/* Sticky header, black lead section, green footer */
:root{--nav-h:76px}
html,body{overflow-x:clip}
html{scroll-padding-top:calc(var(--nav-h) + 16px)}

header.nav{position:sticky;top:env(safe-area-inset-top,0px);z-index:50;padding-right:0;max-width:none;background:#18102b;box-shadow:0 0 0 100vmax #18102b;clip-path:inset(0 -100vmax)}
header.nav::after{content:"";position:absolute;left:-100vmax;right:-100vmax;bottom:0;height:1px;background:var(--border-default)}

/* the animated story sits below the sticky header */
#structure-story .stage{top:var(--nav-h);height:calc(100svh - var(--nav-h))}

/* lead section: completely black */
.lead{background:#18102b;padding:clamp(56px,9vw,112px) 0}
.lead-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:clamp(32px,6vw,88px);align-items:center}
.lead .kicker{display:block;border:0;border-radius:0;padding:0;background:none;color:var(--text-faint);margin-bottom:22px;text-align:left}
.lead h2{margin:0;font-size:clamp(34px,5vw,64px);line-height:1.04;letter-spacing:-.045em;font-weight:600;text-wrap:balance;text-align:left}
.lead-copy p{max-width:30em;margin:20px 0 0;font-size:18px;color:var(--text-secondary)}

.lf{background:var(--surface-card);border:1px solid var(--border-default);border-radius:10px;padding:clamp(20px,3vw,32px);display:grid;gap:20px}
.lf-steps{display:flex;gap:8px;list-style:none;margin:0;padding:0}
.lf-dot{flex:1;display:grid;gap:8px;font-family:var(--font-mono);font-size:10px;font-weight:600;letter-spacing:.1em;text-transform:uppercase;color:var(--text-faint)}
.lf-dot::before{content:"";height:2px;background:var(--border-strong);border-radius:2px;transition:background .2s}
.lf-dot.on{color:var(--text-main)}
.lf-dot.on::before{background:var(--accent)}
.lf h3{margin:0;font-size:22px;font-weight:600;letter-spacing:-.02em}
.lf p{margin:0;color:var(--text-secondary);font-size:15px;line-height:1.55}
.lf [hidden]{display:none!important}

.lf-field{display:grid;gap:6px}
.lf-field label{font-family:var(--font-mono);font-size:11px;font-weight:600;letter-spacing:.12em;text-transform:uppercase;color:var(--text-faint)}
.lf-field input{font:inherit;font-size:16px;color:var(--text-main);background:#18102b;border:1px solid var(--border-strong);border-radius:6px;height:46px;padding:0 14px;width:100%;transition:border-color .13s}
.lf-field input::placeholder{color:var(--text-faint)}
.lf-field input:hover{border-color:#5a4c85}
.lf-field input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px rgba(240,225,0,.28)}
.lf-hp{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}
.lf-form{display:grid;gap:14px}
.lf-error{margin:0;color:#FF5A65;font-size:14px}
.lf-fine{font-size:12px!important;color:var(--text-faint)!important}

.lf-btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:48px;padding:0 20px;border-radius:6px;border:1px solid var(--accent);background:var(--accent);color:var(--on-accent);font:inherit;font-size:15px;font-weight:600;cursor:pointer;transition:background .13s}
.lf-btn:hover{background:var(--accent-hover)}
.lf-btn:active{background:var(--accent-pressed,#d4c700)}
.lf-btn:disabled{opacity:.6;cursor:progress}
.lf-btn.ghost{background:transparent;color:var(--text-main);border-color:var(--border-strong)}
.lf-btn.ghost:hover{background:var(--surface-hover,#2e2450)}
.lf-btn:focus-visible,.lf-link:focus-visible{outline:1px solid var(--accent);outline-offset:2px;box-shadow:0 0 0 3px rgba(240,225,0,.28)}
.lf-row{display:flex;flex-wrap:wrap;align-items:center;gap:12px 18px}
.lf-link{background:none;border:0;padding:0;font:inherit;font-size:14px;color:var(--text-secondary);text-decoration:underline;text-underline-offset:3px;cursor:pointer}
.lf-link:hover{color:var(--text-main)}

#lf-frame{border:1px solid var(--border-default);border-radius:8px;overflow:hidden;background:#fff;min-height:200px}
#lf-frame iframe{display:block;width:100%;height:min(620px,78svh);border:0}
#lf-frame .lf-notice{margin:0;padding:22px;background:#2a1c55;color:#a98bff;font-size:14px;line-height:1.5}
.lf-tick{width:44px;height:44px;border-radius:50%;background:var(--accent);color:var(--on-accent);display:grid;place-items:center;font-size:22px;font-weight:700}

@media(max-width:860px){.lead-grid{grid-template-columns:1fr}}
@media(prefers-reduced-motion:reduce){.lf-dot::before,.lf-btn,.lf-field input{transition:none}}

/* footer: green */
footer{background:var(--accent);color:var(--on-accent);border-top:0;padding:34px 0}
footer .brand,footer p,footer .text-link,footer a{color:var(--on-accent)}
footer .brand{font-weight:700}
footer .text-link{font-weight:600;border-bottom:1px solid currentColor}
footer a:focus-visible{outline:2px solid var(--on-accent);outline-offset:3px}

/* footer: centred mark and tagline */
footer .footer-center{display:grid;justify-items:center;gap:10px;text-align:center;padding-block:12px}
footer .footer-mark{display:block;line-height:0;margin-bottom:6px;border:0}
footer .footer-mark img{display:block;width:clamp(84px,9vw,112px);height:auto}
footer .footer-line{margin:0;font-size:clamp(20px,2.6vw,28px);font-weight:700;letter-spacing:-.02em;line-height:1.2;color:var(--on-accent)}
footer .footer-sub{margin:0;font-size:clamp(15px,1.8vw,18px);font-weight:500;letter-spacing:-.005em;color:var(--on-accent)}