:root{
  --bg:#07070b;
  --panel:#101119;
  --panel-2:#151722;
  --text:#f7f8fb;
  --muted:#a6aebb;
  --muted-2:#737d90;
  --line:rgba(255,255,255,.09);
  --accent:#d84c3d;
  --accent-2:#ff7c70;
  --max:1440px;
  --font:'Inter',system-ui,sans-serif;
  --ease:cubic-bezier(.22,1,.36,1);
}

*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:var(--font);
  background:
    radial-gradient(circle at 12% 10%, rgba(216,76,61,.18), transparent 26%),
    radial-gradient(circle at 100% 18%, rgba(48,77,255,.15), transparent 30%),
    radial-gradient(circle at 50% 100%, rgba(216,76,61,.06), transparent 28%),
    linear-gradient(180deg,#07070b 0%,#08090d 55%,#07070b 100%);
  color:var(--text);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
  overflow-x:hidden;
}

body:before{
  content:"";
  position:fixed;
  inset:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(255,255,255,.016) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.016) 1px, transparent 1px);
  background-size:64px 64px;
  opacity:.18;
  z-index:0;
}

body:after{
  content:"";
  position:fixed;
  inset:-20%;
  pointer-events:none;
  background:
    radial-gradient(circle at 20% 20%, rgba(216,76,61,.08), transparent 22%),
    radial-gradient(circle at 80% 30%, rgba(64,92,255,.08), transparent 24%);
  filter:blur(40px);
  animation:bgFloat 12s var(--ease) infinite alternate;
  z-index:0;
}

@keyframes bgFloat{
  from{transform:translate3d(0,0,0) scale(1)}
  to{transform:translate3d(0,-18px,0) scale(1.03)}
}

a{text-decoration:none;color:inherit}
img{max-width:100%;display:block}
::selection{background:rgba(216,76,61,.28)}

.shell{
  position:relative;
  z-index:1;
  max-width:var(--max);
  margin:0 auto;
  padding:0 24px;
}

header{
  position:sticky;
  top:0;
  z-index:60;
  backdrop-filter:blur(18px);
  background:rgba(7,7,11,.72);
  border-bottom:1px solid rgba(255,255,255,.05);
}

.header-inner{
  max-width:1440px;
  margin:0 auto;
  padding:16px 24px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:20px;
}

.brand,.header-right,.lang-switch,.hero-actions,.footer-links,.lesson-tags{
  display:flex;
  align-items:center;
}

.brand{gap:12px;min-width:0}
.brand img{width:42px;height:42px;object-fit:contain;flex-shrink:0}
.brand strong{font-size:1rem;font-weight:800;letter-spacing:-.03em}
.header-right{gap:10px}
.lang-switch{gap:6px}

.lang-switch a,.header-cta,.menu-button,.btn-primary,.btn-secondary{
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:999px;
  border:1px solid rgba(255,255,255,.09);
  font-weight:800;
  transition:.22s var(--ease);
}

.lang-switch a{height:38px;min-width:38px;padding:0 12px;color:var(--muted);font-size:.76rem;background:rgba(255,255,255,.03)}
.lang-switch a.active,.lang-switch a:hover{color:#fff;background:rgba(216,76,61,.18);border-color:rgba(216,76,61,.34)}
.header-cta{height:40px;padding:0 16px;background:rgba(216,76,61,.16);color:#fff;font-size:.8rem}
.header-cta:hover{transform:translateY(-1px);background:rgba(216,76,61,.24)}
.menu-button{width:40px;height:40px;background:rgba(255,255,255,.04);color:#fff;cursor:pointer;font-size:1.05rem}
.menu-button:hover{background:rgba(255,255,255,.08)}

.menu-overlay{
  position:fixed;
  inset:0;
  background:rgba(0,0,0,.54);
  opacity:0;
  pointer-events:none;
  transition:.25s var(--ease);
  z-index:70;
}

.menu-overlay.visible{opacity:1;pointer-events:auto}
.sidebar{
  position:fixed;
  top:0;
  right:-390px;
  width:min(390px,92vw);
  height:100vh;
  background:rgba(12,13,18,.96);
  backdrop-filter:blur(24px);
  border-left:1px solid rgba(255,255,255,.08);
  z-index:80;
  padding:28px;
  display:flex;
  flex-direction:column;
  gap:10px;
  transition:.3s var(--ease);
  overflow-y:auto;
}
.sidebar.open{right:0}
.sidebar-close{
  align-self:flex-end;
  width:42px;
  height:42px;
  border-radius:50%;
  border:1px solid rgba(255,255,255,.1);
  background:rgba(255,255,255,.05);
  color:#fff;
  cursor:pointer;
  font-size:1.1rem;
}
.sidebar a{
  padding:13px 14px;
  border-radius:14px;
  color:var(--muted);
  font-weight:750;
  border:1px solid transparent;
}
.sidebar a:hover,.sidebar a.active{
  color:#fff;
  background:rgba(255,255,255,.06);
  border-color:rgba(255,255,255,.08);
}
.sidebar .sidebar-pricing{background:rgba(216,76,61,.15);color:#fff}
.sidebar .sidebar-webapp{background:#fff;color:#08090d;text-align:center}

.hero{padding:112px 0 56px}
.breadcrumb{
  color:var(--muted-2);
  font-size:.82rem;
  font-weight:750;
  margin-bottom:26px;
}
.breadcrumb a{color:var(--muted)}
.breadcrumb a:hover{color:#fff}
.eyebrow{
  display:inline-flex;
  margin-bottom:16px;
  color:var(--accent-2);
  font-size:.78rem;
  font-weight:900;
  letter-spacing:.1em;
  text-transform:uppercase;
}
h1{
  max-width:1080px;
  font-size:clamp(2.6rem,6vw,5.8rem);
  line-height:.94;
  letter-spacing:-.06em;
}
.accent{color:var(--accent)}
.hero-copy{
  max-width:850px;
  margin-top:24px;
  color:#d8dce5;
  font-size:clamp(1.04rem,1.8vw,1.3rem);
  line-height:1.7;
}
.hero-actions{gap:12px;flex-wrap:wrap;margin-top:32px}
.btn-primary,.btn-secondary{height:48px;padding:0 20px;font-size:.9rem}
.btn-primary{background:linear-gradient(135deg,var(--accent),var(--accent-2));color:#fff;border-color:transparent}
.btn-secondary{background:rgba(255,255,255,.04);color:#fff}
.btn-primary:hover,.btn-secondary:hover{transform:translateY(-2px)}
.lesson-tags{gap:8px;flex-wrap:wrap;margin-top:28px}
.lesson-tags span{
  padding:8px 10px;
  border:1px solid rgba(255,255,255,.09);
  border-radius:999px;
  color:var(--muted);
  background:rgba(255,255,255,.035);
  font-size:.78rem;
  font-weight:750;
}

.article-shell{
  display:grid;
  grid-template-columns:300px minmax(0,1fr);
  gap:34px;
  padding:34px 0 96px;
}
.lesson-nav{
  position:sticky;
  top:92px;
  align-self:start;
  border:1px solid var(--line);
  background:linear-gradient(180deg, rgba(255,255,255,.045), rgba(255,255,255,.022));
  border-radius:22px;
  padding:20px;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.03);
}
.lesson-nav strong{display:block;margin-bottom:10px;font-size:.9rem}
.lesson-nav a{
  display:block;
  padding:9px 0;
  color:var(--muted);
  font-size:.9rem;
  line-height:1.35;
  border-top:1px solid rgba(255,255,255,.06);
}
.lesson-nav a:hover{color:#fff}
.lesson-content{
  border:1px solid var(--line);
  background:linear-gradient(180deg,rgba(255,255,255,.055),rgba(255,255,255,.026));
  border-radius:24px;
  padding:38px;
  box-shadow:inset 0 1px 0 rgba(255,255,255,.03);
}
.lesson-content section + section{margin-top:38px;padding-top:34px;border-top:1px solid rgba(255,255,255,.08)}
.lesson-content h2{font-size:clamp(1.6rem,3vw,2.35rem);line-height:1.08;letter-spacing:-.04em;margin-bottom:16px}
.lesson-content h3{font-size:1.1rem;margin:24px 0 8px}
.lesson-content p,.lesson-content li{color:#c9ced8;font-size:1rem;line-height:1.78}
.lesson-content p + p{margin-top:14px}
.lesson-content ul,.lesson-content ol{padding-left:21px;margin-top:14px}
.callout{
  margin-top:22px;
  padding:18px;
  border:1px solid rgba(216,76,61,.24);
  background:rgba(216,76,61,.09);
  border-radius:18px;
}
.callout strong{display:block;margin-bottom:6px}
.next-grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:14px;
  margin-top:24px;
}
.next-card{
  padding:18px;
  border:1px solid var(--line);
  border-radius:20px;
  background:rgba(255,255,255,.04);
}
.next-card span{display:block;color:var(--muted-2);font-size:.74rem;font-weight:900;text-transform:uppercase;letter-spacing:.08em;margin-bottom:8px}
.next-card strong{display:block;font-size:1.02rem}
.next-card p{margin-top:7px;color:var(--muted);font-size:.92rem;line-height:1.55}
.next-card:hover{border-color:rgba(216,76,61,.35);background:rgba(216,76,61,.08)}

footer{
  position:relative;
  z-index:1;
  border-top:1px solid rgba(255,255,255,.08);
  padding:26px 0;
  color:var(--muted-2);
}
.footer-inner{
  max-width:1440px;
  margin:0 auto;
  padding:0 24px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:18px;
}
.footer-links{gap:14px;flex-wrap:wrap}
.footer-links a:hover{color:#fff}

@media (max-width:900px){
  .article-shell{grid-template-columns:1fr}
  .lesson-nav{position:relative;top:auto}
}

@media (max-width:620px){
  .shell,.header-inner,.footer-inner{padding-left:18px;padding-right:18px}
  .brand strong{font-size:.92rem}
  .brand img{width:38px;height:38px}
  .header-cta{display:none}
  .hero{padding-top:58px}
  .btn-primary,.btn-secondary{width:100%}
  .lesson-content{padding:22px;border-radius:20px}
  .next-grid{grid-template-columns:1fr}
  .footer-inner{align-items:flex-start;flex-direction:column}
}