/* =====================================================
   pershukov.com — design system "bright" (v6)
   White bg, 1.5px ink borders, blue/coral/lime/violet
   ===================================================== */
:root{
  --white:#ffffff;
  --ink:#111111;
  --gray:#444444;
  --muted:#767676;
  --hairline:#eeeeee;
  --paper:#f7f7f7;
  --blue:#2B4CFF;
  --coral:#FF5C38;
  --lime:#D4F23A;
  --violet:#7C3AED;
  --font:'Archivo','Helvetica Neue',Helvetica,Arial,'Segoe UI',sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,'Liberation Mono',monospace;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{
  font-family:var(--font);
  font-size:16px;
  line-height:1.6;
  color:var(--ink);
  background:var(--white);
  -webkit-font-smoothing:antialiased;
}
::selection{background:var(--lime);color:var(--ink)}
a{color:var(--blue)}
a:focus-visible,button:focus-visible{outline:3px solid var(--blue);outline-offset:3px;border-radius:2px}
img,svg{display:block}
ul{list-style:none}
.container{max-width:1120px;margin-inline:auto;padding-inline:24px}
section[id]{scroll-margin-top:88px}

/* ---------- fixed image backdrop ---------- */
.bg-image{
  position:fixed;inset:0;z-index:-2;
  background:url('/assets/v6-background.png') center/cover no-repeat;
  pointer-events:none;
}
.bg-veil{
  position:fixed;inset:0;z-index:-1;
  background:rgba(255,255,255,.68);
  pointer-events:none;
}

/* ---------- skip link ---------- */
.skip-link{
  position:absolute;left:16px;top:-48px;z-index:100;
  background:var(--blue);color:var(--white);
  font-weight:700;font-size:14px;padding:10px 18px;border-radius:6px;
  text-decoration:none;transition:top .2s ease;
}
.skip-link:focus-visible{top:12px}

/* ---------- header / nav ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:var(--white);
  border-bottom:1.5px solid var(--ink);
}
.nav{display:flex;align-items:center;justify-content:space-between;height:68px}
.nav>nav{display:contents}
.logo{
  font-weight:800;font-size:18px;letter-spacing:-0.02em;
  color:var(--ink);text-decoration:none;
}
.logo .logo-name{
  background:var(--lime);
  padding:3px 7px;border-radius:4px;
  transition:background-color .25s ease;
}
.logo .logo-tld{
  color:var(--gray);
  padding:3px 7px;border-radius:4px;
  transition:background-color .25s ease,color .25s ease;
}
.logo:hover .logo-name{background:transparent}
.logo:hover .logo-tld{background:var(--blue);color:var(--white)}
.nav-links{display:flex;align-items:center;gap:28px}
.nav-links a{
  color:var(--ink);text-decoration:none;
  font-weight:600;font-size:15px;
  transition:color .2s ease;
}
.nav-links a:hover{color:var(--blue)}
.nav-links .nav-cta{
  background:var(--blue);color:var(--white);
  padding:9px 18px;border-radius:6px;font-weight:700;
  transition:background-color .2s ease,color .2s ease;
}
.nav-links .nav-cta:hover{background:var(--ink);color:var(--white)}
.nav-toggle{
  display:none;
  background:none;border:1.5px solid var(--ink);border-radius:6px;
  width:42px;height:42px;cursor:pointer;
  flex-direction:column;align-items:center;justify-content:center;gap:5px;
}
.nav-toggle span{
  width:18px;height:2px;background:var(--ink);
  transition:transform .2s ease,opacity .2s ease;
}
.site-header.open .nav-toggle span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.site-header.open .nav-toggle span:nth-child(2){opacity:0}
.site-header.open .nav-toggle span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ---------- hero ---------- */
.hero{position:relative;padding-block:clamp(80px,11vw,140px) clamp(90px,10vw,120px);overflow:hidden}
.hero-meta{display:flex;flex-wrap:wrap;align-items:center;gap:14px;margin-bottom:28px}
.badge{
  display:inline-flex;align-items:center;gap:8px;
  background:var(--lime);color:var(--ink);
  font-size:13px;font-weight:700;letter-spacing:.04em;
  padding:7px 14px;border-radius:4px;
}
.badge::before{content:"";width:8px;height:8px;background:var(--ink)}
.hero-location{font-family:var(--mono);font-size:14px;color:var(--gray)}
h1{
  font-size:clamp(42px,6.5vw,84px);
  font-weight:800;letter-spacing:-0.02em;line-height:1.0;
  max-width:16ch;
}
.marker{
  background:var(--lime);color:var(--ink);
  padding:.05em .15em;
  box-decoration-break:clone;-webkit-box-decoration-break:clone;
}
.hero-bio{
  color:var(--gray);
  font-size:clamp(17px,1.5vw,19px);
  max-width:620px;
  margin-top:28px;
}
.cta-row{display:flex;flex-wrap:wrap;align-items:center;gap:24px;margin-top:36px}
.btn,.btn-primary{
  display:inline-block;
  background:var(--blue);color:var(--white);
  font-weight:700;font-size:16px;text-decoration:none;
  padding:15px 28px;border-radius:6px;
  border:1.5px solid var(--blue);
  cursor:pointer;
  font-family:var(--font);
  transition:background-color .2s ease,border-color .2s ease,transform .2s ease;
}
.btn:hover,.btn-primary:hover{background:var(--ink);border-color:var(--ink);transform:translateY(-2px)}
.btn-secondary{
  background:var(--white);color:var(--ink);
  border:1.5px solid var(--ink);
}
.btn-secondary:hover{background:var(--ink);color:var(--white)}
.btn-lime{
  background:var(--lime);color:var(--ink);
  border:1.5px solid var(--lime);
}
.btn-lime:hover{background:var(--white);border-color:var(--white);color:var(--ink)}
.link-more{
  color:var(--ink);font-weight:700;font-size:16px;
  text-decoration:underline;text-decoration-color:var(--blue);
  text-decoration-thickness:2px;text-underline-offset:5px;
  transition:color .2s ease;
}
.link-more:hover{color:var(--blue)}
.hero-decor{
  position:absolute;top:96px;right:max(24px,calc((100vw - 1120px)/2));
  display:grid;grid-template-columns:auto auto;gap:16px;align-items:start;
}
.hero-decor i{display:block}
.d-lime{width:104px;height:104px;background:var(--lime)}
.d-blue{width:56px;height:56px;background:var(--blue);justify-self:end;margin-top:48px}
.d-coral{width:48px;height:48px;background:var(--coral);border-radius:50%;margin-top:-8px}
.d-violet{width:32px;height:32px;background:var(--violet);justify-self:end;margin-top:8px}

/* ---------- section headers ---------- */
.section{padding-block:clamp(90px,10vw,120px)}
.eyebrow{
  display:flex;align-items:center;gap:10px;
  font-size:12px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;
  margin-bottom:18px;
}
.eyebrow .glyph{width:10px;height:10px;background:currentColor;flex:none}
.acc-blue{color:var(--blue)}
.acc-coral{color:var(--coral)}
.acc-violet{color:var(--violet)}
.acc-lime{color:var(--lime)}
h2{
  font-size:clamp(30px,4vw,52px);
  font-weight:800;letter-spacing:-0.02em;line-height:1.05;
}
.section-desc{color:var(--gray);max-width:620px;margin-top:16px;font-size:17px}

/* ---------- card system (white, 1.5px ink border) ---------- */
.card{
  background:var(--white);
  border:1.5px solid var(--ink);
  padding:28px;
  transition:transform .2s ease,border-color .2s ease;
}
.grid{display:grid;gap:20px;margin-top:48px}
.grid-4{grid-template-columns:repeat(auto-fit,minmax(240px,1fr))}
.grid-3{grid-template-columns:repeat(auto-fit,minmax(280px,1fr))}
.grid-2{grid-template-columns:repeat(2,1fr)}

.card-index{font-family:var(--mono);font-size:13px;font-weight:700;margin-bottom:36px}
.card h3{font-size:20px;font-weight:800;letter-spacing:-0.01em;margin-bottom:10px}
.card p{color:var(--gray);font-size:15.5px}
.card-kicker{
  font-size:12px;font-weight:700;letter-spacing:.1em;text-transform:uppercase;
  color:var(--gray);margin-bottom:12px;
}

/* expertise */
#ai-expertise .card:hover{transform:translateY(-2px);border-color:var(--blue)}
#ai-expertise .card-index{color:var(--blue)}

/* about */
#about .card:hover{transform:translateY(-2px);border-color:var(--coral)}

/* experience */
.xp-list{margin-top:48px;border-bottom:1px solid var(--hairline)}
.xp-row{
  display:grid;grid-template-columns:230px 1fr;gap:12px 40px;
  padding-block:36px;border-top:1px solid var(--hairline);
}
.xp-dates{font-family:var(--mono);font-size:14px;color:var(--gray);padding-top:5px}
.xp-row h3{font-size:22px;font-weight:800;letter-spacing:-0.01em;display:flex;flex-wrap:wrap;align-items:center;gap:12px}
.tag-present{
  background:var(--coral);color:var(--white);
  font-size:12px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;
  padding:4px 10px;border-radius:4px;
}
.xp-company{font-weight:700;margin-top:6px}
.xp-company span{font-weight:500;color:var(--gray)}
.xp-row ul{margin-top:16px}
.xp-row li{color:var(--gray);font-size:15.5px;padding-left:20px;position:relative;margin-bottom:8px}
.xp-row li::before{content:"";position:absolute;left:0;top:.55em;width:8px;height:8px;background:var(--violet)}

/* education */
.edu-body p{color:var(--gray);font-size:15.5px;margin-top:10px}
.edu-body .edu-thesis{font-style:italic}

/* recommendations */
#recommendations .card:hover{transform:translateY(-2px);border-color:var(--coral)}
.quote-mark{
  width:34px;height:6px;background:var(--coral);margin-bottom:20px;
}
#recommendations blockquote{color:var(--gray);font-size:15.5px;font-style:italic}
#recommendations figcaption{margin-top:18px}
#recommendations figcaption strong{display:block;font-size:16px;font-weight:800;letter-spacing:-0.01em}
#recommendations figcaption span{color:var(--gray);font-size:14px}

/* skills — black band */
#skills{background:var(--ink);color:var(--white)}
#skills h2{color:var(--white)}
#skills .section-desc{color:#cccccc}
#skills a:focus-visible{outline-color:var(--lime)}
.skill-groups{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:36px 28px;margin-top:48px}
.skill-group h3{
  display:flex;align-items:center;gap:10px;
  font-size:14px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;
  margin-bottom:16px;
}
.skill-group h3 .glyph{width:10px;height:10px;flex:none}
.sg-lime .glyph{background:var(--lime)}
.sg-blue .glyph{background:var(--blue)}
.sg-violet .glyph{background:var(--violet)}
.sg-coral .glyph{background:var(--coral)}
.chips{display:flex;flex-wrap:wrap;gap:8px}
.chip{
  border:1px solid var(--ink);color:var(--white);
  font-size:13.5px;font-weight:600;
  padding:7px 13px;border-radius:4px;
  transition:background-color .2s ease,color .2s ease,border-color .2s ease;
}
.sg-lime .chip{border-color:var(--lime)}
.sg-blue .chip{border-color:var(--blue)}
.sg-violet .chip{border-color:var(--violet)}
.sg-coral .chip{border-color:var(--coral)}
.sg-lime .chip:hover{background:var(--lime);color:var(--ink)}
.sg-blue .chip:hover{background:var(--blue);color:var(--white)}
.sg-violet .chip:hover{background:var(--violet);color:var(--white)}
.sg-coral .chip:hover{background:var(--coral);color:var(--ink)}

/* projects & blog cards */
#projects .card,#blog .card,.blog-grid .card{display:flex;flex-direction:column}
#projects .card:hover{transform:translateY(-2px);border-color:var(--blue)}
#blog .card:hover,.blog-grid .card:hover{transform:translateY(-2px);border-color:var(--coral)}
.card h3 a{
  color:var(--ink);text-decoration:none;
  transition:color .2s ease;
}
#projects .card h3 a:hover{color:var(--blue)}
#blog .card h3 a:hover,.blog-grid .card h3 a:hover{color:var(--coral)}
.card-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px;margin-bottom:20px}
.tag,.ai-tag{
  display:inline-block;
  border:1px solid var(--ink);color:var(--ink);
  font-size:12px;font-weight:600;
  padding:4px 10px;border-radius:4px;
  transition:border-color .2s ease,color .2s ease;
}
.tag:hover,.ai-tag:hover{border-color:var(--blue);color:var(--blue)}
.card-link{
  margin-top:auto;
  color:var(--blue);font-weight:700;font-size:15px;text-decoration:none;
  border-bottom:2px solid var(--blue);align-self:flex-start;padding-bottom:2px;
  transition:color .2s ease,border-color .2s ease;
}
.card-link:hover{color:var(--ink);border-color:var(--ink)}

/* blog */
.blog-feature{max-width:760px}
.blog-meta{font-family:var(--mono);font-size:13px;color:var(--gray);margin-bottom:14px}
#blog .card h3,.blog-grid .card h3{font-size:24px}
.blog-all{margin-top:28px}

/* contact */
.contact-cta{margin-top:32px}
.contact-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:20px;margin-top:40px}
.contact-tile{
  display:flex;align-items:center;gap:18px;
  background:var(--white);border:1.5px solid var(--ink);
  padding:22px 24px;text-decoration:none;
  transition:transform .2s ease,background-color .2s ease,border-color .2s ease;
}
.contact-tile:hover{transform:translateY(-3px)}
.contact-icon{
  width:52px;height:52px;flex:none;
  display:flex;align-items:center;justify-content:center;
  border:1.5px solid var(--ink);
  transition:background-color .2s ease,color .2s ease,border-color .2s ease;
}
.contact-icon svg{width:26px;height:26px}
.contact-text{display:flex;flex-direction:column;gap:2px;min-width:0}
.contact-tile .label{
  font-size:12px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;
  color:var(--gray);transition:color .2s ease;
}
.contact-tile .handle{
  font-weight:700;font-size:16px;color:var(--ink);
  overflow-wrap:anywhere;transition:color .2s ease;
}
.contact-arrow{margin-left:auto;flex:none;color:var(--ink);transition:transform .2s ease,color .2s ease}
.contact-tile:hover .contact-arrow{transform:translateX(4px)}

/* per-channel accent colors */
.ct-coral .contact-icon{background:var(--coral);border-color:var(--coral);color:var(--white)}
.ct-blue .contact-icon{background:var(--blue);border-color:var(--blue);color:var(--white)}
.ct-violet .contact-icon{background:var(--violet);border-color:var(--violet);color:var(--white)}
.ct-lime .contact-icon{background:var(--lime);border-color:var(--lime);color:var(--ink)}

/* hover: tile floods with the channel color, icon flips to white */
.ct-coral:hover{background:var(--coral);border-color:var(--coral)}
.ct-blue:hover{background:var(--blue);border-color:var(--blue)}
.ct-violet:hover{background:var(--violet);border-color:var(--violet)}
.ct-lime:hover{background:var(--lime);border-color:var(--lime)}
.contact-tile:hover .contact-icon{background:var(--white);border-color:var(--white)}
.ct-coral:hover .contact-icon{color:var(--coral)}
.ct-blue:hover .contact-icon{color:var(--blue)}
.ct-violet:hover .contact-icon{color:var(--violet)}
.ct-lime:hover .contact-icon{color:var(--ink)}
.contact-tile:hover .label,
.contact-tile:hover .handle,
.contact-tile:hover .contact-arrow{color:var(--white)}
.ct-lime:hover .label,
.ct-lime:hover .handle,
.ct-lime:hover .contact-arrow{color:var(--ink)}

/* footer — black band */
.site-footer{background:var(--ink);color:var(--white);padding-block:44px}
.footer-inner{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:20px}
.footer-inner p{font-size:14.5px;color:#cccccc}
.footer-inner p strong{color:var(--white);font-weight:700}
.footer-links{display:flex;flex-wrap:wrap;gap:24px;align-items:center}
.footer-links a{
  color:var(--lime);font-weight:600;font-size:14.5px;text-decoration:none;
  border-bottom:2px solid transparent;
  transition:border-color .2s ease;
}
.footer-links a:hover{border-color:var(--lime)}
.footer-links a:focus-visible{outline-color:var(--lime)}
.footer-links .btn{padding:10px 20px;font-size:14px;display:inline-flex;align-items:center;gap:8px}
.footer-links .btn svg{display:inline-block}
.footer-links .btn:hover{transform:none}

/* =====================================================
   Blog index, article & project pages
   ===================================================== */
.blog-index{padding-block:clamp(64px,8vw,100px)}

/* article page */
.article-page,.project-page{padding-block:clamp(64px,8vw,100px) 60px}
.article-hero,.project-hero{
  padding-bottom:48px;
  border-bottom:1.5px solid var(--ink);
  margin-bottom:48px;
}
.article-hero-inner{max-width:800px}
.project-hero-inner{max-width:860px}
.article-meta{
  display:flex;gap:16px;align-items:center;
  margin-bottom:20px;
  font-family:var(--mono);font-size:14px;color:var(--gray);
}
.article-date{color:var(--blue);font-weight:600}
.article-read-time::before{content:"·";margin-right:8px}
.article-title,.project-title{
  font-size:clamp(34px,5vw,56px);
  font-weight:800;letter-spacing:-0.02em;line-height:1.05;
  margin-bottom:18px;
}
.article-subtitle,.project-subtitle{
  color:var(--gray);font-size:18px;line-height:1.7;
  max-width:680px;margin-bottom:24px;
}
.article-tags,.project-tags{
  display:flex;flex-wrap:wrap;gap:8px;
}
.project-tags{margin-bottom:28px}
.project-links{display:flex;gap:12px;flex-wrap:wrap}

.article-body{
  max-width:760px;
  font-size:17px;line-height:1.8;
  color:var(--gray);
}
.project-body{margin-bottom:48px}
.article-body h2,.article-body h3{
  color:var(--ink);font-weight:800;letter-spacing:-0.01em;
  margin-top:56px;margin-bottom:20px;line-height:1.2;
}
.article-body h2{font-size:30px}
.article-body h3{font-size:24px}
.article-body p{margin-bottom:20px}
.article-body ul,.article-body ol{margin-bottom:24px;padding-left:24px}
.article-body ul{list-style:none}
.article-body ul li{padding-left:20px;position:relative}
.article-body ul li::before{
  content:"";position:absolute;left:0;top:.62em;
  width:8px;height:8px;background:var(--blue);
}
.article-body ol{list-style:decimal}
.article-body li{margin-bottom:10px}
.article-body a{
  color:var(--blue);text-decoration:none;
  border-bottom:2px solid transparent;
  transition:border-color .2s ease;
}
.article-body a:hover{border-bottom-color:var(--blue)}
.article-body hr{
  border:0;height:1.5px;background:var(--ink);
  margin:48px 0;opacity:.15;
}
.article-body img{
  max-width:100%;
  border:1.5px solid var(--ink);
  margin:24px 0;
}
.article-body blockquote{
  border-left:6px solid var(--lime);
  background:var(--paper);
  padding:20px 24px;margin:28px 0;
  color:var(--ink);font-style:italic;
}
.article-body code{
  font-family:var(--mono);
  font-size:.9em;
  background:var(--paper);
  color:var(--coral);
  padding:2px 6px;border-radius:4px;
}
.article-body pre{
  background:var(--white);
  border:1.5px solid var(--ink);
  padding:24px;
  overflow-x:auto;
  margin:28px 0;
}
.article-body pre code{
  background:transparent;
  color:var(--ink);
  padding:0;
  font-size:14px;line-height:1.6;
}
.article-body table{
  width:100%;border-collapse:collapse;
  margin:28px 0;font-size:15px;
}
.article-body th,.article-body td{
  padding:12px 16px;
  border:1px solid var(--hairline);
  text-align:left;
}
.article-body th{
  background:var(--paper);
  color:var(--ink);font-weight:700;
}
.article-footer{
  max-width:760px;
  margin:64px auto 0;
  padding-top:40px;
  border-top:1.5px solid var(--ink);
  display:flex;justify-content:flex-start;
}
.article-footer .btn{display:inline-flex;align-items:center;gap:10px}
.article-footer .btn svg{display:inline-block}

/* heading anchor links */
.heading-anchor{
  color:var(--muted);text-decoration:none;
  margin-right:8px;font-weight:400;
  opacity:0;transition:opacity .2s ease;
}
.article-body h2:hover .heading-anchor,
.article-body h3:hover .heading-anchor{opacity:1}

/* syntax highlighting (light scheme) */
.token.comment,.token.prolog,.token.doctype,.token.cdata{color:var(--muted)}
.token.punctuation{color:var(--gray)}
.token.property,.token.tag,.token.boolean,.token.number,.token.constant,.token.symbol,.token.deleted{color:var(--blue)}
.token.selector,.token.attr-name,.token.string,.token.char,.token.builtin,.token.inserted{color:#0E9F8A}
.token.operator,.token.entity,.token.url,.language-css .token.string,.style .token.string{color:var(--violet)}
.token.atrule,.token.attr-value,.token.keyword{color:var(--violet)}
.token.function,.token.class-name{color:var(--coral)}
.token.regex,.token.important,.token.variable{color:var(--coral)}

/* ---------- reveal on scroll ---------- */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s ease}
.reveal.in{opacity:1;transform:none}
.reveal-d1{transition-delay:.06s}
.reveal-d2{transition-delay:.12s}
.reveal-d3{transition-delay:.18s}

/* ---------- responsive ---------- */
@media (max-width:1000px){
  .hero-decor{display:none}
}
@media (max-width:760px){
  .grid-2,.contact-grid{grid-template-columns:1fr}
  .hero-meta{display:none}
  .nav-toggle{display:flex}
  .nav-links{
    display:none;
    position:absolute;top:68px;left:0;right:0;
    flex-direction:column;align-items:stretch;gap:4px;
    background:var(--white);
    border-bottom:1.5px solid var(--ink);
    padding:12px 24px 20px;
  }
  .site-header.open .nav-links{display:flex}
  .nav-links a{display:block;padding:10px 0;font-size:16px}
  .nav-links .nav-cta{text-align:center;margin-top:8px}
  .xp-row{grid-template-columns:1fr;gap:8px}
  .xp-dates{padding-top:0}
  .cta-row{gap:18px}
  .article-body pre{padding:16px}
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{transition:none !important;animation:none !important}
  .reveal{opacity:1;transform:none}
}