/* ============================================================
   Basen - design system "Woda i słońce"
   Paleta: głęboki błękit wody + turkus + piasek + bursztyn słońca
   Typografia: Figtree (display) + Cabin (body)
   ============================================================ */

:root {
  --accent: #0b4f6c;            /* głęboki błękit wody */
  --accent-2: #0e9594;          /* turkus */
  --accent-3: #f0a12b;          /* bursztyn słońca */
  --accent-light: #dceef2;      /* błękitne tło akcentowe */
  --accent-subtle: #8fc9d6;     /* subtelny akcent (glow) */
  --sun-soft: #fdf1de;          /* bursztynowe tło */

  --bg: #f7f2e7;                /* piaskowy krem */
  --bg-soft: #efe8d8;           /* głębszy piasek */
  --card: #fffdf8;              /* kremowo-biały */
  --text: #16242e;              /* grafit z odcieniem wody */
  --muted: #55666f;             /* wyciszony tekst (4.5:1+) */
  --border: #e0d6bf;            /* piaskowa linia */

  --box-info-bg: #e9f2f5;  --box-info-border: #b7d3dd;
  --box-tip-bg: #e7f3ec;    --box-tip-border: #b6d8c4;
  --box-warn-bg: #fdeee0;   --box-warn-border: #eec49d;
  --box-key-bg: #eef1f8;    --box-key-border: #c8d2e8;

  --font-display: 'Figtree', system-ui, sans-serif;
  --font-body: 'Cabin', system-ui, sans-serif;

  --header-h: 62px;
  --sidebar-w: 320px;
  --radius: 14px;
  --radius-sm: 9px;
  --transition: all .2s ease-out;
  --shadow-card: 0 1px 3px rgba(22, 36, 46, .06), 0 6px 24px -12px rgba(22, 36, 46, .14);
  --shadow-card-hover: 0 4px 10px rgba(11, 79, 108, .10), 0 14px 34px -14px rgba(11, 79, 108, .22);
}

@media (prefers-color-scheme: dark) {
  :root {
    --accent: #35c3c0;          /* jaśniejszy turkus w ciemnym */
    --accent-2: #2ec4b6;
    --accent-3: #f5a93a;
    --accent-light: #10303d;
    --accent-subtle: #2c7d8c;
    --sun-soft: #3a2c15;

    --bg: #0a1620;              /* granat nocny */
    --bg-soft: #0d1c28;
    --card: #10222e;
    --text: #d9e8ef;            /* jasny błękitny krem */
    --muted: #93a9b6;
    --border: #1d3442;

    --box-info-bg: #0e2430;  --box-info-border: #1e4a5c;
    --box-tip-bg: #0e2519;   --box-tip-border: #1f5a3a;
    --box-warn-bg: #2a1d0d;  --box-warn-border: #6b4a1d;
    --box-key-bg: #131c2e;   --box-key-border: #2b3d63;

    --shadow-card: 0 1px 3px rgba(0, 0, 0, .4), 0 8px 26px -12px rgba(0, 0, 0, .55);
    --shadow-card-hover: 0 4px 12px rgba(0, 0, 0, .5), 0 16px 40px -16px rgba(46, 196, 182, .18);
  }
}

/* ---------- base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  /* atmosfera: dwie subtelne poświaty w rogach */
  background-image:
    radial-gradient(ellipse 900px 520px at 108% -6%, var(--accent-light), transparent 62%),
    radial-gradient(ellipse 760px 480px at -8% 104%, var(--sun-soft), transparent 60%);
  background-attachment: fixed;
  transition: background .3s ease, color .3s ease;
}
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-2); }
h1, h2, h3, h4 { font-family: var(--font-display); line-height: 1.25; text-wrap: balance; }
img { max-width: 100%; height: auto; }
:focus-visible { outline: 3px solid var(--accent-3); outline-offset: 2px; border-radius: 4px; }
::selection { background: var(--accent-2); color: #fff; }

/* ---------- header ---------- */
.app-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 50;
  height: var(--header-h);
  display: flex; align-items: center; gap: 18px;
  padding: 0 22px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  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-subtle), transparent);
  opacity: .3; pointer-events: none;
}
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); flex-shrink: 0; }
.brand:hover { color: var(--text); }
.brand-mark { width: 30px; height: 30px; fill: var(--accent-2); }
.brand-mark .brand-wave { stroke: var(--bg); stroke-width: 7; fill: none; stroke-linecap: round; }
.brand-name { font-family: var(--font-display); font-weight: 800; font-size: 1.25rem; letter-spacing: -.02em; }

.header-search { position: relative; flex: 1; max-width: 460px; margin-left: auto; }
.search-icon { position: absolute; left: 13px; top: 50%; transform: translateY(-50%); width: 17px; height: 17px; stroke: var(--muted); fill: none; stroke-width: 2; stroke-linecap: round; }
#search-input {
  width: 100%; padding: 9px 14px 9px 38px;
  font-family: var(--font-body); font-size: .95rem; color: var(--text);
  background: var(--card); border: 1px solid var(--border); border-radius: 999px;
  transition: var(--transition);
}
#search-input:focus { outline: none; border-color: var(--accent-2); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent-2) 18%, transparent); }
.search-results {
  position: absolute; top: calc(100% + 8px); left: 0; right: 0; z-index: 60;
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius-sm);
  box-shadow: var(--shadow-card-hover); overflow: hidden;
  opacity: 0; transform: translateY(-4px); pointer-events: none;
  transition: var(--transition);
}
.search-results.open { opacity: 1; transform: translateY(0); pointer-events: auto; }
.search-item { display: block; padding: 10px 14px; border-bottom: 1px solid var(--border); }
.search-item:last-child { border-bottom: none; }
.search-item:hover { background: var(--bg-soft); }
.si-title { display: block; font-family: var(--font-display); font-weight: 600; font-size: .92rem; color: var(--text); }
.si-excerpt { display: block; font-size: .8rem; color: var(--muted); margin-top: 2px; }
.search-empty { padding: 12px 14px; font-size: .88rem; color: var(--muted); }

.mobile-menu-btn {
  display: none; width: 40px; height: 40px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: var(--card); color: var(--text); font-size: 1.15rem; cursor: pointer; flex-shrink: 0;
}
.mobile-menu-btn:hover { border-color: var(--accent-2); }

/* ---------- sidebar ---------- */
.sidebar {
  position: fixed; top: var(--header-h); left: 0; bottom: 0; z-index: 40;
  width: var(--sidebar-w); overflow-y: auto;
  padding: 18px 16px 40px;
  background: var(--bg-soft);
  border-right: 1px solid var(--border);
  scrollbar-width: thin;
}
.sidebar-nav { list-style: none; margin: 0; padding: 0; }
.sidebar-nav li.nav-section {
  font-family: var(--font-display); font-weight: 700; font-size: .7rem;
  text-transform: uppercase; letter-spacing: .07em; color: var(--muted);
  margin: 20px 10px 6px;
}
.sidebar-nav li.nav-section:first-child { margin-top: 4px; }
.sidebar-nav a {
  display: flex; align-items: baseline; gap: 8px;
  padding: 7px 10px; border-radius: 8px;
  font-size: .9rem; line-height: 1.4; color: var(--text);
  transition: var(--transition);
}
.sidebar-nav a:hover { background: var(--card); color: var(--accent); }
.sidebar-nav a.active { background: var(--card); color: var(--accent-2); font-weight: 600; box-shadow: inset 3px 0 0 var(--accent-2); }
.nav-icon { font-size: .85rem; flex-shrink: 0; }
.sidebar-overlay {
  display: none; position: fixed; inset: 0; z-index: 39;
  background: rgba(10, 22, 32, .5); backdrop-filter: blur(2px);
}

/* ---------- layout ---------- */
.main { margin-left: var(--sidebar-w); padding: calc(var(--header-h) + 8px) 26px 40px; max-width: 1080px; }
.page { animation: fadeUp .26s ease-out; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(8px); } }

/* ---------- reveal on scroll ---------- */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity .5s ease-out, transform .5s ease-out; }
.reveal.visible { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .page { animation: none; }
  * { transition-duration: .01ms !important; animation-duration: .01ms !important; }
}

/* ---------- hero ---------- */
.home-hero {
  position: relative; overflow: hidden;
  border-radius: var(--radius);
  padding: 52px 48px 40px;
  background: linear-gradient(135deg, #0b4f6c 0%, #0e7d8f 55%, #0e9594 100%);
  color: #f2fafb;
  box-shadow: var(--shadow-card-hover);
}
.home-hero::before {
  content: ''; position: absolute; inset: 0; opacity: .16; pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1200 320'%3E%3Cpath d='M0 160 Q150 100 300 160 T600 160 T900 160 T1200 160 V320 H0 Z' fill='%23ffffff'/%3E%3C/svg%3E");
  background-size: 1200px 320px; background-position: bottom; background-repeat: repeat-x;
}
.hero-eyebrow {
  display: inline-block; font-family: var(--font-display); font-weight: 700; font-size: .8rem;
  text-transform: uppercase; letter-spacing: .1em;
  color: #f5c77e; background: rgba(10, 22, 32, .25);
  padding: 5px 12px; border-radius: 999px; margin-bottom: 16px;
}
.home-hero h1 { margin: 0 0 14px; font-size: clamp(1.9rem, 4vw, 2.7rem); font-weight: 800; color: #fff; max-width: 16em; }
.hero-sub { margin: 0 0 26px; font-size: 1.06rem; max-width: 34em; color: #dceff2; }
.hero-cta {
  display: inline-block; font-family: var(--font-display); font-weight: 700; font-size: .98rem;
  color: #16242e; background: var(--accent-3);
  padding: 12px 24px; border-radius: 999px;
  transition: var(--transition);
}
.hero-cta:hover { transform: translateY(-2px); box-shadow: 0 8px 22px -8px rgba(240, 161, 43, .7); color: #16242e; }
.hero-stats { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 32px; position: relative; }
.hero-stat {
  background: rgba(255, 255, 255, .12); border: 1px solid rgba(255, 255, 255, .18);
  border-radius: var(--radius-sm); padding: 10px 20px; text-align: center;
  backdrop-filter: blur(4px); min-width: 96px;
}
.hs-num { font-family: var(--font-display); font-weight: 800; font-size: 1.5rem; color: #fff; line-height: 1.1; }
.hs-label { font-size: .78rem; color: #cde4e9; text-transform: uppercase; letter-spacing: .05em; }

/* ---------- kalkulator basenu (signature) ---------- */
.pool-calc {
  margin-top: 26px;
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 30px 34px; box-shadow: var(--shadow-card);
}
.pool-calc h2 { margin: 0 0 6px; font-size: 1.35rem; color: var(--text); }
.pool-calc .calc-sub { margin: 0 0 22px; color: var(--muted); font-size: .95rem; }
.calc-fields { display: flex; flex-wrap: wrap; gap: 16px; }
.calc-field label { display: block; font-size: .8rem; font-weight: 600; color: var(--muted); margin-bottom: 5px; text-transform: uppercase; letter-spacing: .04em; }
.calc-field input {
  width: 130px; padding: 10px 12px; font-family: var(--font-body); font-size: 1rem; color: var(--text);
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-sm);
  transition: var(--transition);
}
.calc-field input:focus { outline: none; border-color: var(--accent-2); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent-2) 18%, transparent); }
.calc-result {
  margin-top: 18px; padding: 16px 20px; border-radius: var(--radius-sm);
  background: var(--accent-light); border: 1px solid var(--box-info-border);
  font-size: 1.02rem; min-height: 1.7em;
}
.calc-result strong { color: var(--accent); font-family: var(--font-display); }
.calc-note { margin-top: 10px; font-size: .82rem; color: var(--muted); }

/* ---------- home sections & cards ---------- */
.home-section { margin-top: 44px; }
.section-head-row { display: flex; align-items: baseline; gap: 12px; }
.sec-num { font-family: var(--font-display); font-weight: 800; font-size: .95rem; color: var(--accent-2); }
.home-section h2 { margin: 0; font-size: 1.45rem; color: var(--text); }
.section-desc { margin: 6px 0 18px; color: var(--muted); font-size: .95rem; }
.home-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 16px; }
.home-card {
  display: flex; flex-direction: column; gap: 6px;
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 20px 16px; box-shadow: var(--shadow-card);
  transition: var(--transition);
}
.home-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-card-hover); border-color: color-mix(in srgb, var(--accent-2) 45%, var(--border)); }
.card-icon { font-size: 1.5rem; line-height: 1; }
.home-card h3 { margin: 4px 0 0; font-size: .95rem; font-weight: 700; color: var(--text); line-height: 1.35; }
.home-card p { margin: 0; font-size: .85rem; color: var(--muted); line-height: 1.55; }
.card-arrow { margin-top: auto; padding-top: 8px; font-size: .8rem; font-weight: 600; color: var(--accent-2); opacity: 0; transform: translateX(-8px); transition: var(--transition); }
.home-card:hover .card-arrow { opacity: 1; transform: translateX(0); }

/* ---------- article ---------- */
.article-head { padding: 26px 0 6px; }
.art-eyebrow {
  display: inline-block; font-family: var(--font-display); font-weight: 700; font-size: .78rem;
  text-transform: uppercase; letter-spacing: .08em; color: var(--accent-2);
  margin-bottom: 10px;
}
.article-head h1 { margin: 0 0 12px; font-size: clamp(1.7rem, 3.4vw, 2.3rem); font-weight: 800; color: var(--text); }
.art-excerpt { margin: 0; font-size: 1.08rem; color: var(--muted); max-width: 44em; }
.article-body { padding-bottom: 30px; }
.article-body h2 {
  font-size: 1.35rem; font-weight: 700; color: var(--text);
  margin: 38px 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--border);
  scroll-margin-top: calc(var(--header-h) + 16px);
}
.article-body h2:first-child { margin-top: 26px; }
.article-body h3 { font-size: 1.08rem; font-weight: 700; color: var(--accent); margin: 26px 0 8px; }
.article-body p { margin: 0 0 16px; }
.article-body ul, .article-body ol { margin: 0 0 18px; padding-left: 24px; }
.article-body li { margin-bottom: 6px; }
.article-body strong { color: var(--text); }

/* TOC */
.article-toc {
  margin: 22px 0 6px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: var(--card); padding: 4px 18px;
}
.article-toc summary {
  cursor: pointer; font-family: var(--font-display); font-weight: 700; font-size: .9rem;
  padding: 10px 0; color: var(--accent); list-style: none;
}
.article-toc summary::-webkit-details-marker { display: none; }
.article-toc summary::before { content: 'Spis treści'; }
.article-toc[open] summary::before { content: 'Spis treści'; }
.article-toc ol { margin: 0; padding: 0 0 12px 0; list-style: none; }
.article-toc li { margin: 0; border-top: 1px solid var(--border); }
.article-toc a { display: block; padding: 7px 2px; font-size: .9rem; color: var(--muted); transition: var(--transition); }
.article-toc a:hover { color: var(--accent-2); padding-left: 6px; }

/* ---------- boxes ---------- */
.info-box, .tip-box, .warning-box, .key-takeaways {
  border-radius: var(--radius-sm); padding: 16px 18px; margin: 20px 0;
  color: var(--text); border-left: 4px solid;
}
.info-box { background: var(--box-info-bg); border-color: var(--box-info-border); }
.tip-box  { background: var(--box-tip-bg);  border-color: var(--box-tip-border); }
.warning-box { background: var(--box-warn-bg); border-color: var(--box-warn-border); }
.key-takeaways { background: var(--box-key-bg); border-color: var(--box-key-border); }
.info-box p, .tip-box p, .warning-box p, .key-takeaways p { margin: 0 0 8px; }
.info-box p:last-child, .tip-box p:last-child, .warning-box p:last-child, .key-takeaways p:last-child { margin-bottom: 0; }
.info-box ul, .tip-box ul, .warning-box ul, .key-takeaways ul { margin: 6px 0 0; padding-left: 20px; }
.info-box h3, .tip-box h3, .warning-box h3, .key-takeaways h3 { margin: 0 0 8px; font-size: .98rem; color: var(--text); }
.info-box::before { content: 'ℹ️ '; }
.tip-box::before { content: '💡 '; }
.warning-box::before { content: '⚠️ '; }

/* ---------- tables ---------- */
.table-responsive { overflow-x: auto; margin: 20px 0; border-radius: var(--radius-sm); border: 1px solid var(--border); }
table.compare-table { width: 100%; border-collapse: collapse; font-size: .93rem; background: var(--card); min-width: 560px; }
.compare-table thead th {
  background: var(--accent); color: #fff; font-family: var(--font-display); font-weight: 700;
  text-align: left; padding: 12px 14px; font-size: .88rem;
}
.compare-table tbody td { padding: 11px 14px; border-top: 1px solid var(--border); vertical-align: top; }
.compare-table tbody tr:nth-child(even) { background: var(--bg); }
.compare-table tbody tr:first-child td { border-top: none; }
.compare-table tbody td:first-child { font-weight: 600; color: var(--text); }

/* ---------- FAQ ---------- */
.faq-item {
  border: 1px solid var(--border); border-left: 4px solid var(--accent-2);
  border-radius: var(--radius-sm); background: var(--card);
  padding: 16px 20px; margin: 14px 0;
}
.faq-item h3 { margin: 0 0 8px; font-size: 1rem; color: var(--text); }
.faq-item p { margin: 0; font-size: .95rem; }

/* ---------- glossary ---------- */
.glossary-list dl { margin: 0; }
.glossary-list dt {
  font-family: var(--font-display); font-weight: 700; font-size: .98rem; color: var(--accent);
  margin-top: 18px; padding: 10px 14px 6px; background: var(--card);
  border: 1px solid var(--border); border-bottom: none; border-radius: var(--radius-sm) var(--radius-sm) 0 0;
}
.glossary-list dd {
  margin: 0; padding: 4px 14px 12px; font-size: .93rem; color: var(--muted);
  background: var(--card); border: 1px solid var(--border); border-top: none;
  border-radius: 0 0 var(--radius-sm) var(--radius-sm);
}

/* ---------- related ---------- */
.article-bottom { margin-top: 40px; padding-top: 24px; border-top: 1px solid var(--border); }
.related-links { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; }
.related-link {
  display: block; padding: 14px 16px; background: var(--card);
  border: 1px solid var(--border); border-radius: var(--radius-sm);
  transition: var(--transition);
}
.related-link:hover { border-color: var(--accent-2); transform: translateY(-2px); }
.rl-label { display: block; font-size: .72rem; text-transform: uppercase; letter-spacing: .06em; color: var(--accent-2); font-weight: 700; }
.rl-title { display: block; margin-top: 4px; font-family: var(--font-display); font-weight: 600; font-size: .9rem; color: var(--text); }

/* ---------- footer ---------- */
.site-footer { margin-left: var(--sidebar-w); border-top: 1px solid var(--border); background: var(--bg-soft); }
.footer-inner {
  max-width: 1080px; margin: 0 auto; padding: 34px 26px 18px;
  display: grid; grid-template-columns: 2fr 1fr 1.6fr; gap: 26px;
}
.footer-brand strong { font-family: var(--font-display); font-size: 1.1rem; }
.footer-brand p { margin: 6px 0 0; font-size: .88rem; color: var(--muted); }
.footer-links { list-style: none; margin: 0; padding: 0; }
.footer-links li { margin-bottom: 8px; }
.footer-links a { font-size: .9rem; color: var(--text); }
.footer-links a:hover { color: var(--accent-2); }
.footer-note p { margin: 0; font-size: .8rem; color: var(--muted); }
.footer-bottom {
  border-top: 1px solid var(--border); text-align: center;
  padding: 14px; font-size: .8rem; color: var(--muted);
}

/* ---------- responsive ---------- */
@media (max-width: 900px) {
  .sidebar { transform: translateX(-100%); transition: transform .24s ease-out; box-shadow: none; }
  .sidebar.open { transform: translateX(0); box-shadow: 0 0 40px rgba(0, 0, 0, .3); }
  .sidebar-overlay.open { display: block; }
  .main { margin-left: 0; padding: calc(var(--header-h) + 14px) 16px 40px; }
  .site-footer { margin-left: 0; }
  .mobile-menu-btn { display: block; }
  .brand-name { font-size: 1.1rem; }
  .header-search { max-width: none; }
  .home-hero { padding: 36px 24px 30px; }
  .footer-inner { grid-template-columns: 1fr; gap: 18px; }
}
@media (max-width: 600px) {
  body { font-size: 17px; }
  .home-grid { grid-template-columns: 1fr; }
  .hero-stats { gap: 10px; }
  .hero-stat { min-width: calc(50% - 10px); padding: 9px 12px; }
  .calc-field input { width: 100%; }
  .calc-fields { flex-direction: column; }
  .pool-calc { padding: 24px 20px; }
}