:root {
  --ink: #121619;
  --muted: #5c6870;
  --line: #d8e0e2;
  --paper: #f7f8f5;
  --panel: #ffffff;
  --green: #2f6d5c;
  --green-dark: #183f36;
  --amber: #d7a444;
  --blue: #2b647a;
  --shadow: 0 18px 45px rgba(18, 22, 25, 0.12);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  background: var(--paper);
  font-family: Arial, Helvetica, sans-serif;
  line-height: 1.5;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 14px clamp(18px, 4vw, 54px);
  background: rgba(247, 248, 245, 0.92);
  border-bottom: 1px solid rgba(18, 22, 25, 0.08);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  color: #fff;
  background: var(--green-dark);
  border-radius: 8px;
  font-weight: 800;
}

.brand small, .payment-panel span, .metric-grid span, .upload span {
  display: block;
  color: var(--muted);
  font-size: 0.82rem;
}

nav { display: flex; gap: 18px; }
nav a { color: var(--muted); text-decoration: none; font-weight: 700; }
nav a:hover { color: var(--green); }

.hero {
  position: relative;
  min-height: 680px;
  display: grid;
  align-items: end;
  overflow: hidden;
  color: #fff;
}

.hero-media {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(18, 22, 25, 0.92), rgba(18, 22, 25, 0.5) 46%, rgba(18, 22, 25, 0.08)),
    url("https://upload.wikimedia.org/wikipedia/commons/d/d6/Air-cooled_industrial_and_commercial_battery_energy_storage_system.jpg") center / cover;
  transform: scale(1.02);
}

.hero-overlay {
  position: absolute;
  inset: auto 0 0;
  height: 34%;
  background: linear-gradient(0deg, var(--paper), rgba(247, 248, 245, 0));
}

.hero-content {
  position: relative;
  width: min(760px, calc(100% - 36px));
  margin: 0 0 clamp(56px, 8vw, 94px) clamp(18px, 6vw, 82px);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--amber);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1, h2, h3, p { margin-top: 0; }
h1 {
  max-width: 720px;
  margin-bottom: 20px;
  font-size: clamp(2.7rem, 8vw, 5.8rem);
  line-height: 0.96;
}

h2 { font-size: clamp(2rem, 4vw, 3.4rem); line-height: 1.02; margin-bottom: 14px; }
h3 { margin-bottom: 8px; font-size: 1.05rem; }
.hero-copy { max-width: 650px; color: rgba(255, 255, 255, 0.84); font-size: 1.16rem; }

.hero-actions, .trust-row, .payment-panel {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  font: inherit;
  font-weight: 800;
  text-decoration: none;
}

.primary { color: #fff; background: var(--green); }
.secondary { color: #fff; background: var(--blue); width: 100%; }
.ghost { color: #fff; border-color: rgba(255, 255, 255, 0.38); background: rgba(255, 255, 255, 0.08); }

.trust-row { margin-top: 26px; }
.trust-row span {
  padding: 8px 11px;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 999px;
  color: rgba(255, 255, 255, 0.82);
  font-size: 0.86rem;
}

.section {
  width: min(1180px, calc(100% - 36px));
  margin: 0 auto;
  padding: 76px 0;
}

.section-heading { max-width: 760px; margin-bottom: 28px; }
.brief-grid, .knowledge-grid, .value-grid, .metric-grid, .field-grid, .upload-grid, .process-list {
  display: grid;
  gap: 16px;
}

.brief-grid { grid-template-columns: repeat(4, 1fr); }
.knowledge-grid { grid-template-columns: repeat(4, 1fr); }
.value-grid { grid-template-columns: repeat(4, 1fr); }
.process-list { grid-template-columns: repeat(4, 1fr); }
.brief-grid article, .knowledge-grid article, .value-grid article, .process-list article, .result, .calculator, .fact-panel, .price-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  box-shadow: 0 8px 24px rgba(18, 22, 25, 0.06);
}

.brief-grid article, .knowledge-grid article, .value-grid article, .process-list article, .fact-panel, .price-card { padding: 22px; }
.step { color: var(--green); font-weight: 900; }

.split {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 390px;
  gap: 28px;
  align-items: start;
}

.fact-panel {
  border-left: 5px solid var(--green);
}

.fact-panel ul {
  margin: 14px 0 0;
  padding-left: 20px;
  color: var(--muted);
}

.process-list article span {
  display: grid;
  width: 36px;
  height: 36px;
  margin-bottom: 14px;
  place-items: center;
  border-radius: 50%;
  color: #fff;
  background: var(--green-dark);
  font-weight: 900;
}

.app-shell {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(340px, 0.65fr);
  gap: 20px;
  align-items: start;
}

.calculator, .result { padding: clamp(20px, 3vw, 32px); }
fieldset { margin: 0 0 24px; padding: 0; border: 0; }
legend { margin-bottom: 14px; font-weight: 900; font-size: 1.15rem; }
.field-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.upload-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
label { display: grid; gap: 7px; color: var(--ink); font-weight: 800; }
input, select {
  width: 100%;
  min-height: 44px;
  padding: 10px 12px;
  border: 1px solid #c8d1d3;
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
  font: inherit;
}

.upload {
  padding: 16px;
  border: 1px dashed #aab7ba;
  border-radius: 8px;
  background: #fbfcfa;
}

.payment-panel {
  justify-content: space-between;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.metric-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); margin: 22px 0; }
.metric-grid div {
  padding: 16px;
  border-radius: 8px;
  background: #f0f5f2;
}
.metric-grid strong { display: block; margin-top: 4px; font-size: 1.25rem; }
.report-text { padding: 16px; border-left: 4px solid var(--amber); background: #fffaf0; }
.detail-upgrade { margin-top: 20px; padding-top: 18px; border-top: 1px solid var(--line); }

.checkout-box {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.full {
  width: 100%;
}

.price-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 24px;
  align-items: center;
  border-left: 5px solid var(--amber);
}

.whitepaper {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 28px;
  align-items: start;
}
.keyword-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 0;
  margin: 0;
  list-style: none;
}
.keyword-list li {
  padding: 9px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #fff;
  color: var(--green-dark);
  font-weight: 700;
}

.footer {
  padding: 34px clamp(18px, 4vw, 54px);
  color: rgba(255, 255, 255, 0.72);
  background: var(--ink);
}
.footer p { max-width: 980px; margin-bottom: 10px; }
.footer a { color: #fff; }
.fineprint { font-size: 0.9rem; }

@media (max-width: 980px) {
  .brief-grid, .knowledge-grid, .value-grid, .process-list, .app-shell, .whitepaper, .split, .price-card { grid-template-columns: 1fr; }
  .hero { min-height: 620px; }
}

@media (max-width: 680px) {
  .topbar { align-items: flex-start; flex-direction: column; }
  nav { width: 100%; justify-content: space-between; }
  .hero-content { margin-left: 18px; }
  .field-grid, .upload-grid, .metric-grid { grid-template-columns: 1fr; }
  .payment-panel .button { width: 100%; }
}

.brand-logo{width:46px;height:46px;object-fit:contain;padding:5px;background:#121619;border-radius:8px;}