:root {
  --navy: #061a2b;
  --navy-2: #0b2d47;
  --bg: #f4f9fc;
  --bg-2: #ffffff;
  --card: #ffffff;
  --ink: #0c1f2e;
  --ink-2: #4b6476;
  --line: #dbe8f0;
  --accent: #0a84c6;
  --accent-2: #22c3ee;
  --ice: #e6f6fd;
  --cta: #ffb020;
  --cta-2: #ff8a00;
  --cta-ink: #2b1700;
  --warn: #9a4b00;
  --warn-bg: #fff4e0;
  --warn-line: #ffd59a;
  --ok: #0f8a5f;
  --radius: 18px;
  --shadow: 0 10px 30px -18px rgba(6, 26, 43, 0.45);
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #07131c;
    --bg-2: #0a1a26;
    --card: #0e2232;
    --ink: #e8f3f9;
    --ink-2: #9fb6c5;
    --line: #1d3a4e;
    --accent: #4cc3e6;
    --accent-2: #7fd8f0;
    --ice: #0f2a3b;
    --warn: #ffc77a;
    --warn-bg: #2b1f0c;
    --warn-line: #5c4113;
    --ok: #4fd1a1;
    --shadow: 0 10px 30px -18px rgba(0, 0, 0, 0.8);
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
[id] { scroll-margin-top: 88px; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img, svg { max-width: 100%; }
a { color: var(--accent); }
.wrap { width: 100%; max-width: 1160px; margin: 0 auto; padding: 0 20px; }
.skip { position: absolute; left: -999px; }
.skip:focus { left: 12px; top: 12px; z-index: 99; background: #fff; padding: 8px 12px; border-radius: 8px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(6, 26, 43, 0.86);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}
.site-header .wrap { display: flex; align-items: center; gap: 20px; min-height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; color: #fff; text-decoration: none; font-weight: 750; letter-spacing: -0.01em; white-space: nowrap; }
.logo svg { width: 34px; height: 34px; flex: none; }
.logo span em { font-style: normal; color: var(--accent-2); }
.nav { display: flex; gap: 4px; overflow-x: auto; scrollbar-width: none; margin-left: auto; }
.nav::-webkit-scrollbar { display: none; }
.nav a {
  color: rgba(255, 255, 255, 0.82);
  text-decoration: none;
  font-size: 0.93rem;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 10px;
  white-space: nowrap;
}
.nav a:hover, .nav a[aria-current="page"] { color: #fff; background: rgba(255, 255, 255, 0.1); }
@media (max-width: 860px) {
  .site-header .wrap { flex-wrap: wrap; gap: 4px 12px; padding-top: 10px; padding-bottom: 8px; }
  .nav { margin-left: 0; width: 100%; }
  .nav a { padding: 6px 10px; font-size: 0.88rem; }
}

/* Hero */
.hero {
  position: relative;
  overflow: hidden;
  color: #fff;
  background:
    radial-gradient(900px 500px at 85% -10%, rgba(34, 195, 238, 0.35), transparent 60%),
    radial-gradient(700px 420px at 0% 100%, rgba(10, 132, 198, 0.45), transparent 60%),
    linear-gradient(160deg, var(--navy) 0%, var(--navy-2) 100%);
}
.hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 80px;
  background: linear-gradient(to bottom, transparent, var(--bg));
  pointer-events: none;
}
.hero .wrap { position: relative; z-index: 1; display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 40px; align-items: center; padding-top: 64px; padding-bottom: 96px; }
.hero.small .wrap { grid-template-columns: 1fr; padding-top: 48px; padding-bottom: 72px; }
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin: 0 0 18px;
  padding: 6px 12px;
  border: 1px solid rgba(255, 255, 255, 0.18);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.07);
  font-size: 0.85rem;
  font-weight: 650;
  color: rgba(255, 255, 255, 0.9);
}
.eyebrow .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent-2); box-shadow: 0 0 0 0 rgba(34, 195, 238, 0.6); animation: pulse 2.4s ease-out infinite; }
@keyframes pulse { 70% { box-shadow: 0 0 0 10px rgba(34, 195, 238, 0); } 100% { box-shadow: 0 0 0 0 rgba(34, 195, 238, 0); } }
.hero h1 { margin: 0 0 18px; font-size: clamp(2.1rem, 5.4vw, 3.7rem); line-height: 1.04; letter-spacing: -0.03em; font-weight: 800; }
.hero.small h1 { font-size: clamp(1.9rem, 4.6vw, 3rem); }
.grad { background: linear-gradient(90deg, #7fe3ff, #22c3ee 45%, #ffffff); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero .lead { margin: 0 0 28px; font-size: clamp(1.05rem, 2.1vw, 1.25rem); color: rgba(255, 255, 255, 0.82); max-width: 620px; }
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 14px 22px;
  border-radius: 12px;
  font-weight: 750;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease, background 0.15s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn-cta { background: linear-gradient(180deg, var(--cta), var(--cta-2)); color: var(--cta-ink); box-shadow: 0 10px 24px -10px rgba(255, 138, 0, 0.8); }
.btn-ghost { color: #fff; border: 1px solid rgba(255, 255, 255, 0.28); background: rgba(255, 255, 255, 0.06); }
.btn svg { width: 18px; height: 18px; }
.trust { list-style: none; display: flex; flex-wrap: wrap; gap: 10px 18px; margin: 28px 0 0; padding: 0; font-size: 0.9rem; color: rgba(255, 255, 255, 0.8); }
.trust li { display: inline-flex; align-items: center; gap: 8px; }
.trust svg { width: 18px; height: 18px; color: var(--accent-2); flex: none; }
.hero-art { position: relative; }
.hero-art svg { width: 100%; height: auto; filter: drop-shadow(0 30px 40px rgba(0, 0, 0, 0.35)); }
.wave { animation: drift 4s ease-in-out infinite; }
.wave.w2 { animation-delay: 0.6s; }
.wave.w3 { animation-delay: 1.2s; }
@keyframes drift { 0%, 100% { transform: translateX(0); opacity: 0.9; } 50% { transform: translateX(10px); opacity: 0.45; } }
@media (max-width: 860px) {
  .hero .wrap { grid-template-columns: 1fr; padding-top: 40px; padding-bottom: 72px; }
  .hero-art { max-width: 360px; margin: 0 auto; }
}

/* Sections */
.section { padding: 56px 0; }
.section.tight { padding-top: 24px; }
.section-head { display: flex; flex-wrap: wrap; align-items: end; justify-content: space-between; gap: 12px 24px; margin-bottom: 24px; }
.section-head h2 { margin: 0; font-size: clamp(1.5rem, 3.2vw, 2.2rem); letter-spacing: -0.02em; line-height: 1.15; }
.section-head p { margin: 6px 0 0; color: var(--ink-2); max-width: 680px; }
.section-head .more { font-weight: 700; text-decoration: none; white-space: nowrap; }
.kicker { display: block; margin-bottom: 6px; color: var(--accent); font-size: 0.82rem; font-weight: 750; letter-spacing: 0.06em; text-transform: uppercase; }

/* Season banner */
.season {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 18px;
  align-items: center;
  margin-top: -40px;
  position: relative;
  z-index: 2;
  padding: 20px 24px;
  border-radius: var(--radius);
  background: var(--card);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
}
.season .icon { width: 48px; height: 48px; border-radius: 14px; display: grid; place-items: center; background: var(--warn-bg); color: var(--cta-2); }
.season .icon svg { width: 26px; height: 26px; }
.season strong { display: block; font-size: 1.05rem; }
.season p { margin: 2px 0 0; color: var(--ink-2); font-size: 0.95rem; }
.season p a { color: var(--ink-2); }
@media (max-width: 700px) { .season { grid-template-columns: 1fr; } .season .icon { display: none; } }

/* Category tiles */
.cats { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 14px; }
.cat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 22px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink);
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.cat:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--accent-2); }
.cat .ill { width: 56px; height: 56px; border-radius: 16px; display: grid; place-items: center; background: var(--ice); color: var(--accent); margin-bottom: 6px; }
.cat .ill svg { width: 34px; height: 34px; }
.cat strong { font-size: 1.08rem; }
.cat span { color: var(--ink-2); font-size: 0.93rem; }
.cat .go { margin-top: auto; padding-top: 8px; color: var(--accent); font-weight: 700; font-size: 0.92rem; }

/* Product cards */
.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 16px; }
.card {
  position: relative;
  display: flex;
  flex-direction: column;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: var(--card);
  overflow: hidden;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.card:hover { transform: translateY(-2px); box-shadow: var(--shadow); }
.card.featured { border: 2px solid var(--accent-2); }
.card .art {
  display: grid;
  place-items: center;
  height: 168px;
  background:
    radial-gradient(220px 120px at 70% 20%, rgba(34, 195, 238, 0.28), transparent 70%),
    linear-gradient(160deg, var(--ice), var(--bg-2));
  color: var(--accent);
}
.card .art svg { width: 128px; height: 128px; }
.ribbon {
  position: absolute;
  top: 12px;
  left: 12px;
  padding: 5px 10px;
  border-radius: 999px;
  background: linear-gradient(180deg, var(--cta), var(--cta-2));
  color: var(--cta-ink);
  font-size: 0.78rem;
  font-weight: 800;
  box-shadow: 0 6px 16px -8px rgba(255, 138, 0, 0.9);
}
.card .body { display: flex; flex-direction: column; gap: 10px; padding: 18px 18px 20px; flex: 1; }
.chips { display: flex; flex-wrap: wrap; gap: 6px; }
.chip { padding: 3px 9px; border-radius: 999px; background: var(--ice); color: var(--accent); font-size: 0.76rem; font-weight: 700; }
.card h3 { margin: 0; font-size: 1.06rem; line-height: 1.3; letter-spacing: -0.01em; }
.specs { margin: 0; padding: 0; list-style: none; display: grid; gap: 4px; color: var(--ink-2); font-size: 0.93rem; }
.specs li { position: relative; padding-left: 20px; }
.specs li::before { content: ""; position: absolute; left: 2px; top: 0.55em; width: 10px; height: 6px; border-left: 2px solid var(--ok); border-bottom: 2px solid var(--ok); transform: rotate(-45deg); }
.energy { display: flex; align-items: center; gap: 8px; font-size: 0.8rem; color: var(--ink-2); }
.energy b {
  display: inline-flex;
  align-items: center;
  height: 24px;
  padding: 0 16px 0 9px;
  background: #fff200;
  color: #fff;
  font-size: 0.95rem;
  font-weight: 800;
  text-shadow: 0 0 2px rgba(0, 0, 0, 0.6), 0 0 1px rgba(0, 0, 0, 0.85);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 50%, calc(100% - 10px) 100%, 0 100%);
}
.energy.na b { background: #b9c6cf; }
.note { margin: 0; padding: 10px 12px; border-radius: 10px; font-size: 0.86rem; background: var(--ice); color: var(--ink-2); }
.note.warn { background: var(--warn-bg); color: var(--warn); border: 1px solid var(--warn-line); }
.seller { margin: 0; font-size: 0.82rem; color: var(--ink-2); }
.seller b { color: var(--ink); }
.buy {
  margin-top: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 14px;
  border-radius: 12px;
  background: linear-gradient(180deg, var(--cta), var(--cta-2));
  color: var(--cta-ink);
  font-weight: 800;
  text-decoration: none;
  box-shadow: 0 8px 20px -12px rgba(255, 138, 0, 0.9);
  transition: filter 0.15s ease, transform 0.15s ease;
}
.buy:hover { filter: brightness(1.05); transform: translateY(-1px); }
.buy svg { width: 18px; height: 18px; }

/* Group heading */
.group { display: flex; align-items: center; gap: 10px; margin: 40px 0 14px; font-size: 1.25rem; letter-spacing: -0.01em; }
.group:first-child { margin-top: 0; }
.group .badge { font-size: 0.75rem; font-weight: 700; padding: 3px 9px; border-radius: 999px; background: var(--warn-bg); color: var(--warn); border: 1px solid var(--warn-line); }
.group-intro { margin: -6px 0 16px; color: var(--ink-2); max-width: 760px; }

/* Callout */
.callout {
  padding: 18px 20px;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  border-left: 4px solid var(--accent-2);
  background: var(--card);
  color: var(--ink-2);
  max-width: 860px;
}
.callout strong { color: var(--ink); }

/* Compare table */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); }
table.compare { width: 100%; border-collapse: collapse; font-size: 0.92rem; min-width: 720px; }
.compare th, .compare td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--line); vertical-align: top; }
.compare th { background: var(--ice); font-size: 0.82rem; text-transform: uppercase; letter-spacing: 0.04em; color: var(--ink-2); }
.compare tr:last-child td { border-bottom: 0; }
.compare td a { font-weight: 700; }
.compare .bad { color: var(--warn); font-weight: 700; }
.compare .good { color: var(--ok); font-weight: 700; }

/* Calculator */
.calc {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 0;
  border-radius: 22px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--card);
  box-shadow: var(--shadow);
}
.calc form { padding: 26px; display: grid; gap: 16px; }
.field label { display: flex; justify-content: space-between; font-weight: 700; font-size: 0.95rem; margin-bottom: 6px; }
.field label output { color: var(--accent); }
.field input[type="range"] { width: 100%; accent-color: var(--accent); }
.seg { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; }
.seg input { position: absolute; opacity: 0; pointer-events: none; }
.seg label { display: block; margin: 0; padding: 10px 8px; text-align: center; border: 1px solid var(--line); border-radius: 10px; font-weight: 650; font-size: 0.88rem; cursor: pointer; background: var(--bg-2); }
.seg input:checked + label { border-color: var(--accent); background: var(--ice); color: var(--accent); }
.seg input:focus-visible + label { outline: 2px solid var(--accent); outline-offset: 2px; }
.check { display: flex; align-items: center; gap: 10px; font-weight: 650; font-size: 0.95rem; }
.check input { width: 18px; height: 18px; accent-color: var(--accent); }
.calc .result {
  padding: 26px;
  color: #fff;
  background:
    radial-gradient(400px 260px at 80% 0%, rgba(34, 195, 238, 0.35), transparent 70%),
    linear-gradient(160deg, var(--navy), var(--navy-2));
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.result .big { font-size: clamp(2.4rem, 6vw, 3.4rem); font-weight: 800; letter-spacing: -0.03em; line-height: 1; }
.result .big small { font-size: 1.1rem; font-weight: 700; color: rgba(255, 255, 255, 0.75); }
.result .btu { font-size: 1.1rem; font-weight: 700; color: var(--accent-2); }
.result p { margin: 0; color: rgba(255, 255, 255, 0.82); }
.result .btn { margin-top: auto; align-self: flex-start; }
.result .fine { font-size: 0.8rem; color: rgba(255, 255, 255, 0.6); }
@media (max-width: 760px) { .calc { grid-template-columns: 1fr; } }

/* FAQ */
.faq { display: grid; gap: 10px; max-width: 860px; }
.faq details { border: 1px solid var(--line); border-radius: 14px; background: var(--card); padding: 0 18px; }
.faq summary { cursor: pointer; list-style: none; padding: 16px 0; font-weight: 700; display: flex; justify-content: space-between; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--accent); font-size: 1.3rem; line-height: 1; }
.faq details[open] summary::after { content: "–"; }
.faq details p { margin: 0 0 16px; color: var(--ink-2); }

/* Prose */
.prose { max-width: 780px; }
.prose h2 { margin: 44px 0 10px; font-size: clamp(1.35rem, 2.6vw, 1.75rem); letter-spacing: -0.02em; line-height: 1.2; }
.prose h3 { margin: 26px 0 6px; font-size: 1.12rem; }
.prose p, .prose li { color: var(--ink-2); }
.prose strong { color: var(--ink); }
.prose ul { padding-left: 20px; }
.toc { margin: 0 0 8px; padding: 18px 20px; border-radius: var(--radius); background: var(--card); border: 1px solid var(--line); }
.toc strong { display: block; margin-bottom: 6px; }
.toc ol { margin: 0; padding-left: 20px; columns: 2; column-gap: 28px; }
.toc a { text-decoration: none; }
@media (max-width: 600px) { .toc ol { columns: 1; } }

/* Breadcrumb */
.crumbs { margin: 0 0 14px; padding: 0; list-style: none; display: flex; flex-wrap: wrap; gap: 6px; font-size: 0.85rem; color: rgba(255, 255, 255, 0.7); }
.crumbs a { color: rgba(255, 255, 255, 0.85); text-decoration: none; }
.crumbs li + li::before { content: "›"; margin-right: 6px; opacity: 0.6; }

/* Disclosure + footer */
.disclosure { margin: 28px 0 0; font-size: 0.86rem; color: var(--ink-2); max-width: 860px; }
.site-footer { margin-top: 40px; background: var(--navy); color: rgba(255, 255, 255, 0.75); }
.site-footer .wrap { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 28px; padding-top: 44px; padding-bottom: 28px; }
.site-footer strong { color: #fff; display: block; margin-bottom: 10px; }
.site-footer ul { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; }
.site-footer a { color: rgba(255, 255, 255, 0.82); text-decoration: none; }
.site-footer a:hover { color: #fff; }
.site-footer p { margin: 0 0 10px; font-size: 0.92rem; }
.site-footer .legal { grid-column: 1 / -1; border-top: 1px solid rgba(255, 255, 255, 0.12); padding-top: 18px; font-size: 0.82rem; color: rgba(255, 255, 255, 0.6); }
@media (max-width: 760px) { .site-footer .wrap { grid-template-columns: 1fr; } }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  html { scroll-behavior: auto; }
}