.4 SiteSans,Arial,sans-serif;white-space:nowrap;transition:opacity .15s;user-select:none}
.header .nav-trigger:hover,.header .nav-trigger[aria-expanded=true]{opacity:.55}
.header .nav-trigger svg{width:12px;height:12px;opacity:.5;transition:transform .25s}
.header .nav-trigger[aria-expanded=true] svg{transform:rotate(180deg)}
.header .nav-trigger:focus-visible{outline:2px solid #517fb8;outline-offset:4px}
.header .button:hover{transform:none;box-shadow:none}
.mega-menu{position:absolute;top:64px;left:0;right:0;height:0;max-height:min(520px,calc(100dvh - 180px));z-index:65;background:var(--bg);overflow:hidden;overscroll-behavior:contain;transition:height .32s cubic-bezier(.4,0,.65,1);pointer-events:none}
.mega-menu[hidden],.nav-panel[hidden]{display:none}
.mega-menu.is-open{pointer-events:auto;transition:height .48s cubic-bezier(.22,.75,.28,1)}
.mega-close{position:absolute;top:12px;right:var(--shell-gutter);z-index:1}
.mega-inner{max-width:1536px;max-height:min(520px,calc(100dvh - 180px));overflow:auto;margin:0 auto;padding:48px var(--shell-gutter) 52px;opacity:0;transform:translateY(-18px);transition:transform .3s cubic-bezier(.4,0,.65,1),opacity .22s ease}
.is-open .mega-inner{opacity:1;transform:translateY(0);transition:transform .48s cubic-bezier(.22,.75,.28,1),opacity .28s ease .06s}
.mega-menu .nav-panel{position:static;min-width:0;padding:0;display:grid;grid-template-columns:1.1fr 1.3fr 1fr;gap:clamp(36px,6vw,96px);border-radius:0;box-shadow:none;background:none}
.mega-menu .nav-panel[hidden]{display:none}
.mega-intro h2{font-size:clamp(28px,2.5vw,36px);font-weight:400;line-height:1.12;letter-spacing:-.025em;text-wrap:balance}
.mega-intro p{max-width:30ch;font-size:15px;line-height:1.6;color:var(--muted);margin-top:20px}
.mega-primary,.mega-secondary{display:flex;flex-direction:column;align-items:flex-start}
.mega-primary{gap:17px}
.mega-menu .mega-primary a{font-size:clamp(20px,1.7vw,24px);line-height:1.3;letter-spacing:-.02em;max-width:24ch}
.mega-secondary{gap:14px}
.mega-secondary h3{font-size:14px;font-weight:400;color:var(--muted);margin:4px 0 8px;letter-spacing:0}
.mega-menu .mega-secondary a{font-size:16px;line-height:1.55;max-width:28ch}
.mega-menu a{padding:0;border-radius:0;text-decoration:none;transition:opacity .15s}
.mega-menu a:hover{background:none;opacity:.55}
.mega-menu a:focus-visible{outline:2px solid #517fb8;outline-offset:6px}
.is-open .nav-panel:not([hidden]) .mega-column{animation:mega-content-reduced .3s ease both}
.is-open .mega-column:nth-child(2){animation-delay:35ms}.is-open .mega-column:nth-child(3){animation-delay:70ms}
@keyframes mega-content{from{opacity:0;transform:translateY(-10px)}to{opacity:1;transform:none}}
:root[data-reduced=true] .mega-menu{transition-duration:.16s}
:root[data-reduced=true] .mega-inner{transform:none;transition:opacity .16s}
:root[data-reduced=true] .mega-column{animation-name:mega-content-reduced}
@keyframes mega-content-reduced{from{opacity:0}to{opacity:1}}
@media(max-width:900px){.mega-menu{display:none!important}.header .mobile-nav{height:calc(100dvh - 64px);max-height:none;align-content:start;box-shadow:none;overscroll-behavior:contain;padding:30px 24px 48px;animation:mega-content .25s ease both}.mobile-nav-group>span{font-size:14px;margin-top:12px}.header .mobile-nav a{font-size:18px;line-height:1.4}.mobile-nav-group{gap:8px;align-content:start}.mobile-nav[hidden]{display:none}.mobile-nav .mobile-contact{margin-top:28px}}
:root[data-reduced=true] .header .mobile-nav{animation-name:mega-content-reduced}
.menu-toggle[aria-expanded=true]{position:relative}
.menu-toggle[aria-expanded=true] svg{display:none}
.menu-toggle[aria-expanded=true]::before,.menu-toggle[aria-expanded=true]::after{content:"";position:absolute;width:18px;height:1.5px;background:currentColor;transform:rotate(45deg)}
.menu-toggle[aria-expanded=true]::after{transform:rotate(-45deg)}





.footer-theme{display:flex;align-items:center;gap:10px;color:var(--muted);font-size:13px}
.footer-theme:hover{text-decoration:none}

.appearance-picker{position:relative}
.appearance-trigger{display:flex;align-items:center;justify-content:space-between;gap:24px;min-width:124px;min-height:40px;padding:10px 14px;background:var(--surface);color:var(--ink);font-size:14px;border-radius:999px}
.appearance-trigger>svg{width:16px;height:16px;transition:transform .18s ease}
.appearance-trigger:hover{background:var(--line)}
.appearance-trigger:focus-visible,.appearance-menu button:focus-visible{outline:2px solid var(--ink);outline-offset:3px}
.appearance-menu{position:absolute;z-index:70;right:0;bottom:calc(100% + 10px);width:192px;max-width:calc(100vw - 40px);padding:6px;border-radius:12px;background:var(--surface);color:var(--ink);box-shadow:0 10px 28px rgba(var(--shadow),.2);opacity:0;transform:translateY(5px);visibility:hidden;transition:opacity .16s ease,transform .16s ease,visibility .16s}
.appearance-picker.is-open .appearance-menu{opacity:1;transform:translateY(0);visibility:visible}
.appearance-picker.is-open .appearance-trigger>svg{transform:rotate(180deg)}
.appearance-menu button{display:grid;grid-template-columns:18px 1fr 16px;gap:12px;align-items:center;width:100%;min-height:42px;padding:10px;border-radius:7px;background:transparent;color:var(--ink);text-align:left;font-size:14px}
.appearance-menu button:hover,.appearance-menu button:focus-visible{background:var(--line)}
.appearance-menu button[aria-checked=true]{font-weight:500}
.appearance-menu button>svg{width:18px;height:18px}
.appearance-menu .appearance-check{width:16px;opacity:0}
.appearance-menu [aria-checked=true] .appearance-check{opacity:1}
@media(prefers-reduced-motion:reduce){.appearance-menu,.appearance-trigger>svg{transition:none;transform:none}}