/* =========================================================
   Learnworks / golearn.works
   Pure-black flat minimal / engineered-brutalist system.
   #000 void · 1px line-art containers · sharp corners ·
   massive type · lime (#BEF264) used surgically.
   ========================================================= */

:root {
  --black: #000000;
  --white: #FFFFFF;
  --grey: #A3A3A3;
  --grey-dim: #666666;
  --line: #262626;
  --line-strong: #333333;
  --lime: #BEF264;

  --container: 1280px;
  --gutter: 32px;
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--black);
  color: var(--white);
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  overflow-x: clip;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
::selection { background: var(--lime); color: var(--black); }

.container { max-width: var(--container); margin: 0 auto; padding: 0 var(--gutter); }
@media (max-width: 560px) { .container { padding: 0 20px; } }

/* 12-col grid primitive */
.grid { display: grid; grid-template-columns: repeat(12, 1fr); gap: 24px; }

section { padding: 200px 0; }
@media (max-width: 768px) { section { padding: 120px 0; } }

/* ---- Type ---- */
h1, h2, h3 { font-weight: 600; letter-spacing: -0.04em; line-height: 1.02; }
h1 { font-size: clamp(3.2rem, 8.4vw, 8.2rem); }
h2 { font-size: clamp(2.2rem, 4.6vw, 4.2rem); letter-spacing: -0.03em; }
h3 { font-size: 1.15rem; font-weight: 600; letter-spacing: -0.01em; line-height: 1.3; }
.accent { color: var(--lime); }
.lede { font-size: clamp(1rem, 1.4vw, 1.2rem); color: var(--grey); line-height: 1.7; font-weight: 400; }
.body-text { font-size: 0.95rem; color: var(--grey); line-height: 1.7; }

/* Engineered section label: 01 / PROBLEM */
.sec-label {
  display: flex; align-items: baseline; gap: 16px;
  font-family: 'Inter', monospace;
  font-size: 0.72rem; font-weight: 500; letter-spacing: 0.22em; text-transform: uppercase;
  color: var(--grey-dim); margin-bottom: 56px;
}
.sec-label .idx { color: var(--lime); font-variant-numeric: tabular-nums; }
.sec-label::after { content: ''; flex: 1; height: 1px; background: var(--line); align-self: center; }

.section-head { margin-bottom: 96px; }
.section-head h2 { max-width: 18ch; }
.section-head.wide h2 { max-width: 26ch; }

/* ---- Buttons ---- */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 12px;
  padding: 20px 44px; font-size: 0.9rem; font-weight: 600; letter-spacing: 0.01em;
  border: 1px solid transparent; border-radius: 0; cursor: pointer; white-space: nowrap;
  transition: background 120ms linear, color 120ms linear, border-color 120ms linear;
}
.btn-primary { background: var(--lime); color: var(--black); }
.btn-primary:hover { background: var(--black); color: var(--lime); border-color: var(--lime); }
.btn-ghost { background: var(--black); color: var(--white); border-color: var(--line-strong); }
.btn-ghost:hover { border-color: var(--white); }
.btn-sm { padding: 13px 26px; font-size: 0.82rem; }
.btn-row { display: flex; flex-wrap: wrap; gap: 16px; }
@media (max-width: 560px) {
  .btn { padding: 18px 28px; width: 100%; }
  .btn-row { flex-direction: column; }
}

/* ---- Nav ---- */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(0,0,0,0.85); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 76px; }
.brand {
  display: inline-flex; align-items: center; gap: 14px;
  font-weight: 700; font-size: 1.6rem; letter-spacing: -0.05em; line-height: 1;
  color: var(--white);
}
.brand img { width: 40px; height: 40px; }
.brand .dot { color: var(--lime); }
.nav-links { display: flex; align-items: center; gap: 40px; }
.nav-links a {
  font-size: 0.82rem; font-weight: 500; color: var(--grey);
  transition: color 120ms linear;
}
.nav-links a:hover { color: var(--white); }
.nav-actions { display: flex; align-items: center; gap: 20px; }
.nav-burger { display: none; flex-direction: column; gap: 6px; background: none; border: none; cursor: pointer; padding: 8px; }
.nav-burger span { width: 24px; height: 1px; background: var(--white); }
@media (max-width: 960px) {
  .nav-links { display: none; }
  .nav-burger { display: flex; }
}
@media (max-width: 560px) {
  .nav-actions .btn-primary { display: none; }
  .brand { font-size: 1.2rem; gap: 10px; }
  .brand img { width: 30px; height: 30px; }
}

/* ---- Hero ---- */
.hero { padding: 0; min-height: 100vh; display: flex; flex-direction: column; justify-content: center; border-bottom: 1px solid var(--line); }
.hero-inner { padding-top: 160px; padding-bottom: 120px; }
.hero h1 { margin-bottom: 48px; max-width: 12ch; }
.hero .lede { max-width: 52ch; margin-bottom: 64px; }
.hero-meta {
  display: flex; gap: 48px; flex-wrap: wrap; margin-top: 96px;
  padding-top: 32px; border-top: 1px solid var(--line);
}
.hero-meta div { font-size: 0.78rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--grey-dim); font-weight: 500; }

/* ---- Spec sheet: full-width index rows, hard lime inversion on hover ---- */
.spec { border-top: 1px solid var(--line); }
.spec-row {
  display: grid; grid-template-columns: 96px 1.1fr 1fr; gap: 48px; align-items: center;
  padding: 48px 32px; border-bottom: 1px solid var(--line);
  transition: background 120ms linear; cursor: default;
}
.spec-row .num {
  font-size: 0.75rem; font-weight: 500; letter-spacing: 0.18em;
  color: var(--lime); font-variant-numeric: tabular-nums;
  transition: color 120ms linear;
}
.spec-row h3 {
  font-size: clamp(1.35rem, 2.3vw, 2rem); font-weight: 600; letter-spacing: -0.02em;
  color: var(--white); transition: color 120ms linear, transform 200ms var(--ease);
}
.spec-row p {
  font-size: 0.92rem; color: var(--grey); line-height: 1.7; max-width: 48ch;
  transition: color 120ms linear;
}
.spec-row:hover { background: var(--lime); }
.spec-row:hover .num { color: rgba(0,0,0,0.55); }
.spec-row:hover h3 { color: var(--black); transform: translateX(8px); }
.spec-row:hover p { color: rgba(0,0,0,0.72); }
@media (max-width: 860px) {
  .spec-row { grid-template-columns: 1fr; gap: 12px; padding: 36px 20px; }
  .spec-row:hover h3 { transform: none; }
}

/* ---- Duo / quad: giant outlined numerals in the void ---- */
.duo { display: grid; grid-template-columns: 1fr 1fr; }
.duo > div { padding: 24px 64px; border-left: 1px solid var(--line); }
.duo > div:first-child { border-left: none; padding-left: 0; }
.quad { display: grid; grid-template-columns: 1fr 1fr; row-gap: 112px; }
.quad > div { padding: 0 64px; border-left: 1px solid var(--line); }
.quad > div:nth-child(odd) { border-left: none; padding-left: 0; }
@media (max-width: 860px) {
  .duo, .quad { grid-template-columns: 1fr; row-gap: 72px; }
  .duo > div, .quad > div { border-left: none; padding: 0; }
}
.big-num {
  font-size: clamp(4.5rem, 9vw, 8rem); font-weight: 700; line-height: 0.9;
  letter-spacing: -0.04em; color: transparent;
  -webkit-text-stroke: 1px var(--line-strong); text-stroke: 1px var(--line-strong);
  margin-bottom: 40px; user-select: none;
  transition: -webkit-text-stroke-color 200ms linear;
}
.duo > div:hover .big-num, .quad > div:hover .big-num { -webkit-text-stroke-color: var(--lime); }
.duo h3, .quad h3 { margin-bottom: 16px; font-size: 1.25rem; }
.duo .body-text, .quad .body-text { font-size: 0.92rem; }

/* ---- Tri: rule-topped columns (roadmap) ---- */
.tri { display: grid; grid-template-columns: repeat(3, 1fr); gap: 56px; }
@media (max-width: 860px) { .tri { grid-template-columns: 1fr; gap: 48px; } }
.tri > div { border-top: 1px solid var(--line-strong); padding-top: 36px; transition: border-color 200ms linear; }
.tri > div:hover { border-top-color: var(--lime); }
.tri .num {
  display: block; font-size: 0.75rem; font-weight: 500; letter-spacing: 0.18em;
  color: var(--lime); margin-bottom: 24px; font-variant-numeric: tabular-nums;
}
.tri h3 { margin-bottom: 14px; font-size: 1.15rem; }
.tri .body-text { font-size: 0.92rem; }

/* ---- Split ---- */
.split { display: grid; grid-template-columns: 1fr 1fr; gap: 96px; align-items: center; }
@media (max-width: 960px) { .split { grid-template-columns: 1fr; gap: 64px; } }

/* ---- Flat diagram ---- */
.diagram { border: 1px solid var(--line); padding: 72px 48px; }
.diagram-hub {
  border: 1px solid var(--lime); color: var(--lime);
  font-size: 0.82rem; font-weight: 600; letter-spacing: 0.14em; text-transform: uppercase;
  text-align: center; padding: 18px; max-width: 240px; margin: 0 auto 56px;
}
.diagram-line { width: 1px; height: 40px; background: var(--line-strong); margin: 0 auto; }
.diagram-row { display: flex; justify-content: center; gap: 24px; flex-wrap: wrap; margin-top: 56px; }
.diagram-node {
  border: 1px solid var(--line-strong); padding: 24px 32px; text-align: center;
  font-size: 0.78rem; font-weight: 500; letter-spacing: 0.12em; text-transform: uppercase; color: var(--grey);
}

/* ---- Flow (business model) ---- */
.flow { display: flex; align-items: stretch; justify-content: center; flex-wrap: wrap; border: 1px solid var(--line); }
.flow-node { flex: 1; min-width: 200px; padding: 56px 32px; text-align: center; border-right: 1px solid var(--line); }
.flow-node:last-child { border-right: none; }
.flow-node .flow-step { font-size: 0.7rem; letter-spacing: 0.2em; color: var(--grey-dim); text-transform: uppercase; display: block; margin-bottom: 16px; }
.flow-node p { font-size: 1rem; font-weight: 600; }
.flow-node.is-accent { background: var(--lime); }
.flow-node.is-accent .flow-step { color: rgba(0,0,0,0.55); }
.flow-node.is-accent p { color: var(--black); }
@media (max-width: 760px) {
  .flow { flex-direction: column; }
  .flow-node { border-right: none; border-bottom: 1px solid var(--line); }
  .flow-node:last-child { border-bottom: none; }
}

.callout {
  border: 1px solid var(--lime); color: var(--lime);
  padding: 28px 40px; font-size: 0.9rem; font-weight: 500; text-align: center; margin-top: 24px;
}

/* ---- Statement (vision) ---- */
.statement h2 { max-width: 28ch; font-size: clamp(1.9rem, 3.8vw, 3.4rem); line-height: 1.15; }

/* ---- CTA ---- */
.cta-wrap { border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.cta-inner { padding-top: 160px; padding-bottom: 160px; text-align: left; }
.cta-inner h2 { max-width: 20ch; margin-bottom: 48px; }

/* ---- Footer ---- */
footer { padding: 96px 0 48px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 48px; margin-bottom: 96px; }
@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr; } }
.footer-col h4 {
  font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.2em;
  color: var(--grey-dim); margin-bottom: 24px; font-weight: 500;
}
.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: 14px; }
.footer-col a { font-size: 0.9rem; color: var(--grey); transition: color 120ms linear; }
.footer-col a:hover { color: var(--lime); }
.footer-badge {
  display: flex; align-items: center; flex-wrap: wrap; gap: 16px;
  padding-top: 32px; border-top: 1px solid var(--line);
}
.footer-badge span {
  font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.2em;
  color: var(--grey-dim); font-weight: 500;
}
.footer-badge img { display: block; height: 36px; width: auto; }
.footer-bottom {
  display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px;
  padding-top: 24px;
  font-size: 0.78rem; color: var(--grey-dim);
}

/* ---- Reveal animation (kept from template: rise + fade) ---- */
.reveal { opacity: 0; transform: translateY(32px); transition: opacity 900ms var(--ease), transform 900ms var(--ease); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }

/* ---- Mobile menu ---- */
.mobile-menu {
  position: fixed; inset: 0; z-index: 200; background: var(--black);
  display: flex; flex-direction: column; padding: 120px 32px 48px;
  transform: translateY(-100%); transition: transform 360ms var(--ease); overflow-y: auto;
}
.mobile-menu.is-open { transform: translateY(0); }
.mobile-menu a {
  font-size: 2rem; font-weight: 600; letter-spacing: -0.02em;
  padding: 20px 0; border-bottom: 1px solid var(--line);
}
.mobile-close { position: absolute; top: 22px; right: 28px; background: none; border: none; color: var(--white); font-size: 2rem; cursor: pointer; line-height: 1; }
@media (max-width: 400px) {
  .mobile-menu { padding: 100px 24px 40px; }
  .mobile-menu a { font-size: 1.6rem; padding: 16px 0; }
}