/* ==========================================================================
   Energy Revolution System — Design System
   "Future Energy Laboratory": dark graphite surfaces, electric-cyan accent,
   warm amber for CTAs, editorial typography. Dependency-free.
   ========================================================================== */

:root {
  --bg: #0a0d12;
  --bg-raised: #121721;
  --bg-raised-2: #182030;
  --border: #26303f;
  --border-soft: #1c2430;
  --text: #eef2f7;
  --text-muted: #9aa8ba;
  --text-faint: #838fa0;
  --cyan: #2fd9c7;
  --cyan-dim: #1a8f85;
  --amber: #f2a93b;
  --amber-dim: #c98526;
  --red: #e2645a;
  --green: #4caf7d;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 22px;
  --max-w: 1180px;
  --font-display: "Space Grotesk", "Segoe UI", system-ui, sans-serif;
  --font-body: "Inter", "Segoe UI", system-ui, sans-serif;
  --shadow-card: 0 20px 60px -30px rgba(0, 0, 0, 0.6);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; scroll-behavior: auto !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--cyan); }
a:hover { color: var(--amber); }

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  color: var(--text);
  margin: 0 0 0.6em;
  letter-spacing: -0.01em;
}
h1 { font-size: clamp(2.1rem, 4.5vw, 3.4rem); }
h2 { font-size: clamp(1.6rem, 3.2vw, 2.4rem); }
h3 { font-size: clamp(1.25rem, 2.2vw, 1.6rem); }
p { margin: 0 0 1.1em; color: var(--text-muted); }
p strong, li strong { color: var(--text); }

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--amber);
  color: #14100a;
  padding: 0.8em 1.2em;
  z-index: 1000;
  border-radius: 0 0 var(--radius-sm) 0;
  font-weight: 600;
}
.skip-link:focus { left: 0; }

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
  border-radius: 4px;
}

.wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  padding-inline: 24px;
}

section { padding-block: clamp(48px, 8vw, 96px); }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  font-family: var(--font-display);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 0.9em;
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 2px;
  background: var(--amber);
  display: inline-block;
}

.lede {
  font-size: clamp(1.05rem, 1.6vw, 1.2rem);
  color: var(--text-muted);
  max-width: 62ch;
}

.section-head { max-width: 78ch; margin-bottom: 2.4rem; }
.section-head.center { margin-inline: auto; text-align: center; }

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.55em;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  padding: 0.9em 1.6em;
  border-radius: 999px;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background-color 0.15s ease;
}
.btn:hover { text-decoration: none; }
.btn-primary {
  background: linear-gradient(135deg, var(--amber), var(--amber-dim));
  color: #17110a;
  box-shadow: 0 10px 30px -12px rgba(242, 169, 59, 0.55);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 16px 36px -14px rgba(242, 169, 59, 0.7); color: #17110a; }
.btn-ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}
.btn-ghost:hover { border-color: var(--cyan); color: var(--cyan); transform: translateY(-2px); }
.btn-sm { padding: 0.6em 1.2em; font-size: 0.9rem; }
.btn-row { display: flex; gap: 0.9rem; flex-wrap: wrap; align-items: center; }

/* ---- Header / Nav ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 13, 18, 0.86);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-soft);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  padding-block: 12px;
}
.brand { display: flex; align-items: center; gap: 0.7em; text-decoration: none; color: var(--text); }
.brand img { height: 42px; width: 42px; border-radius: 50%; }
.brand-text { font-family: var(--font-display); font-weight: 700; font-size: 1.02rem; line-height: 1.2; }
.brand-text span { display: block; font-family: var(--font-body); font-weight: 400; font-size: 0.68rem; color: var(--text-faint); letter-spacing: 0.06em; text-transform: uppercase; }

.nav-links { display: flex; align-items: center; gap: 1.8rem; list-style: none; margin: 0; padding: 0; }
.nav-links a { color: var(--text-muted); text-decoration: none; font-size: 0.95rem; font-weight: 500; }
.nav-links a:hover { color: var(--cyan); }
.nav-cta { display: flex; align-items: center; gap: 0.8rem; }

.nav-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 10px;
  color: var(--text);
  cursor: pointer;
}

@media (max-width: 880px) {
  .nav-toggle { display: inline-flex; }
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: flex-start;
    background: var(--bg-raised);
    border-bottom: 1px solid var(--border);
    padding: 1.2rem 24px;
    gap: 1rem;
    display: none;
  }
  .nav-links.is-open { display: flex; }
  .nav-cta .btn-ghost { display: none; }
}

/* ---- Hero ---- */
.hero {
  padding-top: clamp(56px, 10vw, 108px);
  position: relative;
  overflow: clip;
}
.hero::before {
  content: "";
  position: absolute;
  inset: -20% -10% auto -10%;
  height: 620px;
  background: radial-gradient(60% 60% at 30% 20%, rgba(47, 217, 199, 0.16), transparent 70%),
              radial-gradient(50% 50% at 80% 10%, rgba(242, 169, 59, 0.14), transparent 70%);
  pointer-events: none;
  z-index: 0;
}
.hero .wrap { position: relative; z-index: 1; }
.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 5vw, 4rem);
  align-items: center;
}
@media (max-width: 900px) { .hero-grid { grid-template-columns: 1fr; } }

.hero-badges { display: flex; flex-wrap: wrap; gap: 0.6rem; margin-top: 1.6rem; }
.pill {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  font-size: 0.8rem;
  color: var(--text-muted);
  border: 1px solid var(--border);
  background: var(--bg-raised);
  padding: 0.4em 0.9em;
  border-radius: 999px;
}
.pill .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--cyan); }

.hero-art {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-raised);
  box-shadow: var(--shadow-card);
}
.hero-art img { width: 100%; height: auto; }

/* ---- Cards / Grids ---- */
.grid { display: grid; gap: 1.4rem; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
@media (max-width: 880px) { .grid-3, .grid-2 { grid-template-columns: 1fr; } }

.card {
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 1.6rem;
}
.card h3 { margin-bottom: 0.5em; }
.card p:last-child { margin-bottom: 0; }

.card-icon {
  width: 44px; height: 44px;
  border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  background: linear-gradient(135deg, rgba(47,217,199,0.18), rgba(242,169,59,0.12));
  color: var(--cyan);
  margin-bottom: 1rem;
  font-family: var(--font-display); font-weight: 700;
}

/* ---- Alt section background ---- */
.section-alt { background: var(--bg-raised); border-block: 1px solid var(--border-soft); }

/* ---- Answer box (AEO quick-answer) ---- */
.answer-box {
  border: 1px solid var(--cyan-dim);
  background: linear-gradient(180deg, rgba(47,217,199,0.08), transparent);
  border-radius: var(--radius-md);
  padding: 1.4rem 1.6rem;
  margin-bottom: 1.8rem;
}
.answer-box .eyebrow { color: var(--cyan); }
.answer-box p { color: var(--text); margin-bottom: 0; }

/* ---- Limitation / callout boxes ---- */
.callout {
  border-radius: var(--radius-md);
  padding: 1.3rem 1.5rem;
  border: 1px solid var(--border-soft);
  background: var(--bg-raised);
}
.callout-warn { border-color: rgba(226, 100, 90, 0.4); background: rgba(226, 100, 90, 0.07); }
.callout-warn .eyebrow { color: var(--red); }
.callout-warn .eyebrow::before { background: var(--red); }

/* ---- Pathway diagram ---- */
.pathway {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: stretch;
  margin: 2rem 0;
}
.pathway-step {
  flex: 1 1 150px;
  background: var(--bg-raised);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 1.1rem 1rem;
  cursor: pointer;
  text-align: left;
  color: var(--text);
  font-family: var(--font-body);
  transition: border-color 0.15s ease, background-color 0.15s ease, transform 0.15s ease;
}
.pathway-step:hover, .pathway-step:focus-visible { border-color: var(--cyan); transform: translateY(-3px); }
.pathway-step[aria-expanded="true"] { border-color: var(--amber); background: var(--bg-raised-2); }
.pathway-step .num { font-family: var(--font-display); color: var(--cyan); font-size: 0.78rem; letter-spacing: 0.08em; }
.pathway-step .label { display: block; font-weight: 600; margin-top: 0.3rem; }
.pathway-arrow { display: flex; align-items: center; color: var(--text-faint); font-size: 1.2rem; padding-inline: 0.1rem; }
@media (max-width: 720px) { .pathway-arrow { display: none; } }
.pathway-detail {
  margin-top: 1rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-soft);
  background: var(--bg-raised);
  padding: 1.4rem 1.6rem;
}
.pathway-detail[hidden] { display: none; }

/* ---- Steps ---- */
.steps { display: grid; gap: 1rem; counter-reset: step; }
.step {
  display: grid;
  grid-template-columns: 56px 1fr;
  gap: 1.1rem;
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 1.2rem 1.4rem;
  background: var(--bg-raised);
}
.step-num {
  width: 44px; height: 44px;
  border-radius: 50%;
  border: 1px solid var(--cyan-dim);
  color: var(--cyan);
  font-family: var(--font-display);
  font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}

/* ---- Table ---- */
.table-wrap { overflow-x: auto; border: 1px solid var(--border-soft); border-radius: var(--radius-md); }
table { width: 100%; border-collapse: collapse; min-width: 560px; }
th, td { text-align: left; padding: 0.9rem 1.1rem; border-bottom: 1px solid var(--border-soft); font-size: 0.94rem; }
th { font-family: var(--font-display); color: var(--cyan); font-weight: 600; background: var(--bg-raised); }
td { color: var(--text-muted); }
tr:last-child td { border-bottom: none; }

/* ---- FAQ (native details) ---- */
.faq-item {
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  background: var(--bg-raised);
  margin-bottom: 0.8rem;
  overflow: hidden;
}
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: 1.1rem 1.4rem;
  font-family: var(--font-display);
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-size: 1.4rem;
  color: var(--cyan);
  flex-shrink: 0;
  transition: transform 0.15s ease;
}
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item .faq-body { padding: 0 1.4rem 1.3rem; color: var(--text-muted); }

/* ---- Offer / pricing card ---- */
.offer-card {
  border: 1px solid var(--amber-dim);
  background: linear-gradient(180deg, rgba(242,169,59,0.09), var(--bg-raised));
  border-radius: var(--radius-lg);
  padding: clamp(1.6rem, 4vw, 2.4rem);
}
.offer-price { font-family: var(--font-display); font-size: clamp(2.2rem, 5vw, 3rem); font-weight: 700; color: var(--text); }
.offer-price small { font-family: var(--font-body); font-size: 0.9rem; color: var(--text-faint); font-weight: 400; }
.offer-list { list-style: none; padding: 0; margin: 1.2rem 0; display: grid; gap: 0.55rem; }
.offer-list li { display: flex; gap: 0.6em; color: var(--text-muted); }
.offer-list li::before { content: "✓"; color: var(--cyan); font-weight: 700; }
.offer-fineprint { font-size: 0.82rem; color: var(--text-faint); margin-top: 1rem; }

/* ---- Footer ---- */
.site-footer { border-top: 1px solid var(--border-soft); padding-block: 3rem; background: var(--bg-raised); }
.footer-grid { display: grid; grid-template-columns: 1.2fr 1fr 1fr 1fr; gap: 2rem; }
@media (max-width: 980px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .footer-grid { grid-template-columns: 1fr; } }
.checklist-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.7rem; }
.checklist-list li { display: flex; gap: 0.7em; align-items: flex-start; color: var(--text-muted); background: var(--bg-raised); border: 1px solid var(--border-soft); border-radius: var(--radius-sm); padding: 0.85rem 1rem; }
.checklist-list li::before { content: "☐"; color: var(--cyan); font-size: 1.1rem; line-height: 1.4; flex-shrink: 0; }
.verdict-card { border: 1px solid var(--cyan-dim); background: linear-gradient(180deg, rgba(47,217,199,0.09), var(--bg-raised)); border-radius: var(--radius-lg); padding: clamp(1.4rem, 3vw, 2rem); }
.pros-cons { display: grid; grid-template-columns: 1fr 1fr; gap: 1.2rem; }
@media (max-width: 700px) { .pros-cons { grid-template-columns: 1fr; } }
.pros-cons .card ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.5rem; }
.pros-cons .card.pros ul li::before { content: "+ "; color: var(--green); font-weight: 700; }
.pros-cons .card.cons ul li::before { content: "− "; color: var(--red); font-weight: 700; }
.err-page { min-height: 50vh; display: flex; align-items: center; }
.footer-heading { font-family: var(--font-display); font-size: 0.85rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-faint); margin: 0 0 0.9rem; font-weight: 600; }
.footer-links { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.55rem; }
.footer-links a { color: var(--text-muted); text-decoration: none; font-size: 0.92rem; }
.footer-links a:hover { color: var(--cyan); }
.footer-bottom {
  margin-top: 2.4rem;
  padding-top: 1.6rem;
  border-top: 1px solid var(--border-soft);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.8rem;
  font-size: 0.82rem;
  color: var(--text-faint);
}
.footer-disclosure { font-size: 0.8rem; color: var(--text-faint); max-width: 70ch; margin-top: 1rem; }

/* ---- Breadcrumb ---- */
.breadcrumb { font-size: 0.85rem; color: var(--text-faint); margin-bottom: 1.2rem; }
.breadcrumb a { color: var(--text-faint); }
.breadcrumb a:hover { color: var(--cyan); }

/* ---- Legal pages ---- */
.legal-content h2 { margin-top: 2rem; }
.legal-content h2:first-child { margin-top: 0; }
.legal-content ul { color: var(--text-muted); }
.legal-updated { color: var(--text-faint); font-size: 0.88rem; }

/* ---- Scroll reveal (progressive enhancement) ---- */
.reveal { opacity: 1; transform: none; }
.js .reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.5s ease, transform 0.5s ease; }
.js .reveal.is-visible { opacity: 1; transform: none; }

/* ---- Utility ---- */
.text-center { text-align: center; }
.mt-lg { margin-top: 2.4rem; }
.small { font-size: 0.86rem; color: var(--text-faint); }