/* Writer – strona główna i instalacja.
   Motyw: szkolny zeszyt – kratka w tle, granatowy atrament, żółty zakreślacz, odręczne dopiski. */
:root {
  --paper: #fbfbf8;
  --paper-2: #f3f3ee;
  --ink: #16203a;
  --ink-2: #4b5470;
  --ink-3: #8a90a3;
  --blue: #2f5fe0;
  --blue-deep: #2346b5;
  --blue-soft: #e7edfc;
  --hl: #ffe066;
  --grid: rgba(47, 95, 224, .075);
  --line: #e4e4dc;
  --card: #ffffff;
  --shadow: 0 1px 2px rgba(22, 32, 58, .06), 0 18px 50px rgba(22, 32, 58, .12);
  --shot-shadow: 0 2px 6px rgba(22, 32, 58, .08), 0 30px 80px rgba(22, 32, 58, .18);
  --font-display: "Lexend", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-body: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-hand: "Caveat", "Bradley Hand", cursive;
  --radius: 18px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #12141a; --paper-2: #181b22; --ink: #eef0f6; --ink-2: #aab1c3; --ink-3: #6f7689;
    --blue: #7499ff; --blue-deep: #5a82f5; --blue-soft: #1d2640; --hl: rgba(255, 210, 60, .42);
    --grid: rgba(116, 153, 255, .07); --line: #2a2e38; --card: #1b1e26;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 18px 50px rgba(0, 0, 0, .45);
    --shot-shadow: 0 2px 6px rgba(0, 0, 0, .4), 0 30px 80px rgba(0, 0, 0, .6);
    color-scheme: dark;
  }
}
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 17px/1.6 var(--font-body); -webkit-font-smoothing: antialiased; overflow-x: hidden; }
img { max-width: 100%; height: auto; display: block; }
a { color: inherit; }
h1, h2, h3 { font-family: var(--font-display); letter-spacing: -.025em; line-height: 1.1; margin: 0; text-wrap: balance; }
p { margin: 0; }
.wrap { width: min(1180px, 100% - 40px); margin: 0 auto; }
.hl { background: linear-gradient(transparent 58%, var(--hl) 58%, var(--hl) 92%, transparent 92%); padding: 0 .08em; border-radius: 2px; }
.hand { font-family: var(--font-hand); font-weight: 700; color: var(--blue); font-size: 1.35em; line-height: 1; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; font: 600 13px/1 var(--font-body); letter-spacing: .08em; text-transform: uppercase; color: var(--blue); }
.muted { color: var(--ink-3); }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 2px; border-radius: 6px; }

/* Przyciski */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 9px; height: 52px; padding: 0 24px; border-radius: 999px; border: 0; font: 600 16px/1 var(--font-body); text-decoration: none; cursor: pointer; transition: transform .15s, box-shadow .15s, background .15s; white-space: nowrap; }
.btn svg { width: 19px; height: 19px; }
.btn.primary { background: var(--blue); color: #fff; box-shadow: 0 1px 0 rgba(255, 255, 255, .25) inset, 0 8px 24px color-mix(in srgb, var(--blue) 40%, transparent); }
.btn.primary:hover { transform: translateY(-1px); background: var(--blue-deep); }
.btn.ghost { background: var(--card); color: var(--ink); box-shadow: inset 0 0 0 1px var(--line); }
.btn.ghost:hover { box-shadow: inset 0 0 0 1px var(--ink-3); }
.btn.small { height: 40px; padding: 0 18px; font-size: 14.5px; }

/* Nawigacja */
.nav { position: sticky; top: 0; z-index: 50; transition: background .2s, box-shadow .2s; }
.nav.scrolled { background: color-mix(in srgb, var(--paper) 78%, transparent); -webkit-backdrop-filter: blur(18px) saturate(1.6); backdrop-filter: blur(18px) saturate(1.6); box-shadow: 0 1px 0 var(--line); }
.nav .wrap { display: flex; align-items: center; gap: 28px; height: 68px; }
.logo { display: flex; align-items: center; gap: 10px; font: 700 20px/1 var(--font-display); text-decoration: none; letter-spacing: -.02em; }
.logo img { width: 30px; height: 30px; border-radius: 8px; }
.nav-links { display: flex; gap: 26px; margin-left: auto; font-size: 15px; }
.nav-links a { text-decoration: none; color: var(--ink-2); }
.nav-links a:hover { color: var(--ink); }

/* Hero */
.hero { position: relative; padding: 56px 0 40px; overflow: hidden; }
.hero::before { content: ""; position: absolute; inset: 0; background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px); background-size: 28px 28px; -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 30%, #000 40%, transparent 85%); mask-image: radial-gradient(ellipse 80% 70% at 50% 30%, #000 40%, transparent 85%); pointer-events: none; }
.hero .wrap { position: relative; text-align: center; }
.hero h1 { font-size: clamp(44px, 7.4vw, 92px); font-weight: 700; margin: 18px auto 0; max-width: 13ch; }
.hero .lead { font-size: clamp(18px, 2vw, 21px); color: var(--ink-2); max-width: 640px; margin: 22px auto 0; }
.cta-row { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 32px; }
.hero .meta { margin-top: 18px; font-size: 14px; color: var(--ink-3); }
.hero-shot { position: relative; margin: 56px auto 0; max-width: 1120px; }
.shot { border-radius: 16px; overflow: hidden; box-shadow: var(--shot-shadow); background: var(--card); border: 1px solid var(--line); }
.shot img { width: 100%; height: auto; }
.note { position: absolute; display: flex; align-items: flex-start; gap: 6px; pointer-events: none; z-index: 2; }
.note svg { flex: none; color: var(--blue); }
.note.n1 { left: 3%; top: -58px; align-items: flex-end; }
.note.n2 { right: 3%; top: -58px; align-items: flex-end; }
.note.n1 svg { transform: translateY(18px); }
.note.n2 svg { transform: translateY(18px) scaleX(-1); }
.note .hand { max-width: 170px; }

/* Kroki */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 90px; }
.step { position: relative; padding: 26px 26px 28px; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); }
.step-n { font: 700 54px/1 var(--font-hand); color: var(--blue); }
.step h3 { font-size: 21px; margin-top: 8px; }
.step p { color: var(--ink-2); margin-top: 8px; font-size: 16px; }

/* Sekcje funkcji */
section.feature { padding: 110px 0 0; }
.feature .grid { display: grid; grid-template-columns: 5fr 7fr; gap: 64px; align-items: center; }
.feature.flip .grid { grid-template-columns: 7fr 5fr; }
.feature.flip .text { order: 2; }
.feature h2 { font-size: clamp(34px, 4.4vw, 52px); margin-top: 14px; }
.feature .text > p { color: var(--ink-2); margin-top: 18px; font-size: 18px; }
.checks { list-style: none; padding: 0; margin: 24px 0 0; display: grid; gap: 12px; }
.checks li { display: flex; gap: 12px; align-items: flex-start; }
.checks li::before { content: ""; flex: none; width: 22px; height: 22px; margin-top: 2px; border-radius: 7px; background: var(--blue-soft) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='m5 10.5 3.2 3.2L15 6.8' fill='none' stroke='%232f5fe0' stroke-width='2.2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E") center/16px no-repeat; }
.feature .shot { transform: perspective(1600px) rotateY(-4deg) rotateX(1deg); transition: transform .4s; }
.feature.flip .shot { transform: perspective(1600px) rotateY(4deg) rotateX(1deg); }
.feature .shot:hover { transform: none; }

/* Wzory – żywe demo */
.math-demo { margin-top: 28px; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.math-demo label { font: 600 13px/1 var(--font-body); color: var(--ink-3); letter-spacing: .04em; text-transform: uppercase; }
.math-demo input { width: 100%; margin-top: 10px; border: 1px solid var(--line); background: var(--paper-2); color: var(--ink); border-radius: 12px; padding: 13px 15px; font: 16px/1.4 ui-monospace, "SF Mono", "JetBrains Mono", Menlo, monospace; outline: none; }
.math-demo input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px var(--blue-soft); }
.math-out { min-height: 92px; display: grid; place-items: center; font-size: 22px; padding: 12px 0 4px; overflow-x: auto; }
.math-chips { display: flex; flex-wrap: wrap; gap: 6px; }
.math-chips button { border: 1px solid var(--line); background: transparent; color: var(--ink-2); border-radius: 999px; padding: 6px 12px; font: 13.5px/1 ui-monospace, "SF Mono", Menlo, monospace; cursor: pointer; }
.math-chips button:hover { border-color: var(--blue); color: var(--blue); }

/* Siatka mniejszych funkcji */
.more { padding: 120px 0 0; }
.more h2 { font-size: clamp(34px, 4.4vw, 52px); text-align: center; }
.more .sub { text-align: center; color: var(--ink-2); margin: 16px auto 0; max-width: 600px; font-size: 18px; }
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; margin-top: 48px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 24px; transition: transform .2s, box-shadow .2s; }
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.card .ic { width: 44px; height: 44px; border-radius: 12px; display: grid; place-items: center; background: var(--blue-soft); color: var(--blue); }
.card .ic svg { width: 22px; height: 22px; }
.card h3 { font-size: 19px; margin-top: 16px; letter-spacing: -.015em; }
.card p { color: var(--ink-2); font-size: 15.5px; margin-top: 6px; }

/* Wszędzie */
.everywhere { padding: 120px 0 0; }
.everywhere .grid { display: grid; grid-template-columns: 1.15fr .85fr; gap: 40px; align-items: end; }
.everywhere h2 { font-size: clamp(34px, 4.4vw, 52px); }
.everywhere .text > p { color: var(--ink-2); margin-top: 18px; font-size: 18px; max-width: 520px; }
.devices { position: relative; display: flex; gap: 22px; justify-content: center; align-items: flex-end; }
.phone { width: 260px; border-radius: 42px; padding: 10px; background: #0d0f14; box-shadow: var(--shot-shadow); }
.phone img { border-radius: 33px; }
.phone.b { width: 220px; transform: translateY(-30px) rotate(4deg); opacity: .96; }
.platforms { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 26px; }
.platforms span { display: inline-flex; align-items: center; gap: 8px; padding: 8px 14px; border-radius: 999px; background: var(--card); border: 1px solid var(--line); font-size: 14.5px; color: var(--ink-2); }

/* FAQ */
.faq { padding: 120px 0 0; }
.faq h2 { font-size: clamp(34px, 4.4vw, 52px); text-align: center; }
.faq-list { max-width: 760px; margin: 40px auto 0; display: grid; gap: 10px; }
.faq details { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 4px 22px; }
.faq summary { cursor: pointer; list-style: none; padding: 16px 0; font: 600 17.5px/1.4 var(--font-display); letter-spacing: -.01em; display: flex; justify-content: space-between; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font: 400 26px/1 var(--font-body); color: var(--blue); transition: transform .2s; }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { padding: 0 0 18px; color: var(--ink-2); }

/* Końcowe CTA i stopka */
.final { margin: 130px 0 0; }
.final .box { position: relative; overflow: hidden; border-radius: 28px; padding: 70px 40px; text-align: center; background: var(--blue); color: #fff; }
.final .box::before { content: ""; position: absolute; inset: 0; background-image: linear-gradient(rgba(255, 255, 255, .08) 1px, transparent 1px), linear-gradient(90deg, rgba(255, 255, 255, .08) 1px, transparent 1px); background-size: 28px 28px; }
.final h2 { position: relative; font-size: clamp(34px, 5vw, 58px); }
.final p { position: relative; margin: 16px auto 0; max-width: 520px; color: rgba(255, 255, 255, .85); font-size: 18px; }
.final .cta-row { position: relative; }
.final .btn.primary { background: #fff; color: #1d3aa0; box-shadow: 0 10px 30px rgba(0, 0, 0, .2); }
.final .btn.ghost { background: rgba(255, 255, 255, .14); color: #fff; box-shadow: inset 0 0 0 1px rgba(255, 255, 255, .35); }
.final .hl-w { background: linear-gradient(transparent 60%, #ffd84d 60%, #ffd84d 92%, transparent 92%); color: #fff; }
footer { padding: 50px 0 40px; color: var(--ink-3); font-size: 14.5px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 14px 28px; align-items: center; justify-content: space-between; }
footer nav { display: flex; gap: 22px; }
footer a { text-decoration: none; }
footer a:hover { color: var(--ink); }

/* Strona instalacji */
.dl-hero { position: relative; padding: 60px 0 10px; text-align: center; overflow: hidden; }
.dl-hero::before { content: ""; position: absolute; inset: 0; background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px); background-size: 28px 28px; -webkit-mask-image: radial-gradient(ellipse 70% 80% at 50% 20%, #000 30%, transparent 80%); mask-image: radial-gradient(ellipse 70% 80% at 50% 20%, #000 30%, transparent 80%); }
.dl-hero .wrap { position: relative; }
.dl-hero h1 { font-size: clamp(42px, 6.4vw, 78px); margin-top: 16px; }
.dl-hero .lead { color: var(--ink-2); max-width: 600px; margin: 18px auto 0; font-size: 19px; }
.app-icon { width: 104px; height: 104px; margin: 0 auto; border-radius: 24px; box-shadow: 0 16px 40px color-mix(in srgb, var(--blue) 35%, transparent); }
.platform-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-top: 54px; }
.pf { position: relative; background: var(--card); border: 1px solid var(--line); border-radius: 24px; padding: 30px; display: flex; flex-direction: column; }
.pf.recommended { border-color: var(--blue); box-shadow: 0 0 0 1px var(--blue), var(--shadow); }
.pf .badge { position: absolute; top: 22px; right: 22px; font: 600 12px/1 var(--font-body); letter-spacing: .04em; color: var(--blue); background: var(--blue-soft); padding: 6px 10px; border-radius: 999px; }
.pf-head { display: flex; align-items: center; gap: 14px; }
.pf-ic { width: 52px; height: 52px; border-radius: 15px; display: grid; place-items: center; background: var(--paper-2); color: var(--ink); }
.pf-ic svg { width: 28px; height: 28px; }
.pf h2 { font-size: 26px; }
.pf .pf-sub { color: var(--ink-3); font-size: 14.5px; margin-top: 4px; }
.pf ol { margin: 22px 0 0; padding: 0; list-style: none; counter-reset: s; display: grid; gap: 12px; }
.pf ol li { counter-increment: s; display: flex; gap: 12px; color: var(--ink-2); font-size: 16px; }
.pf ol li::before { content: counter(s); flex: none; width: 26px; height: 26px; border-radius: 50%; display: grid; place-items: center; background: var(--blue-soft); color: var(--blue); font: 700 13px/1 var(--font-body); margin-top: 1px; }
.pf ol li b { color: var(--ink); }
.pf .actions { margin-top: auto; padding-top: 26px; display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.pf .fine { font-size: 13.5px; color: var(--ink-3); }
.callout { margin-top: 18px; padding: 14px 16px; border-radius: 14px; background: var(--paper-2); font-size: 14.5px; color: var(--ink-2); }
.callout b { color: var(--ink); }
.kbdk { font: 600 13px/1 var(--font-body); padding: 3px 7px; border-radius: 6px; border: 1px solid var(--line); background: var(--paper); }
.web-strip { margin-top: 20px; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 18px; padding: 26px 30px; border-radius: 24px; border: 1px dashed var(--ink-3); }
.web-strip h3 { font-size: 22px; }
.web-strip p { color: var(--ink-2); margin-top: 4px; }

/* Wejście sekcji */
.reveal { opacity: 1; transform: none; }
.js .reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s cubic-bezier(.2, .7, .2, 1), transform .7s cubic-bezier(.2, .7, .2, 1); }
.js .reveal.in { opacity: 1; transform: none; }

@media (max-width: 980px) {
  .note { display: none; }
  .feature .grid, .feature.flip .grid, .everywhere .grid { grid-template-columns: 1fr; gap: 36px; }
  .feature.flip .text { order: 0; }
  .feature .shot, .feature.flip .shot { transform: none; }
  .cards { grid-template-columns: repeat(2, 1fr); }
  .platform-grid { grid-template-columns: 1fr; }
}
@media (max-width: 680px) {
  body { font-size: 16px; }
  .nav-links { display: none; }
  .nav .wrap { gap: 12px; }
  .nav .btn.small { margin-left: auto; }
  .hero { padding-top: 34px; }
  .steps { grid-template-columns: 1fr; margin-top: 60px; }
  .cards { grid-template-columns: 1fr; }
  section.feature, .more, .everywhere, .faq { padding-top: 80px; }
  .final .box { padding: 50px 22px; }
  .phone { width: 200px; border-radius: 34px; }
  .phone img { border-radius: 26px; }
  .phone.b { width: 160px; }
  .btn { height: 50px; }
  .cta-row .btn { flex: 1 1 100%; }
  .pf { padding: 24px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transform: none; transition: none; }
  .feature .shot { transform: none; }
}