/* ============================================================
   Klima - design system
   Paleta: granat nocy + lód-cyjan + bursztyn (oswajanie upału)
   Typografia: Space Grotesk (display) + Hanken Grotesk (body)
              + IBM Plex Mono (etykiety techniczne)
   WCAG 2.1 AA: kontrast >= 4.5:1, body 17px, nav 15px
   ============================================================ */

:root{
  /* Light (domyślne) */
  --bg:#f0f6fa;
  --surface:#ffffff;
  --surface-2:#e6f0f5;
  --border:#d3e2eb;
  --border-strong:#b9cdd9;
  --text:#1f2e3a;
  --text-dim:#52697a;
  --accent:#08707e;
  --accent-strong:#065e6a;
  --accent-soft:#d9edf2;
  --amber:#8a5d1a;
  --amber-soft:#f6ecd9;
  --header-bg:rgba(240,246,250,.88);
  --shadow:0 1px 2px rgba(12,27,42,.05),0 4px 16px rgba(12,27,42,.06);
  --shadow-hover:0 2px 4px rgba(12,27,42,.07),0 10px 28px rgba(12,27,42,.10);
  --hero-glow-1:rgba(53,195,214,.20);
  --hero-glow-2:rgba(232,163,61,.14);
  --code-bg:#eef4f8;
}
@media (prefers-color-scheme: dark){
  :root{
    --bg:#0c1b2a;
    --surface:#12243a;
    --surface-2:#0e1f30;
    --border:#1e3648;
    --border-strong:#2c4a5f;
    --text:#e8eef2;
    --text-dim:#9fb4c2;
    --accent:#35c3d6;
    --accent-strong:#5fd4e3;
    --accent-soft:#12303c;
    --amber:#e8a33d;
    --amber-soft:#2c2417;
    --header-bg:rgba(12,27,42,.9);
    --shadow:0 1px 2px rgba(0,0,0,.3),0 4px 16px rgba(0,0,0,.25);
    --shadow-hover:0 2px 4px rgba(0,0,0,.4),0 10px 28px rgba(0,0,0,.35);
    --hero-glow-1:rgba(53,195,214,.12);
    --hero-glow-2:rgba(232,163,61,.08);
    --code-bg:#16293c;
  }
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;scroll-padding-top:84px;overflow-x:clip}
body{
  font-family:'Hanken Grotesk',system-ui,-apple-system,sans-serif;
  font-size:17px;line-height:1.7;color:var(--text);background:var(--bg);
  -webkit-font-smoothing:antialiased;
  background-image:
    radial-gradient(ellipse 55% 40% at 92% -5%, var(--hero-glow-1), transparent 70%),
    radial-gradient(ellipse 45% 35% at -8% 105%, var(--hero-glow-2), transparent 70%);
  background-attachment:fixed;
  min-height:100vh;
}
::selection{background:var(--accent);color:#fff}
a{color:var(--accent);text-decoration:none}
a:hover{color:var(--accent-strong)}
img{max-width:100%;height:auto;display:block}
h1,h2,h3,h4{font-family:'Space Grotesk',system-ui,sans-serif;line-height:1.2;text-wrap:balance;color:var(--text)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:3px}
.skip-link{position:absolute;left:-9999px;top:0;background:var(--accent);color:#fff;padding:8px 16px;z-index:300;border-radius:0 0 8px 0}
.skip-link:focus{left:0}

/* ===== HEADER ===== */
.app-header{
  position:fixed;top:0;left:0;right:0;z-index:200;height:60px;
  display:flex;align-items:center;gap:16px;padding:0 20px;
  background:var(--header-bg);backdrop-filter:blur(14px);
  -webkit-backdrop-filter:blur(14px);
  border-bottom:1px solid var(--border);
}
.app-header::after{
  content:'';position:absolute;left:0;right:0;bottom:-1px;height:1px;
  background:linear-gradient(90deg,transparent,var(--accent),transparent);
  opacity:.35;pointer-events:none;
}
.logo{display:flex;align-items:center;gap:9px;flex-shrink:0;color:var(--text)}
.logo-mark{
  width:34px;height:34px;border-radius:9px;display:grid;place-items:center;
  background:linear-gradient(135deg,var(--accent),#0e2f3a);color:#cfeeF5;
  box-shadow:0 0 0 1px rgba(53,195,214,.25),0 2px 8px rgba(12,27,42,.25);
}
.logo-text{font-family:'Space Grotesk',sans-serif;font-weight:700;font-size:1.08rem;letter-spacing:-.01em;white-space:nowrap}
.logo-text em{font-style:normal;color:var(--accent)}
.mobile-menu-btn{
  display:none;flex-direction:column;gap:4px;background:none;border:none;cursor:pointer;
  padding:8px;border-radius:8px;
}
.mobile-menu-btn span{display:block;width:20px;height:2px;background:var(--text);border-radius:2px;transition:all .2s ease}
.mobile-menu-btn[aria-expanded="true"] span:nth-child(1){transform:translateY(6px) rotate(45deg)}
.mobile-menu-btn[aria-expanded="true"] span:nth-child(2){opacity:0}
.mobile-menu-btn[aria-expanded="true"] span:nth-child(3){transform:translateY(-6px) rotate(-45deg)}

/* ===== SEARCH ===== */
.header-search{position:relative;margin-left:auto;max-width:340px;width:100%}
.search-icon{position:absolute;left:12px;top:50%;transform:translateY(-50%);color:var(--text-dim);pointer-events:none}
#search-input{
  width:100%;padding:9px 14px 9px 36px;border-radius:10px;
  border:1px solid var(--border);background:var(--surface);color:var(--text);
  font-family:inherit;font-size:.92rem;
  transition:border-color .15s,box-shadow .15s;
}
#search-input::placeholder{color:var(--text-dim)}
#search-input:focus{outline:none;border-color:var(--accent);box-shadow:0 0 0 3px var(--accent-soft)}
.search-results{
  display:none;position:absolute;top:calc(100% + 6px);left:0;right:0;z-index:300;
  background:var(--surface);border:1px solid var(--border);border-radius:12px;
  box-shadow:var(--shadow-hover);overflow:hidden;max-height:420px;overflow-y:auto;
}
.search-results a{display:flex;gap:10px;align-items:flex-start;padding:11px 14px;border-bottom:1px solid var(--border);color:var(--text)}
.search-results a:last-child{border-bottom:none}
.search-results a:hover{background:var(--accent-soft)}
.search-results .sr-ico{font-size:1.05rem;line-height:1.4}
.search-results .sr-title{font-weight:600;font-size:.9rem;line-height:1.35}
.search-results .sr-exc{font-size:.8rem;color:var(--text-dim);line-height:1.35;margin-top:2px}
.search-results mark{background:var(--amber-soft);color:var(--amber);padding:0 2px;border-radius:2px}
.search-results .sr-empty{padding:14px;font-size:.85rem;color:var(--text-dim)}

/* ===== SIDEBAR ===== */
.sidebar{
  position:fixed;top:60px;left:0;bottom:0;width:272px;z-index:150;
  background:var(--bg);border-right:1px solid var(--border);
  overflow-y:auto;padding:14px 0 40px;
  scrollbar-width:thin;scrollbar-color:var(--border) transparent;
}
.sidebar::-webkit-scrollbar{width:4px}
.sidebar::-webkit-scrollbar-thumb{background:var(--border-strong);border-radius:4px}
.sidebar-nav{list-style:none}
.sidebar-nav .nav-home{
  display:flex;align-items:center;gap:8px;padding:9px 18px;margin:0 10px 8px;
  border-radius:9px;font-weight:600;font-size:.9rem;color:var(--text);
  background:var(--surface);border:1px solid var(--border);
}
.sidebar-nav .nav-home:hover{border-color:var(--accent)}
.nav-section{
  padding:16px 18px 5px;font-size:.7rem;font-weight:700;text-transform:uppercase;
  letter-spacing:.11em;color:var(--text-dim);
}
.sidebar-link{
  display:flex;align-items:center;gap:9px;padding:8px 18px;
  font-size:.9rem;line-height:1.35;color:var(--text);
  border-left:2px solid transparent;transition:background .15s,color .15s,border-color .15s;
}
.sidebar-link:hover{background:var(--surface-2);color:var(--text)}
.sidebar-link.active{color:var(--accent);border-left-color:var(--accent);background:var(--accent-soft);font-weight:600}
.sidebar-link .sl-ico{font-size:.95rem;flex-shrink:0}

/* ===== MAIN ===== */
.main-content{margin-left:272px;padding:84px 44px 40px;max-width:980px;min-height:100vh}
@keyframes fadeUp{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:translateY(0)}}
.content-article{animation:fadeUp .25s ease-out}

/* ===== HERO (home) ===== */
.home-hero{
  position:relative;border-radius:18px;overflow:hidden;
  background:linear-gradient(135deg,#0c1b2a 0%,#123043 55%,#0e2736 100%);
  border:1px solid rgba(53,195,214,.22);
  padding:44px 44px 36px;color:#e8eef2;margin-bottom:34px;
  box-shadow:var(--shadow-hover);
}
.home-hero::before{
  content:'';position:absolute;top:-120px;right:-80px;width:420px;height:420px;border-radius:50%;
  background:radial-gradient(circle,var(--hero-glow-1),transparent 70%);pointer-events:none;
}
.home-hero::after{
  content:'';position:absolute;bottom:-140px;left:-60px;width:380px;height:380px;border-radius:50%;
  background:radial-gradient(circle,var(--hero-glow-2),transparent 70%);pointer-events:none;
}
.hero-eyebrow{
  font-family:'IBM Plex Mono',monospace;font-size:.78rem;letter-spacing:.14em;text-transform:uppercase;
  color:#5fd4e3;margin-bottom:10px;position:relative;z-index:1;
}
.home-hero h1{
  font-size:clamp(1.7rem,4.2vw,2.7rem);font-weight:700;color:#fff;
  letter-spacing:-.02em;position:relative;z-index:1;margin-bottom:10px;
}
.home-hero h1 em{font-style:normal;color:#35c3d6}
.home-hero p{color:#c2d4de;max-width:620px;font-size:1.02rem;position:relative;z-index:1;margin-bottom:18px}
.hero-cta{
  display:inline-flex;align-items:center;gap:8px;position:relative;z-index:1;
  background:linear-gradient(135deg,#35c3d6,#1d93a5);color:#06222b;font-weight:700;
  padding:11px 22px;border-radius:10px;font-size:.95rem;
  transition:transform .15s ease,box-shadow .15s ease;
}
.hero-cta:hover{transform:translateY(-2px);box-shadow:0 6px 20px rgba(53,195,214,.35);color:#06222b}
.hero-stats{display:flex;gap:28px;margin-top:26px;position:relative;z-index:1;flex-wrap:wrap}
.hero-stat .num{font-family:'Space Grotesk',sans-serif;font-size:1.7rem;font-weight:700;color:#35c3d6;display:block;line-height:1.1}
.hero-stat .lbl{font-size:.78rem;color:#9fb4c2;text-transform:uppercase;letter-spacing:.08em}

/* SVG signature - obieg chlodniczy */
.hero-ac-wrap{margin-top:26px;position:relative;z-index:1;max-width:560px}
.hero-ac-wrap svg{width:100%;height:auto;display:block}
.ac-pipe{stroke:#35c3d6;stroke-width:5;stroke-linecap:round;fill:none}
.ac-pipe-gas{stroke:var(--amber,#e8a33d);stroke-width:5;stroke-linecap:round;fill:none}
.ac-box{fill:rgba(255,255,255,.06);stroke:rgba(255,255,255,.25);stroke-width:1.5}
.ac-box text{font-family:'IBM Plex Mono',monospace;font-size:11px;fill:#9fb4c2}
.ac-flow{stroke:#5fd4e3;stroke-width:2.5;fill:none;stroke-linecap:round;stroke-dasharray:6 10;animation:acFlow 3.2s linear infinite}
.ac-flow-gas{stroke:var(--amber,#e8a33d);stroke-width:2.5;fill:none;stroke-linecap:round;stroke-dasharray:5 9;animation:acFlow 4s linear infinite reverse}
.ac-fan{fill:rgba(53,195,214,.25);stroke:#5fd4e3;stroke-width:1.5;animation:acSpin 6s linear infinite;transform-origin:center;transform-box:fill-box}
@keyframes acFlow{to{stroke-dashoffset:-32}}
@keyframes acSpin{to{transform:rotate(360deg)}}
@keyframes acFlick{0%,100%{opacity:.55}50%{opacity:1}}
.ac-flame{animation:acFlick 1.6s ease-in-out infinite}
@media (prefers-reduced-motion: reduce){
  .ac-flow,.ac-flow-gas,.ac-fan,.ac-flame{animation:none}
}

/* ===== HOME GRID ===== */
.home-section-label{
  display:flex;align-items:center;gap:10px;font-size:1.15rem;font-weight:700;
  margin:30px 0 14px;letter-spacing:-.01em;
}
.home-section-label::before{content:'';width:4px;height:22px;border-radius:2px;background:linear-gradient(180deg,var(--accent),var(--amber))}
.home-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(265px,1fr));gap:14px}
.home-card{
  display:flex;flex-direction:column;gap:6px;padding:18px 20px;
  background:var(--surface);border:1px solid var(--border);border-radius:14px;
  color:var(--text);box-shadow:var(--shadow);
  transition:transform .18s ease-out,box-shadow .18s ease-out,border-color .18s ease-out;
  position:relative;overflow:hidden;
}
.home-card::before{
  content:'';position:absolute;top:0;left:0;right:0;height:3px;
  background:linear-gradient(90deg,var(--accent),var(--amber));
  opacity:0;transition:opacity .2s ease;
}
.home-card:hover{transform:translateY(-3px);box-shadow:var(--shadow-hover);border-color:var(--border-strong)}
.home-card:hover::before{opacity:1}
.card-icon{font-size:1.45rem;line-height:1.2}
.home-card h3{font-size:.95rem;font-weight:600;line-height:1.35}
.home-card p{font-size:.85rem;color:var(--text-dim);line-height:1.5;flex-grow:1}
.card-meta{display:flex;align-items:center;gap:8px;font-size:.75rem;color:var(--text-dim);font-family:'IBM Plex Mono',monospace;text-transform:uppercase;letter-spacing:.05em}
.card-meta .dot{width:3px;height:3px;border-radius:50%;background:var(--border-strong)}

/* ===== ARTICLE ===== */
.content-article h1{font-size:clamp(1.6rem,3.6vw,2.35rem);font-weight:700;letter-spacing:-.02em;margin-bottom:10px}
.article-meta{
  display:flex;align-items:center;gap:10px;flex-wrap:wrap;
  font-size:.82rem;color:var(--text-dim);margin-bottom:22px;padding-bottom:16px;
  border-bottom:1px solid var(--border);
  font-family:'IBM Plex Mono',monospace;
}
.article-meta .tag{
  background:var(--accent-soft);color:var(--accent);padding:2px 10px;border-radius:20px;
  font-weight:600;font-size:.75rem;letter-spacing:.04em;
}
.content-article h2{
  font-size:1.35rem;font-weight:700;margin:34px 0 12px;letter-spacing:-.01em;
  padding-bottom:8px;border-bottom:1px solid var(--border);
}
.content-article h3{font-size:1.08rem;font-weight:600;margin:26px 0 8px}
.content-article p{margin-bottom:14px}
.content-article ul,.content-article ol{margin:0 0 16px;padding-left:24px}
.content-article li{margin-bottom:6px}
.content-article strong{font-weight:700}
.content-article a{border-bottom:1px solid var(--accent-soft)}
.content-article a:hover{border-bottom-color:var(--accent)}

/* TOC */
.article-toc{
  background:var(--surface);border:1px solid var(--border);border-radius:12px;
  padding:16px 20px;margin:18px 0 26px;font-size:.9rem;
}
.article-toc h3{font-size:.78rem;text-transform:uppercase;letter-spacing:.1em;color:var(--text-dim);margin:0 0 10px;font-family:'IBM Plex Mono',monospace}
.article-toc a{display:block;padding:4px 0;color:var(--text);border:none}
.article-toc a:hover{color:var(--accent)}
.article-toc .toc-h3{padding-left:18px;font-size:.86rem;color:var(--text-dim)}

/* Tables */
.table-responsive{overflow-x:auto;margin:18px 0;border-radius:12px;border:1px solid var(--border)}
.content-article table{width:100%;border-collapse:collapse;font-size:.9rem;background:var(--surface)}
.content-article th,.content-article td{padding:11px 14px;text-align:left;border-bottom:1px solid var(--border);vertical-align:top}
.content-article th{
  background:var(--accent-soft);color:var(--accent);font-weight:700;font-size:.8rem;
  text-transform:uppercase;letter-spacing:.05em;font-family:'Space Grotesk',sans-serif;
}
.content-article tr:last-child td{border-bottom:none}
.content-article tbody tr:nth-child(even){background:var(--surface-2)}
.content-article tbody tr:hover{background:var(--accent-soft)}
.error-table th{background:var(--amber-soft);color:var(--amber)}
.error-table td:first-child{font-family:'IBM Plex Mono',monospace;font-weight:600;color:var(--accent);white-space:nowrap}

/* Info box */
.info-box{
  background:var(--accent-soft);border:1px solid rgba(53,195,214,.3);border-left:4px solid var(--accent);
  border-radius:10px;padding:16px 18px;margin:18px 0;font-size:.93rem;
}
.info-box strong{color:var(--accent)}
.warn-box{
  background:var(--amber-soft);border:1px solid rgba(232,163,61,.35);border-left:4px solid var(--amber);
  border-radius:10px;padding:16px 18px;margin:18px 0;font-size:.93rem;
}
.warn-box strong{color:var(--amber)}

/* FAQ */
.faq-item{border-bottom:1px solid var(--border);padding:18px 0}
.faq-item:last-child{border-bottom:none}
.faq-item h3{font-size:1rem;font-weight:700;margin:0 0 8px;color:var(--text)}
.faq-item h3::before{content:'Q: ';color:var(--accent)}
.faq-item p{margin:0}
.faq-item p::before{content:'A: ';color:var(--amber);font-weight:700}

/* Glossary */
.glossary dt{
  font-family:'Space Grotesk',sans-serif;font-weight:700;color:var(--text);
  margin-top:18px;font-size:.98rem;
}
.glossary dt::before{content:'▸ ';color:var(--accent)}
.glossary dd{color:var(--text-dim);margin:3px 0 0;padding-left:16px;font-size:.92rem}

/* Checklist */
.checklist{list-style:none;padding:0!important}
.checklist li{padding:9px 0 9px 34px;position:relative;border-bottom:1px dashed var(--border)}
.checklist li::before{
  content:'';position:absolute;left:4px;top:13px;width:17px;height:17px;border-radius:5px;
  border:2px solid var(--accent);background:var(--surface);
}
.checklist li::after{
  content:'✓';position:absolute;left:7px;top:10px;color:var(--accent);font-weight:700;font-size:.85rem;
}
.checklist li:last-child{border-bottom:none}

/* 404 */
.error-page{text-align:center;padding:70px 0}
.error-page .err-code{font-family:'Space Grotesk',sans-serif;font-size:4.5rem;font-weight:700;color:var(--accent)}
.error-page a{display:inline-block;margin-top:18px;padding:10px 26px;background:var(--accent);color:#fff;border-radius:10px;font-weight:600;font-size:.92rem}

/* FOOTER */
.app-footer{
  margin-left:272px;padding:34px 44px 44px;border-top:1px solid var(--border);
  color:var(--text-dim);font-size:.88rem;
}
.app-footer .foot-note{font-size:.8rem;margin-top:6px;max-width:700px}
.app-footer .foot-copy{margin-top:12px;font-size:.78rem}
.app-footer a{color:var(--text-dim);border-bottom:1px solid var(--border)}
.app-footer a:hover{color:var(--accent)}

/* LOADING */
.loading{display:grid;place-items:center;padding:120px 0}
.spinner{width:34px;height:34px;border-radius:50%;border:3px solid var(--border);border-top-color:var(--accent);animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}

/* ===== RESPONSIVE ===== */
@media (max-width:900px){
  .mobile-menu-btn{display:flex}
  .sidebar{transform:translateX(-100%);transition:transform .25s ease;box-shadow:none}
  .sidebar.open{transform:translateX(0);box-shadow:0 0 60px rgba(12,27,42,.35)}
  .sidebar-overlay{display:none;position:fixed;inset:0;background:rgba(12,27,42,.5);z-index:140}
  .sidebar-overlay.show{display:block}
  .main-content{margin-left:0;padding:76px 18px 40px}
  .app-footer{margin-left:0;padding:28px 18px 40px}
  .header-search{max-width:180px}
  .home-hero{padding:34px 24px 28px}
}
@media (max-width:600px){
  .home-grid{grid-template-columns:1fr}
  .header-search{max-width:44px}
  .header-search:focus-within{max-width:calc(100vw - 130px)}
  #search-input{padding-left:34px}
  .logo-text{font-size:.98rem}
}
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
}