/* ============================================================
   Case study one-pager: unit economics dashboard
   for an Ozon auto parts seller (owner's tool)
   Shared stylesheet for index-en.html / index-ru.html
   Brand: GitHub-dark. bg #0f1117, cards #161b22, nested #1a2535,
   header gradient #1e3a5f -> #0d2137, accent #60a5fa / #3b82f6,
   profit #34d399, loss #f87171, warn #fbbf24
   ============================================================ */

:root{
  --bg:#0f1117;
  --bg-deep:#0a0e1a;
  --card:#161b22;
  --nested:#1a2535;
  --line:#21262d;
  --line-2:#30363d;
  --line-3:#374151;
  --hdr-a:#1e3a5f;
  --hdr-b:#0d2137;
  --hdr-line:#2d4a6e;
  --accent:#60a5fa;
  --accent-2:#3b82f6;
  --accent-soft:rgba(59,130,246,.12);
  --pos:#34d399;
  --pos-soft:rgba(52,211,153,.10);
  --neg:#f87171;
  --neg-soft:rgba(248,113,113,.10);
  --warn:#fbbf24;
  --warn-soft:rgba(251,191,36,.10);
  --text:#e2e8f0;
  --head:#f0f6fc;
  --muted:#94a3b8;
  --dim:#6b7280;
  --r-sm:8px; --r-md:12px; --r-lg:16px; --r-xl:20px;
  --shadow:0 1px 2px rgba(0,0,0,.35), 0 12px 32px -18px rgba(0,0,0,.55);
  --font:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --mono:Consolas,"Cascadia Mono",Menlo,monospace;
}

*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:var(--font);
  font-size:16.5px;
  line-height:1.6;
  color:var(--text);
  background:var(--bg);
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img{max-width:100%;display:block}
a{color:var(--accent)}
a:hover{color:#93c5fd}

::-webkit-scrollbar{width:9px;height:9px}
::-webkit-scrollbar-track{background:var(--bg)}
::-webkit-scrollbar-thumb{background:var(--line-2);border-radius:5px}
::-webkit-scrollbar-thumb:hover{background:var(--line-3)}

.wrap{max-width:1120px;margin:0 auto;padding:0 24px}

h1,h2,h3,h4{line-height:1.2;margin:0 0 .5em;font-weight:800;letter-spacing:-.015em;color:var(--head)}
h2{font-size:clamp(1.6rem,3vw,2.2rem)}
h3{font-size:1.24rem}
h4{font-size:1rem}
p{margin:0 0 1em}
b,strong{font-weight:700;color:var(--head)}

.lead{font-size:1.1rem;color:var(--muted);max-width:52em}
.lead b{color:var(--text)}
.small{font-size:.86rem;color:var(--dim)}
.num-tab{font-variant-numeric:tabular-nums}

/* ---------- top nav ---------- */
.topbar{
  position:sticky;top:0;z-index:50;
  background:rgba(15,17,23,.88);
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.topbar-in{
  display:flex;align-items:center;gap:18px;
  height:58px;max-width:1120px;margin:0 auto;padding:0 24px;
}
.brandmark{
  display:flex;align-items:center;gap:10px;
  font-weight:800;font-size:.92rem;letter-spacing:.08em;text-transform:uppercase;
  white-space:nowrap;color:var(--head);text-decoration:none;
}
.brandmark:hover{color:var(--accent)}
.brandmark .dot{
  width:24px;height:24px;border-radius:7px;flex:0 0 auto;
  background:linear-gradient(135deg,var(--hdr-a),var(--hdr-b));
  border:1px solid var(--hdr-line);
  position:relative;
}
.brandmark .dot::after{
  content:"";position:absolute;left:5px;right:5px;bottom:5px;height:4px;border-radius:2px;
  background:linear-gradient(90deg,var(--accent-2) 55%,var(--pos) 55%);
}
.topnav{display:flex;gap:2px;overflow-x:auto;flex:1;scrollbar-width:none}
.topnav::-webkit-scrollbar{display:none}
.topnav a{
  font-size:.82rem;font-weight:600;color:var(--muted);text-decoration:none;
  padding:6px 11px;border-radius:999px;white-space:nowrap;
}
.topnav a:hover{color:var(--head);background:var(--nested)}
.topnav a.active{color:var(--accent);background:#1f3050;box-shadow:inset 0 0 0 1px var(--hdr-line)}
.lang-switch{
  display:flex;align-items:center;flex:0 0 auto;
  border:1px solid var(--line-2);border-radius:999px;overflow:hidden;background:var(--card);
}
.lang-switch a,.lang-switch span{
  font-size:.78rem;font-weight:800;padding:5px 12px;text-decoration:none;letter-spacing:.05em;
}
.lang-switch span{background:var(--accent-2);color:#fff}
.lang-switch a{color:var(--muted)}
.lang-switch a:hover{color:var(--head);background:var(--nested)}

/* ---------- hero ---------- */
.hero{
  background:
    radial-gradient(900px 460px at 82% -12%, rgba(59,130,246,.28), transparent 62%),
    radial-gradient(640px 380px at -8% 108%, rgba(52,211,153,.10), transparent 55%),
    linear-gradient(135deg,var(--hdr-a),var(--hdr-b));
  border-bottom:1px solid var(--hdr-line);
  padding:72px 0 146px;
}
.hero .eyebrow{color:var(--accent)}
.hero .eyebrow::before{background:var(--accent)}
.hero h1{
  font-size:clamp(2rem,4.4vw,3.2rem);
  max-width:20em;color:#fff;margin-bottom:.45em;
}
.hero .sub{
  font-size:clamp(1rem,1.5vw,1.18rem);
  color:#b6c8dd;max-width:47em;line-height:1.65;
}
.hero .sub b{color:#fff}
.hero-tags{display:flex;flex-wrap:wrap;gap:8px;margin-top:26px}
.hero-tags span{
  font-size:.78rem;font-weight:600;color:#cfe1f5;
  border:1px solid rgba(96,165,250,.35);border-radius:999px;padding:5px 13px;
  background:rgba(13,33,55,.5);
}

/* KPI strip overlapping hero bottom */
.kpi-strip{
  display:grid;grid-template-columns:repeat(6,1fr);gap:12px;
  margin-top:-84px;position:relative;z-index:2;
}
.kpi{
  background:var(--card);border:1px solid var(--line-2);
  border-radius:var(--r-lg);padding:18px 16px 14px;box-shadow:var(--shadow);
}
.kpi-num{
  font-size:1.66rem;font-weight:800;letter-spacing:-.02em;line-height:1.05;
  color:var(--head);white-space:nowrap;font-variant-numeric:tabular-nums;
}
.kpi-num small{font-size:.9rem;font-weight:800;color:var(--accent)}
.kpi-cap{font-size:.78rem;color:var(--muted);margin-top:7px;line-height:1.4}
@media (max-width:980px){.kpi-strip{grid-template-columns:repeat(3,1fr)}}
@media (max-width:560px){.kpi-strip{grid-template-columns:repeat(2,1fr)}.kpi-num{font-size:1.36rem}}

/* ---------- sections ---------- */
section.block{padding:80px 0 10px}
.eyebrow{
  display:flex;align-items:center;gap:10px;
  font-size:.78rem;font-weight:800;letter-spacing:.16em;text-transform:uppercase;
  color:var(--accent);margin-bottom:14px;
}
.eyebrow::before{content:"";width:26px;height:3px;border-radius:2px;background:var(--accent-2)}
.eyebrow .num{color:var(--dim);letter-spacing:.06em}

/* cards / grids */
.grid{display:grid;gap:14px}
.g2{grid-template-columns:1fr 1fr}
.g3{grid-template-columns:repeat(3,1fr)}
.g4{grid-template-columns:repeat(4,1fr)}
@media (max-width:900px){.g3,.g4{grid-template-columns:1fr 1fr}}
@media (max-width:620px){.g2,.g3,.g4{grid-template-columns:1fr}}

.card{
  background:var(--card);border:1px solid var(--line);
  border-radius:var(--r-lg);padding:20px 20px 16px;box-shadow:var(--shadow);
}
.card h4{margin-bottom:.45em;color:var(--head)}
.card p{font-size:.93rem;color:var(--muted);margin-bottom:0}
.card.accent{border-top:3px solid var(--accent-2)}
.card.pain{border-top:3px solid var(--neg)}
.card.good{border-top:3px solid var(--pos)}
.card.deep{background:var(--nested);border-color:var(--hdr-line)}
.card.deep p{color:#a8b8cc}

/* fact rows (inline stats) */
.facts{display:flex;flex-wrap:wrap;gap:11px;margin:22px 0 8px}
.fact{
  background:var(--card);border:1px solid var(--line-2);border-radius:var(--r-md);
  padding:11px 16px;min-width:126px;
}
.fact b{
  display:block;font-size:1.28rem;font-weight:800;line-height:1.15;color:var(--head);
  font-variant-numeric:tabular-nums;
}
.fact span{font-size:.76rem;color:var(--muted)}

/* callouts */
.callout{
  border-radius:var(--r-lg);padding:20px 24px;margin:26px 0;
  border:1px solid var(--hdr-line);background:var(--nested);
}
.callout.warn{background:var(--warn-soft);border-color:rgba(251,191,36,.35)}
.callout.green{background:var(--pos-soft);border-color:rgba(52,211,153,.35)}
.callout h4{margin-bottom:.35em}
.callout p{margin-bottom:0;font-size:.95rem;color:var(--muted)}
.callout .tag{
  display:inline-block;font-size:.7rem;font-weight:800;letter-spacing:.1em;text-transform:uppercase;
  background:var(--card);border:1px solid var(--line-2);color:var(--warn);
  border-radius:999px;padding:3px 10px;margin-bottom:10px;
}
.callout.green .tag{color:var(--pos)}

/* chips */
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0}
.chips span{
  font-size:.8rem;font-weight:600;color:var(--text);
  background:var(--nested);border:1px solid var(--line-2);border-radius:999px;padding:5px 12px;
}
.chips.blue span{border-color:rgba(96,165,250,.4);color:#93c5fd;background:var(--accent-soft)}
.chips.warn span{border-color:rgba(251,191,36,.4);color:var(--warn);background:var(--warn-soft)}

/* numbered steps */
.steps{list-style:none;counter-reset:st;margin:20px 0;padding:0;display:grid;gap:10px}
.steps li{
  counter-increment:st;
  background:var(--card);border:1px solid var(--line);border-radius:var(--r-md);
  padding:13px 18px 13px 56px;position:relative;font-size:.94rem;color:var(--muted);
}
.steps li b{color:var(--head)}
.steps li::before{
  content:counter(st,decimal-leading-zero);
  position:absolute;left:15px;top:13px;
  font-weight:800;font-size:.82rem;color:var(--accent);
  background:#1f3050;border-radius:7px;padding:2px 7px;
  font-variant-numeric:tabular-nums;
}

/* ---------- unit economics ledger (waterfall) ---------- */
.ledger{
  background:var(--card);border:1px solid var(--line-2);border-radius:var(--r-lg);
  overflow:hidden;box-shadow:var(--shadow);margin:8px 0 4px;
}
.ln{display:flex;gap:14px;padding:11px 18px;border-bottom:1px solid var(--line);align-items:baseline}
.ln:last-child{border-bottom:none}
.ln-sign{
  flex:0 0 20px;text-align:center;font-weight:800;font-size:1.05rem;
  font-family:var(--mono);font-variant-numeric:tabular-nums;
}
.ln-plus .ln-sign{color:var(--pos)}
.ln-minus .ln-sign{color:var(--neg)}
.ln-res .ln-sign{color:var(--pos)}
.ln-body b{display:block;font-size:.95rem;color:var(--head)}
.ln-body span{font-size:.82rem;color:var(--muted);line-height:1.45}
.ln-plus{background:var(--pos-soft)}
.ln-res{background:var(--pos-soft)}
.ln-res .ln-body b{color:var(--pos);font-size:1.02rem}
.ln-res .ln-body span{color:var(--muted)}

/* two-column split that collapses on mobile */
.grid.split{grid-template-columns:1.15fr .85fr;gap:16px}
@media (max-width:860px){.grid.split{grid-template-columns:1fr}}

/* policy filter pills */
.policy{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:18px 0}
.policy.p1{grid-template-columns:1fr}
.policy.p2{grid-template-columns:1fr 1fr}
@media (max-width:640px){.policy{grid-template-columns:1fr}.policy.p2{grid-template-columns:1fr}}
.pol{
  background:var(--nested);border:1px solid var(--hdr-line);border-radius:var(--r-md);
  padding:14px 18px;text-align:center;
}
.pol b{display:block;font-size:.78rem;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--muted);margin-bottom:4px}
.pol .pv{
  font-size:1.4rem;font-weight:800;color:var(--pos);
  font-variant-numeric:tabular-nums;letter-spacing:-.01em;
}
.pol .pv.warn{color:var(--warn)}

/* ---------- diagrams ---------- */
.diagram{
  background:var(--card);border:1px solid var(--line-2);border-radius:var(--r-xl);
  padding:16px;margin:26px 0;overflow-x:auto;box-shadow:var(--shadow);
}
.diagram svg{min-width:860px;width:100%;height:auto;display:block}
.diagram svg text{font-family:var(--font)}
.legend{
  display:flex;flex-wrap:wrap;gap:18px;margin:4px 4px 2px;padding-top:14px;
  border-top:1px dashed var(--line-2);font-size:.78rem;color:var(--muted);
}
.legend i{display:inline-block;width:13px;height:13px;border-radius:4px;margin-right:6px;vertical-align:-2px}
.legend .k-ext i{background:var(--hdr-a);border:1px solid var(--hdr-line)}
.legend .k-svc i{background:var(--card);border:2px solid var(--accent-2)}
.legend .k-db i{background:var(--nested);border:2px solid var(--accent)}
.legend .k-own i{background:#10231c;border:2px solid var(--pos)}

/* ---------- tables ---------- */
.tbl-wrap{
  overflow-x:auto;margin:24px 0;border-radius:var(--r-lg);
  border:1px solid var(--line-2);background:var(--card);box-shadow:var(--shadow);
}
table.tbl{width:100%;border-collapse:collapse;font-size:.9rem;min-width:640px}
table.tbl th{
  text-align:left;font-size:.73rem;letter-spacing:.09em;text-transform:uppercase;
  color:var(--dim);font-weight:800;
  padding:13px 18px 9px;border-bottom:2px solid var(--line-2);background:#10141b;
}
table.tbl td{
  padding:12px 18px;border-bottom:1px solid var(--line);vertical-align:top;
  color:var(--muted);font-variant-numeric:tabular-nums;
}
table.tbl tr:last-child td{border-bottom:none}
table.tbl td.metric{font-weight:700;white-space:nowrap;color:var(--head)}
table.tbl code{
  font-family:var(--mono);font-size:.82em;
  background:var(--nested);border-radius:6px;padding:2px 6px;color:#93c5fd;white-space:normal;
}

/* was / now table */
table.tbl.wasnow td:nth-child(2){color:var(--dim)}
table.tbl.wasnow td:nth-child(3){color:var(--text)}
table.tbl.wasnow td:nth-child(3) b{color:var(--pos)}

/* ---------- screenshots ---------- */
.shots{display:grid;gap:16px;grid-template-columns:1fr 1fr;margin:26px 0}
.shots.one{grid-template-columns:1fr}
@media (max-width:760px){.shots{grid-template-columns:1fr}}
.shot{
  margin:0;background:var(--card);border:1px solid var(--line-2);
  border-radius:var(--r-lg);overflow:hidden;box-shadow:var(--shadow);
}
.shot img{width:100%;height:auto}
.shot figcaption{
  font-size:.8rem;color:var(--muted);padding:11px 16px;border-top:1px solid var(--line);
}
.shot.is-pending::before{
  content:attr(data-label);
  display:flex;align-items:center;justify-content:center;text-align:center;
  min-height:280px;padding:30px;
  font-weight:800;font-size:1rem;color:#7d8590;
  background:
    radial-gradient(420px 200px at 50% 0%, rgba(59,130,246,.12), transparent 70%),
    repeating-linear-gradient(-45deg,#141821 0 14px,#10141b 14px 28px);
}
.shot.is-pending figcaption::after{content:" · " attr(data-note);color:var(--dim)}

/* ---------- section divider ---------- */
.divider{height:1px;background:var(--line);margin:72px auto 0;max-width:1120px}

/* ---------- methodology ---------- */
.method-grid{display:grid;grid-template-columns:1.2fr .8fr;gap:16px}
@media (max-width:860px){.method-grid{grid-template-columns:1fr}}

/* commit strip */
.commits{display:grid;gap:10px;margin:18px 0}
.commit{
  display:flex;gap:14px;align-items:baseline;
  background:var(--card);border:1px solid var(--line-2);border-radius:var(--r-md);
  padding:12px 16px;font-size:.9rem;
}
.commit .hash{
  font-family:var(--mono);font-size:.8rem;color:var(--accent);
  background:var(--nested);border-radius:6px;padding:2px 8px;flex:0 0 auto;
}
.commit .msg{color:var(--muted)}
.commit .msg b{color:var(--head)}
.commit .msg .co{
  display:inline-block;font-family:var(--mono);font-size:.78rem;color:var(--pos);
  background:var(--pos-soft);border-radius:6px;padding:1px 8px;margin-top:4px;
}

/* ---------- CTA ---------- */
.cta{
  background:
    radial-gradient(720px 380px at 88% -20%, rgba(59,130,246,.35), transparent 60%),
    radial-gradient(520px 300px at 0% 120%, rgba(52,211,153,.12), transparent 55%),
    linear-gradient(135deg,var(--hdr-a),var(--hdr-b));
  border:1px solid var(--hdr-line);
  border-radius:var(--r-xl);color:#fff;
  padding:44px 46px;margin:40px 0 0;
  display:flex;flex-wrap:wrap;align-items:center;gap:28px;
  box-shadow:var(--shadow);
}
.cta .cta-txt{flex:1 1 380px}
.cta h3{color:#fff;font-size:1.5rem;margin-bottom:.35em}
.cta p{color:#b6c8dd;margin:0;font-size:.98rem;max-width:40em}
.cta .btn{
  display:inline-block;background:var(--accent-2);color:#fff;
  font-weight:800;font-size:.98rem;text-decoration:none;
  border-radius:999px;padding:13px 28px;white-space:nowrap;
  box-shadow:0 8px 24px -8px rgba(59,130,246,.65);
}
.cta .btn:hover{background:#2563eb;color:#fff}

/* ---------- footer ---------- */
footer{
  margin-top:70px;padding:32px 0 44px;border-top:1px solid var(--line);
  font-size:.82rem;color:var(--dim);
}
footer .wrap{display:flex;flex-wrap:wrap;gap:14px;justify-content:space-between}

/* ---------- print ---------- */
@media print{
  :root{--shadow:none}
  body{font-size:12px;background:var(--bg);-webkit-print-color-adjust:exact;print-color-adjust:exact}
  .topbar{display:none!important}
  .hero{padding:40px 0 90px}
  .kpi-strip{margin-top:-60px}
  section.block{padding:32px 0 6px;break-inside:auto}
  .card,.kpi,.callout,.shot,.tbl-wrap,.diagram,.steps li,.ledger,.pol,.commit{break-inside:avoid;box-shadow:none}
  .diagram{overflow:visible}
  .diagram svg{min-width:0}
  .cta{break-inside:avoid}
  a{text-decoration:none;color:inherit}
  .cta .btn::after{content:"  ->  linkedin.com/in/sedovkirill";font-weight:700;font-size:.85em}
  .shot.is-pending{display:none}
}