/* Heliogenesis — design tokens taken from the Arc Institute build */

@font-face{font-family:"IBM Plex Sans";src:url(fonts/ibm-plex-sans-400.woff2) format("woff2");font-weight:400;font-style:normal;font-display:swap}
@font-face{font-family:"IBM Plex Sans";src:url(fonts/ibm-plex-sans-500.woff2) format("woff2");font-weight:500;font-style:normal;font-display:swap}
@font-face{font-family:"IBM Plex Sans";src:url(fonts/ibm-plex-sans-600.woff2) format("woff2");font-weight:600;font-style:normal;font-display:swap}
@font-face{font-family:"IBM Plex Mono";src:url(fonts/ibm-plex-mono-300.woff2) format("woff2");font-weight:300;font-style:normal;font-display:swap}
@font-face{font-family:"IBM Plex Mono";src:url(fonts/ibm-plex-mono-500.woff2) format("woff2");font-weight:500;font-style:normal;font-display:swap}
@font-face{font-family:"Tiempos Headline";src:url(fonts/tiempos-headline-light.woff2) format("woff2");font-style:normal;font-weight:300;font-display:swap}
@font-face{font-family:"Tiempos Headline";src:url(fonts/tiempos-headline-regular.woff2) format("woff2");font-style:normal;font-weight:400;font-display:swap}
@font-face{font-family:"Tiempos Headline";src:url(fonts/tiempos-headline-medium.woff2) format("woff2");font-style:normal;font-weight:500;font-display:swap}
@font-face{font-family:"Tiempos";src:url(fonts/tiempos-regular-italic.woff2) format("woff2");font-style:italic;font-weight:400;font-display:swap}

:root{
  --primary-light:#fbf8f2;
  --primary-dark:#001f44;
  --accent-blue:#0073e6;
  --accent-yellow:#ffd74b;
  --light-olive:#eff3ef;
  --medium-olive:#aec3b0;
  --dark-olive:#455e48;
  --night:#0c2043;
  --arctic:#f7f9fb;
  --blue-light:#66a8ed;
  --body-blue:#2d4773;
  --font-sans:"IBM Plex Sans",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;
  --font-mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace;
  --font-display:"Tiempos Headline",Georgia,serif;
  --container-padding:32px;
  --bar-height:56px;
}

*,*::before,*::after{box-sizing:border-box}
html{font-family:var(--font-sans);font-size:16px;line-height:24px;-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background-color:var(--primary-light);color:var(--body-blue)}
h1,h2,h3,h4,h5,h6,p,ol,ul,figure{margin:0}
ol,ul{padding:0;list-style:none}
img{max-width:100%;display:block}
a{color:inherit}

/* ---------- type scale ---------- */
h1{font-family:var(--font-display);font-weight:300;font-size:30px;line-height:40px;margin-bottom:30px}
h2{font-family:var(--font-display);font-weight:400;font-size:28px;line-height:38px;margin-bottom:20px}
h3{font-family:var(--font-display);font-weight:500;font-size:22px;line-height:30px;margin-bottom:20px}
h4{font-family:var(--font-sans);font-weight:600;font-size:16px;line-height:24px;margin-bottom:10px;color:var(--section-accent)}
h5,.eyebrow{font-family:var(--font-mono);font-weight:500;font-size:13px;line-height:24px;text-transform:uppercase;letter-spacing:.02em;color:var(--section-accent)}
@media (min-width:900px){
  h1{font-size:44px;line-height:56px}
  h2{font-size:36px;line-height:48px}
  h3{font-size:24px;line-height:32px}
}

/* ---------- layout ---------- */
.container{width:100%;max-width:1080px;padding:0 var(--container-padding);margin:0 auto}
.section{
  --section-padding-normal:100px;
  --section-padding-hero:130px;
  --section-padding-compact:55px;
  --section-padding-minimal:24px;
  --section-padding:var(--section-padding-normal);
  --section-background:var(--primary-light);
  --section-accent:var(--accent-blue);
  padding:var(--section-padding) 0;
  background-color:var(--section-background);
  position:relative;
}
.section.hero{--section-padding:var(--section-padding-hero)}
.section.compact{--section-padding:var(--section-padding-compact)}
.section.minimal{--section-padding:var(--section-padding-minimal)}
@media (min-width:900px){.section.hero{--section-padding:180px}}

.section.light{--section-accent:var(--accent-blue);--section-background:var(--primary-light);color:var(--body-blue)}
.section.white{--section-accent:var(--accent-blue);--section-background:#fff;color:var(--body-blue)}
.section.dark{--section-accent:var(--accent-yellow);--section-background:var(--primary-dark);color:rgba(255,255,255,.8)}
.section.blue{--section-accent:var(--accent-yellow);--section-background:var(--accent-blue);color:var(--arctic)}
.section.light-olive{--section-accent:var(--dark-olive);--section-background:var(--light-olive);color:var(--primary-dark)}
.section.medium-olive{--section-accent:var(--dark-olive);--section-background:var(--medium-olive);color:var(--primary-dark)}

.columns{display:grid;gap:20px;grid-auto-flow:row}
@media (min-width:900px){.columns{grid-template-columns:repeat(2,1fr);gap:0 100px}}
.columns.three{gap:20px}
@media (min-width:900px){.columns.three{grid-template-columns:repeat(3,1fr);gap:0 60px}}

.title{position:relative;color:var(--title-color,inherit)}
.title.blue{--title-color:var(--accent-blue)}
.title.yellow{--title-color:var(--accent-yellow)}
.title.dark{--title-color:var(--primary-dark)}
.title.olive{--title-color:var(--dark-olive)}
.title.white{--title-color:#fff}
.title.decorated{border-top:1px solid currentColor;padding-top:30px}

.intro{font-size:18px;line-height:30px}
p+p{margin-top:20px}
.section p{font-size:16px;line-height:26px}
.section p.intro{font-size:18px;line-height:30px}
b,strong{font-weight:600}
em,i{font-family:var(--font-display);font-style:italic}

.button{
  display:inline-block;margin-top:20px;background:transparent;border:1px solid var(--section-accent);color:var(--section-accent);
  cursor:pointer;
  font-family:var(--font-sans);font-weight:600;font-size:15px;line-height:24px;padding:8px 20px;
  text-decoration:none;transition:background-color .2s ease,color .2s ease;
}
.button:hover{background-color:var(--section-accent);color:var(--section-background)}
.button+.button{margin-left:12px}

/* ---------- top bar ---------- */
.topbar{
  position:sticky;top:0;z-index:50;background-color:var(--arctic);color:var(--primary-dark);
  border-bottom:1px solid rgba(0,31,68,.08);
}
.topbar .bar{
  /* same width and padding as .container, so the wordmark lines up with the copy */
  max-width:1080px;margin:0 auto;padding:0 var(--container-padding);
  min-height:var(--bar-height);display:flex;align-items:center;gap:28px;
}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--primary-dark);flex:none}
.brand .mark{flex:none;width:30px;height:30px}
.brand span{font-family:var(--font-display);font-weight:400;font-size:25px;letter-spacing:0;line-height:1}
.navs{display:flex;align-items:center;gap:28px;flex:1 1 auto}
.topnav{display:flex;align-items:center;gap:24px;flex-wrap:wrap}
.topnav.left{flex:1 1 auto}
.topnav.right{flex:none}
.nav-toggle{display:none}
.topnav a{
  font-family:var(--font-sans);font-size:16px;line-height:24px;font-weight:400;
  text-decoration:none;color:var(--primary-dark);padding:4px 0;border-bottom:1px solid transparent;
}
.topnav a:hover{border-bottom-color:var(--primary-dark)}
.topnav a[aria-current="page"]{color:var(--accent-blue);border-bottom-color:var(--accent-blue)}
@media (max-width:900px){
  .topbar .bar{padding:0 20px;min-height:60px}
  .nav-toggle{
    display:flex;align-items:center;justify-content:center;width:44px;height:44px;margin:0 -10px 0 auto;
    background:transparent;border:0;cursor:pointer;color:var(--primary-dark);
  }
  .nav-toggle svg{display:block}
  .nav-toggle .close{display:none}
  .topbar.open .nav-toggle .close{display:block}
  .topbar.open .nav-toggle .open-icon{display:none}
  .navs{
    display:none;position:absolute;left:0;right:0;top:100%;flex-direction:column;align-items:stretch;gap:0;
    background:var(--arctic);border-bottom:1px solid rgba(0,31,68,.12);padding:6px 20px 18px;
  }
  .topbar.open .navs{display:flex}
  .topnav{flex-direction:column;align-items:stretch;gap:0}
  .topnav a{
    font-size:18px;padding:13px 0;border-bottom:1px solid rgba(0,31,68,.08);
  }
  .topnav a[aria-current="page"]{border-bottom-color:var(--accent-blue)}
  .topbar{position:sticky}
}

/* ---------- cards ---------- */
.cards{display:grid;gap:0}
.card{border-top:1px solid rgba(0,31,68,.15);padding:30px 0;display:grid;gap:20px}
@media (min-width:900px){.card{grid-template-columns:220px 1fr;gap:0 60px}}
.card-meta{display:flex;flex-wrap:wrap;gap:8px;align-items:flex-start}
.tag{
  font-family:var(--font-mono);font-size:12px;line-height:20px;text-transform:uppercase;letter-spacing:.04em;
  border:1px solid currentColor;padding:1px 8px;color:var(--section-accent);white-space:nowrap;
}
.tag.plain{border:none;padding:1px 0;color:inherit;opacity:.7}
.card h3{margin-bottom:12px}
.card .read{
  display:inline-block;margin-top:16px;font-family:var(--font-mono);font-size:12px;text-transform:uppercase;
  letter-spacing:.06em;color:var(--section-accent);text-decoration:none;border-bottom:1px solid currentColor;
}

/* ---------- numbered list ---------- */
.numbered{counter-reset:item;margin-top:40px;display:grid;gap:30px}
@media (min-width:900px){.numbered{grid-template-columns:repeat(2,1fr);gap:40px 100px}}
.numbered li{counter-increment:item;position:relative;padding-top:14px;border-top:1px solid currentColor}
.numbered li::before{
  content:counter(item,decimal-leading-zero);position:absolute;top:14px;right:0;
  font-family:var(--font-mono);font-size:12px;opacity:.5;
}
.list-intro{font-family:var(--font-mono);font-size:13px;text-transform:uppercase;letter-spacing:.04em;margin-top:60px;color:var(--section-accent)}

/* ---------- people ---------- */
.people{display:grid;gap:30px;margin-top:40px}
@media (min-width:600px){.people{grid-template-columns:repeat(2,1fr)}}
@media (min-width:900px){.people{grid-template-columns:repeat(4,1fr);gap:40px 30px}}
.person .avatar{aspect-ratio:1/1;background:var(--medium-olive);margin-bottom:14px}
.person .avatar.open{background:rgba(0,31,68,.08)}
.person h4{margin-bottom:2px;color:inherit;font-size:17px}
.person p{font-size:14px !important;line-height:22px !important;opacity:.75}

/* ---------- roles ---------- */
.roles{margin-top:24px;border-top:1px solid rgba(0,31,68,.15)}
.role{
  display:flex;justify-content:space-between;gap:20px;padding:18px 0;
  border-bottom:1px solid rgba(0,31,68,.15);text-decoration:none;align-items:baseline;
}
.role:hover .role-title{color:var(--section-accent)}
.role-title{font-size:17px;line-height:26px}
.role-place{font-family:var(--font-mono);font-size:12px;text-transform:uppercase;letter-spacing:.04em;opacity:.7;white-space:nowrap}
.section.dark .roles,.section.dark .role{border-color:rgba(255,255,255,.2)}

/* ---------- signup + footer ---------- */
.signup form{display:flex;gap:12px;flex-wrap:wrap;margin-top:20px}
.signup input{
  flex:1 1 260px;background:transparent;border:1px solid rgba(255,255,255,.4);color:inherit;
  font-family:var(--font-sans);font-size:15px;padding:10px 14px;
}
.signup input::placeholder{color:rgba(255,255,255,.5)}
.signup .button{margin-top:0}

.footer{background:var(--night);color:rgba(255,249,251,.7);padding:40px 0}
.footer .bar{display:flex;justify-content:space-between;gap:20px 28px;flex-wrap:wrap;font-family:var(--font-mono);font-size:12px;text-transform:uppercase;letter-spacing:.04em}
.footer a{text-decoration:none;opacity:.8}
.footer a:hover{opacity:1}
.footer nav{display:flex;gap:18px;flex-wrap:wrap}

/* ---------- accessibility ---------- */
.skip-link{
  position:absolute;left:-9999px;top:0;z-index:100;background:var(--accent-yellow);color:var(--primary-dark);
  padding:10px 16px;font-family:var(--font-mono);font-size:13px;text-decoration:none;
}
.skip-link:focus{left:0}
a:focus-visible,button:focus-visible,input:focus-visible{outline:2px solid var(--accent-blue);outline-offset:3px}
.topbar a:focus-visible{outline-color:var(--accent-yellow)}

/* ---------- article ---------- */
.container.narrow{max-width:760px}
.article .byline{
  display:flex;gap:20px;flex-wrap:wrap;font-family:var(--font-mono);font-size:12px;
  text-transform:uppercase;letter-spacing:.06em;color:var(--section-accent);margin-bottom:24px;
}
.article h1{margin-bottom:36px}
.article p{font-size:18px !important;line-height:31px !important}
.article p+p{margin-top:24px}
.article .title{margin-top:56px}
.article figure{margin:0 0 40px}
.article figure img{width:100%;height:auto;background:var(--light-olive)}
.article figcaption{font-size:15px;line-height:24px;margin-top:12px;opacity:.85}
.article .credit{font-family:var(--font-mono);font-size:12px;text-transform:uppercase;letter-spacing:.04em;opacity:.6;margin-top:6px}

/* ---------- legal pages ---------- */
.legal h3{font-size:20px;line-height:28px;margin-top:36px;margin-bottom:12px}
.legal p{font-size:16px;line-height:26px}
.legal .todo{
  border-left:3px solid var(--accent-yellow);background:rgba(255,215,75,.18);
  padding:12px 16px;font-size:15px !important;line-height:24px !important;margin-bottom:20px;
}
.legal a,.article a:not(.button){color:var(--accent-blue)}

/* founder portraits */
.person .avatar{overflow:hidden}
.person .avatar img{width:100%;height:100%;object-fit:cover;display:block;filter:grayscale(1) contrast(1.02);transition:filter .3s ease}
.person:hover .avatar img{filter:grayscale(0)}

/* wide diagrams between sections */
.wide-figure{margin:0}
/* a figure that follows body copy needs air on both sides */
.columns+.wide-figure,.wide-figure+.columns{margin-top:64px}
.columns+.wide-figure figcaption{margin-top:20px}
@media (max-width:760px){.columns+.wide-figure,.wide-figure+.columns{margin-top:40px}}
.wide-figure img{width:100%;height:auto;border:1px solid rgba(0,31,68,.12)}
.wide-figure figcaption{font-size:15px;line-height:24px;margin-top:14px;opacity:.8;max-width:760px}


/* ---------- hero with helix ---------- */
.section.hero.with-helix{overflow:hidden}
.hero-head,.hero-body{position:relative;z-index:2}
@media (min-width:1000px){
  /* 540px is half the container and 32px is its padding, so the hero text
     starts on the same line as the wordmark and as every other section */
  .hero-head,.hero-body{max-width:640px;margin-left:max(32px,calc(50% - 508px));padding:0}
}
.hero-body p+p{margin-top:26px}
.helix{
  position:absolute;top:0;right:0;bottom:0;left:0;z-index:1;pointer-events:none;
  opacity:0;transition:opacity 1.2s ease;
}
.helix.ready{opacity:1}
.helix canvas{display:block;width:100%;height:100%}
@media (max-width:999px){
  /* headline, then the graphic, then the copy: the animation is on screen at once */
  .section.hero.with-helix{display:flex;flex-direction:column;padding-top:64px;padding-bottom:48px}
  .hero-head{order:1}
  .helix{order:2;position:relative;width:100%;height:min(100vw,460px);margin:14px 0 4px;opacity:0}
  .hero-body{order:3}
  .helix.ready{opacity:1}
}

/* a sources line under a set of claims */
.sources{margin-top:36px;font-family:var(--font-mono);font-size:13px;line-height:22px;letter-spacing:.02em;color:var(--dark-olive);max-width:820px}

/* the stage trail inside the hero canvas: DNA to Cities */
.helix-trail{
  position:absolute;left:0;right:0;bottom:18px;z-index:3;
  display:flex;justify-content:center;align-items:center;flex-wrap:wrap;gap:8px;
  font-family:var(--font-mono);font-size:11px;text-transform:uppercase;letter-spacing:.08em;
}
.helix-trail .helix-step{color:var(--primary-dark);opacity:.4;transition:opacity .45s ease,color .45s ease}
.helix-trail .helix-step.on{opacity:1;color:var(--accent-blue)}
.helix-trail i{font-style:normal;color:var(--primary-dark);opacity:.22}
@media (min-width:1000px){
  .helix-trail{left:auto;right:32px;width:min(560px,46%);bottom:44px}
}
@media (max-width:520px){
  .helix-trail{font-size:10px;gap:6px;bottom:6px}
}

/* ---------- signup feedback ---------- */
.signup .note{margin-top:16px;font-size:15px;line-height:24px;color:var(--accent-yellow)}
.signup .note.error{color:#ffb4a8}
.signup button[disabled]{opacity:.5;cursor:default}

/* ---------- model diagram ---------- */
.model-figure{margin:40px 0 0}
.model-figure img{width:100%;height:auto}
.model-head{display:flex;justify-content:space-between;align-items:baseline;gap:20px 40px;flex-wrap:wrap;
  border-bottom:1px solid rgba(255,255,255,.35);padding-bottom:18px}
.model-head h2{flex:1 1 520px;max-width:820px;margin-bottom:0}
.model-head .read{flex:none;white-space:nowrap}


/* logo marks */
.foot-brand{display:flex;align-items:center;gap:10px}
.foot-brand .mark{width:22px;height:22px;flex:none}
.foot-brand span{font-family:var(--font-mono);font-size:12px;text-transform:uppercase;letter-spacing:.04em}


/* page titles: h1 for structure, sized like h2 */
h1.page-title{font-size:28px;line-height:38px;font-weight:400;margin-bottom:20px}
@media (min-width:900px){h1.page-title{font-size:36px;line-height:48px}}

/* ---------- catalogue ---------- */
.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
.cat-controls{display:flex;flex-direction:column;gap:14px;margin-bottom:28px}
.cat-search input{
  width:100%;max-width:520px;padding:11px 14px;font-family:var(--font-sans);font-size:16px;
  border:1px solid rgba(0,31,68,.25);background:#fff;color:var(--primary-dark);
}
.cat-filters{display:flex;flex-wrap:wrap;gap:8px}
.chip{
  font-family:var(--font-mono);font-size:12px;text-transform:uppercase;letter-spacing:.05em;
  padding:6px 12px;border:1px solid var(--dark-olive);background:transparent;color:var(--dark-olive);cursor:pointer;
}
.chip:hover{background:rgba(69,94,72,.1)}
.chip.on{background:var(--dark-olive);color:var(--light-olive)}
.cat-count{font-family:var(--font-mono);font-size:13px;opacity:.75}
.cat-table-wrap{overflow-x:auto;border-top:1px solid rgba(0,31,68,.18)}
.cat-table{width:100%;border-collapse:collapse;font-size:15px;line-height:22px;min-width:860px}
.cat-table th{
  text-align:left;font-family:var(--font-mono);font-size:11px;text-transform:uppercase;letter-spacing:.06em;
  padding:12px 14px 12px 0;border-bottom:1px solid rgba(0,31,68,.18);font-weight:500;
}
.cat-table td{padding:14px 14px 14px 0;border-bottom:1px solid rgba(0,31,68,.1);vertical-align:top}
.cat-table td:nth-child(2),.cat-table td:nth-child(3){max-width:300px}
.cat-name{display:block;font-weight:600;margin-bottom:6px}
.cat-tags{display:flex;flex-wrap:wrap;gap:6px}
.cat-scale{font-family:var(--font-mono);font-size:11px;text-transform:uppercase;letter-spacing:.04em;white-space:nowrap}
.cat-scale.s-commercial{color:var(--dark-olive)}
.cat-scale.s-early{color:var(--dark-olive)}
.cat-scale.s-pilot{color:var(--accent-blue)}
.cat-scale.s-lab{color:#8a6d1f}
.cat-scale.s-paused{opacity:.6}
.cat-note{margin-top:22px;font-size:14px !important;opacity:.75}
@media (max-width:700px){
  .cat-table{min-width:600px;font-size:14px}
  .cat-table td:nth-child(3){display:none}
  .cat-table th:nth-child(3){display:none}
}

/* ---------- the cycle graphic ---------- */
.cycle-wrap{margin-top:44px}
.cycle{position:relative;width:100%;height:520px;opacity:0;transition:opacity 1s ease}
.cycle.ready{opacity:1}
.cycle canvas{display:block;width:100%;height:100%}
.cycle-stages{display:grid;grid-template-columns:repeat(5,1fr);gap:0;margin-top:8px;border-top:1px solid rgba(0,31,68,.14)}
.cycle-stage{position:relative;padding:16px 12px 0 0;opacity:.35;transition:opacity .45s ease}
.cycle-stage.on{opacity:1}
.cycle-stage b{display:block;font-family:var(--font-display);font-weight:400;font-size:19px;color:var(--primary-dark)}
.cycle-stage span{display:block;font-family:var(--font-mono);font-size:11px;text-transform:uppercase;letter-spacing:.06em;color:var(--dark-olive);margin-top:2px}
.cycle-stage i{position:absolute;top:-1px;left:0;right:12px;height:2px;background:var(--accent-blue);transform:scaleX(0);transform-origin:left}
.cycle-stage.on i{background:var(--accent-blue)}
.cycle-caption{font-size:15px;line-height:24px;margin-top:26px;opacity:.8;max-width:660px}
@media (max-width:900px){
  .cycle{height:380px}
  .cycle-stages{grid-template-columns:repeat(5,1fr)}
  .cycle-stage{padding:12px 6px 0 0}
  .cycle-stage b{font-size:14px}
  .cycle-stage span{display:none}
}
@media (max-width:520px){.cycle{height:320px}.cycle-stage b{font-size:12px}}

/* ---------- writing index ---------- */
.writing-list{border-top:1px solid rgba(0,31,68,.16)}
.write-row{
  display:grid;grid-template-columns:150px 1fr 190px;gap:24px;align-items:baseline;
  padding:22px 0;border-bottom:1px solid rgba(0,31,68,.12);text-decoration:none;color:inherit;
}
.write-row:hover .write-title{color:var(--accent-blue)}
.write-date,.write-kind{font-family:var(--font-mono);font-size:12px;text-transform:uppercase;letter-spacing:.05em;opacity:.7}
.write-kind{text-align:right}
.write-title{display:block;font-family:var(--font-display);font-size:21px;line-height:29px;margin-bottom:6px}
.write-sum{display:block;font-size:15px;line-height:24px;opacity:.85}
@media (max-width:820px){
  .write-row{grid-template-columns:1fr;gap:6px}
  .write-kind{text-align:left}
}