:root {
  --brand-charcoal: #0d1321;
  --brand-accent: #e23a1a;
  --brand-accent-dark: #b52e15;
  --brand-steel: #6b7280;
  --brand-coolgray: #f1f3f5;

  /* Legacy variable names kept (referenced throughout this file) but now aliased
     to the Industrial Thermal Design brand palette instead of Powerblanket green. */
  --green-900: var(--brand-charcoal);
  --green-800: var(--brand-accent-dark);
  --green-700: var(--brand-accent-dark);
  --green-600: var(--brand-accent);
  --green-100: var(--brand-coolgray);
  --green-50: var(--brand-coolgray);
  --ink: #1a1f1b;
  --ink-soft: #4b5563;
  --paper: #ffffff;
  --paper-alt: var(--brand-coolgray);
  --border: #e5e9e5;
  --radius: 14px;
  --radius-sm: 10px;
  --shadow: 0 1px 2px rgba(13, 19, 33, 0.06), 0 8px 24px -8px rgba(13, 19, 33, 0.12);
  --shadow-lg: 0 20px 45px -18px rgba(13, 19, 33, 0.35);

  /* Thermal ("ironbow") accent palette — used sparingly as the hub's signature motif */
  --thermal-cold: #2447c9;
  --thermal-purple: #7c2fd6;
  --thermal-magenta: #c0299a;
  --thermal-red: #e0413f;
  --thermal-orange: #f2822e;
  --thermal-yellow: #f9c04a;
  --thermal-white: #fff6e0;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  line-height: 1.68;
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  font-size: 17px;
}

.container { max-width: 1120px; margin: 0 auto; padding: 0 24px; }

h1, h2, h3 {
  font-family: inherit;
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.02em;
  text-wrap: balance;
  color: var(--green-900);
  margin: 0 0 0.5em;
}

p { margin: 0 0 1em; }
a { color: inherit; }

.kicker {
  text-transform: uppercase;
  letter-spacing: 0.09em;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--green-700);
  margin: 0 0 12px;
}
.kicker-on-dark { color: var(--thermal-yellow); }

.section { padding: 88px 0; }
.section-alt { background: var(--paper-alt); }
.section-intro { color: var(--ink-soft); max-width: 640px; margin-bottom: 2.2rem; font-size: 1.05rem; }

/* ---------- Scroll reveal — shared across subdomain pages ---------- */

.reveal { opacity: 0; transform: translateY(22px); transition: opacity 0.7s cubic-bezier(0.2,0.7,0.2,1), transform 0.7s cubic-bezier(0.2,0.7,0.2,1); }
.reveal.is-visible { opacity: 1; transform: translateY(0); }

/* ---------- Ask an Engineer — closing CTA band, reused verbatim across every subdomain page ---------- */

.section-cta-band { background: var(--green-900); color: #fff; text-align: center; }
.section-cta-band h2 { color: #fff; }
.section-cta-band p { color: #d1d5db; }
.cta-band-inner { max-width: 560px; margin: 0 auto; }
.cta-band-inner .btn { margin-top: 8px; }

/* ---------- Banner (matches the Sample Line Guide subsite) ---------- */

.hub-banner { background: #fff; border-bottom: 3px solid var(--green-700); padding: 14px 0; position: sticky; top: 0; z-index: 100; }
.hub-banner-inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 16px; }
.hub-banner-brand { display: flex; flex-direction: column; align-items: flex-start; }
.hub-banner-title-link { text-decoration: none; }
.hub-banner-title { margin: 0; font-size: 1.6rem; font-weight: 900; color: var(--brand-charcoal); letter-spacing: -0.01em; line-height: 1.15; }
.brand-accent { color: var(--brand-accent); }
.hub-banner-byline { display: flex; align-items: center; gap: 7px; margin: 6px 0 0; font-size: 0.72rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.05em; color: var(--ink-soft); }
.hub-banner-byline a { display: block; line-height: 0; }
.hub-banner-byline-logo { width: 180px; max-width: 100%; height: auto; display: block; }
.btn-banner { padding: 12px 22px; font-size: 0.85rem; white-space: nowrap; }

/* ---------- Hero — same real-photo Ken Burns slideshow as the Sample Line Guide subsite ---------- */

.hero {
  position: relative;
  padding: 130px 0 110px;
  overflow: hidden;
  isolation: isolate;
  background: #0a0d12;
  text-align: center;
}

.hero-big { min-height: 84vh; display: flex; align-items: center; padding: 160px 0 100px; }

.hero-slideshow { position: absolute; inset: 0; z-index: -2; overflow: hidden; }

.hero-slide {
  position: absolute;
  inset: -3%;
  background-size: cover;
  background-position: center;
  opacity: 0;
  filter: saturate(1.25) contrast(1.05);
  animation: heroSlideCycle 120s infinite;
  animation-fill-mode: backwards;
}

/* 10-slide rotation, 12s each, slower/more contemplative Ken Burns pacing for the
   homepage's real-photo hero (the Sample Line Guide subsite still uses its own
   4-slide/10s real-photo timing, defined in its own stylesheet). */
.hero-slide:nth-child(1) { animation-delay: 0s; }
.hero-slide:nth-child(2) { animation-delay: 12s; }
.hero-slide:nth-child(3) { animation-delay: 24s; }
.hero-slide:nth-child(4) { animation-delay: 36s; }
.hero-slide:nth-child(5) { animation-delay: 48s; }
.hero-slide:nth-child(6) { animation-delay: 60s; }
.hero-slide:nth-child(7) { animation-delay: 72s; }
.hero-slide:nth-child(8) { animation-delay: 84s; }
.hero-slide:nth-child(9) { animation-delay: 96s; }
.hero-slide:nth-child(10) { animation-delay: 108s; }

@keyframes heroSlideCycle {
  0%     { opacity: 0; transform: scale(1.1) translate(0, 0); }
  0.8%   { opacity: 1; }
  9%     { opacity: 1; transform: scale(1.22) translate(-2.2%, -1.4%); }
  10%    { opacity: 0; }
  100%   { opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  .hero-slide { animation: none; opacity: 0; }
  .hero-slide:first-child { opacity: 1; }
}

.hero-scrim {
  position: absolute;
  inset: 0;
  z-index: -1;
  background: linear-gradient(180deg, rgba(13,19,33,0.32) 0%, rgba(13,19,33,0.22) 45%, rgba(13,19,33,0.58) 100%);
}

.hub-hero-inner { position: relative; z-index: 1; max-width: 720px; margin: 0 auto; }
.hero h1 { color: #fff; font-size: clamp(2.4rem, 5vw, 3.6rem); margin-bottom: 0.4em; font-weight: 900; letter-spacing: -0.025em; }
.hero-big h1 { font-size: clamp(2.1rem, 4.9vw, 3.75rem); margin-bottom: 0; text-shadow: 0 4px 30px rgba(0,0,0,0.35); }
.hub-hero-lede { color: #dde1e6; font-size: 1.15rem; max-width: 620px; margin: 0 auto 2rem; }
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; justify-content: center; }

.credibility-line {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  color: #dde1e6;
  background: rgba(255,255,255,0.1);
  border: 1px solid rgba(255,255,255,0.22);
  padding: 7px 16px;
  border-radius: 999px;
  margin-bottom: 10px;
  margin-right: 10px;
}
.credibility-sub {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 500;
  color: #9aa1ab;
  margin-bottom: 22px;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-block;
  padding: 15px 30px;
  border-radius: 999px;
  font-weight: 700;
  text-decoration: none;
  border: none;
  cursor: pointer;
  font-size: 0.92rem;
  letter-spacing: 0.01em;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}
.btn-primary { background: var(--green-600); color: #fff; box-shadow: 0 10px 24px -8px rgba(226,58,26,0.5); }
.btn-primary:hover { background: var(--green-700); transform: translateY(-2px); }
.btn-outline { background: rgba(255,255,255,0.05); color: #fff; border: 1px solid rgba(255,255,255,0.7); }
.btn-outline:hover { background: rgba(255,255,255,0.14); transform: translateY(-2px); }

/* ---------- Tile grid ---------- */

.hub-tiles-section { background: var(--paper); }

.tile-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.tile {
  position: relative;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  min-height: 360px;
  padding: 32px;
  border-radius: 24px;
  background-color: #0d1117;
  background-size: cover;
  background-position: center;
  overflow: hidden;
  text-decoration: none;
  color: #fff;
  box-shadow: var(--shadow);
  transition: transform 0.35s cubic-bezier(0.22,1,0.36,1), opacity 0.35s ease, filter 0.35s ease, box-shadow 0.35s ease;
}

/* Hover-spotlight: hovering any tile dims its siblings; the hovered one stays full-strength. */
.tile-grid:hover .tile { opacity: 0.45; filter: saturate(0.7); }
.tile-grid .tile:hover { opacity: 1; filter: none; transform: translateY(-4px) scale(1.015); box-shadow: var(--shadow-lg); z-index: 2; }

.tile-icon { width: 44px; height: 44px; margin-bottom: 20px; opacity: 0.95; }
.tile-icon svg { width: 100%; height: 100%; }
.tile h3 { color: #fff; font-size: 1.45rem; margin-bottom: 0.35em; }
.tile p { color: rgba(255,255,255,0.8); font-size: 0.95rem; max-width: 30em; margin-bottom: 0.6em; }
.tile-cta { font-weight: 700; font-size: 0.95rem; color: #fff; }
.tile-badge {
  position: absolute; top: 26px; right: 26px;
  font-size: 0.7rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.06em;
  background: rgba(255,255,255,0.14); color: rgba(255,255,255,0.9);
  padding: 6px 12px; border-radius: 999px;
}

.tile-sampleline {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('heatedsamplelines/photos/real-hero-lowangle.jpg');
}
.tile-tank {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/tank-heating.jpg');
}
.tile-hopper {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/hopper-heating.jpg');
}
.tile-groundthaw {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/ground-thawing.jpg');
}
.tile-transmitter {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/transmitter-heating.jpg');
}
.tile-propane {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/propane-tanks.jpg');
}
.tile-fractank {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/frac-tanks.jpg');
}
.tile-composite {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/composite-curing.jpg');
}
.tile-pipe {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/pipe-heating.jpg');
}
.tile-skid {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/skid-heating.jpg');
}
.tile-boxes {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/boxes.jpg');
}
.tile-windblade {
  background-image:
    linear-gradient(180deg, rgba(13,19,33,0.25) 0%, rgba(13,19,33,0.45) 55%, rgba(13,19,33,0.92) 100%),
    url('assets/tiles/wind-blade-curing.jpg');
}

.tile-soon { cursor: default; filter: grayscale(0.45) brightness(0.82); }
.tile-grid:hover .tile-soon { filter: grayscale(0.45) brightness(0.82) saturate(0.7); }
.tile-grid .tile-soon:hover { filter: grayscale(0.45) brightness(0.9); transform: translateY(-4px); }

@media (max-width: 900px) {
  .tile-grid { grid-template-columns: repeat(2, 1fr); }
  .tile { min-height: 340px; padding: 32px; }
  .tile h3 { font-size: 1.5rem; }
  .hub-banner-title { font-size: 1.4rem; }
  .hub-banner-byline-logo { width: 150px; }
}
@media (max-width: 640px) {
  .tile-grid { grid-template-columns: 1fr; }
  .hub-banner-inner { flex-direction: column; align-items: flex-start; }
  .btn-banner { align-self: stretch; text-align: center; }
  .hub-banner-title { font-size: 1.15rem; }
  .hub-banner-byline-logo { width: 130px; }
  .hero { padding: 70px 0 56px; }
  .hero h1 { font-size: 2rem; }
  .hero-big { min-height: 62vh; padding: 90px 0 60px; }
  .hero-big h1 { font-size: 1.6rem; }
  .section { padding: 56px 0; }
}

/* ---------- Footer ---------- */

.hub-footer { background: var(--paper-alt); border-top: 1px solid var(--border); padding: 32px 0; color: var(--ink-soft); font-size: 0.88rem; }
.hub-footer-meta { margin-top: 6px; font-size: 0.8rem; color: #94a396; }

/* ---------- Subdomain content components — shared across every subdomain page ---------- */

.content-anatomy-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.content-anatomy-grid img { width: 100%; height: auto; display: block; border-radius: var(--radius); }
.content-anatomy-list { list-style: none; margin: 0; padding: 0; }
.content-anatomy-list li { padding: 16px 0; border-top: 1px solid var(--border); }
.content-anatomy-list li:first-child { border-top: none; }
.content-anatomy-list strong { display: block; color: var(--ink); margin-bottom: 4px; }
.content-anatomy-list span { color: var(--ink-soft); font-size: 0.94rem; }

.spec-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1px; background: var(--border); border: 1px solid var(--border); border-radius: 14px; overflow: hidden; margin-top: 32px; }
.spec-item { background: #fff; padding: 24px; }
.spec-item dt { font-size: 0.76rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-soft); margin-bottom: 8px; }
.spec-item dd { margin: 0; font-size: 1.05rem; font-weight: 700; color: var(--ink); }

.badge-pill { display: inline-flex; align-items: center; gap: 8px; margin-top: 24px; padding: 10px 18px; background: var(--brand-coolgray); border-radius: 999px; font-size: 0.88rem; font-weight: 700; color: var(--brand-charcoal); }
.badge-pill svg { width: 18px; height: 18px; color: var(--brand-accent); }

.case-study-block { background: var(--brand-charcoal); border-radius: var(--radius); padding: 48px; color: #fff; margin-top: 32px; }
.case-study-kicker { text-transform: uppercase; letter-spacing: 0.1em; font-size: 0.76rem; font-weight: 700; color: var(--brand-accent); margin: 0 0 12px; }
.case-study-block h3 { color: #fff; font-size: 1.4rem; margin: 0 0 16px; }
.case-study-block p { color: #c7ccd4; }
.case-study-block blockquote { margin: 24px 0 0; padding-left: 20px; border-left: 3px solid var(--brand-accent); font-size: 1.1rem; font-style: italic; color: #fff; }
.case-study-block cite { display: block; margin-top: 12px; font-style: normal; font-size: 0.88rem; color: #94a3b8; }

.content-gallery { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-top: 32px; }
.content-gallery img { width: 100%; height: 320px; object-fit: cover; border-radius: var(--radius); box-shadow: var(--shadow); }

.comparison-table-wrap { overflow-x: auto; margin-top: 32px; }
.comparison-table { width: 100%; border-collapse: collapse; min-width: 560px; }
.comparison-table th, .comparison-table td { padding: 14px 16px; text-align: left; border-bottom: 1px solid var(--border); font-size: 0.92rem; }
.comparison-table th { font-size: 0.76rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--ink-soft); font-weight: 700; }
.comparison-table td { color: var(--ink); }
.comparison-table tr.is-winner td { font-weight: 700; color: var(--brand-accent-dark); }
.comparison-table tfoot td { font-weight: 800; border-bottom: none; border-top: 2px solid var(--brand-charcoal); }

@media (max-width: 900px) {
  .content-anatomy-grid { grid-template-columns: 1fr; }
  .spec-grid { grid-template-columns: 1fr; }
  .content-gallery { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .case-study-block { padding: 32px 24px; }
}