:root{
  --serpen-slope:#131719;
  --serpen-slope-2:#1b2124;
  --serpen-slope-3:#232a2e;
  --serpen-mark:#d4813f;
  --serpen-mark-soft:rgba(212,129,63,.16);
  --serpen-fog:#e2e7e9;
  --serpen-fog-dim:#a8b3b8;
  --serpen-line:rgba(226,231,233,.14);
  --serpen-rad:14px;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{
  margin:0;
  background:
    radial-gradient(1100px 600px at 78% -8%,rgba(212,129,63,.13),transparent 62%),
    linear-gradient(180deg,#101416 0%,var(--serpen-slope) 42%,#0e1214 100%);
  color:var(--serpen-fog);
  font-family:"Sarabun",-apple-system,"Segoe UI",Roboto,Arial,sans-serif;
  font-weight:300;
  font-size:17px;
  line-height:1.68;
}
h1,h2,h3,.serpen-num,.serpen-logo-word{font-family:"Arvo",Georgia,"Times New Roman",serif;font-weight:700;letter-spacing:-.01em}
h1{font-size:clamp(28px,4.4vw,45px);line-height:1.2;margin:.15em 0 .45em}
h2{font-size:clamp(23px,3vw,32px);line-height:1.26;margin:0 0 .55em}
h3{font-size:clamp(17px,2vw,20px);line-height:1.32;margin:0 0 .4em;color:#f2f5f6}
p{margin:0 0 1em}
a{color:var(--serpen-mark)}

/* --- шапка --- */
.serpen-top{
  position:sticky;top:0;z-index:20;
  display:flex;align-items:center;gap:20px;
  padding:12px clamp(16px,4vw,56px);
  background:rgba(16,20,22,.9);
  backdrop-filter:blur(9px);
  border-bottom:1px solid var(--serpen-line);
}
.serpen-logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--serpen-fog);min-height:44px}
.serpen-logo-word{font-size:21px;letter-spacing:.02em}
.serpen-logo-tail{color:var(--serpen-mark);margin-left:5px;font-size:15px;letter-spacing:.16em;text-transform:uppercase}
.serpen-nav{display:flex;gap:6px;margin-left:auto;flex-wrap:wrap}
.serpen-nav a{
  display:inline-flex;align-items:center;min-height:44px;padding:0 13px;
  border-radius:9px;text-decoration:none;color:var(--serpen-fog-dim);font-size:15px;
}
.serpen-nav a:hover{color:var(--serpen-fog);background:var(--serpen-mark-soft)}

/* --- кнопка --- */
.serpen-cta{
  display:inline-flex;align-items:center;justify-content:center;
  min-height:54px;padding:14px 30px;
  border-radius:999px;
  background:linear-gradient(135deg,var(--serpen-mark),#b96a2c);
  color:#151011;font-family:"Arvo",Georgia,serif;font-weight:700;font-size:17px;
  text-decoration:none;text-align:center;
  box-shadow:0 12px 30px rgba(212,129,63,.24);
}
.serpen-cta:hover{filter:brightness(1.07)}
.serpen-cta-sm{min-height:44px;padding:10px 18px;font-size:15px;box-shadow:none;white-space:nowrap}

/* --- сетка секций --- */
main{max-width:1140px;margin:0 auto;padding:0 clamp(16px,4vw,40px)}
section{padding:clamp(44px,6vw,74px) 0;border-bottom:1px solid var(--serpen-line)}
section:last-child{border-bottom:0}

.serpen-kicker{
  display:inline-block;margin:0 0 14px;padding:6px 14px;
  border:1px solid var(--serpen-mark);border-radius:999px;
  color:var(--serpen-mark);font-size:13px;letter-spacing:.12em;text-transform:uppercase;
}
.serpen-lead{font-size:clamp(17px,2.1vw,20px);max-width:64ch;color:#dfe5e7}
.serpen-sub{max-width:74ch;color:var(--serpen-fog-dim)}
.serpen-note{max-width:88ch;font-size:15.5px;color:var(--serpen-fog-dim);margin-top:18px}

.serpen-kpi{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:30px 0 20px}
.serpen-kpi-cell{
  padding:20px 18px;border-radius:var(--serpen-rad);
  background:linear-gradient(160deg,var(--serpen-slope-2),var(--serpen-slope-3));
  border:1px solid var(--serpen-line);border-left:3px solid var(--serpen-mark);
}
.serpen-num{display:block;font-size:clamp(21px,2.6vw,28px);color:#fff}
.serpen-cap{display:block;margin-top:5px;font-size:14.5px;color:var(--serpen-fog-dim)}

.serpen-strip{display:flex;flex-wrap:wrap;gap:9px;margin-bottom:28px}
.serpen-strip span{
  padding:8px 15px;border-radius:999px;font-size:14.5px;
  background:var(--serpen-mark-soft);border:1px solid rgba(212,129,63,.32);color:#f0d9c4;
}

.serpen-grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}
.serpen-grid4{display:grid;grid-template-columns:repeat(4,1fr);gap:18px}
.serpen-cat{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:24px}

.serpen-card,.serpen-slot,.serpen-review{
  padding:22px 20px;border-radius:var(--serpen-rad);
  background:var(--serpen-slope-2);border:1px solid var(--serpen-line);
}
.serpen-card p,.serpen-slot p,.serpen-review p{margin:0}
.serpen-card p{font-size:15.5px;color:var(--serpen-fog-dim)}
.serpen-slot p{font-size:14.5px;color:var(--serpen-fog-dim)}
.serpen-step{
  display:inline-block;margin-bottom:9px;padding:4px 11px;border-radius:7px;
  background:var(--serpen-mark-soft);color:var(--serpen-mark);
  font-size:12.5px;letter-spacing:.1em;text-transform:uppercase;
}
.serpen-slot h3{font-size:17px;color:var(--serpen-mark)}

.serpen-terms{margin:22px 0 0;padding:0;list-style:none;max-width:80ch}
.serpen-terms li{position:relative;padding-left:24px;margin-bottom:9px;font-size:15.5px;color:var(--serpen-fog-dim)}
.serpen-terms li::before{content:"";position:absolute;left:2px;top:11px;width:9px;height:9px;border-radius:50%;background:var(--serpen-mark)}

.serpen-tablewrap{overflow-x:auto;-webkit-overflow-scrolling:touch;margin-top:22px;border-radius:var(--serpen-rad);border:1px solid var(--serpen-line)}
.serpen-table{width:100%;min-width:640px;border-collapse:collapse;font-size:15.5px}
.serpen-table th{
  text-align:left;padding:14px 16px;background:var(--serpen-slope-3);
  font-family:"Arvo",Georgia,serif;font-size:14px;letter-spacing:.03em;color:#fff;
}
.serpen-table td{padding:13px 16px;border-top:1px solid var(--serpen-line);color:var(--serpen-fog-dim)}
.serpen-table tbody tr:nth-child(odd){background:rgba(226,231,233,.03)}
.serpen-table td:first-child{color:#f2f5f6}

.serpen-review{border-left:3px solid var(--serpen-mark)}
.serpen-quote{font-size:15.5px;color:#dfe5e7}
.serpen-who{margin-top:12px !important;font-size:14px;color:var(--serpen-mark)}

.serpen-final{text-align:center}
.serpen-final .serpen-lead{margin:0 auto 26px}

.serpen-faq details{
  border:1px solid var(--serpen-line);border-radius:var(--serpen-rad);
  background:var(--serpen-slope-2);margin-bottom:10px;
}
.serpen-faq summary{
  cursor:pointer;list-style:none;padding:16px 46px 16px 20px;position:relative;
  min-height:44px;font-family:"Arvo",Georgia,serif;font-size:16px;color:#f2f5f6;
}
.serpen-faq summary::-webkit-details-marker{display:none}
.serpen-faq summary::after{
  content:"+";position:absolute;right:20px;top:50%;transform:translateY(-50%);
  color:var(--serpen-mark);font-size:22px;line-height:1;
}
.serpen-faq details[open] summary::after{content:"\2013"}
.serpen-faq details p{margin:0;padding:0 20px 18px;font-size:15.5px;color:var(--serpen-fog-dim)}

.serpen-author-note{max-width:82ch;font-size:15.5px;color:var(--serpen-fog-dim)}
.serpen-age{
  max-width:82ch;margin-top:18px;padding:18px 20px;border-radius:var(--serpen-rad);
  background:rgba(212,129,63,.09);border:1px solid rgba(212,129,63,.28);
  font-size:14.5px;color:#e8d5c3;
}

.serpen-foot{
  padding:30px clamp(16px,4vw,56px) 46px;
  border-top:1px solid var(--serpen-line);
  font-size:14px;color:var(--serpen-fog-dim);
  max-width:1140px;margin:0 auto;
}
.serpen-foot p{margin:0 0 8px}
.serpen-foot-dim{color:#7d888d}

@media (max-width:1000px){
  .serpen-kpi{grid-template-columns:repeat(2,1fr)}
  .serpen-grid4{grid-template-columns:repeat(2,1fr)}
  .serpen-grid3,.serpen-cat{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:620px){
  body{font-size:16.5px}
  .serpen-top{flex-wrap:wrap;gap:10px;padding:10px 16px}
  .serpen-nav{margin-left:0;order:3;width:100%}
  .serpen-cta-sm{margin-left:auto}
  .serpen-kpi,.serpen-grid4,.serpen-grid3,.serpen-cat{grid-template-columns:1fr}
  .serpen-cta{width:100%}
  section{padding:38px 0}
}