/* RackPilot — base stylesheet
   Deliberately dependency-free beyond one Google Fonts request: no JS
   framework, no CSS framework, small payload, fast paint. */

:root{
  --ink:#111827;
  --ink-soft:#4b5563;
  --paper:#ffffff;
  --paper-soft:#f6f7f9;
  --line:#e5e7eb;
  --brand:#0f5fdc;
  --brand-dark:#0a3f94;
  --brand-soft:#eaf1fd;
  --accent:#e8590c;
  --accent-soft:#fdeee4;
  --code-bg:#0d1424;
  --code-ink:#e2e8f0;
  --radius:10px;
  --maxw:1120px;
  --content-w:760px;
  --font-body:"Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  --font-head:"Space Grotesk","Inter",-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;
}

*{box-sizing:border-box;}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth;}
body{
  margin:0;
  font-family:var(--font-body);
  color:var(--ink);
  background:var(--paper);
  line-height:1.65;
}
img{max-width:100%;height:auto;display:block;}
a{color:var(--brand);text-decoration:none;}
a:hover{text-decoration:underline;}
h1,h2,h3,h4{font-family:var(--font-head);line-height:1.22;font-weight:700;letter-spacing:-0.015em;}
h1{font-size:2.1rem;margin:0 0 .5rem;}
h2{font-size:1.5rem;margin:2.2rem 0 .8rem;}
h3{font-size:1.2rem;margin:1.6rem 0 .6rem;}
p{margin:0 0 1.1rem;}
ul,ol{margin:0 0 1.1rem;padding-left:1.4rem;}
li{margin-bottom:.4rem;}
code{
  background:var(--paper-soft);
  border:1px solid var(--line);
  border-radius:4px;
  padding:.1rem .35rem;
  font-size:.88em;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
.code-block{position:relative;margin:0 0 1.3rem;}
.code-block pre{margin:0;}
.code-copy-btn{
  position:absolute;top:.55rem;right:.55rem;
  background:rgba(255,255,255,.08);color:#cbd5e1;
  border:1px solid rgba(255,255,255,.16);border-radius:6px;
  font-size:.72rem;font-weight:600;padding:.3rem .6rem;
  cursor:pointer;font-family:var(--font-body);
  transition:background .15s,color .15s;
}
.code-copy-btn:hover{background:rgba(255,255,255,.18);color:#fff;}
.code-copy-btn.copied{background:var(--brand);color:#fff;border-color:var(--brand);}
pre{
  background:var(--code-bg);
  color:var(--code-ink);
  padding:1rem 1.2rem;
  border-radius:var(--radius);
  overflow-x:auto;
}
pre code{background:none;border:none;padding:0;color:inherit;font-size:.86em;}
blockquote{
  margin:0 0 1.2rem;
  padding:.2rem 1.1rem;
  border-left:3px solid var(--brand);
  color:var(--ink-soft);
  background:var(--brand-soft);
  border-radius:0 6px 6px 0;
}
table{width:100%;border-collapse:collapse;margin:0 0 1.3rem;font-size:.95rem;}
th,td{text-align:left;padding:.55rem .7rem;border-bottom:1px solid var(--line);}
th{background:var(--paper-soft);font-weight:700;}
hr{border:none;border-top:1px solid var(--line);margin:2rem 0;}

.wrap{max-width:var(--maxw);margin:0 auto;padding:0 1.25rem;}
.prose{max-width:var(--content-w);}

/* Reading progress */
.reading-progress{position:fixed;top:0;left:0;height:3px;width:0%;background:linear-gradient(90deg,var(--brand),var(--accent));z-index:100;transition:width .1s linear;}

/* Header */
.site-header{border-bottom:1px solid var(--line);position:sticky;top:0;background:rgba(255,255,255,.92);backdrop-filter:blur(6px);z-index:20;}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;height:64px;}
.brand{display:flex;align-items:center;gap:.55rem;font-family:var(--font-head);font-weight:700;font-size:1.15rem;color:var(--ink);}
.brand:hover{text-decoration:none;}
.brand .mark{width:28px;height:28px;border-radius:7px;background:linear-gradient(135deg,var(--brand),var(--brand-dark));display:flex;align-items:center;justify-content:center;color:#fff;font-size:.85rem;font-weight:700;font-family:var(--font-head);flex-shrink:0;}
nav.main-nav{display:flex;align-items:center;gap:1.5rem;}
nav.main-nav a{position:relative;color:var(--ink-soft);font-weight:600;font-size:.94rem;padding:.3rem 0;}
nav.main-nav a::after{content:"";position:absolute;left:0;right:0;bottom:-2px;height:2px;background:var(--brand);transform:scaleX(0);transition:transform .15s;}
nav.main-nav a:hover{color:var(--brand);text-decoration:none;}
nav.main-nav a:hover::after,nav.main-nav a.active::after{transform:scaleX(1);}
nav.main-nav a.active{color:var(--brand);}

.nav-toggle{
  display:none;background:none;border:1px solid var(--line);border-radius:8px;
  width:40px;height:40px;cursor:pointer;position:relative;flex-shrink:0;
}
.nav-toggle span{position:absolute;left:9px;right:9px;height:2px;background:var(--ink);border-radius:2px;transition:transform .2s,opacity .2s;}
.nav-toggle span:nth-child(1){top:13px;}
.nav-toggle span:nth-child(2){top:19px;}
.nav-toggle span:nth-child(3){top:25px;}
.nav-toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(6px) rotate(45deg);}
.nav-toggle[aria-expanded="true"] span:nth-child(2){opacity:0;}
.nav-toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-6px) rotate(-45deg);}

.mobile-nav{display:none;}

@media (max-width:760px){
  .nav-toggle{display:block;}
  nav.main-nav{
    display:none;
  }
  .mobile-nav{
    display:block;
    position:fixed;top:64px;left:0;right:0;bottom:0;
    background:var(--paper);z-index:19;
    padding:1rem 1.25rem 2rem;
    overflow-y:auto;
    transform:translateY(-8px);
    opacity:0;pointer-events:none;
    transition:opacity .18s,transform .18s;
  }
  .mobile-nav.open{opacity:1;transform:translateY(0);pointer-events:auto;}
  .mobile-nav a{display:block;padding:.9rem .2rem;font-size:1.05rem;font-weight:600;color:var(--ink);border-bottom:1px solid var(--line);}
  .mobile-nav a.active{color:var(--brand);}
}

/* Hero */
.hero{background:linear-gradient(165deg,var(--brand-soft) 0%,var(--paper) 65%);padding:3.4rem 0 2.8rem;border-bottom:1px solid var(--line);overflow:hidden;}
.hero--split .wrap{display:flex;align-items:center;gap:2.5rem;}
.hero-copy{flex:1;min-width:0;}
.hero h1{font-size:2.5rem;max-width:640px;}
.hero p.lead{font-size:1.13rem;color:var(--ink-soft);max-width:600px;}
.tag-pill{display:inline-block;background:var(--brand-soft);color:var(--brand-dark);font-weight:700;font-size:.76rem;letter-spacing:.04em;text-transform:uppercase;padding:.32rem .75rem;border-radius:999px;margin-bottom:1.1rem;}
.hero-stats{display:flex;gap:1.8rem;margin-top:1.6rem;flex-wrap:wrap;}
.hero-stats div{display:flex;flex-direction:column;}
.hero-stats strong{font-family:var(--font-head);font-size:1.4rem;color:var(--ink);}
.hero-stats span{font-size:.82rem;color:var(--ink-soft);}

/* Hero terminal decoration */
.hero-terminal{
  flex-shrink:0;width:380px;background:var(--code-bg);border-radius:12px;
  box-shadow:0 20px 50px -12px rgba(15,23,42,.35);overflow:hidden;
  font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.82rem;
  transform:rotate(1.2deg);
}
.hero-terminal .term-bar{display:flex;gap:6px;padding:.7rem .85rem;background:rgba(255,255,255,.05);}
.hero-terminal .term-bar span{width:10px;height:10px;border-radius:50%;background:#475569;}
.hero-terminal .term-bar span:nth-child(1){background:#ef4444;}
.hero-terminal .term-bar span:nth-child(2){background:#f59e0b;}
.hero-terminal .term-bar span:nth-child(3){background:#22c55e;}
.hero-terminal .term-body{padding:1rem 1.1rem 1.3rem;color:#cbd5e1;}
.hero-terminal .term-body .line{margin-bottom:.55rem;white-space:pre-wrap;}
.hero-terminal .prompt{color:#22c55e;}
.hero-terminal .comment{color:#64748b;}
.hero-terminal .out{color:#93c5fd;}
@media (max-width:900px){.hero-terminal{display:none;}}
@media (max-width:640px){.hero--split .wrap{flex-direction:column;}.hero h1{font-size:2rem;}}

/* Cards / grid */
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1.5rem;margin:2rem 0;}
@media (max-width:900px){.grid{grid-template-columns:repeat(2,1fr);}}
@media (max-width:640px){.grid{grid-template-columns:1fr;}}

.card{
  --cat-color:var(--brand);
  border:1px solid var(--line);border-top:3px solid var(--cat-color);
  border-radius:var(--radius);padding:1.3rem;display:flex;flex-direction:column;
  background:var(--paper);transition:box-shadow .15s,transform .15s;
}
.card:hover{box-shadow:0 10px 26px -8px rgba(15,23,42,.16);transform:translateY(-3px);}
.card .cat{font-size:.72rem;text-transform:uppercase;letter-spacing:.05em;color:var(--cat-color);font-weight:700;margin-bottom:.5rem;}
.card h3{margin:.1rem 0 .5rem;font-size:1.05rem;}
.card h3 a{color:var(--ink);}
.card p{color:var(--ink-soft);font-size:.92rem;margin-bottom:0;}

.article-list{display:flex;flex-direction:column;gap:0;margin:1.5rem 0;}
.article-row{
  --cat-color:var(--brand);
  display:flex;justify-content:space-between;gap:1.5rem;padding:1.3rem 0 1.3rem 1rem;
  border-bottom:1px solid var(--line);border-left:3px solid var(--cat-color);
  transition:background .15s;
}
.article-row:hover{background:var(--paper-soft);}
.article-row .cat{font-size:.72rem;text-transform:uppercase;letter-spacing:.05em;color:var(--cat-color);font-weight:700;margin-bottom:.35rem;display:block;}
.article-row h3{margin:.1rem 0 .4rem;font-size:1.15rem;}
.article-row h3 a{color:var(--ink);}
.article-row p{color:var(--ink-soft);margin:0;font-size:.95rem;}
.article-row .meta{white-space:nowrap;color:#9ca3af;font-size:.85rem;padding-top:.15rem;}

/* Category quick-jump pills */
.cat-pills{display:flex;flex-wrap:wrap;gap:.6rem;margin:1.6rem 0 .5rem;}
.cat-pills a{
  display:inline-flex;align-items:center;gap:.4rem;
  border:1px solid var(--line);border-radius:999px;padding:.4rem .85rem;
  font-size:.86rem;font-weight:600;color:var(--ink-soft);
}
.cat-pills a:hover{border-color:var(--pill-color,var(--brand));color:var(--pill-color,var(--brand));text-decoration:none;}
.cat-pills a .dot{width:8px;height:8px;border-radius:50%;background:var(--pill-color,var(--brand));display:inline-block;}

/* Article page */
.article-header{--cat-color:var(--brand);padding:2.5rem 0 1.5rem;border-bottom:1px solid var(--line);border-top:3px solid var(--cat-color);}
.article-header .cat{font-size:.78rem;text-transform:uppercase;letter-spacing:.05em;color:var(--cat-color);font-weight:700;margin-bottom:.6rem;}
.breadcrumbs{font-size:.85rem;color:var(--ink-soft);margin-bottom:1rem;}
.breadcrumbs a{color:var(--ink-soft);}
.article-meta{color:#9ca3af;font-size:.9rem;margin-top:.6rem;}
.article-body{padding:2.2rem 0 1rem;}
.byline{display:flex;align-items:center;gap:.6rem;margin-top:1rem;font-size:.9rem;color:var(--ink-soft);}
.byline .avatar{width:32px;height:32px;border-radius:50%;background:var(--brand-soft);color:var(--brand-dark);display:flex;align-items:center;justify-content:center;font-weight:700;font-size:.85rem;font-family:var(--font-head);}

.callout{background:var(--paper-soft);border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:var(--radius);padding:1.1rem 1.3rem;margin:1.6rem 0;}
.callout strong{color:var(--ink);}

.ad-slot{background:var(--paper-soft);border:1px dashed var(--line);border-radius:var(--radius);padding:1.5rem;text-align:center;color:#9ca3af;font-size:.85rem;margin:2rem 0;}

.toc{background:var(--paper-soft);border:1px solid var(--line);border-radius:var(--radius);padding:1.1rem 1.4rem;margin:1.6rem 0 2rem;}
.toc-title{font-family:var(--font-head);font-weight:700;font-size:.85rem;text-transform:uppercase;letter-spacing:.04em;color:var(--ink-soft);margin-bottom:.5rem;}
.toc ol{margin:0;padding-left:1.2rem;}
.toc li{margin-bottom:.3rem;font-size:.94rem;}

.related{border-top:1px solid var(--line);padding:2.5rem 0;}
.related h2{margin-top:0;}

/* CTA band */
.cta-band{background:var(--ink);color:#fff;padding:3rem 0;margin-top:2rem;position:relative;overflow:hidden;}
.cta-band::before{content:"";position:absolute;inset:0;background:radial-gradient(circle at 15% 20%,rgba(15,95,220,.35),transparent 45%),radial-gradient(circle at 85% 80%,rgba(232,89,12,.25),transparent 45%);}
.cta-band .wrap{position:relative;}
.cta-band h2{color:#fff;margin-top:0;}
.cta-band p{color:#cbd5e1;}
.btn{display:inline-block;background:var(--brand);color:#fff;font-weight:700;padding:.75rem 1.4rem;border-radius:8px;margin-top:.5rem;transition:background .15s,transform .15s,box-shadow .15s;}
.btn:hover{background:var(--brand-dark);text-decoration:none;transform:translateY(-2px);box-shadow:0 8px 20px -6px rgba(15,95,220,.5);}
.btn.secondary{background:transparent;border:1px solid #475569;color:#e2e8f0;}
.btn.secondary:hover{background:#1e293b;box-shadow:none;}

/* Forms */
.form-field{margin-bottom:1.1rem;}
.form-field label{display:block;font-weight:700;font-size:.9rem;margin-bottom:.35rem;}
.form-field input,.form-field textarea{
  width:100%;padding:.7rem .8rem;border:1px solid var(--line);border-radius:8px;font-family:inherit;font-size:.95rem;
}
.form-field textarea{min-height:140px;resize:vertical;}

/* Footer */
.site-footer{border-top:1px solid var(--line);background:var(--paper-soft);margin-top:3rem;padding:2.5rem 0 1.5rem;position:relative;}
.site-footer::before{content:"";position:absolute;top:-1px;left:0;right:0;height:2px;background:linear-gradient(90deg,var(--brand),var(--accent));}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:2rem;margin-bottom:2rem;}
@media (max-width:760px){.footer-grid{grid-template-columns:1fr 1fr;}}
.footer-grid h4{font-family:var(--font-head);font-size:.85rem;text-transform:uppercase;letter-spacing:.03em;color:var(--ink-soft);margin:0 0 .8rem;}
.footer-grid ul{list-style:none;padding:0;margin:0;}
.footer-grid li{margin-bottom:.5rem;}
.footer-grid a{color:var(--ink-soft);font-size:.92rem;}
.footer-bottom{border-top:1px solid var(--line);padding-top:1.3rem;display:flex;justify-content:space-between;flex-wrap:wrap;gap:.6rem;color:#9ca3af;font-size:.85rem;}
.footer-desc{color:var(--ink-soft);font-size:.92rem;max-width:320px;}

.section-pad{padding:3rem 0;}
.section-pad.tight{padding:2rem 0;}
.center{text-align:center;}
.small{font-size:.85rem;color:#9ca3af;}