/* ============================================================
   ERP•AI — Proto skills site
   Dark, modern, single-page marketing design system
   ============================================================ */

:root {
  --bg: #0b0f1a;
  --bg-soft: #101626;
  --bg-card: #141b2e;
  --bg-card-hover: #18213a;
  --line: rgba(148, 163, 184, 0.14);
  --line-strong: rgba(148, 163, 184, 0.28);
  --text: #e7ecf5;
  --text-dim: #9aa8c0;
  --text-faint: #6b7a94;
  --indigo: #6366f1;
  --cyan: #22d3ee;
  --emerald: #34d399;
  --grad: linear-gradient(100deg, var(--indigo), var(--cyan) 55%, var(--emerald));
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 20px 60px rgba(2, 6, 23, 0.55);
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }

.container {
  width: min(1120px, 92%);
  margin-inline: auto;
}

.grad {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ===== Nav ===== */
.site-nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  background: rgba(11, 15, 26, 0.72);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s ease, background 0.3s ease;
}

.site-nav.scrolled {
  background: rgba(11, 15, 26, 0.88);
  border-bottom-color: var(--line);
}

.nav-inner {
  width: min(1120px, 92%);
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}

.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 1.12rem; letter-spacing: -0.01em; }
.brand-mark { color: var(--indigo); display: inline-flex; }
.brand-name { color: var(--text); }
.brand-name .dot { color: var(--cyan); }

.nav-links { display: flex; align-items: center; gap: 28px; font-size: 0.92rem; font-weight: 500; color: var(--text-dim); }

.nav-links a { transition: color 0.2s ease; }
.nav-links a:hover { color: var(--text); }

.nav-links .nav-cta {
  color: #fff;
  background: var(--grad);
  padding: 8px 16px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.88rem;
  box-shadow: 0 4px 20px rgba(99, 102, 241, 0.35);
}
.nav-links .nav-cta:hover { color: #fff; filter: brightness(1.08); }

.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 8px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); margin: 5px 0; border-radius: 2px; transition: transform 0.25s ease, opacity 0.25s ease; }
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ===== Hero ===== */
.hero { position: relative; padding: 180px 0 110px; overflow: hidden; }

.hero-bg { position: absolute; inset: 0; pointer-events: none; }

.grid-lines {
  position: absolute; inset: 0;
  background-image:
    linear-gradient(rgba(148, 163, 184, 0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(148, 163, 184, 0.05) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 30%, transparent 75%);
  -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 30%, transparent 75%);
}

.orb { position: absolute; border-radius: 50%; filter: blur(90px); opacity: 0.5; }
.orb-a { width: 480px; height: 480px; top: -160px; left: -120px; background: radial-gradient(circle, rgba(99, 102, 241, 0.55), transparent 65%); }
.orb-b { width: 420px; height: 420px; top: 40px; right: -140px; background: radial-gradient(circle, rgba(34, 211, 238, 0.4), transparent 65%); }

.hero-inner { position: relative; text-align: center; }

.eyebrow {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
  border: 1px solid rgba(34, 211, 238, 0.3);
  background: rgba(34, 211, 238, 0.07);
  padding: 7px 16px;
  border-radius: 999px;
  margin-bottom: 26px;
}

.hero h1 {
  font-size: clamp(2.4rem, 6vw, 4.3rem);
  font-weight: 800;
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin-bottom: 22px;
}

.hero-sub {
  max-width: 640px;
  margin: 0 auto 34px;
  color: var(--text-dim);
  font-size: clamp(1rem, 2vw, 1.15rem);
}

.hero-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-bottom: 56px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: 13px 26px; border-radius: 12px; font-weight: 600; font-size: 0.95rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.btn:hover { transform: translateY(-2px); }

.btn-primary { background: var(--grad); color: #fff; box-shadow: 0 8px 30px rgba(99, 102, 241, 0.4); }
.btn-primary:hover { box-shadow: 0 12px 36px rgba(99, 102, 241, 0.55); }

.btn-ghost { border: 1px solid var(--line-strong); color: var(--text); background: rgba(255, 255, 255, 0.02); }
.btn-ghost:hover { border-color: var(--cyan); color: var(--cyan); }

.hero-stats {
  display: flex; justify-content: center; gap: 56px; flex-wrap: wrap;
}
.hero-stats div { text-align: center; }
.hero-stats dt { font-size: clamp(1.8rem, 4vw, 2.6rem); font-weight: 800; color: var(--text); letter-spacing: -0.02em; }
.hero-stats dt::after { content: ""; display: block; width: 36px; height: 3px; margin: 8px auto 0; border-radius: 2px; background: var(--grad); }
.hero-stats dd { margin-top: 8px; color: var(--text-faint); font-size: 0.86rem; }

/* ===== Sections ===== */
.section { padding: 110px 0; }
.section-alt { background: var(--bg-soft); border-block: 1px solid var(--line); }

.section-label {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 14px;
}

.section-title {
  font-size: clamp(1.9rem, 4.4vw, 2.9rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.12;
  margin-bottom: 16px;
}

.section-sub { color: var(--text-dim); max-width: 620px; font-size: 1.02rem; margin-bottom: 48px; }

/* ===== Platform cards ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 26px;
  transition: transform 0.25s ease, border-color 0.25s ease, background 0.25s ease;
}

.card:hover { transform: translateY(-4px); border-color: rgba(99, 102, 241, 0.45); background: var(--bg-card-hover); }

.card-icon { font-size: 1.7rem; display: inline-block; margin-bottom: 16px; }
.card h3 { font-size: 1.12rem; font-weight: 700; margin-bottom: 10px; }
.card p { color: var(--text-dim); font-size: 0.94rem; }

/* ===== Capabilities ===== */
.cap-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.cap {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
  transition: border-color 0.25s ease, transform 0.25s ease;
}
.cap:hover { border-color: rgba(34, 211, 238, 0.4); transform: translateY(-3px); }

.cap-num {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--cyan);
  display: block;
  margin-bottom: 12px;
}

.cap h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.cap p { color: var(--text-dim); font-size: 0.92rem; }

/* ===== Skills catalog ===== */
.filters { display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 36px; }

.chip {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--line);
  color: var(--text-dim);
  font: 500 0.85rem var(--font);
  padding: 8px 16px;
  border-radius: 999px;
  cursor: pointer;
  transition: all 0.2s ease;
}
.chip:hover { color: var(--text); border-color: var(--line-strong); }
.chip.active { background: var(--grad); color: #fff; border-color: transparent; font-weight: 600; }

.skills-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 14px;
}

.skill {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 20px;
  transition: border-color 0.2s ease, transform 0.2s ease, opacity 0.25s ease;
}
.skill:hover { border-color: rgba(99, 102, 241, 0.5); transform: translateY(-3px); }

.skill h4 {
  font-family: var(--mono);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
  word-break: break-word;
}

.skill p { color: var(--text-dim); font-size: 0.86rem; margin-bottom: 14px; }

.skill .tag {
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--cyan);
  background: rgba(34, 211, 238, 0.08);
  border: 1px solid rgba(34, 211, 238, 0.22);
  padding: 3px 10px;
  border-radius: 999px;
}

.skills-grid .skill.hidden { display: none; }

/* ===== Steps ===== */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
  counter-reset: step;
}

.step {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 24px;
  position: relative;
  transition: border-color 0.25s ease, transform 0.25s ease;
}
.step:hover { border-color: rgba(52, 211, 153, 0.45); transform: translateY(-3px); }

.step-num {
  font-family: var(--mono);
  font-size: 0.85rem;
  color: #0b0f1a;
  background: var(--grad);
  width: 34px; height: 34px;
  border-radius: 10px;
  display: grid;
  place-items: center;
  font-weight: 700;
  margin-bottom: 18px;
}

.step h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; }
.step p { color: var(--text-dim); font-size: 0.92rem; }

/* ===== CTA ===== */
.cta-section { padding-top: 40px; }

.cta-box {
  text-align: center;
  background:
    radial-gradient(ellipse 70% 90% at 50% 0%, rgba(99, 102, 241, 0.18), transparent 60%),
    var(--bg-card);
  border: 1px solid var(--line-strong);
  border-radius: 24px;
  padding: 72px 32px;
  box-shadow: var(--shadow);
}

.cta-box h2 { font-size: clamp(1.9rem, 4.4vw, 2.8rem); font-weight: 800; letter-spacing: -0.025em; margin-bottom: 18px; }
.cta-box p { color: var(--text-dim); max-width: 560px; margin: 0 auto 32px; }

/* ===== Footer ===== */
.site-footer { border-top: 1px solid var(--line); padding: 36px 0; margin-top: 40px; }

.footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

.footer-note { color: var(--text-faint); font-size: 0.86rem; }

/* ===== Reveal animation ===== */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.7s ease, transform 0.7s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ===== Responsive ===== */
@media (max-width: 860px) {
  .nav-links {
    position: fixed;
    inset: 68px 0 auto 0;
    flex-direction: column;
    gap: 6px;
    background: rgba(11, 15, 26, 0.97);
    border-bottom: 1px solid var(--line);
    padding: 18px 24px 26px;
    transform: translateY(-12px);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.25s ease, transform 0.25s ease;
  }
  .nav-links.open { opacity: 1; transform: translateY(0); pointer-events: auto; }
  .nav-links a { padding: 10px 6px; font-size: 1rem; }
  .nav-links .nav-cta { margin-top: 8px; text-align: center; }
  .nav-toggle { display: block; }
  .section { padding: 80px 0; }
  .hero { padding: 150px 0 90px; }
  .hero-stats { gap: 32px; }
  .footer-inner { justify-content: center; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  .orb { filter: none; }
}