/* ===== Tokens ===== */
:root{
  --bg: #0A0E17;
  --bg-panel: #10182B;
  --bg-panel-raised: #161F38;
  --copper: #22D3EE;
  --copper-dim: #0E8FA3;
  --copper-soft: rgba(34,211,238,0.14);
  --signal: #7EF0DE;
  --text: #EAF0FA;
  --text-dim: #90A0BD;
  --line: #24304D;

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

  --rail-w: 88px;
  --maxw: 1160px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *{animation-duration:0.001ms !important; animation-iteration-count:1 !important; transition-duration:0.001ms !important;}
}

body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  font-family:var(--font-body);
  line-height:1.55;
  -webkit-font-smoothing:antialiased;
}

/* subtle PCB dot-grid on the whole page */
body::before{
  content:"";
  position:fixed;
  inset:0;
  background-image: radial-gradient(circle, rgba(234,240,250,0.045) 1px, transparent 1px);
  background-size: 26px 26px;
  pointer-events:none;
  z-index:0;
}

.wrap{
  max-width:var(--maxw);
  margin:0 auto;
  padding:0 28px;
  position:relative;
  z-index:1;
}

h1,h2,h3{
  font-family:var(--font-display);
  font-weight:600;
  margin:0 0 0.5em;
  letter-spacing:-0.01em;
}

p{margin:0 0 1em;color:var(--text-dim);}
a{color:inherit;}

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

/* ===== Buttons ===== */
.btn{
  display:inline-flex;
  align-items:center;
  gap:0.5em;
  font-family:var(--font-body);
  font-weight:600;
  font-size:0.95rem;
  padding:0.7em 1.3em;
  border-radius:8px;
  text-decoration:none;
  border:1px solid transparent;
  cursor:pointer;
  transition:transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
  white-space:nowrap;
}
.btn-copper{
  background:linear-gradient(180deg,#7FE6F5,var(--copper));
  color:#1A1206;
}
.btn-copper:hover{
  box-shadow:0 0 0 3px var(--copper-soft), 0 8px 24px -8px rgba(34,211,238,0.5);
  transform:translateY(-1px);
}
.btn-ghost{
  background:transparent;
  color:var(--text);
  border-color:var(--line);
}
.btn-ghost:hover{
  border-color:var(--copper-dim);
  color:var(--copper);
}
.btn-lg{padding:0.85em 1.6em; font-size:1rem;}

/* ===== Trace Rail (left circuit nav) ===== */
.trace-rail{
  position:fixed;
  top:0; left:0;
  width:var(--rail-w);
  height:100vh;
  z-index:50;
  display:flex;
  align-items:center;
  pointer-events:none;
}
.trace-line{
  position:absolute;
  left:0; top:0;
  width:100%; height:100%;
}
.trace-line path{
  fill:none;
  stroke:var(--line);
  stroke-width:2;
}
.trace-pulse{
  position:absolute;
  left:calc(var(--rail-w)/2 - 4px);
  top:6%;
  width:8px; height:8px;
  border-radius:50%;
  background:var(--copper);
  box-shadow:0 0 10px 2px var(--copper-soft);
  transition: top 0.35s cubic-bezier(.4,0,.2,1);
}
.trace-rail ul{
  list-style:none;
  margin:0; padding:0;
  width:100%;
  display:flex;
  flex-direction:column;
  justify-content:space-between;
  height:88%;
  pointer-events:auto;
}
.trace-node{
  position:relative;
  display:flex;
  align-items:center;
  gap:10px;
  text-decoration:none;
  padding:6px 0;
  color:var(--text-dim);
}
.node-dot{
  position:relative;
  left:calc(var(--rail-w)/2 - 4px - 28px);
  width:9px; height:9px;
  border-radius:50%;
  background:var(--bg-panel);
  border:2px solid var(--line);
  transition:border-color 0.2s, background 0.2s;
  flex-shrink:0;
  margin-left:0;
}
.trace-node .node-dot{ position:absolute; left:calc(var(--rail-w)/2 - 4px - 4.5px); }
.node-label{
  position:absolute;
  left:calc(var(--rail-w)/2 + 12px);
  font-family:var(--font-mono);
  font-size:0.68rem;
  letter-spacing:0.04em;
  text-transform:uppercase;
  white-space:nowrap;
  opacity:0;
  transform:translateX(-4px);
  transition:opacity 0.15s, transform 0.15s;
}
.trace-node:hover .node-label,
.trace-node:focus-visible .node-label{
  opacity:1;
  transform:translateX(0);
}
.trace-node.active .node-dot{
  border-color:var(--copper);
  background:var(--copper);
  box-shadow:0 0 8px 1px var(--copper-soft);
}
.trace-node.active{color:var(--copper);}
.trace-node.active .node-label{opacity:1; transform:translateX(0);}

@media (max-width:1000px){
  .trace-rail{display:none;}
}

/* ===== Header ===== */
.site-header{
  position:sticky;
  top:0;
  z-index:40;
  background:rgba(10,14,23,0.85);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.header-inner{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding-top:14px;
  padding-bottom:14px;
  padding-left:calc(28px + var(--rail-w));
}
@media (max-width:1000px){.header-inner{padding-left:28px;}}
.brand{
  display:flex;
  align-items:center;
  gap:10px;
  text-decoration:none;
  font-family:var(--font-display);
  font-weight:700;
  font-size:1.15rem;
  color:var(--text);
}
.brand-icon{border-radius:8px;}
.header-nav{display:flex; gap:28px;}
.header-nav a{
  text-decoration:none;
  color:var(--text-dim);
  font-size:0.92rem;
  font-weight:500;
  transition:color 0.15s;
}
.header-nav a:hover{color:var(--text);}
@media (max-width:760px){.header-nav{display:none;} .header-cta{font-size:0.85rem; padding:0.6em 1em;}}

/* ===== Hero ===== */
.hero{
  position:relative;
  padding:96px 0 64px;
  padding-left:var(--rail-w);
  overflow:hidden;
}
@media (max-width:1000px){.hero{padding-left:0;}}
.hero-bg{
  position:absolute;
  inset:0;
  background:
    radial-gradient(ellipse 60% 50% at 80% 0%, rgba(34,211,238,0.14), transparent 60%),
    radial-gradient(ellipse 40% 40% at 10% 80%, rgba(95,225,176,0.08), transparent 60%);
  z-index:0;
}
.hero-inner{
  display:grid;
  grid-template-columns:1.1fr 0.9fr;
  gap:56px;
  align-items:center;
}
@media (max-width:900px){
  .hero-inner{grid-template-columns:1fr; gap:48px;}
}
.eyebrow{
  font-family:var(--font-mono);
  font-size:0.72rem;
  letter-spacing:0.1em;
  color:var(--copper);
  margin-bottom:16px;
}
.hero h1{
  font-size:clamp(2.2rem, 4.2vw, 3.4rem);
  line-height:1.08;
  color:var(--text);
}
.hero-sub{
  font-size:1.08rem;
  max-width:480px;
}
.hero-actions{
  display:flex;
  gap:14px;
  flex-wrap:wrap;
  margin:28px 0 16px;
}
.hero-meta{
  font-family:var(--font-mono);
  font-size:0.78rem;
  color:var(--text-dim);
  opacity:0.8;
}

.hero-device{position:relative; display:flex; justify-content:center;}
.device-frame{
  position:relative;
  width:100%;
  max-width:380px;
  border-radius:20px;
  border:1px solid var(--line);
  background:var(--bg-panel);
  padding:10px;
  box-shadow:0 30px 60px -20px rgba(0,0,0,0.6);
}
.device-screen{
  width:100%;
  display:block;
  border-radius:12px;
}
.device-glow{
  position:absolute;
  width:70%; height:70%;
  top:15%; left:15%;
  background:radial-gradient(circle, var(--copper-soft), transparent 70%);
  filter:blur(30px);
  z-index:-1;
}

/* ===== Stats strip ===== */
.stats-strip{
  border-top:1px solid var(--line);
  border-bottom:1px solid var(--line);
  background:var(--bg-panel);
  padding:36px 0;
  padding-left:var(--rail-w);
}
@media (max-width:1000px){.stats-strip{padding-left:0;}}
.stats-grid{
  display:grid;
  grid-template-columns:repeat(4,1fr);
  gap:24px;
  text-align:center;
}
@media (max-width:700px){.stats-grid{grid-template-columns:repeat(2,1fr);}}
.stat-node{display:flex; flex-direction:column; gap:6px;}
.stat-value{
  font-family:var(--font-display);
  font-size:clamp(1.5rem,3vw,2.1rem);
  font-weight:700;
  color:var(--copper);
}
.stat-label{
  font-family:var(--font-mono);
  font-size:0.72rem;
  letter-spacing:0.03em;
  color:var(--text-dim);
  text-transform:uppercase;
}

/* ===== Section shared ===== */
section{padding:96px 0; padding-left:var(--rail-w);}
@media (max-width:1000px){section{padding-left:0;}}
.section-eyebrow{
  font-family:var(--font-mono);
  font-size:0.72rem;
  letter-spacing:0.1em;
  color:var(--signal);
  margin-bottom:14px;
}
.section-title{
  font-size:clamp(1.7rem,3vw,2.3rem);
  color:var(--text);
  max-width:640px;
}
.section-sub{max-width:560px; font-size:1.02rem;}

/* ===== Features ===== */
.feature-grid{
  display:grid;
  grid-template-columns:repeat(3,1fr);
  gap:20px;
  margin-top:40px;
}
@media (max-width:900px){.feature-grid{grid-template-columns:repeat(2,1fr);}}
@media (max-width:600px){.feature-grid{grid-template-columns:1fr;}}
.feature-card{
  background:var(--bg-panel);
  border:1px solid var(--line);
  border-radius:14px;
  padding:26px 24px;
  transition:border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}
.feature-card:hover{
  border-color:var(--copper-dim);
  transform:translateY(-3px);
  box-shadow:0 16px 32px -20px rgba(34,211,238,0.35);
}
.feature-card--muted{opacity:0.85;}
.feature-icon{
  color:var(--copper);
  margin-bottom:16px;
  width:44px;
  height:22px;
}
.feature-card h3{font-size:1.08rem; color:var(--text);}
.feature-card p{font-size:0.94rem; margin:0;}

/* ===== Formulas ===== */
.formulas{background:var(--bg-panel);}
.formula-rail{
  display:flex;
  gap:16px;
  overflow-x:auto;
  padding:36px 0 12px;
  margin:0 -4px;
  scrollbar-width:thin;
}
.formula-chip{
  flex:0 0 auto;
  min-width:200px;
  background:var(--bg-panel-raised);
  border:1px solid var(--line);
  border-radius:12px;
  padding:20px;
  display:flex;
  flex-direction:column;
  gap:8px;
}
.f-topic{
  font-family:var(--font-mono);
  font-size:0.66rem;
  letter-spacing:0.06em;
  text-transform:uppercase;
  color:var(--signal);
}
.f-eq{
  font-family:var(--font-mono);
  font-size:1.15rem;
  color:var(--copper);
  font-weight:500;
}
.f-name{font-size:0.85rem; color:var(--text-dim);}
.formula-note{margin-top:20px; font-size:0.9rem;}

/* ===== Screenshots ===== */
.screens-rail{
  display:flex;
  gap:18px;
  overflow-x:auto;
  padding:20px 28px 20px calc(28px + var(--rail-w));
  scroll-snap-type:x mandatory;
}
@media (max-width:1000px){.screens-rail{padding-left:28px;}}
.screens-rail img{
  scroll-snap-align:start;
  height:380px;
  border-radius:16px;
  border:1px solid var(--line);
  flex:0 0 auto;
}

/* ===== About ===== */
.about-grid{
  display:grid;
  grid-template-columns:1.3fr 1fr;
  gap:48px;
  align-items:start;
}
@media (max-width:900px){.about-grid{grid-template-columns:1fr;}}
.about-list{
  list-style:none;
  padding:0;
  margin:20px 0 0;
  display:flex;
  flex-direction:column;
  gap:10px;
  font-family:var(--font-mono);
  font-size:0.85rem;
  color:var(--text-dim);
}
.about-list strong{color:var(--text); font-weight:500;}
.about-card{
  background:var(--bg-panel);
  border:1px solid var(--line);
  border-radius:14px;
  padding:28px;
}
.about-card h3{
  font-family:var(--font-mono);
  font-size:0.75rem;
  letter-spacing:0.08em;
  text-transform:uppercase;
  color:var(--signal);
  margin-bottom:16px;
}
.dev-name{color:var(--text); font-weight:600; margin-bottom:2px;}
.dev-role{font-size:0.88rem; margin-bottom:10px;}
.dev-badge{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:0.72rem;
  letter-spacing:0.06em;
  text-transform:uppercase;
  color:var(--bg);
  background:var(--signal);
  padding:4px 10px;
  border-radius:100px;
  margin-bottom:20px;
}
.about-links{display:flex; flex-direction:column; gap:10px;}
.about-links a{
  text-decoration:none;
  color:var(--copper);
  font-size:0.9rem;
}
.about-links a:hover{text-decoration:underline;}

/* ===== FAQ ===== */
.faq-list{
  margin-top:32px;
  display:flex;
  flex-direction:column;
  gap:10px;
  max-width:720px;
}
.faq-item{
  background:var(--bg-panel);
  border:1px solid var(--line);
  border-radius:10px;
  padding:6px 20px;
}
.faq-item summary{
  cursor:pointer;
  padding:14px 0;
  font-weight:600;
  color:var(--text);
  list-style:none;
  display:flex;
  justify-content:space-between;
  align-items:center;
}
.faq-item summary::-webkit-details-marker{display:none;}
.faq-item summary::after{
  content:"+";
  font-family:var(--font-mono);
  color:var(--copper);
  font-size:1.2rem;
  margin-left:12px;
}
.faq-item[open] summary::after{content:"–";}
.faq-item p{padding-bottom:16px; margin:0;}
.faq-item a{color:var(--copper); text-decoration:underline;}

/* ===== Download CTA ===== */
.download-cta{
  background:linear-gradient(180deg, var(--bg-panel), var(--bg));
  border-top:1px solid var(--line);
  text-align:center;
}
.download-inner h2{font-size:clamp(1.8rem,3.4vw,2.6rem);}
.download-inner p{max-width:480px; margin:0 auto 28px;}

/* ===== Footer ===== */
.site-footer{
  border-top:1px solid var(--line);
  padding:36px 0;
  padding-left:var(--rail-w);
}
@media (max-width:1000px){.site-footer{padding-left:0;}}
.footer-inner{
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:16px;
}
.footer-brand{
  display:flex;
  align-items:center;
  gap:10px;
  font-family:var(--font-display);
  font-weight:600;
  font-size:0.95rem;
}
.footer-brand img{border-radius:6px;}
.footer-links{display:flex; gap:20px; flex-wrap:wrap;}
.footer-links a{
  text-decoration:none;
  color:var(--text-dim);
  font-size:0.86rem;
}
.footer-links a:hover{color:var(--copper);}
.footer-copy{
  width:100%;
  font-size:0.78rem;
  color:var(--text-dim);
  opacity:0.7;
  margin:0;
}