/* ==========================================================================
   6dB.ai — "Gain Margin" design system
   Dark room, lime signal. One stylesheet, no framework.
   ========================================================================== */

:root{
  --room:      #04181c;
  --room-2:    #082227;
  --room-3:    #0c2c32;
  --lime:      #c3f24a;
  --lime-dim:  #9ec93a;
  --teal:      #2fa39c;
  --teal-dim:  #1a6f7a;
  --ink:       #e8f4ef;
  --ink-2:     #a9c6c0;
  --muted:     #7e9d99;
  --line:      rgba(195,242,74,.14);
  --line-2:    rgba(232,244,239,.09);
  --card:      rgba(255,255,255,.028);
  --card-2:    rgba(255,255,255,.05);

  --font-display: "Space Grotesk", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body:    "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono:    ui-monospace, "SFMono-Regular", "JetBrains Mono", Menlo, Consolas, monospace;

  --wrap: 1140px;
  --gap: clamp(56px, 8vw, 104px);
  --r: 14px;
}

*,*::before,*::after{ box-sizing:border-box; }

html{ scroll-behavior:smooth; -webkit-text-size-adjust:100%; }

body{
  margin:0;
  background:var(--room);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:17px;
  line-height:1.68;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}

img{ max-width:100%; height:auto; display:block; }

a{ color:var(--lime); text-decoration:none; }
a:hover{ text-decoration:underline; text-underline-offset:3px; }

h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:700;
  line-height:1.08;
  letter-spacing:-.02em;
  margin:0 0 .5em;
  text-wrap:balance;
}
h1{ font-size:clamp(2.3rem, 5.4vw, 4.1rem); }
h2{ font-size:clamp(1.75rem, 3.4vw, 2.7rem); }
h3{ font-size:clamp(1.12rem, 1.7vw, 1.35rem); }
h4{ font-size:1.02rem; }

p{ margin:0 0 1.15em; }
p:last-child{ margin-bottom:0; }

.wrap{ width:min(100% - 40px, var(--wrap)); margin-inline:auto; }
.wrap-narrow{ width:min(100% - 40px, 820px); margin-inline:auto; }

/* --- skip link ---------------------------------------------------------- */
.skip{
  position:absolute; left:-9999px; top:0; z-index:999;
  background:var(--lime); color:#04181c; padding:12px 18px; border-radius:0 0 8px 0;
  font-weight:600;
}
.skip:focus{ left:0; }

:focus-visible{ outline:2px solid var(--lime); outline-offset:3px; border-radius:4px; }

/* --- header ------------------------------------------------------------- */
.site-header{
  position:sticky; top:0; z-index:60;
  background:rgba(4,24,28,.78);
  backdrop-filter:saturate(150%) blur(14px);
  border-bottom:1px solid var(--line-2);
}
.nav{
  display:flex; align-items:center; gap:22px;
  min-height:68px;
}
.brand{
  display:flex; align-items:center; gap:11px;
  font-family:var(--font-display); font-weight:700; font-size:1.16rem;
  color:var(--ink); letter-spacing:-.02em; text-decoration:none;
  margin-right:auto;
}
.brand:hover{ text-decoration:none; }
.brand img{ width:34px; height:34px; border-radius:50%; }

.nav-links{
  display:flex; align-items:center; gap:5px;
  list-style:none; margin:0; padding:0;
}
.nav-links a{
  display:block; padding:8px 13px; border-radius:8px;
  color:var(--ink-2); font-size:.94rem; font-weight:500; text-decoration:none;
  transition:color .16s, background .16s;
}
.nav-links a:hover{ color:var(--ink); background:rgba(255,255,255,.05); text-decoration:none; }
.nav-links a[aria-current="page"]{ color:var(--lime); }

.nav-toggle{
  display:none; background:none; border:1px solid var(--line-2); color:var(--ink);
  border-radius:8px; padding:8px 11px; font-size:.9rem; cursor:pointer;
}

@media (max-width:900px){
  .nav-toggle{ display:block; order:3; }
  .nav-links{
    order:4; flex-basis:100%; flex-direction:column; align-items:stretch;
    gap:0; padding:6px 0 14px; display:none;
  }
  .nav-links.open{ display:flex; }
  .nav-links a{ padding:11px 12px; }
  .nav .btn{ order:2; }
}

/* --- buttons ------------------------------------------------------------ */
.btn{
  display:inline-flex; align-items:center; justify-content:center; gap:9px;
  padding:13px 24px; border-radius:10px;
  font-family:var(--font-display); font-weight:600; font-size:.97rem;
  text-decoration:none; cursor:pointer; border:1px solid transparent;
  transition:transform .14s, background .16s, border-color .16s;
}
.btn:hover{ text-decoration:none; transform:translateY(-1px); }
.btn-primary{ background:var(--lime); color:#04181c; }
.btn-primary:hover{ background:#d3fb63; }
.btn-ghost{ background:transparent; color:var(--ink); border-color:rgba(232,244,239,.22); }
.btn-ghost:hover{ border-color:var(--lime); color:var(--lime); }
.btn-sm{ padding:10px 17px; font-size:.9rem; }

/* --- hero --------------------------------------------------------------- */
.hero{ position:relative; isolation:isolate; overflow:hidden; }
.hero-canvas{
  position:absolute; inset:0; width:100%; height:100%;
  z-index:-2; display:block;
  background:radial-gradient(120% 90% at 68% 18%, #0d3a3c 0%, #061e23 46%, #04181c 100%);
}
.hero::after{
  content:""; position:absolute; inset:0; z-index:-1; pointer-events:none;
  background:
    linear-gradient(180deg, rgba(4,24,28,.52) 0%, rgba(4,24,28,.10) 36%, rgba(4,24,28,.86) 100%),
    radial-gradient(66% 58% at 20% 46%, rgba(4,24,28,.68) 0%, rgba(4,24,28,0) 74%);
}
.hero-inner{ padding:clamp(84px,13vw,168px) 0 clamp(64px,9vw,110px); }
.hero h1{ max-width:16ch; }
.hero .lede{
  font-size:clamp(1.06rem, 1.55vw, 1.25rem);
  color:var(--ink-2); max-width:60ch; margin-top:26px;
}
.hero-cta{ display:flex; flex-wrap:wrap; gap:13px; margin-top:34px; }

.kicker{
  display:inline-flex; align-items:center; gap:9px;
  font-family:var(--font-mono); font-size:.72rem; font-weight:500;
  letter-spacing:.19em; text-transform:uppercase; color:var(--lime);
  margin-bottom:22px;
}
.kicker::before{
  content:""; width:26px; height:1px; background:var(--lime); opacity:.6;
}

/* --- section ------------------------------------------------------------ */
.section{ padding:var(--gap) 0; }
.section-alt{ background:var(--room-2); border-block:1px solid var(--line-2); }
.section-head{ max-width:64ch; margin-bottom:46px; }
.section-head p{ color:var(--ink-2); font-size:1.04rem; }

/* --- gain meter (the signature element) --------------------------------- */
.meter{
  display:flex; align-items:flex-end; gap:4px; height:74px;
  margin:0 0 26px; padding:0; list-style:none;
}
.meter li{
  flex:1; border-radius:2px 2px 0 0;
  background:linear-gradient(180deg, var(--teal-dim), rgba(47,163,156,.22));
}
.meter li.hot{ background:linear-gradient(180deg, var(--lime), var(--lime-dim)); }
.meter li.over{ background:linear-gradient(180deg, #ff6b57, #c9412f); }

.gain-strip{
  display:grid; grid-template-columns:repeat(auto-fit, minmax(150px, 1fr));
  gap:1px; background:var(--line-2);
  border:1px solid var(--line-2); border-radius:var(--r); overflow:hidden;
  margin-top:44px;
}
.gain-strip div{ background:var(--room); padding:24px 22px; }
.gain-strip .num{
  font-family:var(--font-display); font-weight:700; font-size:2rem;
  color:var(--lime); line-height:1; letter-spacing:-.03em;
}
.gain-strip .lbl{
  font-family:var(--font-mono); font-size:.68rem; letter-spacing:.15em;
  text-transform:uppercase; color:var(--muted); margin-top:10px;
}

/* --- cards -------------------------------------------------------------- */
.grid{ display:grid; gap:20px; }
.grid-2{ grid-template-columns:repeat(auto-fit, minmax(320px, 1fr)); }
.grid-3{ grid-template-columns:repeat(auto-fit, minmax(272px, 1fr)); }

.card{
  background:var(--card); border:1px solid var(--line-2);
  border-radius:var(--r); padding:28px 26px;
  transition:border-color .18s, background .18s;
}
.card:hover{ border-color:var(--line); background:var(--card-2); }
.card h3{ margin-bottom:.55em; }
.card p{ color:var(--ink-2); font-size:.98rem; }
.card p:last-child{ margin-bottom:0; }

.spec{
  display:flex; align-items:baseline; gap:12px; flex-wrap:wrap;
  margin:0 0 14px; padding-bottom:12px;
  border-bottom:1px solid var(--line-2);
  font-family:var(--font-body); font-size:.9rem; color:var(--ink); line-height:1.5;
}
.spec span{
  font-family:var(--font-display); font-weight:700; font-size:.64rem;
  letter-spacing:.16em; text-transform:uppercase; color:var(--lime); flex:0 0 auto;
}

/* --- split -------------------------------------------------------------- */
.split{
  display:grid; grid-template-columns:1.05fr .95fr;
  gap:clamp(32px, 5vw, 64px); align-items:center;
}
@media (max-width:860px){ .split{ grid-template-columns:1fr; } }
.split-vis{
  border-radius:var(--r); overflow:hidden;
  border:1px solid var(--line-2);
  background:var(--room-3);
}
.split-vis img{ width:100%; }

/* --- numbered flow ------------------------------------------------------ */
.flow{ counter-reset:s; display:grid; gap:2px; }
.flow-step{
  display:grid; grid-template-columns:auto 1fr; gap:22px; align-items:start;
  padding:24px 4px; border-top:1px solid var(--line-2);
}
.flow-step:last-child{ border-bottom:1px solid var(--line-2); }
.flow-step .n{
  counter-increment:s;
  font-family:var(--font-mono); font-size:.74rem; letter-spacing:.1em;
  color:var(--lime); padding-top:6px; min-width:34px;
}
.flow-step .n::before{ content:"0" counter(s); }
.flow-step h3{ font-size:1.08rem; margin-bottom:.35em; }
.flow-step p{ color:var(--ink-2); font-size:.97rem; margin:0; }

/* --- faq ---------------------------------------------------------------- */
.faq{ border-top:1px solid var(--line-2); }
.faq details{ border-bottom:1px solid var(--line-2); }
.faq summary{
  cursor:pointer; list-style:none; padding:22px 44px 22px 0; position:relative;
  font-family:var(--font-display); font-weight:600; font-size:1.04rem; color:var(--ink);
}
.faq summary::-webkit-details-marker{ display:none; }
.faq summary::after{
  content:"+"; position:absolute; right:6px; top:19px;
  font-size:1.5rem; font-weight:400; color:var(--lime); line-height:1;
  transition:transform .2s;
}
.faq details[open] summary::after{ transform:rotate(45deg); }
.faq .ans{ padding:0 44px 24px 0; color:var(--ink-2); font-size:.99rem; }
.faq .ans p:last-child{ margin-bottom:0; }

/* --- case studies ------------------------------------------------------- */
.case{
  border:1px solid var(--line-2); border-radius:var(--r);
  padding:clamp(26px, 4vw, 44px); background:var(--card);
  margin-bottom:22px;
}
.case-meta{
  display:flex; flex-wrap:wrap; gap:8px 18px; align-items:center;
  font-family:var(--font-mono); font-size:.7rem; letter-spacing:.14em;
  text-transform:uppercase; color:var(--muted); margin-bottom:18px;
}
.case-meta .tag{ color:var(--lime); }
.case h2{ font-size:clamp(1.4rem, 2.5vw, 2rem); }
.case .result{
  display:inline-flex; align-items:baseline; gap:12px;
  background:rgba(195,242,74,.09); border:1px solid var(--line);
  border-radius:10px; padding:14px 20px; margin:22px 0;
}
.case .result .val{
  font-family:var(--font-display); font-size:1.7rem; font-weight:700;
  color:var(--lime); line-height:1;
}
.case .result .cap{ font-style:normal; color:var(--ink-2); font-size:.92rem; }

.tick{ list-style:none; margin:0 0 1.15em; padding:0; }
.tick li{
  position:relative; padding-left:26px; margin-bottom:9px;
  color:var(--ink-2); font-size:.98rem;
}
.tick li::before{
  content:""; position:absolute; left:2px; top:.62em;
  width:9px; height:9px; border-radius:2px; background:var(--lime); opacity:.75;
}

/* --- signal chain diagram ----------------------------------------------- */
.chain{
  display:flex; flex-wrap:wrap; align-items:center; gap:10px;
  padding:26px; border:1px solid var(--line-2); border-radius:var(--r);
  background:var(--room-3); margin:32px 0;
  font-family:var(--font-mono); font-size:.78rem; letter-spacing:.06em;
}
.chain .node{
  background:rgba(195,242,74,.11); border:1px solid var(--line);
  color:var(--lime); border-radius:7px; padding:9px 14px; font-weight:500;
}
.chain .arw{ color:var(--muted); font-style:normal; }

/* --- form --------------------------------------------------------------- */
.form-card{
  background:var(--room-2); border:1px solid var(--line-2);
  border-radius:var(--r); padding:clamp(26px, 4vw, 40px);
}
.field{ margin-bottom:18px; }
.field label{
  display:block; font-size:.82rem; font-weight:500; color:var(--ink-2);
  margin-bottom:7px; letter-spacing:.01em;
}
.field input, .field select, .field textarea{
  width:100%; padding:12px 14px;
  background:rgba(0,0,0,.24); color:var(--ink);
  border:1px solid rgba(232,244,239,.16); border-radius:9px;
  font-family:var(--font-body); font-size:.97rem;
}
.field input:focus, .field select:focus, .field textarea:focus{
  outline:none; border-color:var(--lime); background:rgba(0,0,0,.34);
}
.field textarea{ min-height:110px; resize:vertical; }
.field-row{ display:grid; grid-template-columns:1fr 1fr; gap:16px; }
@media (max-width:560px){ .field-row{ grid-template-columns:1fr; } }
.form-note{ font-size:.84rem; color:var(--muted); margin-top:14px; }

/* --- cta band ----------------------------------------------------------- */
.cta-band{
  background:linear-gradient(135deg, #0b3035 0%, #07242a 60%, #04181c 100%);
  border-block:1px solid var(--line);
}
.cta-band .wrap{ padding:var(--gap) 0; text-align:center; }
.cta-band h2{ max-width:20ch; margin-inline:auto; }
.cta-band p{ color:var(--ink-2); max-width:56ch; margin:18px auto 30px; }

/* --- footer ------------------------------------------------------------- */
.site-footer{
  background:#031316; border-top:1px solid var(--line-2);
  padding:56px 0 30px; font-size:.93rem;
}
.foot-grid{
  display:grid; grid-template-columns:1.5fr 1fr 1fr 1.2fr; gap:36px;
}
@media (max-width:860px){ .foot-grid{ grid-template-columns:1fr 1fr; } }
@media (max-width:520px){ .foot-grid{ grid-template-columns:1fr; } }
.site-footer h4{
  font-family:var(--font-mono); font-size:.68rem; letter-spacing:.16em;
  text-transform:uppercase; color:var(--muted); font-weight:500; margin-bottom:14px;
}
.site-footer ul{ list-style:none; margin:0; padding:0; }
.site-footer li{ margin-bottom:8px; }
.site-footer a{ color:var(--ink-2); text-decoration:none; }
.site-footer a:hover{ color:var(--lime); }
.site-footer .about{ color:var(--muted); max-width:38ch; }
.foot-bottom{
  margin-top:44px; padding-top:22px; border-top:1px solid var(--line-2);
  display:flex; flex-wrap:wrap; gap:14px 26px; justify-content:space-between;
  color:var(--muted); font-size:.85rem;
}

/* --- reveal ------------------------------------------------------------- */
[data-reveal]{ opacity:0; transform:translateY(16px); transition:opacity .6s ease, transform .6s ease; }
[data-reveal].in{ opacity:1; transform:none; }

@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{ animation:none !important; transition:none !important; }
  [data-reveal]{ opacity:1; transform:none; }
  html{ scroll-behavior:auto; }
}