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

:root {
  --blue-dark:  #0a1628;
  --blue-mid:   #0d2045;
  --blue:       #1a3a6b;
  --accent:     #2563eb;
  --accent-lt:  #3b82f6;
  --teal:       #0ea5e9;
  --green:      #10b981;
  --amber:      #f59e0b;
  --purple:     #8b5cf6;
  --text:       #e2e8f0;
  --text-muted: #94a3b8;
  --border:     rgba(255,255,255,0.08);
  --card-bg:    rgba(255,255,255,0.04);
  --card-hover: rgba(255,255,255,0.07);
}

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--blue-dark);
  color: var(--text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ── Nav ── */
nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(10,22,40,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 2rem;
  display: flex; align-items: center; justify-content: space-between;
  height: 56px;
}
.nav-brand {
  font-size: 1rem; font-weight: 700; letter-spacing: 0.02em;
  color: var(--teal); text-decoration: none;
}
.nav-links { display: flex; gap: 1.5rem; list-style: none; }
.nav-links a {
  font-size: 0.8rem; font-weight: 500; letter-spacing: 0.04em;
  text-transform: uppercase; color: var(--text-muted);
  text-decoration: none; transition: color 0.2s;
}
.nav-links a:hover { color: var(--text); }

/* ── Hero ── */
.hero {
  position: relative; overflow: hidden;
  padding: 7rem 2rem 6rem;
  text-align: center;
  background: radial-gradient(ellipse 80% 60% at 50% 0%, #112d5e 0%, transparent 70%);
}
.hero::before {
  content: '';
  position: absolute; inset: 0;
  background: url("data:image/svg+xml,%3Csvg width='60' height='60' viewBox='0 0 60 60' xmlns='http://www.w3.org/2000/svg'%3E%3Cg fill='none' fill-rule='evenodd'%3E%3Cg fill='%232563eb' fill-opacity='0.06'%3E%3Cpath d='M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z'/%3E%3C/g%3E%3C/g%3E%3C/svg%3E");
  opacity: 0.5;
}
.hero-eyebrow {
  display: inline-block;
  font-size: 0.75rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--teal);
  background: rgba(14,165,233,0.12);
  border: 1px solid rgba(14,165,233,0.25);
  padding: 0.3rem 0.9rem; border-radius: 999px;
  margin-bottom: 1.5rem;
}
.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  font-weight: 800; letter-spacing: -0.02em; line-height: 1.15;
  margin-bottom: 1.25rem;
}
.hero h1 span { color: var(--accent-lt); }
.hero p {
  max-width: 700px; margin: 0 auto 2.5rem;
  font-size: 1.125rem; color: var(--text-muted); line-height: 1.75;
}
.hero-badges {
  display: flex; flex-wrap: wrap; gap: 0.75rem;
  justify-content: center;
}
.badge {
  font-size: 0.8rem; font-weight: 600;
  padding: 0.4rem 1rem; border-radius: 999px;
  border: 1px solid;
}
.badge-blue   { color: var(--accent-lt);  background: rgba(37,99,235,0.12);  border-color: rgba(37,99,235,0.3); }
.badge-teal   { color: var(--teal);        background: rgba(14,165,233,0.1);  border-color: rgba(14,165,233,0.25); }
.badge-green  { color: var(--green);       background: rgba(16,185,129,0.1);  border-color: rgba(16,185,129,0.25); }
.badge-amber  { color: var(--amber);       background: rgba(245,158,11,0.1);  border-color: rgba(245,158,11,0.25); }
.badge-purple { color: var(--purple);      background: rgba(139,92,246,0.1);  border-color: rgba(139,92,246,0.25); }

/* ── Sections ── */
section { padding: 5rem 2rem; }
section + section { padding-top: 0; }
.container { max-width: 1200px; margin: 0 auto; }

.section-label {
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--teal);
  margin-bottom: 0.5rem;
}
.section-title {
  font-size: clamp(1.6rem, 3vw, 2.25rem);
  font-weight: 800; letter-spacing: -0.015em;
  margin-bottom: 0.75rem;
}
.section-desc {
  max-width: 680px;
  font-size: 1rem; color: var(--text-muted); line-height: 1.75;
  margin-bottom: 3rem;
}

/* ── What is IEC 62443 ── */
.intro-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.25rem;
}
.intro-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  transition: background 0.2s, border-color 0.2s;
}
.intro-card:hover { background: var(--card-hover); border-color: rgba(255,255,255,0.14); }
.intro-icon {
  width: 40px; height: 40px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem; margin-bottom: 1rem;
}
.intro-card h3 { font-size: 0.95rem; font-weight: 700; margin-bottom: 0.4rem; }
.intro-card p  { font-size: 0.85rem; color: var(--text-muted); line-height: 1.6; }

/* ── Audience blocks ── */
.audience-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}
.audience-card {
  border-radius: 12px; padding: 1.5rem;
  border: 1px solid;
}
.audience-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 0.35rem; }
.audience-card p  { font-size: 0.85rem; line-height: 1.6; }
.aud-owner  { background: rgba(37,99,235,0.08);  border-color: rgba(37,99,235,0.25);  color: var(--accent-lt); }
.aud-owner  p  { color: #93c5fd; }
.aud-integr { background: rgba(16,185,129,0.07); border-color: rgba(16,185,129,0.25); color: var(--green); }
.aud-integr p  { color: #6ee7b7; }
.aud-mfr    { background: rgba(245,158,11,0.07); border-color: rgba(245,158,11,0.25); color: var(--amber); }
.aud-mfr    p  { color: #fcd34d; }

/* ── Series ── */
.series-section { padding-bottom: 2rem; }
.series-block { margin-bottom: 4rem; }
.series-header {
  display: flex; align-items: center; gap: 1rem;
  margin-bottom: 1.5rem; padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}
.series-badge {
  min-width: 52px; height: 52px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.1rem; font-weight: 800; letter-spacing: 0.01em;
  flex-shrink: 0;
}
.s1 { background: rgba(14,165,233,0.15);  color: var(--teal); }
.s2 { background: rgba(37,99,235,0.15);   color: var(--accent-lt); }
.s3 { background: rgba(16,185,129,0.15);  color: var(--green); }
.s4 { background: rgba(245,158,11,0.15);  color: var(--amber); }

.series-header-text h2 {
  font-size: 1.3rem; font-weight: 800; letter-spacing: -0.01em;
}
.series-header-text p {
  font-size: 0.85rem; color: var(--text-muted);
  margin-top: 0.15rem;
}
.parts-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(330px, 1fr));
  gap: 1rem;
}
.part-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.25rem 1.4rem;
  transition: background 0.2s, border-color 0.2s, transform 0.15s;
  position: relative;
}
.part-card:hover {
  background: var(--card-hover);
  border-color: rgba(255,255,255,0.14);
  transform: translateY(-2px);
}
.part-num {
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.1em;
  text-transform: uppercase; margin-bottom: 0.4rem;
}
.part-card h3 { font-size: 0.9rem; font-weight: 700; margin-bottom: 0.5rem; line-height: 1.4; }
.part-card p  { font-size: 0.82rem; color: var(--text-muted); line-height: 1.6; }
.part-status {
  position: absolute; top: 1rem; right: 1rem;
  font-size: 0.65rem; font-weight: 700; letter-spacing: 0.06em;
  text-transform: uppercase; padding: 0.2rem 0.55rem; border-radius: 999px;
}
.status-pub      { background: rgba(16,185,129,0.15);  color: var(--green); }
.status-tr       { background: rgba(139,92,246,0.15); color: var(--purple); }
.status-ts       { background: rgba(14,165,233,0.15); color: var(--teal); }
.status-pas      { background: rgba(249,115,22,0.15); color: #fb923c; }
.status-dev      { background: rgba(245,158,11,0.15); color: var(--amber); }
.status-withdrawn { background: rgba(239,68,68,0.15); color: #f87171; }

/* ── Security Levels ── */
.sl-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
}
.sl-card {
  border-radius: 12px; padding: 1.5rem;
  border: 1px solid; text-align: center;
}
.sl-card .sl-num {
  font-size: 2.5rem; font-weight: 900; letter-spacing: -0.03em;
  line-height: 1;
}
.sl-card h3  { font-size: 0.85rem; font-weight: 700; margin: 0.5rem 0 0.4rem; }
.sl-card p   { font-size: 0.8rem; line-height: 1.55; }
.sl0 { background: rgba(148,163,184,0.07); border-color: rgba(148,163,184,0.2); color: var(--text-muted); }
.sl0 .sl-num { color: var(--text-muted); }
.sl1 { background: rgba(16,185,129,0.07);  border-color: rgba(16,185,129,0.25); color: var(--green); }
.sl1 p  { color: #6ee7b7; }
.sl2 { background: rgba(14,165,233,0.07);  border-color: rgba(14,165,233,0.25); color: var(--teal); }
.sl2 p  { color: #7dd3fc; }
.sl3 { background: rgba(139,92,246,0.08);  border-color: rgba(139,92,246,0.3);  color: var(--purple); }
.sl3 p  { color: #c4b5fd; }
.sl4 { background: rgba(239,68,68,0.07);   border-color: rgba(239,68,68,0.3);   color: #f87171; }
.sl4 p  { color: #fca5a5; }

/* ── Lifecycle ── */
.lifecycle-steps {
  display: flex; flex-wrap: wrap; gap: 0;
  counter-reset: step;
  margin-top: 2rem;
}
.lifecycle-step {
  flex: 1 1 160px;
  padding: 1.5rem 1.25rem;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-right: none;
  position: relative;
}
.lifecycle-step:last-child { border-right: 1px solid var(--border); border-radius: 0 10px 10px 0; }
.lifecycle-step:first-child { border-radius: 10px 0 0 10px; }
.lifecycle-step::before {
  counter-increment: step;
  content: counter(step);
  display: flex; align-items: center; justify-content: center;
  width: 28px; height: 28px; border-radius: 50%;
  font-size: 0.75rem; font-weight: 800;
  background: rgba(37,99,235,0.2); color: var(--accent-lt);
  margin-bottom: 0.75rem;
}
.lifecycle-step h4 { font-size: 0.85rem; font-weight: 700; margin-bottom: 0.3rem; }
.lifecycle-step p  { font-size: 0.78rem; color: var(--text-muted); line-height: 1.5; }

/* ── Divider ── */
.divider {
  border: none;
  border-top: 1px solid var(--border);
  margin: 0 2rem;
}

/* ── Footer ── */
footer {
  border-top: 1px solid var(--border);
  padding: 2rem;
  display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 1rem;
}
footer p { font-size: 0.8rem; color: var(--text-muted); }
footer a { color: var(--teal); text-decoration: none; }
footer a:hover { text-decoration: underline; }
.footer-brand { color: var(--text); }

/* ── Intro icon colours ── */
.icon-teal   { background: rgba(14,165,233,0.15); }
.icon-blue   { background: rgba(37,99,235,0.15); }
.icon-green  { background: rgba(16,185,129,0.15); }
.icon-amber  { background: rgba(245,158,11,0.15); }
.icon-purple { background: rgba(139,92,246,0.15); }
.icon-red    { background: rgba(239,68,68,0.15); }

/* ── Part legend ── */
.part-legend {
  display: flex; flex-wrap: wrap; gap: 0.6rem;
  margin-bottom: 2.5rem; align-items: center;
}
.part-legend-label { font-size: 0.75rem; color: var(--text-muted); margin-right: 0.25rem; }
.part-legend .part-status { position: static; }

/* ── Part number series colours ── */
.part-num-s1 { color: var(--teal); }
.part-num-s2 { color: var(--accent-lt); }
.part-num-s3 { color: var(--green); }
.part-num-s4 { color: var(--amber); }
.part-num-s6 { color: #fb923c; }

/* ── Series 6 ── */
.s6 { background: rgba(249,115,22,0.15); color: #fb923c; }

/* ── CTA ── */
.cta-section { padding: 3rem 2rem; text-align: center; }
.cta-section .container { max-width: 620px; }
.cta-text { font-size: 0.95rem; color: var(--text-muted); line-height: 1.75; }
.cta-link { color: var(--teal); text-decoration: none; font-weight: 600; white-space: nowrap; }

@media (max-width: 640px) {
  nav { padding: 0 1rem; }
  .nav-links { display: none; }
  section { padding: 3.5rem 1rem; }
  .lifecycle-steps { flex-direction: column; }
  .lifecycle-step { border-right: 1px solid var(--border); border-bottom: none; border-radius: 0; }
  .lifecycle-step:first-child { border-radius: 10px 10px 0 0; }
  .lifecycle-step:last-child  { border-bottom: 1px solid var(--border); border-radius: 0 0 10px 10px; }
  footer { flex-direction: column; text-align: center; }
}