@charset "utf-8";
/* ═══════════════════════════════════════
   RESET & BASE
═══════════════════════════════════════ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Segoe UI', Arial, sans-serif;
  background-color: #F8F3E7;
  color: #2F3437;
  font-size: 16px;
  line-height: 1.6;
}

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

/* ═══════════════════════════════════════
   SITE HEADER & NAV
═══════════════════════════════════════ */
.site-header {
  background-color: #1D3557;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0,0,0,0.25);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 16px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  min-height: 60px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
  margin-right: auto;
}

.nav-logo-block {
  width: 52px;
  height: 44px;
}

.square-logo { width: 74px; height: 64px; margin: 5px; }

.nav-logo-block svg {
  width: 100%;
  height: 100%;
}

.nav-brand-text {
  font-size: 0.9rem;
  font-weight: 700;
  color: #F8F3E7;
  letter-spacing: 0.03em;
}

.nav-list {
  display: flex;
  list-style: none;
  gap: 4px;
  align-items: center;
}

.nav-list li a {
  display: block;
  color: rgba(248,243,231,0.8);
  font-size: 0.875rem;
  font-weight: 600;
  padding: 8px 14px;
  border-radius: 4px;
  transition: color 0.18s, background-color 0.18s;
}

.nav-list li a:hover {
  color: #F5B041;
  background-color: rgba(255,255,255,0.08);
}

.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 8px;
  border-radius: 4px;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: #F8F3E7;
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.2s;
}

/* ═══════════════════════════════════════
   BREADCRUMB
═══════════════════════════════════════ */
.breadcrumb {
  background-color: #e8e2d6;
  padding: 10px 24px;
  font-size: 0.85rem;
  color: #555;
  border-bottom: 1px solid #d5cfc5;
}

.breadcrumb a { color: #1D3557; font-weight: 600; }
.breadcrumb a:hover { text-decoration: underline; }
.bc-sep { margin: 0 6px; color: #aaa; }
.bc-current { color: #2F3437; font-weight: 600; }

/* ═══════════════════════════════════════
   PAGE WRAPPER
═══════════════════════════════════════ */
.page-wrapper {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 20px 40px;
}

/* ═══════════════════════════════════════
   PAGE TITLE BLOCK
═══════════════════════════════════════ */
.page-title-block {
  background: linear-gradient(135deg, #1D3557 0%, #2a4d73 100%);
  color: #F8F3E7;
  border-radius: 8px;
  padding: 36px 32px;
  margin-bottom: 28px;
  position: relative;
  overflow: hidden;
}

.page-title-block::after {
  content: '⚠';
  position: absolute;
  right: 28px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 7rem;
  opacity: 0.06;
  pointer-events: none;
  line-height: 1;
}

.page-title-label {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #F5B041;
  margin-bottom: 8px;
}

.page-title-main {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 12px;
}

.page-title-sub {
  font-size: 1rem;
  opacity: 0.85;
  line-height: 1.6;
  max-width: 680px;
}

.title-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 20px;
}

.title-pill {
  background-color: rgba(245, 176, 65, 0.2);
  border: 1px solid rgba(245, 176, 65, 0.4);
  color: #F5B041;
  font-size: 0.78rem;
  font-weight: 700;
  padding: 4px 12px;
  border-radius: 20px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ═══════════════════════════════════════
   ARTICLE / SECTION
═══════════════════════════════════════ */
.section-art-txt {
  margin: 0 0 28px 0;
  padding: 28px 28px 24px;
  background-color: #ffffff;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.07);
}

.section-art-title {
  font-size: 1.2rem;
  font-weight: 700;
  color: #1D3557;
  border-left: 4px solid #E63946;
  padding-left: 12px;
  margin-bottom: 20px;
  line-height: 1.3;
}

.section-art-txt > p {
  font-size: 1rem;
  color: #2F3437;
  line-height: 1.6;
  margin-bottom: 16px;
}

.subsection-heading {
  font-size: 1rem;
  font-weight: 700;
  color: #1D3557;
  margin: 24px 0 12px;
  padding-bottom: 6px;
  border-bottom: 2px solid #e8e2d6;
}

/* ═══════════════════════════════════════
   DEFINITION CARDS
═══════════════════════════════════════ */
.definition-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-top: 8px;
}

.def-card {
  border-radius: 8px;
  padding: 20px 18px;
  border-top: 5px solid transparent;
}

.def-card--blue  { background: #EBF2FA; border-top-color: #1D3557; }
.def-card--red   { background: #FEF0F0; border-top-color: #E63946; }
.def-card--gold  { background: #FEF9EC; border-top-color: #F5B041; }

.def-card-icon { font-size: 1.8rem; margin-bottom: 8px; }

.def-card h4 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: #1D3557;
}

.def-card p {
  font-size: 0.9rem;
  line-height: 1.55;
  color: #3a3f42;
  margin-bottom: 6px;
}

.def-card-list {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.def-card-list li {
  font-size: 0.87rem;
  line-height: 1.5;
  color: #3a3f42;
  padding-left: 14px;
  position: relative;
}

.def-card-list li::before {
  content: '–';
  position: absolute;
  left: 0;
  color: #888;
}

/* ═══════════════════════════════════════
   INCIDENT CARDS  (1.3.2)
═══════════════════════════════════════ */
.incident-card {
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 24px;
  box-shadow: 0 3px 12px rgba(0,0,0,0.1);
  border: 1px solid #e0dbd2;
}

.incident-header {
  padding: 20px 22px 16px;
  color: #F8F3E7;
  position: relative;
}

.incident-hdr--ammonia { background: linear-gradient(135deg, #7B0D1E 0%, #a31a2e 100%); }
.incident-hdr--co      { background: linear-gradient(135deg, #455A64 0%, #607D8B 100%); }
.incident-hdr--boiler  { background: linear-gradient(135deg, #4A235A 0%, #6C3483 100%); }

.incident-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  opacity: 0.7;
  margin-bottom: 6px;
}

.incident-header h3 {
  font-size: 1.1rem;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 10px;
}

.incident-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.incident-tag {
  background-color: rgba(0,0,0,0.25);
  font-size: 0.78rem;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 20px;
  white-space: nowrap;
}

.incident-body {
  padding: 20px 22px;
  background-color: #fdfcfa;
}

.incident-body > p {
  font-size: 0.95rem;
  line-height: 1.65;
  color: #2F3437;
  margin-bottom: 14px;
}

.incident-refs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-bottom: 16px;
  padding: 10px 14px;
  background-color: #f0ede6;
  border-radius: 6px;
  font-size: 0.82rem;
}

.ref-label {
  font-weight: 700;
  color: #555;
  text-transform: uppercase;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  margin-right: 4px;
}

.incident-refs a {
  color: #1D3557;
  font-weight: 600;
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color 0.18s;
}

.incident-refs a:hover { color: #E63946; }

.incident-two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 4px;
}

/* ═══════════════════════════════════════
   EXPLORE BOX
═══════════════════════════════════════ */
.explore-box {
  background-color: #FEF9EC;
  border: 1px solid #F5B041;
  border-radius: 8px;
  padding: 16px 18px;
}

.explore-icon {
  font-size: 1.3rem;
  margin-bottom: 6px;
}

.explore-box strong {
  display: block;
  font-size: 0.88rem;
  color: #1D3557;
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.explore-box ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.explore-box ul li {
  font-size: 0.88rem;
  line-height: 1.5;
  color: #3a3f42;
  padding-left: 18px;
  position: relative;
}

.explore-box ul li::before {
  content: '?';
  position: absolute;
  left: 0;
  color: #F5B041;
  font-weight: 700;
  font-size: 0.85rem;
}

/* ═══════════════════════════════════════
   REGULATION BLOCKS
═══════════════════════════════════════ */
.reg-block {
  border: 1px solid #e0dbd2;
  border-radius: 8px;
  overflow: hidden;
  margin-bottom: 20px;
}

.reg-block--featured {
  border-color: #F5B041;
  box-shadow: 0 0 0 3px rgba(245,176,65,0.25);
}

.reg-block-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  position: relative;
}

.reg-hdr--blue   { background-color: #1D3557; color: #F8F3E7; }
.reg-hdr--red    { background-color: #E63946; color: #F8F3E7; }
.reg-hdr--green  { background-color: #2E7D52; color: #F8F3E7; }
.reg-hdr--orange { background-color: #E67E22; color: #F8F3E7; }
.reg-hdr--slate  { background-color: #455A64; color: #F8F3E7; }
.reg-hdr--gold   { background-color: #D4890A; color: #fff; }

.reg-icon { font-size: 1.3rem; flex-shrink: 0; }

.reg-block-header h4 {
  font-size: 1rem;
  font-weight: 700;
  flex: 1;
  line-height: 1.3;
}

.featured-badge {
  background-color: #fff;
  color: #D4890A;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 3px 8px;
  border-radius: 20px;
  white-space: nowrap;
}

.reg-block-body {
  padding: 18px 20px;
  background-color: #fdfcfa;
}

.reg-block-body > p {
  font-size: 0.95rem;
  line-height: 1.6;
  color: #2F3437;
  margin-bottom: 12px;
}

/* ═══════════════════════════════════════
   CHECK LIST
═══════════════════════════════════════ */
.check-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.check-list li {
  font-size: 0.95rem;
  color: #2F3437;
  padding-left: 24px;
  position: relative;
  line-height: 1.5;
}

.check-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: #2E7D52;
  font-weight: 700;
}

/* ═══════════════════════════════════════
   CALLOUT
═══════════════════════════════════════ */
.callout {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  border-radius: 8px;
  padding: 16px 18px;
  margin-top: 4px;
}

.callout--tip {
  background-color: #EBF2FA;
  border-left: 4px solid #1D3557;
}

.callout-icon { font-size: 1.4rem; flex-shrink: 0; }

.callout strong {
  display: block;
  font-size: 0.9rem;
  color: #1D3557;
  margin-bottom: 4px;
}

.callout p {
  font-size: 0.9rem;
  line-height: 1.55;
  color: #2F3437;
  margin: 0;
}

/* ═══════════════════════════════════════
   RIGHTS & RESPONSIBILITIES GRID
═══════════════════════════════════════ */
.rights-resp-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 12px;
}

.hazard-groups-grid {
  grid-template-columns: 1fr 1fr 1fr;
}

.rr-col {
  border-radius: 6px;
  padding: 14px 16px;
}

.rr-col--rights {
  background-color: #EBF2FA;
  border-left: 3px solid #1D3557;
}

.rr-col--resp {
  background-color: #FEF9EC;
  border-left: 3px solid #F5B041;
}

.rr-col--green {
  background-color: #EBF5EE;
  border-left: 3px solid #2E7D52;
}

.rr-col h5 {
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  margin-bottom: 10px;
  color: #1D3557;
}

.rr-col ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.rr-col ul li {
  font-size: 0.9rem;
  line-height: 1.5;
  color: #2F3437;
  padding-left: 16px;
  position: relative;
}

.rr-col ul li::before {
  content: '•';
  position: absolute;
  left: 0;
  color: #888;
}

/* ═══════════════════════════════════════
   WHMIS GRID
═══════════════════════════════════════ */
.whmis-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 12px;
}

.whmis-item {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  background: #FEF9EC;
  border-radius: 6px;
  padding: 12px 14px;
}

.whmis-icon { font-size: 1.4rem; flex-shrink: 0; }

.whmis-item strong {
  display: block;
  font-size: 0.9rem;
  color: #1D3557;
  margin-bottom: 4px;
}

.whmis-item p {
  font-size: 0.85rem;
  line-height: 1.45;
  color: #555;
  margin: 0;
}

/* ═══════════════════════════════════════
   LABEL REQUIREMENTS GRID  (1.3.3)
═══════════════════════════════════════ */
.label-req-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 12px;
}

.label-req-item {
  background: #f9f7f2;
  border: 1px solid #e0dbd2;
  border-radius: 8px;
  padding: 16px 14px;
  position: relative;
}

.label-req-num {
  display: inline-block;
  background-color: #1D3557;
  color: #F5B041;
  font-size: 0.7rem;
  font-weight: 700;
  width: 22px;
  height: 22px;
  line-height: 22px;
  text-align: center;
  border-radius: 50%;
  margin-bottom: 8px;
}

.label-req-item strong {
  display: block;
  font-size: 0.9rem;
  color: #1D3557;
  margin-bottom: 4px;
}

.label-req-item p {
  font-size: 0.85rem;
  color: #555;
  line-height: 1.45;
  margin: 0;
}

/* ═══════════════════════════════════════
   SDS 16-SECTION GRID  (1.3.3)
═══════════════════════════════════════ */
.sds-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-top: 12px;
}

.sds-item {
  background: #f4f1ea;
  border-radius: 6px;
  padding: 12px 12px 10px;
  display: flex;
  flex-direction: column;
  gap: 3px;
  transition: background-color 0.18s, box-shadow 0.18s;
}

.sds-item:hover {
  background-color: #EBF2FA;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.sds-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  background-color: #E63946;
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  border-radius: 4px;
  margin-bottom: 4px;
  flex-shrink: 0;
}

.sds-item strong {
  font-size: 0.83rem;
  color: #1D3557;
  line-height: 1.3;
}

.sds-item span {
  font-size: 0.78rem;
  color: #666;
  line-height: 1.4;
}

/* ═══════════════════════════════════════
   STORAGE GRID  (1.3.6 / 1.3.8)
═══════════════════════════════════════ */
.storage-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.storage-grid .reg-block { margin-bottom: 0; }

/* ═══════════════════════════════════════
   INCOMPATIBLE MATERIALS GRID
═══════════════════════════════════════ */
.incompatible-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin-top: 12px;
}

.incompat-item {
  background: #FEF0F0;
  border: 1px solid #f5c6c9;
  border-radius: 8px;
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 8px;
}

.incompat-icon { font-size: 1.5rem; }

.incompat-item p {
  font-size: 0.88rem;
  line-height: 1.5;
  color: #3a3f42;
  margin: 0;
}

/* ═══════════════════════════════════════
   TDG CLASS GRID  (1.3.7)
═══════════════════════════════════════ */
.tdg-classes {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-top: 12px;
}

.tdg-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: 6px;
  font-size: 0.88rem;
  font-weight: 600;
  line-height: 1.35;
  color: #2F3437;
}

.tdg-item span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  font-size: 0.85rem;
  font-weight: 700;
  color: #fff;
  flex-shrink: 0;
}

.tdg-item em {
  display: block;
  font-size: 0.76rem;
  font-weight: 400;
  font-style: normal;
  color: #E63946;
}

.tdg-item--1 { background: #fce8e8; } .tdg-item--1 span { background: #c0392b; }
.tdg-item--2 { background: #e8f0fb; } .tdg-item--2 span { background: #1D3557; }
.tdg-item--3 { background: #fef0e0; } .tdg-item--3 span { background: #E67E22; }
.tdg-item--4 { background: #fef9e0; } .tdg-item--4 span { background: #D4890A; }
.tdg-item--5 { background: #eef8e8; } .tdg-item--5 span { background: #2E7D52; }
.tdg-item--6 { background: #f4edf9; } .tdg-item--6 span { background: #6C3483; }
.tdg-item--7 { background: #fce8e8; } .tdg-item--7 span { background: #922B21; }
.tdg-item--8 { background: #e8f0fb; } .tdg-item--8 span { background: #2471A3; }
.tdg-item--9 { background: #f0efee; } .tdg-item--9 span { background: #555; }


/* QUIZ NAV */
.quiz-nav-container {
  text-align: center;
  margin-bottom: 0.75rem;
}

.quiz-nav {
  display: flex;
  justify-content: center;
}

.quiz-nav-btn {
  display: inline-block;
  background-color: #E63946;
  color: #F8F3E7;
  text-decoration: none;
  padding: 0.85rem 1.4rem;
  border-radius: 0.5rem;
  font-weight: 600;
  transition: background-color 0.2s, transform 0.2s, box-shadow 0.2s;
  box-shadow: 0 4px 12px rgba(29, 53, 87, 0.18);
  border: 2px solid transparent;
}

.quiz-nav-btn:hover {
  background-color: #C92F3B;
  transform: translateY(-1px);
  box-shadow: 0 6px 14px rgba(29, 53, 87, 0.24);
}

.quiz-nav-btn:focus {
  outline: none;
  border-color: #F1C40F;
}

/* FOOTER NAV */
.main-footer-nav {
  background-color: #1D3557;
  display: flex;
  justify-content: center;
  gap: 12px;
  padding: 16px 24px;
  flex-wrap: wrap;
}

.main-footer-nav-btn {
  display: inline-block;
  background-color: #F5B041;
  color: #2F3437;
  font-weight: 700;
  font-size: 0.9rem;
  padding: 10px 24px;
  border-radius: 4px;
  transition: background-color 0.2s;
  text-decoration: none;
}

.main-footer-nav-btn:hover { background-color: #F8C471; }

/* ═══════════════════════════════════════
   SITE FOOTER
═══════════════════════════════════════ */
.site-footer {
  background-color: #2F3437;
  color: #F8F3E7;
  padding: 40px 24px 24px;
}

.footer-container {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  color: #F1C40F;
  gap: 32px;
  max-width: 1200px;
  margin: 0 auto;
}

.footer-col {
  text-align: left;
  color: #F1C40F;
  margin: 0 50px;
}

.footer-col a {
  color: #F1C40F;
  text-decoration: underline;
  transition: opacity 0.2s;
}

.footer-col a:hover { opacity: 0.5; }

.footer-col h3 {
  font-size: 1.05rem;
  color: #F1C40F;
  margin-bottom: 10px;
}

.footer-col p {
  font-size: 0.9rem;
  opacity: 0.8;
  line-height: 1.7;
}

.footer-credit {
  text-align: center;
  font-size: 0.8rem;
  opacity: 0.6;
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid rgba(255,255,255,0.15);
  max-width: 1200px;
  margin-left: auto;
  margin-right: auto;
}

/* ═══════════════════════════════════════
   RESPONSIVE
═══════════════════════════════════════ */
@media (max-width: 900px) {
  .sds-grid { grid-template-columns: repeat(3, 1fr); }
  .hazard-groups-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .page-title-main { font-size: 1.5rem; }
  .page-title-block { padding: 24px 20px; }
  .page-title-block::after { display: none; }

  .section-art-txt { padding: 20px 16px; }
  .section-art-title { font-size: 1rem; }

  .definition-cards { grid-template-columns: 1fr; }
  .rights-resp-grid { grid-template-columns: 1fr; }
  .hazard-groups-grid { grid-template-columns: 1fr; }
  .whmis-grid { grid-template-columns: 1fr; }
  .label-req-grid { grid-template-columns: 1fr 1fr; }
  .sds-grid { grid-template-columns: repeat(2, 1fr); }
  .storage-grid { grid-template-columns: 1fr; }
  .incompatible-grid { grid-template-columns: 1fr; }
  .tdg-classes { grid-template-columns: repeat(2, 1fr); }
  .incident-two-col { grid-template-columns: 1fr; }

  .hamburger { display: flex; }

  .nav-list {
    display: none;
    flex-direction: column;
    width: 100%;
    background-color: #1D3557;
    gap: 0;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    border-top: 1px solid rgba(255,255,255,0.1);
  }

  .nav-list.nav-open { display: flex; }
  .nav-list li a { border-top: 1px solid rgba(255,255,255,0.1); border-radius: 0; }

  .site-nav { position: relative; flex-wrap: wrap; }

  .footer-container { flex-direction: column; gap: 20px; }
}

@media (max-width: 480px) {
  .label-req-grid { grid-template-columns: 1fr; }
  .sds-grid { grid-template-columns: repeat(2, 1fr); }
  .tdg-classes { grid-template-columns: 1fr; }
  .incident-tag { font-size: 0.72rem; }
}
/* ── Back to Top Button ── */
.back-to-top {
  position: fixed;
  bottom: 28px;
  right: 24px;
  z-index: 999;
  padding: 10px 18px;
  font-size: 0.85rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease;
  transform: translateY(10px);
  border-radius: 4px;
  box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.back-to-top.visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
/* ── Scroll Margin for Quick Nav Anchor Targets ── */
.section-art-txt[id],
.ppe-category[id],
.subsection-block[id],
.hazard-nav-card[id],
div[id].section-art-txt,
article[id] {
  scroll-margin-top: 80px;
}