:root{
  --bg1:#0d47a1;
  --bg2:#5b2be0;
  --bg3:#7b1fa2;
  --bg4:#00bcd4;
  --card: rgba(255,255,255,0.10);
  --card-border: rgba(255,255,255,0.25);
  --white:#fff;
  --muted: rgba(255,255,255,0.8);
  --accent:#ffd166; /* тёплый акцент для контраста с фоном */
  --link:#e3f2fd;
  --link-contrast:#ffd166;
}
*{box-sizing:border-box}
html,body{
  margin:0;
  font-family: "Segoe UI", Arial, sans-serif;
  color: var(--white);
  /* Fallback: плавный двухцветный градиент */
  background: linear-gradient(120deg, #1337a3 0%, #00b7ff 100%);
  background-attachment: fixed;
  background-repeat: no-repeat;
  background-size: 100% 100%;
  overflow-x:hidden;
}
body{
  margin:0;
  font-family: "Segoe UI", Arial, sans-serif;
  color: var(--white);
  background: linear-gradient(135deg, var(--bg1) 0%, var(--bg2) 40%, var(--bg3) 70%, var(--bg4) 100%);
  overflow-x:hidden;
}
/* сияние-аўрора поверх фона */
body::before{
  content:"";
  position:fixed; inset:-20% -10% -10% -10%;
  background:
    radial-gradient(50% 40% at 20% 10%, rgba(0,231,255,.25) 0%, rgba(0,0,0,0) 60%),
    radial-gradient(35% 45% at 80% 0%, rgba(255,0,200,.18) 0%, rgba(0,0,0,0) 60%);
  filter: blur(30px);
  pointer-events:none;
  z-index:0;
}

#snow{position:fixed; inset:0; pointer-events:none; z-index:2}
.snowflake{position:absolute; top:-10px; animation:fall var(--fall) linear infinite}
.snowflake .inner{display:block; width:var(--size); height:var(--size); 
  background-image:url('assets/snowflake.svg'); background-size:contain; background-repeat:no-repeat; 
  opacity:var(--opacity); animation:sway var(--sway) ease-in-out infinite}

@keyframes fall{to{transform:translateY(110vh)}}
@keyframes sway{0%,100%{transform:translateX(0)}50%{transform:translateX(var(--sway-x))}}

.container{max-width:1200px;margin:0 auto;padding:30px 60px; position:relative; z-index:5}
.site-header{
  position:relative; z-index:10;
  display:flex;align-items:center;justify-content:space-between;
  padding:38px 60px; /* увеличили */
  border-bottom:1px solid var(--card-border);
  background: linear-gradient(135deg, rgba(255,255,255,0.08), rgba(255,255,255,0.02));
  backdrop-filter: blur(4px);
}
.brand{display:flex;align-items:center;gap:22px}
.logo{width:260px;height:auto} /* увеличили логотип */
.brand-name{font-size:28px;font-weight:800;letter-spacing:.2px}
.brand-tagline{font-size:15px;color:var(--muted)}
.nav a{color:#fff;text-decoration:none;margin-left:18px;font-weight:700;border-bottom:2px solid transparent;padding-bottom:6px}
.nav a:hover{border-color:var(--accent)}

.card{background:var(--card);border:1px solid var(--card-border);border-radius:16px;padding:28px;margin:28px 0; backdrop-filter: blur(2px)}
h2{margin:0 0 16px 0;font-size:24px}
.key-facts{display:flex;gap:12px;margin-top:12px}
.fact{background:rgba(0,0,0,0.35);padding:10px 11px;border-radius:10px;border:1px solid var(--card-border);font-weight:700}

.services-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px;margin-top:10px}
.service{background:rgba(0,0,0,0.35);padding:16px;border-radius:12px;border:1px solid var(--card-border)}

.cert-table{width:100%;border-collapse:collapse}
.cert-table th,.cert-table td{border:1px solid var(--card-border);padding:12px 14px;text-align:left}
.cert-table thead th{background:rgba(255,255,255,0.15)}

.cert-photos{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin-top:16px}
.cert-photo{background:rgba(0,0,0,0.35);border:1px solid var(--card-border);border-radius:12px;padding:10px;text-align:center}
.cert-photo img{width:100%;height:425px;object-fit:cover;border-radius:8px;border:1px solid var(--card-border)}
.hint{margin-top:10px;color:var(--muted);font-size:13px}

.resume-grid{display:grid;grid-template-columns:1fr 1fr;gap:26px}
.mt{margin-top:16px}
.bullets{margin:8px 0 0 18px}
.bullets li{margin:6px 0}

.contacts{display:grid;grid-template-columns:1fr 1fr;gap:18px}
.contact{display:flex;gap:12px;background:rgba(0,0,0,0.35);border:1px solid var(--card-border);border-radius:12px;padding:14px}
.icon{width:32px;height:32px}
.label{font-size:12px;color:var(--muted)}
a{color:var(--link);}
a:hover{color:#fff;text-decoration:underline}
.link-contrast{color:var(--link-contrast)}
.link-contrast:hover{color:#fff;text-decoration:underline wavy}

.books-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.book-card{display:block;background:rgba(0,0,0,0.35);border:1px solid var(--card-border);border-radius:12px;overflow:hidden;text-decoration:none;color:#fff}
.book-card img{width:100%;height:220px;object-fit:cover}
.book-title{padding:10px;font-weight:700}
.reader iframe{border:none;border-radius:10px;border:1px solid var(--card-border)}

.btn{display:inline-block;padding:10px 16px;background:var(--accent);color:#003049;text-decoration:none;font-weight:800;border-radius:10px}
.btn:hover{filter:brightness(0.95)}

.site-footer{padding:24px 60px;text-align:center;border-top:1px solid var(--card-border);background:rgba(255,255,255,0.06)}
.site-footer .footer-links{margin-top:8px}
.site-footer .footer-links a{color:var(--link-contrast);text-decoration:none;margin:0 10px;font-weight:700}
.site-footer .footer-links a:hover{text-decoration:underline}



/* Ultra-smooth gradient (new browsers) */
@supports (background: linear-gradient(in oklch, red, blue)) {
  body{
    background: linear-gradient(
      in oklch 120deg,
      oklch(44% 0.12 265) 0%,
      oklch(56% 0.08 250) 50%,
      oklch(72% 0.08 230) 100%
    );
    background-attachment: fixed;
    background-repeat: no-repeat;
    background-size: 100% 100%;
  }
}

/* Dithering/noise overlay to убрать бэндинг без картинок (inline SVG) */
body::after{
  content:"";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: .035; /* достаточно, чтобы скрыть полосы */
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='120' height='120'><filter id='n'><feTurbulence type='fractalNoise' baseFrequency='0.8' numOctaves='4' stitchTiles='stitch'/></filter><rect width='100%%' height='100%%' filter='url(%%23n)'/></svg>");
  background-size: 120px 120px;
}



/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .services-grid{grid-template-columns:repeat(2,1fr)}
  .books-grid{grid-template-columns:repeat(2,1fr)}
  .resume-grid{grid-template-columns:1fr}
}

@media (max-width: 768px) {
  header{padding:20px 10px;flex-direction:column;align-items:flex-start}
  .logo{width:160px}
  .brand-name{font-size:22px}
  .brand-tagline{font-size:14px}
  .services-grid{grid-template-columns:1fr}
  .books-grid{grid-template-columns:1fr}
  .contacts{grid-template-columns:1fr}
  .container{padding:20px}
  footer{padding:20px 10px;text-align:center}
  footer .footer-links{display:flex;flex-direction:column;gap:10px}
}

@media (max-width: 480px) {
  .logo{width:120px}
  .brand-name{font-size:18px}
  .brand-tagline{font-size:12px}
  h2{font-size:20px}
  .cert-photos{grid-template-columns:1fr}
  .cert-table,.cert-table tr,.cert-table td,.cert-table th{display:block;width:100%}
  .cert-table td,.cert-table th{padding:8px 0;border:none;border-bottom:1px solid rgba(255,255,255,0.3)}
  .books-grid{grid-template-columns:1fr}
  .book-card img{height:160px}
  footer .footer-links a{font-size:14px}
}