/* NIU Inglês — design system */
:root {
  --bg: #050d24;
  --bg-2: #081538;
  --surface: #0c1d4a;
  --surface-2: #112761;
  --line: rgba(140, 170, 230, .18);
  --text: #eaf0ff;
  --muted: #a4b4d6;
  --blue: #7db8ff;
  --royal: #3b6df0;
  --orange: #f98a3d;
  --amber: #ffb26b;
  --grad: linear-gradient(120deg, #ffb26b, #f98a3d 55%, #f0701f);
  --grad-text: linear-gradient(120deg, #8fc4ff, #f98a3d);
  --radius: 18px;
  --maxw: 1180px;
  --font-head: "Space Grotesk", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, "Cascadia Code", Consolas, monospace;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 84px; -webkit-text-size-adjust: 100%; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font: 400 1.0625rem/1.65 var(--font-body);
  -webkit-font-smoothing: antialiased; overflow-x: hidden;
}
img, svg { max-width: 100%; display: block; }
a { color: var(--blue); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { font-family: var(--font-head); line-height: 1.12; margin: 0 0 .5em; letter-spacing: -.02em; }
h1 { font-size: clamp(2.5rem, 6vw, 4.6rem); font-weight: 700; }
h2 { font-size: clamp(1.9rem, 4vw, 3rem); font-weight: 700; }
h3 { font-size: 1.25rem; font-weight: 600; }
p { margin: 0 0 1em; }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; border-radius: 6px; }
.container { width: min(100% - 40px, var(--maxw)); margin-inline: auto; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--blue); color: #00131a; padding: 10px 16px; border-radius: 8px; z-index: 100; font-weight: 600; }
.skip:focus { left: 8px; text-decoration: none; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.grad-text { background: var(--grad-text); -webkit-background-clip: text; background-clip: text; color: transparent; }
.eyebrow {
  display: inline-flex; gap: 8px; align-items: center; font: 500 .8rem var(--font-mono);
  color: var(--blue); text-transform: uppercase; letter-spacing: .12em; margin-bottom: 16px;
}
.eyebrow::before { content: ""; width: 22px; height: 1px; background: var(--blue); }
.lead { font-size: 1.2rem; color: var(--muted); max-width: 58ch; }
section { padding: clamp(64px, 9vw, 120px) 0; position: relative; }
.section-head { max-width: 720px; margin-bottom: 48px; }
.section-head.center { margin-inline: auto; text-align: center; }
.section-head.center .lead { margin-inline: auto; }

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 10px;
  padding: 14px 26px; border-radius: 999px; font: 600 1rem var(--font-head);
  border: 1px solid transparent; cursor: pointer; transition: transform .2s, box-shadow .2s, background .2s;
  text-decoration: none !important; white-space: nowrap;
}
.btn-primary { background: var(--grad); color: #04101a; box-shadow: 0 10px 40px -10px rgba(249, 138, 61, .6); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 50px -10px rgba(249, 138, 61, .85); }
.btn-ghost { border-color: var(--line); color: var(--text); background: rgba(255, 255, 255, .03); }
.btn-ghost:hover { border-color: var(--blue); background: rgba(125, 184, 255, .08); }
.btn-sm { padding: 10px 20px; font-size: .92rem; }

/* Header */
.site-header {
  position: sticky; top: 0; z-index: 50; backdrop-filter: blur(14px);
  background: rgba(5, 13, 36, .72); border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 68px; gap: 20px; }
.brand { display: flex; align-items: center; gap: 10px; font: 700 1.35rem var(--font-head); color: var(--text); letter-spacing: -.03em; }
.brand:hover { text-decoration: none; }
.brand-mark { width: 44px; height: 44px; object-fit: contain; }
.brand small { font: 500 .7rem var(--font-mono); color: var(--blue); letter-spacing: .1em; text-transform: uppercase; display: block; margin-top: -2px; }
.nav-links { display: flex; gap: 6px; list-style: none; margin: 0; padding: 0; align-items: center; }
.nav-links a { color: var(--muted); padding: 8px 14px; border-radius: 999px; font-size: .95rem; font-weight: 500; }
.nav-links a:hover, .nav-links a[aria-current="page"] { color: var(--text); background: rgba(255, 255, 255, .06); text-decoration: none; }
.menu-btn { display: none; background: none; border: 1px solid var(--line); border-radius: 10px; width: 44px; height: 44px; color: var(--text); cursor: pointer; }
.menu-btn svg { margin: auto; }

/* Hero */
.hero { padding-top: clamp(48px, 7vw, 96px); overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: -2;
  background:
    radial-gradient(60% 50% at 80% 10%, rgba(59, 109, 240, .38), transparent 70%),
    radial-gradient(45% 40% at 5% 25%, rgba(249, 138, 61, .16), transparent 70%);
}
.hero::after {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background-image: linear-gradient(var(--line) 1px, transparent 1px), linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 56px 56px; opacity: .45;
  mask-image: radial-gradient(70% 60% at 50% 30%, #000, transparent 80%);
  -webkit-mask-image: radial-gradient(70% 60% at 50% 30%, #000, transparent 80%);
}
.hero-grid { display: grid; grid-template-columns: 1.05fr .95fr; gap: 56px; align-items: center; }
.badge {
  display: inline-flex; align-items: center; gap: 10px; padding: 6px 14px 6px 8px; border-radius: 999px;
  border: 1px solid var(--line); background: rgba(255, 255, 255, .04); font-size: .85rem; color: var(--muted); margin-bottom: 24px;
}
.badge .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--orange); box-shadow: 0 0 0 4px rgba(249, 138, 61, .2); animation: pulse 2s infinite; }
@keyframes pulse { 50% { box-shadow: 0 0 0 8px rgba(249, 138, 61, 0); } }
.hero h1 { margin-bottom: 22px; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 14px; margin: 32px 0 40px; }
.stats { display: flex; flex-wrap: wrap; gap: 36px; }
.stat strong { display: block; font: 700 2.1rem var(--font-head); letter-spacing: -.03em; }
.stat span { color: var(--muted); font-size: .9rem; }

/* Chat mockup */
.device {
  background: linear-gradient(180deg, var(--surface-2), var(--surface)); border: 1px solid var(--line);
  border-radius: 22px; box-shadow: 0 40px 100px -30px rgba(59, 109, 240, .45), 0 0 0 1px rgba(255, 255, 255, .03) inset;
  overflow: hidden;
}
.device-bar { display: flex; align-items: center; gap: 8px; padding: 14px 18px; border-bottom: 1px solid var(--line); font: 500 .78rem var(--font-mono); color: var(--muted); }
.device-bar i { width: 11px; height: 11px; border-radius: 50%; background: #334155; }
.device-bar i:nth-child(1) { background: #fb7185; } .device-bar i:nth-child(2) { background: #fbbf24; } .device-bar i:nth-child(3) { background: #4ade80; }
.device-bar span { margin-left: auto; display: inline-flex; gap: 6px; align-items: center; color: var(--orange); }
.chat { padding: 22px; display: flex; flex-direction: column; gap: 14px; min-height: 330px; }
.msg { max-width: 86%; padding: 12px 16px; border-radius: 16px; font-size: .96rem; line-height: 1.5; animation: rise .5s both; }
.msg small { display: block; font: 500 .68rem var(--font-mono); text-transform: uppercase; letter-spacing: .1em; opacity: .7; margin-bottom: 4px; }
.msg.teacher { background: var(--surface-2); border: 1px solid var(--line); border-top-left-radius: 4px; }
.msg.student { background: linear-gradient(120deg, rgba(125, 184, 255, .22), rgba(59, 109, 240, .28)); border: 1px solid rgba(59, 109, 240, .4); align-self: flex-end; border-top-right-radius: 4px; }
.msg.ai { background: rgba(249, 138, 61, .08); border: 1px dashed rgba(249, 138, 61, .45); font-family: var(--font-mono); font-size: .85rem; color: #ffd9b8; }
.msg.ai b { color: var(--orange); }
.typing { display: inline-flex; gap: 4px; padding: 14px 16px; background: var(--surface-2); border: 1px solid var(--line); border-radius: 16px; border-top-left-radius: 4px; width: fit-content; }
.typing i { width: 7px; height: 7px; border-radius: 50%; background: var(--muted); animation: blink 1.2s infinite; }
.typing i:nth-child(2) { animation-delay: .2s; } .typing i:nth-child(3) { animation-delay: .4s; }
@keyframes blink { 0%, 80%, 100% { opacity: .25; } 40% { opacity: 1; } }
@keyframes rise { from { opacity: 0; transform: translateY(10px); } }

/* Marquee */
.strip { padding: 22px 0; border-block: 1px solid var(--line); background: var(--bg-2); overflow: hidden; }
.marquee { display: flex; gap: 56px; width: max-content; animation: scroll 38s linear infinite; }
.marquee span { font: 500 .9rem var(--font-mono); color: var(--muted); text-transform: uppercase; letter-spacing: .1em; display: inline-flex; gap: 14px; align-items: center; }
.marquee span::before { content: "◆"; color: var(--blue); font-size: .6rem; }
@keyframes scroll { to { transform: translateX(-50%); } }

/* Cards / bento */
.bento { display: grid; grid-template-columns: repeat(6, 1fr); gap: 18px; }
.card {
  background: linear-gradient(180deg, var(--surface), var(--bg-2)); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 28px; position: relative; overflow: hidden; transition: border-color .3s, transform .3s;
}
.card:hover { border-color: rgba(249, 138, 61, .55); transform: translateY(-3px); }
.card::after { content: ""; position: absolute; inset: auto -20% -60% auto; width: 240px; height: 240px; background: radial-gradient(closest-side, rgba(59, 109, 240, .18), transparent); pointer-events: none; }
.card p { color: var(--muted); margin: 0; }
.icon { width: 46px; height: 46px; border-radius: 12px; display: grid; place-items: center; background: rgba(125, 184, 255, .1); border: 1px solid rgba(125, 184, 255, .3); margin-bottom: 18px; color: var(--blue); }
.span-2 { grid-column: span 2; } .span-3 { grid-column: span 3; } .span-4 { grid-column: span 4; }
.big-num { font: 700 4rem/1 var(--font-head); letter-spacing: -.04em; margin-bottom: 8px; }

/* Steps */
.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; counter-reset: step; }
.step { padding: 30px; border-left: 1px solid var(--line); position: relative; }
.step::before { counter-increment: step; content: "0" counter(step); font: 700 3.2rem var(--font-head); background: var(--grad-text); -webkit-background-clip: text; background-clip: text; color: transparent; display: block; margin-bottom: 8px; }
.step p { color: var(--muted); }

/* Split sections */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.checks { list-style: none; padding: 0; margin: 24px 0 32px; display: grid; gap: 14px; }
.checks li { display: flex; gap: 12px; align-items: flex-start; }
.checks svg { flex: none; margin-top: 4px; color: var(--orange); }
.bank { padding: 26px; }
.bank-top { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; }
.coins { font: 700 2.2rem var(--font-head); display: flex; gap: 10px; align-items: center; }
.coin { width: 30px; height: 30px; border-radius: 50%; background: radial-gradient(circle at 30% 30%, #fde68a, #f59e0b); box-shadow: 0 0 20px rgba(245, 158, 11, .5); display: inline-block; }
.task { display: flex; align-items: center; gap: 14px; padding: 14px; border-radius: 14px; border: 1px solid var(--line); background: rgba(255, 255, 255, .02); margin-bottom: 10px; }
.task .ok { width: 26px; height: 26px; border-radius: 50%; display: grid; place-items: center; background: rgba(249, 138, 61, .15); color: var(--orange); flex: none; }
.task .ok.todo { background: rgba(148, 163, 184, .12); color: var(--muted); }
.task b { display: block; font-size: .96rem; } .task small { color: var(--muted); }
.task em { margin-left: auto; font: 600 .85rem var(--font-mono); color: #fbbf24; font-style: normal; white-space: nowrap; }
.bar { height: 8px; border-radius: 99px; background: rgba(255, 255, 255, .08); overflow: hidden; margin-top: 16px; }
.bar i { display: block; height: 100%; width: 68%; background: var(--grad); border-radius: 99px; }

/* Audience */
.aud { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; }
.aud .card { padding: 36px; }
.aud h3 { font-size: 1.7rem; }
.tag { display: inline-block; font: 500 .75rem var(--font-mono); padding: 4px 12px; border-radius: 999px; border: 1px solid var(--line); color: var(--muted); margin: 0 6px 6px 0; }

/* Testimonial */
.quote { max-width: 860px; margin: 0 auto; text-align: center; }
.quote blockquote { margin: 0 0 24px; font: 500 clamp(1.4rem, 3vw, 2.1rem)/1.35 var(--font-head); letter-spacing: -.02em; }
.quote blockquote::before { content: "“"; display: block; font-size: 5rem; line-height: .6; color: var(--royal); }
.quote cite { font-style: normal; color: var(--muted); }
.stars { color: #fbbf24; letter-spacing: 4px; margin-bottom: 14px; }

/* Blog cards */
.posts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.post-card { display: flex; flex-direction: column; padding: 0; }
.post-cover { aspect-ratio: 16/9; display: grid; place-items: center; position: relative; overflow: hidden; border-bottom: 1px solid var(--line); }
.post-cover span { font: 700 3.4rem var(--font-head); opacity: .9; mix-blend-mode: overlay; letter-spacing: -.05em; }
.post-body { padding: 24px; display: flex; flex-direction: column; flex: 1; }
.post-body h3 { font-size: 1.2rem; margin-bottom: 10px; }
.post-body h3 a { color: var(--text); }
.post-body h3 a::after { content: ""; position: absolute; inset: 0; }
.post-body h3 a:hover { text-decoration: none; color: var(--blue); }
.meta { font: 500 .78rem var(--font-mono); color: var(--muted); display: flex; gap: 14px; flex-wrap: wrap; margin-bottom: 12px; }
.meta .cat { color: var(--blue); text-transform: uppercase; letter-spacing: .08em; }

/* FAQ */
.faq { max-width: 820px; margin: 0 auto; display: grid; gap: 12px; }
.faq details { border: 1px solid var(--line); border-radius: 14px; background: var(--surface); transition: border-color .2s; }
.faq details[open] { border-color: rgba(125, 184, 255, .5); }
.faq summary { cursor: pointer; padding: 20px 24px; font: 600 1.08rem var(--font-head); list-style: none; display: flex; justify-content: space-between; gap: 16px; align-items: center; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font: 400 1.6rem var(--font-mono); color: var(--blue); transition: transform .25s; flex: none; }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details p { padding: 0 24px 22px; margin: 0; color: var(--muted); }

/* CTA */
.cta-box {
  border-radius: 28px; padding: clamp(40px, 7vw, 84px) clamp(24px, 5vw, 64px); text-align: center; position: relative; overflow: hidden;
  background: radial-gradient(80% 120% at 50% 0%, rgba(59, 109, 240, .45), transparent 70%), linear-gradient(180deg, var(--surface-2), var(--surface));
  border: 1px solid rgba(59, 109, 240, .4);
}
.cta-box .lead { margin-inline: auto; }
.cta-box .hero-cta { justify-content: center; margin-bottom: 0; }

/* Footer */
.site-footer { border-top: 1px solid var(--line); padding: 64px 0 32px; background: var(--bg-2); }
.foot-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 48px; }
.foot-grid h4 { font: 600 .8rem var(--font-mono); text-transform: uppercase; letter-spacing: .12em; color: var(--muted); margin-bottom: 16px; }
.foot-grid ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.foot-grid a { color: var(--text); font-size: .96rem; }
.foot-grid p { color: var(--muted); font-size: .95rem; max-width: 36ch; }
.copy { border-top: 1px solid var(--line); padding-top: 24px; color: var(--muted); font-size: .85rem; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 12px; }

/* WhatsApp float */
.wa-float {
  position: fixed; right: 20px; bottom: 20px; z-index: 60; width: 58px; height: 58px; border-radius: 50%;
  background: #25d366; display: grid; place-items: center; box-shadow: 0 10px 30px rgba(37, 211, 102, .45); transition: transform .2s;
}
.wa-float:hover { transform: scale(1.08); }

/* Reveal */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }
.no-js .reveal { opacity: 1; transform: none; }

/* Blog / article */
.page-hero { padding: clamp(56px, 8vw, 104px) 0 24px; position: relative; }
.page-hero::before { content: ""; position: absolute; inset: 0; z-index: -1; background: radial-gradient(50% 70% at 70% 0%, rgba(59, 109, 240, .25), transparent 70%); }
.crumbs { font: 500 .82rem var(--font-mono); color: var(--muted); margin-bottom: 24px; }
.crumbs ol { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.crumbs li + li::before { content: "/"; margin-right: 8px; opacity: .5; }
.crumbs a { color: var(--muted); } .crumbs a:hover { color: var(--blue); }
.article-wrap { display: grid; grid-template-columns: minmax(0, 720px) 280px; gap: 64px; justify-content: center; padding-bottom: 80px; }
.prose { font-size: 1.12rem; line-height: 1.8; }
.prose h2 { font-size: 1.9rem; margin: 2.2em 0 .6em; }
.prose h3 { font-size: 1.35rem; margin: 1.8em 0 .5em; }
.prose p, .prose li { color: #cbd5e6; }
.prose ul, .prose ol { padding-left: 1.3em; } .prose li { margin-bottom: .5em; }
.prose strong { color: var(--text); }
.prose blockquote { margin: 1.6em 0; padding: 18px 24px; border-left: 3px solid var(--royal); background: rgba(59, 109, 240, .08); border-radius: 0 12px 12px 0; }
.prose blockquote p { margin: 0; }
.prose table { width: 100%; border-collapse: collapse; margin: 1.6em 0; font-size: .96rem; }
.prose th, .prose td { text-align: left; padding: 12px 14px; border-bottom: 1px solid var(--line); }
.prose th { color: var(--blue); font: 600 .78rem var(--font-mono); text-transform: uppercase; letter-spacing: .08em; }
.prose code { font-family: var(--font-mono); background: var(--surface-2); padding: 2px 7px; border-radius: 6px; font-size: .9em; }
.toc { position: sticky; top: 92px; align-self: start; border: 1px solid var(--line); border-radius: var(--radius); padding: 22px; background: var(--surface); }
.toc h2 { font: 600 .78rem var(--font-mono); text-transform: uppercase; letter-spacing: .12em; color: var(--muted); margin-bottom: 14px; }
.toc ol { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; font-size: .92rem; }
.toc a { color: var(--text); opacity: .8; } .toc a:hover { opacity: 1; color: var(--blue); }
.toc .btn { width: 100%; margin-top: 20px; }
.post-cta { margin: 56px 0 0; padding: 32px; border-radius: var(--radius); border: 1px solid rgba(125, 184, 255, .4); background: linear-gradient(120deg, rgba(125, 184, 255, .1), rgba(59, 109, 240, .14)); }
.post-cta h2 { font-size: 1.5rem !important; margin: 0 0 8px !important; }
.related { margin-top: 64px; }
.filters { display: flex; flex-wrap: wrap; gap: 10px; margin: 28px 0 0; }
.chip { padding: 8px 18px; border-radius: 999px; border: 1px solid var(--line); background: transparent; color: var(--muted); font: 500 .85rem var(--font-body); cursor: pointer; }
.chip[aria-pressed="true"], .chip:hover { color: #04101a; background: var(--orange); border-color: var(--orange); }
.progress { position: fixed; top: 0; left: 0; height: 3px; width: 0; background: var(--grad); z-index: 70; }

/* Responsive */
@media (max-width: 960px) {
  .hero-grid, .split, .aud { grid-template-columns: 1fr; gap: 40px; }
  .bento { grid-template-columns: repeat(2, 1fr); }
  .span-2, .span-3, .span-4 { grid-column: span 2; }
  .steps, .posts { grid-template-columns: 1fr; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
  .article-wrap { grid-template-columns: minmax(0, 1fr); }
  .toc { position: static; order: -1; }
  .menu-btn { display: block; }
  .nav-links {
    position: absolute; top: 68px; left: 0; right: 0; flex-direction: column; align-items: stretch; padding: 16px 20px 24px;
    background: rgba(5, 13, 36, .97); border-bottom: 1px solid var(--line); display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { display: block; padding: 14px; }
}
@media (max-width: 560px) {
  .bento { grid-template-columns: 1fr; } .span-2, .span-3, .span-4 { grid-column: auto; }
  .foot-grid { grid-template-columns: 1fr; }
  .stats { gap: 24px; } .hero-cta .btn { width: 100%; }
}
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; }
}
@media print { .site-header, .wa-float, .toc, .post-cta { display: none; } body { background: #fff; color: #000; } .prose p, .prose li { color: #000; } }