/* ===== Vertex Dynamics — design tokens ===== */
:root{
  --bg:        #0B0E16;
  --bg-raise:  #11151F;
  --ink:       #ECEEF3;
  --ink-dim:   #9AA1B2;
  --line:      #232838;
  --copper:    #FF8A3D;
  --copper-dim:#C96B2E;
  --violet:    #6C7CFF;
  --violet-dim:#4A55B0;

  --display: 'Space Grotesk', sans-serif;
  --body:    'IBM Plex Sans', sans-serif;
  --mono:    'IBM Plex Mono', monospace;

  --wrap: 1180px;
  --radius: 10px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--bg);
  color:var(--ink);
  font-family:var(--body);
  font-size:16px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block;}
a{color:inherit;text-decoration:none;}
.mono{font-family:var(--mono);}

.wrap{
  max-width:var(--wrap);
  margin:0 auto;
  padding:0 28px;
}

.skip-link{
  position:absolute;left:-999px;top:0;
  background:var(--copper);color:#0B0E16;padding:8px 14px;z-index:200;
}
.skip-link:focus{left:8px;top:8px;}

h1,h2,h3{
  font-family:var(--display);
  font-weight:600;
  line-height:1.08;
  margin:0;
  letter-spacing:-0.01em;
}
p{margin:0;color:var(--ink-dim);}

.eyebrow{
  font-size:12px;
  letter-spacing:.14em;
  color:var(--copper);
  margin:0 0 18px;
}

.section-title{
  font-size:clamp(28px,4vw,40px);
  color:var(--ink);
  margin-bottom:10px;
}
.section-lede{
  max-width:560px;
  font-size:17px;
  margin-bottom:48px;
}

/* ===== Buttons ===== */
.btn{
  display:inline-flex;
  align-items:center;
  gap:8px;
  padding:13px 24px;
  border-radius:6px;
  font-family:var(--body);
  font-weight:600;
  font-size:14.5px;
  cursor:pointer;
  border:1px solid transparent;
  transition:transform .15s ease, background .2s ease, border-color .2s ease;
}
.btn:focus-visible{outline:2px solid var(--copper);outline-offset:3px;}
.btn-primary{
  background:var(--copper);
  color:#16110A;
}
.btn-primary:hover{background:#ffa066; transform:translateY(-1px);}
.btn-line{
  border-color:var(--line);
  color:var(--ink);
}
.btn-line:hover{border-color:var(--violet); color:var(--violet);}
.btn-ghost{
  border-color:var(--line);
  color:var(--ink);
  padding:9px 18px;
  font-size:13.5px;
}
.btn-ghost:hover{border-color:var(--copper); color:var(--copper);}

/* ===== Header ===== */
.site-header{
  position:fixed;top:0;left:0;right:0;
  z-index:100;
  background:rgba(11,14,22,.82);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.header-inner{
  display:flex;align-items:center;gap:32px;
  height:72px;
}
.brand{display:flex;align-items:center;gap:10px;}
.brand-mark{width:22px;height:22px;color:var(--copper);flex-shrink:0;}
.brand-name{
  font-family:var(--display);
  font-weight:600;
  font-size:15px;
  letter-spacing:.04em;
  color:var(--ink);
}
.brand-name-light{color:var(--ink-dim);font-weight:400;}
.main-nav{display:flex;gap:28px;margin-left:auto;font-size:14.5px;}
.main-nav a{color:var(--ink-dim);transition:color .2s;}
.main-nav a:hover{color:var(--ink);}
.nav-cta{margin-left:8px;}
.menu-toggle{display:none;}

.mobile-nav{
  display:none;
  flex-direction:column;
  background:var(--bg-raise);
  border-bottom:1px solid var(--line);
  padding:8px 28px 18px;
}
.mobile-nav a{padding:10px 0;color:var(--ink-dim);border-bottom:1px solid var(--line);}
.mobile-nav.open{display:flex;}

/* ===== Hero ===== */
.hero{
  position:relative;
  padding:168px 0 96px;
  overflow:hidden;
}
#vertex-canvas{
  position:absolute;
  inset:0;
  width:100%;height:100%;
  z-index:0;
  opacity:.85;
}
.hero-inner{position:relative;z-index:1;}
.hero h1{
  font-size:clamp(40px,6.4vw,76px);
  max-width:780px;
  color:var(--ink);
}
.hero h1 em{
  font-style:normal;
  color:var(--copper);
}
.hero-sub{
  max-width:560px;
  font-size:18px;
  margin-top:24px;
}
.hero-ctas{display:flex;gap:14px;margin-top:38px;flex-wrap:wrap;}
.hero-status{
  margin-top:56px;
  font-size:12.5px;
  color:var(--ink-dim);
  display:flex;align-items:center;gap:8px;
}
.dot{width:7px;height:7px;border-radius:50%;display:inline-block;}
.dot-live{background:var(--copper); box-shadow:0 0 0 0 rgba(255,138,61,.6); animation:pulse 2.4s infinite;}
@keyframes pulse{
  0%{box-shadow:0 0 0 0 rgba(255,138,61,.5);}
  70%{box-shadow:0 0 0 8px rgba(255,138,61,0);}
  100%{box-shadow:0 0 0 0 rgba(255,138,61,0);}
}

/* ===== Strip ===== */
.strip{
  border-top:1px solid var(--line);
  border-bottom:1px solid var(--line);
  padding:22px 0;
}
.strip-inner{
  display:flex;align-items:center;gap:18px;
  flex-wrap:wrap;
  font-family:var(--mono);
  font-size:13px;
  letter-spacing:.08em;
  color:var(--ink-dim);
}
.strip .sep{color:var(--line);}

/* ===== Systems ===== */
.systems{padding:120px 0;}
.system-grid{
  display:grid;
  grid-template-columns:repeat(2,1fr);
  gap:1px;
  background:var(--line);
  border:1px solid var(--line);
}
.system-card{
  background:var(--bg);
  padding:36px;
  position:relative;
}
.card-top{margin-bottom:16px;}
.card-index{
  display:block;
  font-size:12px;
  color:var(--violet);
  margin-bottom:10px;
  letter-spacing:.06em;
}
.system-card h3{font-size:22px;color:var(--ink);margin-bottom:4px;}
.system-card p{margin-top:14px;font-size:15px;}
.card-tags{
  list-style:none;
  display:flex;flex-wrap:wrap;gap:8px 14px;
  margin:20px 0 0;
  padding:0;
  font-size:11.5px;
  color:var(--ink-dim);
}
.card-tags li{
  border:1px solid var(--line);
  padding:4px 9px;
  border-radius:4px;
}

/* ===== Approach ===== */
.approach{padding:120px 0; background:var(--bg-raise); border-top:1px solid var(--line); border-bottom:1px solid var(--line);}
.approach-inner{
  display:grid;
  grid-template-columns:1.4fr .6fr;
  gap:64px;
}
.layer{
  padding:26px 0;
  border-top:1px solid var(--line);
}
.layer:last-child{border-bottom:1px solid var(--line);}
.layer-head{display:flex;align-items:baseline;gap:16px;margin-bottom:8px;flex-wrap:wrap;}
.layer-tag{font-size:12px;color:var(--copper);letter-spacing:.06em;}
.layer h3{font-size:19px;color:var(--ink);}
.layer p{max-width:480px;font-size:15px;}
.approach-graphic{display:flex;align-items:center;justify-content:center;}
.layer-svg{width:100%;max-width:200px;}
.layer-node{fill:var(--bg-raise);stroke:var(--violet);stroke-width:2;}

/* ===== Stack ===== */
.stack{padding:120px 0;}
.stack-grid{
  display:grid;
  grid-template-columns:repeat(4,1fr);
  gap:32px;
}
.stack-label{
  display:block;
  font-size:11.5px;
  letter-spacing:.1em;
  color:var(--copper);
  margin-bottom:10px;
}
.stack-col p{font-size:14px;color:var(--ink);line-height:1.7;}

/* ===== Contact ===== */
.contact{padding:120px 0 140px; border-top:1px solid var(--line);}
.contact-inner{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:64px;
}
.contact h2{font-size:clamp(28px,3.4vw,38px); margin-bottom:18px; color:var(--ink);}
.contact-meta{margin:40px 0 0; padding:0; display:flex; flex-direction:column; gap:14px;}
.contact-meta div{display:flex; gap:14px; font-size:14px;}
.contact-meta dt{color:var(--ink-dim); width:70px; flex-shrink:0;}
.contact-meta dd{margin:0; color:var(--ink);}
.contact-meta a:hover{color:var(--copper);}

.contact-form{display:flex; flex-direction:column; gap:18px;}
.field{display:flex; flex-direction:column; gap:8px;}
.field label{font-size:13px; color:var(--ink-dim);}
.field input, .field select, .field textarea{
  background:var(--bg-raise);
  border:1px solid var(--line);
  color:var(--ink);
  padding:12px 14px;
  border-radius:6px;
  font-family:var(--body);
  font-size:14.5px;
  resize:vertical;
}
.field input:focus, .field select:focus, .field textarea:focus{
  outline:none; border-color:var(--violet);
}
.form-submit{align-self:flex-start; margin-top:6px;}
.form-note{min-height:18px; font-size:12.5px; color:var(--violet);}

/* ===== Footer ===== */
.site-footer{border-top:1px solid var(--line); padding:40px 0;}
.footer-inner{
  display:flex; align-items:center; justify-content:space-between; flex-wrap:wrap; gap:16px;
}
.brand-small .brand-mark{width:18px;height:18px;}
.brand-small .brand-name{font-size:13px;}
.footer-line, .footer-copy{font-size:12px; color:var(--ink-dim);}

/* ===== Reduced motion ===== */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  .dot-live{animation:none;}
}

/* ===== Responsive ===== */
@media (max-width:920px){
  .approach-inner{grid-template-columns:1fr;}
  .approach-graphic{display:none;}
  .contact-inner{grid-template-columns:1fr;}
  .stack-grid{grid-template-columns:repeat(2,1fr);}
}
@media (max-width:720px){
  .main-nav, .nav-cta{display:none;}
  .menu-toggle{
    display:flex; flex-direction:column; justify-content:center; gap:5px;
    width:36px; height:36px; margin-left:auto;
    background:none; border:none; cursor:pointer;
  }
  .menu-toggle span{width:100%; height:2px; background:var(--ink); display:block;}
  .system-grid{grid-template-columns:1fr;}
  .stack-grid{grid-template-columns:1fr;}
  .hero{padding-top:140px;}
}

/* ===== FAQ ===== */
.faq { padding: 120px 0; background: var(--bg-raise); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.faq-grid { display: flex; flex-direction: column; gap: 0; }
.faq-item {
  border-top: 1px solid var(--line);
  padding: 0;
}
.faq-item:last-child { border-bottom: 1px solid var(--line); }
.faq-item summary {
  font-family: var(--display);
  font-size: 17px;
  font-weight: 500;
  color: var(--ink);
  padding: 22px 0;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: '+';
  font-size: 22px;
  color: var(--copper);
  flex-shrink: 0;
  transition: transform .2s ease;
  font-weight: 300;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item p {
  font-size: 15px;
  color: var(--ink-dim);
  padding-bottom: 22px;
  max-width: 680px;
  line-height: 1.7;
}