/* ==========================================================================
   Sterig Pharmaceuticals — Corporate Website Stylesheet
   ========================================================================== */

:root {
  --color-primary: #0056D2;
  --color-primary-dark: #00409e;
  --color-dark: #0B1F3A;
  --color-white: #FFFFFF;
  --color-light: #F7F9FC;
  --color-accent: #00A676;
  --color-accent-dark: #00875f;
  --color-text: #2B3A4F;
  --color-text-muted: #64748B;
  --color-border: #E4E9F2;

  --font-heading: 'Montserrat', 'Segoe UI', sans-serif;
  --font-body: 'Inter', 'Segoe UI', sans-serif;

  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --radius-pill: 999px;

  --shadow-sm: 0 2px 10px rgba(11, 31, 58, 0.06);
  --shadow-md: 0 10px 30px rgba(11, 31, 58, 0.10);
  --shadow-lg: 0 20px 50px rgba(11, 31, 58, 0.14);

  --container-width: 1200px;
  --nav-height: 84px;
  --transition: all 0.25s ease;
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-white);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
h1, h2, h3, h4, h5 {
  font-family: var(--font-heading);
  color: var(--color-dark);
  font-weight: 700;
  line-height: 1.25;
}
.container {
  width: 100%;
  max-width: var(--container-width);
  margin: 0 auto;
  padding: 0 24px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
}

:focus-visible {
  outline: 3px solid var(--color-accent);
  outline-offset: 2px;
}

/* ---------- Utility ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 14px;
}
.eyebrow::before {
  content: "";
  width: 24px;
  height: 2px;
  background: var(--color-accent);
  display: inline-block;
}
.section { padding: 96px 0; }
.section--tight { padding: 64px 0; }
.section--light { background: var(--color-light); }
.section--dark {
  background: linear-gradient(160deg, var(--color-dark) 0%, #102a4c 100%);
  color: #C9D4E4;
}
.section--dark h2, .section--dark h3 { color: var(--color-white); }
.section-head {
  max-width: 680px;
  margin: 0 0 56px;
}
.section-head.center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head h2 { font-size: clamp(28px, 4vw, 40px); margin-bottom: 16px; }
.section-head p { color: var(--color-text-muted); font-size: 17px; }
.section--dark .section-head p { color: #A9B7CC; }

.text-muted { color: var(--color-text-muted); }

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 15px 32px;
  border-radius: var(--radius-pill);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14.5px;
  letter-spacing: 0.02em;
  transition: var(--transition);
  white-space: nowrap;
}
.btn-primary {
  background: var(--color-primary);
  color: var(--color-white);
  box-shadow: 0 8px 20px rgba(0, 86, 210, 0.28);
}
.btn-primary:hover { background: var(--color-primary-dark); transform: translateY(-2px); box-shadow: 0 12px 26px rgba(0, 86, 210, 0.34); }
.btn-outline {
  background: transparent;
  color: var(--color-white);
  border: 1.5px solid rgba(255,255,255,0.55);
}
.btn-outline:hover { background: rgba(255,255,255,0.12); border-color: #fff; transform: translateY(-2px); }
.btn-ghost {
  background: var(--color-white);
  color: var(--color-primary);
  border: 1.5px solid var(--color-border);
}
.btn-ghost:hover { border-color: var(--color-primary); background: #EEF4FF; transform: translateY(-2px); }
.btn-accent {
  background: var(--color-accent);
  color: var(--color-white);
  box-shadow: 0 8px 20px rgba(0, 166, 118, 0.28);
}
.btn-accent:hover { background: var(--color-accent-dark); transform: translateY(-2px); }
.btn-sm { padding: 10px 22px; font-size: 13px; }
.btn-block { width: 100%; }

/* ---------- Navbar ---------- */
.navbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid transparent;
  transition: var(--transition);
}
.navbar.is-scrolled {
  height: 68px;
  box-shadow: var(--shadow-sm);
  border-bottom-color: var(--color-border);
}
.navbar .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand img { height: 46px; width: auto; transition: var(--transition); }
.navbar.is-scrolled .brand img { height: 38px; }
.nav-links {
  display: flex;
  align-items: center;
  gap: 40px;
}
.nav-links a {
  font-family: var(--font-heading);
  font-size: 14.5px;
  font-weight: 600;
  color: var(--color-dark);
  position: relative;
  padding: 6px 0;
  transition: var(--transition);
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 0; height: 2px;
  background: var(--color-accent);
  transition: var(--transition);
}
.nav-links a:hover, .nav-links a.active { color: var(--color-primary); }
.nav-links a:hover::after, .nav-links a.active::after { width: 100%; }
.nav-cta { display: flex; align-items: center; gap: 18px; }
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  width: 32px;
  z-index: 1200;
}
.nav-toggle span {
  height: 2.5px;
  background: var(--color-dark);
  border-radius: 2px;
  transition: var(--transition);
  width: 100%;
}
.nav-toggle.is-open span:nth-child(1) { transform: translateY(7.5px) rotate(45deg); }
.nav-toggle.is-open span:nth-child(2) { opacity: 0; }
.nav-toggle.is-open span:nth-child(3) { transform: translateY(-7.5px) rotate(-45deg); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: calc(var(--nav-height) + 100px) 0 120px;
  background: linear-gradient(155deg, var(--color-dark) 0%, #0E2A4D 55%, #0B3A5C 100%);
  color: var(--color-white);
  overflow: hidden;
}
.hero-bg-pattern {
  position: absolute;
  inset: 0;
  opacity: 0.5;
  pointer-events: none;
}
.hero .container { position: relative; z-index: 2; }
.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 60px;
  align-items: center;
}
.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 18px;
  border-radius: var(--radius-pill);
  background: rgba(0, 166, 118, 0.16);
  border: 1px solid rgba(0, 166, 118, 0.4);
  color: #4FD8AA;
  font-family: var(--font-heading);
  font-size: 12.5px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 26px;
}
.hero h1 {
  color: var(--color-white);
  font-size: clamp(34px, 4.6vw, 54px);
  line-height: 1.15;
  margin-bottom: 22px;
  letter-spacing: -0.01em;
}
.hero h1 .accent-word { color: #4FD8AA; }
.hero p.lead {
  font-size: 18px;
  color: #B9C6DA;
  max-width: 540px;
  margin-bottom: 38px;
}
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 56px; }
.hero-stats {
  display: grid;
  grid-template-columns: repeat(3, auto);
  gap: 36px;
}
.hero-stats .stat-num {
  font-family: var(--font-heading);
  font-size: 30px;
  font-weight: 700;
  color: var(--color-white);
}
.hero-stats .stat-label {
  font-size: 12.5px;
  color: #90A0BB;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 4px;
}

/* Hero visual — abstract vial/seal graphic */
.hero-visual { position: relative; display: flex; align-items: center; justify-content: center; }
.hero-visual svg { width: 100%; height: auto; max-width: 460px; }
.float-slow { animation: floatY 6s ease-in-out infinite; }
.float-slow.delay { animation-delay: -3s; }
@keyframes floatY {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-14px); }
}
.spin-slow { animation: spin 40s linear infinite; transform-origin: center; }
@keyframes spin { from { transform: rotate(0deg); } to { transform: rotate(360deg); } }

/* ---------- Page hero (inner pages) ---------- */
.page-hero {
  padding: calc(var(--nav-height) + 70px) 0 80px;
  background: linear-gradient(155deg, var(--color-dark) 0%, #0E2A4D 55%, #0B3A5C 100%);
  color: var(--color-white);
  position: relative;
  overflow: hidden;
}
.page-hero .container { position: relative; z-index: 2; }
.breadcrumb {
  font-family: var(--font-heading);
  font-size: 13px;
  font-weight: 600;
  color: #90A0BB;
  letter-spacing: 0.04em;
  margin-bottom: 18px;
}
.breadcrumb a { color: #90A0BB; }
.breadcrumb a:hover { color: var(--color-white); }
.breadcrumb .sep { margin: 0 8px; color: #4A5C79; }
.breadcrumb .current { color: #4FD8AA; }
.page-hero h1 { color: var(--color-white); font-size: clamp(30px, 4vw, 46px); max-width: 720px; }
.page-hero p.lead { color: #B9C6DA; font-size: 17px; max-width: 620px; margin-top: 16px; }

/* ---------- Cards ---------- */
.card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 36px 30px;
  transition: var(--transition);
}
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); border-color: transparent; }
.card-icon {
  width: 58px; height: 58px;
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  background: #EAF1FF;
  color: var(--color-primary);
  font-size: 24px;
  margin-bottom: 22px;
  transition: var(--transition);
}
.card:hover .card-icon { background: var(--color-primary); color: var(--color-white); }
.card h3 { font-size: 19px; margin-bottom: 10px; }
.card p { color: var(--color-text-muted); font-size: 15px; }

.grid { display: grid; gap: 28px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-6 { grid-template-columns: repeat(3, 1fr); }

/* ---------- About / split sections ---------- */
.split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}
.split-visual {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: linear-gradient(150deg, #EAF1FF, #F7F9FC);
  padding: 50px;
  display: flex; align-items: center; justify-content: center;
  min-height: 380px;
}
.split-visual svg { width: 100%; max-width: 360px; }

.value-list { display: grid; gap: 18px; margin-top: 28px; }
.value-item { display: flex; gap: 16px; align-items: flex-start; }
.value-item .dot {
  flex-shrink: 0;
  width: 34px; height: 34px;
  border-radius: 50%;
  background: #E4F7EF;
  color: var(--color-accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 15px;
  margin-top: 2px;
}
.value-item h4 { font-size: 16px; margin-bottom: 4px; }
.value-item p { color: var(--color-text-muted); font-size: 14.5px; }

/* ---------- Tabs (vision/mission/values) ---------- */
.vm-tabs { display: flex; gap: 12px; margin-bottom: 32px; flex-wrap: wrap; }
.vm-tab {
  padding: 12px 26px;
  border-radius: var(--radius-pill);
  border: 1.5px solid var(--color-border);
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14px;
  color: var(--color-text-muted);
  transition: var(--transition);
}
.vm-tab.is-active, .vm-tab:hover {
  background: var(--color-primary);
  border-color: var(--color-primary);
  color: var(--color-white);
}
.vm-panel { display: none; }
.vm-panel.is-active { display: block; animation: fadeIn 0.4s ease; }

/* ---------- Process / numbered steps ---------- */
.process-steps {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0;
  position: relative;
}
.process-step {
  position: relative;
  padding: 0 22px;
  text-align: center;
}
.process-step:not(:last-child)::after {
  content: "";
  position: absolute;
  top: 30px;
  right: -10%;
  width: 20%;
  height: 2px;
  background: repeating-linear-gradient(90deg, var(--color-border) 0 8px, transparent 8px 14px);
}
.process-num {
  width: 60px; height: 60px;
  border-radius: 50%;
  background: var(--color-white);
  border: 2px solid var(--color-primary);
  color: var(--color-primary);
  display: flex; align-items: center; justify-content: center;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 20px;
  margin: 0 auto 20px;
  position: relative; z-index: 2;
}
.process-step h4 { font-size: 16px; margin-bottom: 8px; }
.process-step p { font-size: 14px; color: var(--color-text-muted); }

/* ---------- Product cards ---------- */
.product-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
}
.product-card:hover { box-shadow: var(--shadow-md); transform: translateY(-6px); }
.product-card-top {
  padding: 34px 30px 0;
}
.product-card-icon {
  width: 56px; height: 56px;
  border-radius: var(--radius-sm);
  background: #E4F7EF;
  color: var(--color-accent);
  display: flex; align-items: center; justify-content: center;
  font-size: 24px;
  margin-bottom: 20px;
}
.product-card-body { padding: 0 30px 30px; flex: 1; display: flex; flex-direction: column; }
.product-card h3 { font-size: 19px; margin-bottom: 10px; }
.product-card p { color: var(--color-text-muted); font-size: 14.5px; margin-bottom: 22px; flex: 1; }
.product-card-tag {
  display: inline-block;
  font-family: var(--font-heading);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: #EAF1FF;
  padding: 5px 12px;
  border-radius: var(--radius-pill);
  margin-bottom: 16px;
  width: fit-content;
}
.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 14px;
  color: var(--color-primary);
  transition: var(--transition);
}
.link-arrow i { transition: var(--transition); font-size: 12px; }
.link-arrow:hover i { transform: translateX(4px); }

/* ---------- Certifications strip ---------- */
.strip {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 30px;
  padding: 30px 0;
}
.strip-item {
  display: flex; align-items: center; gap: 12px;
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-dark);
  font-size: 14px;
  letter-spacing: 0.03em;
  opacity: 0.75;
}
.strip-item i { color: var(--color-accent); font-size: 18px; }

/* ---------- Contact ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 0.85fr 1.15fr;
  gap: 50px;
}
.contact-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 28px;
  margin-bottom: 22px;
}
.contact-card h4 {
  font-size: 12.5px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-accent);
  margin-bottom: 14px;
}
.contact-card address { font-style: normal; font-size: 15px; color: var(--color-text); line-height: 1.8; }
.contact-quick { display: flex; gap: 14px; margin-top: 18px; flex-wrap: wrap; }
.contact-quick a {
  display: flex; align-items: center; gap: 8px;
  font-size: 14px; font-weight: 600;
  color: var(--color-primary);
}
.form-card {
  background: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 44px;
  box-shadow: var(--shadow-sm);
}
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin-bottom: 20px; }
.form-group { margin-bottom: 20px; display: flex; flex-direction: column; gap: 8px; }
.form-group label { font-size: 13.5px; font-weight: 600; color: var(--color-dark); font-family: var(--font-heading); }
.form-group input,
.form-group select,
.form-group textarea {
  width: 100%;
  padding: 13px 16px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-body);
  font-size: 14.5px;
  color: var(--color-text);
  background: var(--color-light);
  transition: var(--transition);
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  background: var(--color-white);
  box-shadow: 0 0 0 4px rgba(0, 86, 210, 0.10);
}
.form-group textarea { resize: vertical; min-height: 130px; }
.form-note { font-size: 13px; color: var(--color-text-muted); margin-top: 14px; }
.form-status {
  display: none;
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  margin-bottom: 20px;
}
.form-status.is-success { display: block; background: #E4F7EF; color: var(--color-accent-dark); }
.form-status.is-error { display: block; background: #FDECEC; color: #C0392B; }

.map-wrap {
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--color-border);
  margin-top: 30px;
  height: 340px;
}
.map-wrap iframe { width: 100%; height: 100%; border: 0; }

/* ---------- CTA band ---------- */
.cta-band {
  background: linear-gradient(120deg, var(--color-primary), #0071F0);
  border-radius: var(--radius-lg);
  padding: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 30px;
  flex-wrap: wrap;
  color: var(--color-white);
}
.cta-band h3 { color: var(--color-white); font-size: 26px; margin-bottom: 8px; }
.cta-band p { color: #D6E6FF; font-size: 15px; }

/* ---------- Footer ---------- */
.footer {
  background: var(--color-dark);
  color: #9FADC4;
  padding: 80px 0 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.2fr;
  gap: 50px;
  padding-bottom: 60px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.footer-brand img { height: 42px; margin-bottom: 18px; }
.footer-brand p { font-size: 14px; line-height: 1.8; max-width: 300px; }
.footer h5 {
  color: var(--color-white);
  font-size: 14.5px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 22px;
}
.footer-links { display: grid; gap: 13px; }
.footer-links a { font-size: 14.5px; transition: var(--transition); }
.footer-links a:hover { color: var(--color-white); padding-left: 4px; }
.footer-contact-item { display: flex; gap: 12px; margin-bottom: 16px; font-size: 14px; line-height: 1.6; }
.footer-contact-item i { color: var(--color-accent); margin-top: 3px; flex-shrink: 0; }
.footer-bottom {
  padding: 26px 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 13.5px;
}
.footer-bottom-links { display: flex; gap: 24px; }
.footer-bottom-links a:hover { color: var(--color-white); }

/* ---------- Back to top ---------- */
.back-to-top {
  position: fixed;
  bottom: 30px;
  right: 30px;
  width: 48px; height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-white);
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: var(--transition);
  z-index: 900;
}
.back-to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: var(--color-primary-dark); }

/* ---------- Fade-in on scroll ---------- */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.fade-in.is-visible { opacity: 1; transform: translateY(0); }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }

/* ---------- Misc pages: 404 ---------- */
.error-page {
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  padding: 40px 24px;
  background: var(--color-light);
}
.error-page .code {
  font-family: var(--font-heading);
  font-size: clamp(90px, 15vw, 150px);
  font-weight: 700;
  color: var(--color-primary);
  line-height: 1;
}
.error-page h1 { margin: 10px 0 16px; font-size: 26px; }
.error-page p { color: var(--color-text-muted); margin-bottom: 30px; }

/* ---------- Responsive ---------- */
@media (max-width: 991px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3, .grid-6 { grid-template-columns: repeat(2, 1fr); }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-visual { order: -1; max-width: 320px; margin: 0 auto 20px; }
  .split { grid-template-columns: 1fr; }
  .split-visual { order: -1; }
  .contact-grid { grid-template-columns: 1fr; }
  .process-steps { grid-template-columns: repeat(2, 1fr); gap: 40px 0; }
  .process-step::after { display: none; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 767px) {
  .section { padding: 64px 0; }
  .nav-links { 
    position: fixed;
    top: 0; right: -100%;
    width: min(320px, 84%);
    height: 100vh;
    background: var(--color-white);
    flex-direction: column;
    align-items: flex-start;
    justify-content: flex-start;
    padding: 110px 32px 40px;
    gap: 26px;
    box-shadow: -10px 0 40px rgba(0,0,0,0.15);
    transition: right 0.35s ease;
    z-index: 1100;
  }
  .nav-links.is-open { right: 0; }
  .nav-cta .btn-ghost { display: none; }
  .nav-toggle { display: flex; }
  .grid-2, .grid-3, .grid-4, .grid-6 { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .cta-band { flex-direction: column; text-align: center; padding: 40px 28px; }
  .footer-grid { grid-template-columns: 1fr; gap: 40px; }
  .process-steps { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: repeat(3, 1fr); gap: 18px; }
  .footer-bottom { flex-direction: column; text-align: center; }
}

/* Overlay behind mobile nav */
.nav-overlay {
  position: fixed; inset: 0;
  background: rgba(11, 31, 58, 0.5);
  opacity: 0; visibility: hidden;
  transition: var(--transition);
  z-index: 1050;
}
.nav-overlay.is-open { opacity: 1; visibility: visible; }