:root {
  --paper: #f6f1e6;
  --card: #fffdf8;
  --ink: #2a241c;
  --muted: #6b6258;
  --forest: #2f4a3c;
  --forest-2: #1f3329;
  --copper: #b45a2e;
  --line: #e4d9c6;
  --ok: #2f6b45;
  --bad: #9b2f2f;
  --shadow: 0 10px 30px rgba(42, 36, 28, 0.08);
  --radius: 18px;
  --font: "Segoe UI", "Liberation Sans", system-ui, sans-serif;
  --serif: Georgia, "Liberation Serif", "Times New Roman", serif;
  --mono: "Cascadia Mono", "Liberation Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 10% -10%, #efe4cc 0%, transparent 55%),
    var(--paper);
  line-height: 1.55;
}
img, svg { max-width: 100%; }
a { color: var(--forest); }
a:hover { color: var(--copper); }
code, pre { font-family: var(--mono); }
.skip {
  position: absolute;
  left: -999px;
  top: 0;
}
.skip:focus {
  left: 12px;
  top: 12px;
  background: #fff;
  padding: 8px 12px;
  z-index: 20;
}

.top {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  gap: 12px;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background: rgba(246, 241, 230, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.brand {
  text-decoration: none;
  color: inherit;
}
.brand small {
  display: block;
  color: var(--muted);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: 0.7rem;
}
.brand strong {
  font-family: var(--serif);
  font-size: 1.15rem;
  color: var(--forest);
}
.top-actions { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; }
.btn, button.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink);
  border-radius: 999px;
  padding: 8px 14px;
  text-decoration: none;
  cursor: pointer;
  font: inherit;
}
.btn.primary {
  background: var(--forest);
  color: #f7f3ea;
  border-color: var(--forest);
}
.btn.primary:hover { background: var(--forest-2); color: #fff; }
.menu-btn { display: none; }

.layout {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  width: 100%;
  min-height: calc(100vh - 62px);
}
.toc {
  border-right: 1px solid var(--line);
  padding: 18px 14px 40px;
  background: rgba(255, 253, 248, 0.55);
}
.toc h2 {
  margin: 0 12px 10px;
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}
.toc a {
  display: grid;
  grid-template-columns: 2.1rem 1fr;
  gap: 8px;
  padding: 7px 10px;
  border-radius: 10px;
  text-decoration: none;
  color: inherit;
  font-size: 0.92rem;
}
.toc a:hover, .toc a.active { background: #efe6d4; }
.toc a.active { box-shadow: inset 3px 0 0 var(--copper); }
.toc .nr { color: var(--copper); font-variant-numeric: tabular-nums; }
.toc .dzial {
  margin: 14px 12px 6px;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--forest);
}

.wrap, .lesson {
  width: 100%;
  max-width: none;
  padding: 28px 28px 80px;
}
.hero h1, .lesson h1 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.2;
  margin: 8px 0 12px;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
}
.kicker {
  color: var(--copper);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-size: 0.78rem;
}
.lead { font-size: 1.15rem; color: #433c34; }
.grid {
  display: grid;
  gap: 14px;
}
.cards { grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  box-shadow: var(--shadow);
  text-decoration: none;
  color: inherit;
  display: block;
}
.card:hover { border-color: #cbb896; }
.meta { color: var(--muted); font-size: 0.88rem; }
.pill {
  display: inline-block;
  background: #efe6d4;
  color: var(--forest-2);
  border-radius: 999px;
  padding: 2px 8px;
  font-size: 0.78rem;
}
.card .pill.ok { display: none; margin-left: 6px; }
.card.done .pill.ok { display: inline-block; background: #d7eadc; color: var(--ok); }

.lesson h2 {
  font-family: var(--serif);
  margin-top: 2rem;
  font-size: 1.45rem;
}
.lesson h3 { margin-top: 1.4rem; }
.lesson p, .lesson li { font-size: 1.02rem; }
.note, .warn, .okbox {
  border-radius: 14px;
  padding: 12px 14px;
  margin: 16px 0;
}
.note { background: #efe6d4; }
.warn { background: #f8e4d8; }
.okbox { background: #dcefe3; }
.goals { padding-left: 1.1rem; }
.table-wrap {
  overflow-x: auto;
  margin: 14px 0 22px;
}
.table-wrap table { margin: 0; min-width: 38rem; }
table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  margin: 14px 0 22px;
  font-size: 0.95rem;
}
th, td {
  border: 1px solid var(--line);
  padding: 8px 10px;
  text-align: left;
  vertical-align: top;
}
th { background: var(--forest); color: #f6f1e6; }
tr:nth-child(even) td { background: #faf6ee; }
pre {
  background: #24342c;
  color: #f3ead8;
  padding: 14px;
  border-radius: 12px;
  overflow: auto;
  font-size: 0.9rem;
}
.formula {
  font-family: var(--serif);
  background: var(--card);
  border: 1px dashed #cbb896;
  padding: 10px 14px;
  border-radius: 12px;
  text-align: center;
  font-size: 1.15rem;
  margin: 14px 0;
}
.pager {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 36px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}
.quiz {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  margin: 18px 0;
}
.quiz .choices { display: flex; flex-direction: column; gap: 8px; margin-top: 10px; }
.quiz button {
  text-align: left;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 10px;
  padding: 8px 10px;
  cursor: pointer;
  font: inherit;
}
.quiz button.good { background: #dcefe3; border-color: var(--ok); }
.quiz button.bad { background: #f8e0dc; border-color: var(--bad); }
.feedback { margin: 10px 0 0; font-weight: 600; }

.widget {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 16px;
  margin: 18px 0 24px;
  box-shadow: var(--shadow);
}
.widget h3 { margin-top: 0; }
.fields {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 10px;
}
.fields label { display: flex; flex-direction: column; gap: 4px; font-size: 0.88rem; color: var(--muted); }
.fields input {
  font: inherit;
  padding: 8px;
  border-radius: 8px;
  border: 1px solid var(--line);
  color: var(--ink);
}
.result {
  margin-top: 12px;
  padding: 10px 12px;
  background: #efe6d4;
  border-radius: 12px;
  font-weight: 600;
}
canvas.chart {
  width: 100%;
  height: 220px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  margin-top: 12px;
}

.home-hero {
  width: 100%;
  padding: 42px 28px 10px;
}
.home-hero h1 {
  font-family: var(--serif);
  font-size: clamp(2rem, 5vw, 3.2rem);
  margin: 8px 0 12px;
}
.actions { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0 8px; }
.section { width: 100%; padding: 10px 28px 40px; }
.progress-bar {
  height: 10px;
  background: #e7dcc8;
  border-radius: 99px;
  overflow: hidden;
}
.progress-bar span {
  display: block;
  height: 100%;
  background: var(--forest);
  width: 0;
}
footer.site {
  border-top: 1px solid var(--line);
  padding: 20px 22px 40px;
  color: var(--muted);
  font-size: 0.92rem;
}

@media (max-width: 860px) {
  .menu-btn { display: inline-flex; }
  .layout { grid-template-columns: 1fr; }
  .toc {
    display: none;
    position: fixed;
    inset: 62px 0 0 0;
    z-index: 9;
    overflow: auto;
    background: var(--paper);
  }
  .toc.open { display: block; }
  .wrap, .lesson { padding: 18px 16px 70px; }
}

details.odpowiedzi {
  margin: 16px 0 24px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px 14px;
}
details.odpowiedzi summary { cursor: pointer; font-weight: 600; }
ol.cwiczenia { padding-left: 1.2rem; }
ol.cwiczenia li { margin: 8px 0; }

@media print {
  .top, .toc, .pager, .menu-btn, .top-actions { display: none !important; }
  .layout { display: block; }
  body { background: #fff; }
}