:root {
  --bg: #fffaf2;
  --surface: #ffffff;
  --surface-soft: #f3f8ff;
  --ink: #1f2937;
  --muted: #5f6b7a;
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --secondary: #f59e0b;
  --success: #15803d;
  --danger: #b91c1c;
  --line: #dce4ee;
  --wood: #b87937;
  --wood-dark: #75451e;
  --bead: #e6a84b;
  --shadow: 0 12px 30px rgba(31, 41, 55, .08);
  --radius: 20px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.6;
}
a { color: var(--primary-dark); }
a:hover { text-decoration-thickness: 2px; }
button, input, select { font: inherit; }
button { cursor: pointer; }
img { max-width: 100%; }

.skip-link {
  position: absolute;
  left: -999px;
  top: 8px;
  z-index: 999;
  background: #fff;
  color: #000;
  padding: .7rem 1rem;
  border-radius: 10px;
}
.skip-link:focus { left: 8px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(255, 250, 242, .95);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}
.nav-wrap {
  max-width: 1180px;
  margin: 0 auto;
  padding: .75rem 1rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  text-decoration: none;
  color: var(--ink);
  font-weight: 800;
  letter-spacing: -.02em;
}
.brand-mark { font-size: 1.55rem; }
.site-nav { display: flex; flex-wrap: wrap; gap: .35rem; }
.site-nav a {
  color: var(--ink);
  text-decoration: none;
  padding: .55rem .7rem;
  border-radius: 10px;
  font-weight: 650;
}
.site-nav a:hover, .site-nav a[aria-current="page"] { background: #eaf2ff; color: var(--primary-dark); }

.container { max-width: 1180px; margin: 0 auto; padding: 0 1rem; }
.hero {
  padding: 4rem 0 2.5rem;
  display: grid;
  grid-template-columns: 1.05fr .95fr;
  gap: 2rem;
  align-items: center;
}
.eyebrow {
  display: inline-block;
  margin-bottom: .7rem;
  padding: .35rem .65rem;
  background: #fff0cf;
  border: 1px solid #f3d28e;
  border-radius: 999px;
  font-size: .9rem;
  font-weight: 750;
}
h1, h2, h3 { line-height: 1.15; letter-spacing: -.025em; }
h1 { font-size: clamp(2.25rem, 6vw, 4.6rem); margin: 0 0 1rem; }
h2 { font-size: clamp(1.7rem, 3vw, 2.5rem); margin-top: 0; }
h3 { font-size: 1.25rem; }
.lead { font-size: 1.16rem; color: var(--muted); max-width: 66ch; }
.actions { display: flex; flex-wrap: wrap; gap: .8rem; margin-top: 1.4rem; }
.btn {
  display: inline-flex;
  justify-content: center;
  align-items: center;
  min-height: 44px;
  border: 0;
  border-radius: 13px;
  padding: .72rem 1rem;
  text-decoration: none;
  font-weight: 800;
  transition: transform .15s ease, background .15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-secondary { background: #fff; color: var(--ink); border: 1px solid var(--line); }
.btn-small { min-height: 38px; padding: .55rem .75rem; font-size: .94rem; }

.hero-card, .card, .lesson-card, .exercise-panel, .parent-note, .content-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.hero-card { padding: 1.25rem; }
.hero-list { margin: .7rem 0 0; padding-left: 1.2rem; }
.hero-list li { margin: .35rem 0; }

.section { padding: 2.6rem 0; }
.section-head { margin-bottom: 1.3rem; max-width: 760px; }
.section-head p { color: var(--muted); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.card { padding: 1.25rem; }
.card-icon { font-size: 2rem; }
.card p { color: var(--muted); }

.soroban-shell {
  margin-top: 1.2rem;
  background: #f8ead8;
  border: 10px solid var(--wood-dark);
  border-radius: 22px;
  padding: 1rem .7rem .8rem;
  overflow-x: auto;
  box-shadow: inset 0 0 0 4px var(--wood), var(--shadow);
}
.soroban {
  min-width: 590px;
  display: flex;
  gap: 24px;
  justify-content: center;
  align-items: flex-start;
  padding: .4rem .8rem .9rem;
}
.rod-wrap { text-align: center; }
.rod {
  width: 62px;
  height: 340px;
  position: relative;
  border-left: 4px solid #5c3a20;
  border-right: 4px solid #5c3a20;
}
.divider {
  position: absolute;
  top: 120px;
  left: -14px;
  right: -14px;
  height: 7px;
  background: var(--wood-dark);
  border-radius: 5px;
  z-index: 3;
}
.bead {
  width: 40px;
  height: 34px;
  background: linear-gradient(#f5bd65, var(--bead));
  border: 2px solid #a76c25;
  border-radius: 50% 50% 45% 45%;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  cursor: pointer;
  transition: transform .18s ease, filter .15s ease;
  box-shadow: 0 3px 5px rgba(73, 44, 17, .25);
}
.bead:hover { filter: brightness(1.05); }
.bead:focus-visible { outline: 4px solid #fff; box-shadow: 0 0 0 7px var(--primary); }
.upper { top: 20px; }
.upper.active { transform: translate(-50%, 50px); }
.lower.b1 { top: 160px; }
.lower.b2 { top: 200px; }
.lower.b3 { top: 240px; }
.lower.b4 { top: 280px; }
.lower.active { transform: translate(-50%, -35px); }
.rod-label { margin-top: .45rem; font-size: .82rem; font-weight: 800; color: #5c3a20; }

.soroban-toolbar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: .8rem;
  margin-top: 1rem;
}
.value-box {
  min-width: 190px;
  padding: .7rem 1rem;
  border-radius: 13px;
  background: #eef6ff;
  border: 1px solid #cbdff8;
  font-size: 1.12rem;
  font-weight: 850;
}
.value-hidden .value-number { filter: blur(8px); user-select: none; }

.learning-strip {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .9rem;
}
.lesson-card { padding: 1.15rem; }
.lesson-card strong { display: block; margin-bottom: .35rem; }
.lesson-card p { margin-bottom: 0; color: var(--muted); }

.exercise-panel { padding: 1.3rem; }
.controls {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: .8rem;
  margin-bottom: 1rem;
}
.field { text-align: left; }
.field label { display: block; font-weight: 750; margin-bottom: .35rem; }
.field select, .field input {
  width: 100%;
  min-height: 44px;
  padding: .65rem .75rem;
  border: 1px solid #bfcbd9;
  border-radius: 11px;
  background: #fff;
  color: var(--ink);
}
.task-box {
  background: var(--surface-soft);
  border: 2px dashed #b8ccea;
  border-radius: 16px;
  padding: 1.2rem;
  text-align: center;
}
.task-text { font-size: clamp(1.45rem, 3vw, 2.1rem); font-weight: 900; margin: .3rem 0 .8rem; }
.feedback { min-height: 1.9rem; margin-top: .7rem; font-weight: 800; }
.feedback.ok { color: var(--success); }
.feedback.bad { color: var(--danger); }
.answer-row { display: flex; flex-wrap: wrap; gap: .6rem; align-items: center; justify-content: center; }
.answer-row input { width: min(220px, 100%); min-height: 44px; border: 1px solid #bfcbd9; border-radius: 11px; padding: .65rem .8rem; }
.score { margin-top: .8rem; color: var(--muted); font-weight: 700; }

.steps { counter-reset: step; display: grid; gap: .85rem; }
.step {
  position: relative;
  padding: 1rem 1rem 1rem 3.6rem;
  border-left: 4px solid #b9cff4;
  background: #f8fbff;
  border-radius: 0 14px 14px 0;
}
.step::before {
  counter-increment: step;
  content: counter(step);
  position: absolute;
  left: 1rem;
  top: .95rem;
  width: 1.8rem;
  height: 1.8rem;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  font-weight: 900;
}

.faq details { background: #fff; border: 1px solid var(--line); border-radius: 14px; padding: .9rem 1rem; margin: .65rem 0; }
.faq summary { cursor: pointer; font-weight: 800; }

.parent-note { padding: 1.25rem; border-left: 6px solid var(--secondary); }
.parent-note p:last-child { margin-bottom: 0; }

.ad-placeholder {
  margin: 1.3rem auto;
  max-width: 970px;
  min-height: 100px;
  border: 1px dashed #aab5c2;
  background: #f7f8fa;
  color: #697586;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 1rem;
  border-radius: 12px;
  font-size: .9rem;
}
.ad-placeholder strong { display: block; color: #465261; }

.site-footer { margin-top: 2rem; border-top: 1px solid var(--line); background: #fff; }
.footer-grid { padding: 2rem 1rem; display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 1.5rem; }
.footer-links { display: grid; gap: .45rem; align-content: start; }
.footer-bottom { border-top: 1px solid var(--line); padding: 1rem; color: var(--muted); font-size: .9rem; }

.content-page { padding: 3rem 0; }
.content-card { padding: clamp(1.2rem, 3vw, 2.2rem); max-width: 900px; margin: 0 auto; }
.content-card h1 { font-size: clamp(2rem, 5vw, 3.5rem); }
.content-card h2 { margin-top: 2rem; font-size: 1.55rem; }
.content-card li { margin: .45rem 0; }
.notice { padding: .9rem 1rem; background: #fff7db; border: 1px solid #efd78b; border-radius: 12px; }

@media (max-width: 900px) {
  .hero { grid-template-columns: 1fr; padding-top: 2.5rem; }
  .grid-3, .learning-strip { grid-template-columns: repeat(2, 1fr); }
  .controls { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 620px) {
  .nav-wrap { align-items: flex-start; flex-direction: column; }
  .site-nav { width: 100%; overflow-x: auto; flex-wrap: nowrap; padding-bottom: .2rem; }
  .site-nav a { white-space: nowrap; }
  .grid-3, .learning-strip, .controls, .footer-grid { grid-template-columns: 1fr; }
  h1 { font-size: 2.4rem; }
  .section { padding: 2rem 0; }
  .soroban { gap: 16px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; }
}

/* Nauka dodawania i odejmowania */
.arithmetic-school { background: linear-gradient(180deg, rgba(238,246,255,.55), rgba(255,250,242,.35)); }
.rule-intro {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 1.2rem;
  align-items: center;
  padding: 1.25rem;
  margin-bottom: 1rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.rule-big {
  width: 92px;
  height: 92px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: #fff1cf;
  border: 4px solid #e2a838;
  font-size: 3.4rem;
  font-weight: 950;
  color: #6f4712;
}
.friend-pairs { display: flex; flex-wrap: wrap; gap: .65rem; margin-top: .65rem; }
.friend-pairs span {
  padding: .5rem .75rem;
  background: #eef6ff;
  border: 1px solid #cbdff8;
  border-radius: 999px;
  font-weight: 900;
}
.arithmetic-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; }
.teach-card {
  padding: 1.25rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.teach-card-accent { border: 3px solid #f0c363; background: #fffdf6; }
.teach-tag {
  display: inline-block;
  margin-bottom: .55rem;
  padding: .28rem .55rem;
  border-radius: 999px;
  background: #eef6ff;
  color: #244f89;
  font-size: .82rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: .03em;
}
.equation {
  margin: .8rem 0;
  padding: .75rem 1rem;
  background: #f4f8fd;
  border: 1px solid #d6e3f2;
  border-radius: 12px;
  text-align: center;
  font-size: clamp(1.25rem, 3vw, 1.65rem);
  font-weight: 950;
}
.move-list { padding-left: 1.35rem; }
.move-list li { margin: .48rem 0; }
.kid-note { padding: .75rem .85rem; background: #fff7db; border-radius: 10px; }
.complement-box {
  margin-top: 1rem;
  padding: 1.3rem;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}
.complement-columns { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; }
.complement-columns > div { padding: 1rem; background: #f8fbff; border-radius: 14px; }
.complement-columns p { margin: .42rem 0; }
.rule-warning { margin: 1rem 0 0; padding: .85rem 1rem; border-left: 5px solid #e2a838; background: #fff9e8; }
.mini-practice { margin-top: 1rem; padding: 1.2rem; text-align: center; background: #fff; border: 1px solid var(--line); border-radius: var(--radius); }
.practice-chips { display: flex; flex-wrap: wrap; justify-content: center; gap: .55rem; margin: .8rem 0; }
.practice-chips span { padding: .55rem .75rem; border-radius: 10px; background: #f2f7ff; border: 1px solid #d7e5f7; font-weight: 900; }

@media (max-width: 720px) {
  .rule-intro { grid-template-columns: 1fr; text-align: center; }
  .rule-big { margin: 0 auto; }
  .friend-pairs { justify-content: center; }
  .arithmetic-grid, .complement-columns { grid-template-columns: 1fr; }
}


/* Language switch and production polish */
.header-actions { display:flex; align-items:center; gap:.7rem; }
.lang-switch { display:inline-flex; align-items:center; gap:.18rem; padding:.2rem; border:1px solid var(--line); background:#fff; border-radius:999px; box-shadow:0 4px 12px rgba(31,41,55,.05); }
.lang-switch a { min-width:38px; padding:.35rem .55rem; text-align:center; border-radius:999px; text-decoration:none; color:var(--muted); font-weight:850; font-size:.86rem; }
.lang-switch a[aria-current="true"] { background:var(--primary); color:#fff; }
.lang-switch a:focus-visible { outline:3px solid #93b4ee; outline-offset:2px; }
.privacy-note { font-size:.92rem; color:var(--muted); }
.ad-disclosure { margin:1rem 0 0; padding:.8rem 1rem; border-left:4px solid #9fbce8; background:#f7fbff; border-radius:0 10px 10px 0; font-size:.92rem; color:var(--muted); }
@media (max-width: 900px) { .nav-wrap { flex-wrap:wrap; } .header-actions { width:100%; justify-content:space-between; } }
@media (max-width: 620px) { .header-actions { width:100%; align-items:flex-start; } .lang-switch { flex:0 0 auto; } }