:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --surface-soft: #eef2f7;
  --text: #111827;
  --muted: #667085;
  --border: #d8dee9;
  --brand: #0f172a;
  --accent: #2563eb;
  --shadow: 0 20px 60px rgba(15, 23, 42, 0.10);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
}

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

.container {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.site-header {
  background: rgba(255, 255, 255, 0.9);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(12px);
}

.nav {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  font-size: 1.45rem;
  font-weight: 800;
  letter-spacing: -0.04em;
}

nav {
  display: flex;
  align-items: center;
  gap: 22px;
  color: var(--muted);
  font-size: 0.95rem;
}

nav a:hover { color: var(--text); }

.nav-button {
  color: #fff;
  background: var(--brand);
  padding: 10px 16px;
  border-radius: 999px;
}

.hero {
  padding: 78px 0 56px;
  background:
    radial-gradient(circle at top right, rgba(37, 99, 235, .16), transparent 34%),
    linear-gradient(180deg, #ffffff 0%, #f5f7fb 100%);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 42px;
  align-items: center;
}

.eyebrow {
  color: var(--accent);
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: 0.78rem;
  margin: 0 0 10px;
}

h1, h2, h3, p { margin-top: 0; }

h1 {
  font-size: clamp(2.55rem, 6vw, 4.9rem);
  line-height: 0.98;
  letter-spacing: -0.07em;
  margin-bottom: 22px;
}

.lead {
  font-size: 1.18rem;
  color: var(--muted);
  max-width: 650px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  margin-top: 30px;
}

.button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  padding: 13px 20px;
  border-radius: 14px;
  font-weight: 800;
  border: 1px solid transparent;
}

.button.primary {
  color: #fff;
  background: var(--brand);
}

.button.primary:hover { background: #000; }

.button.secondary {
  color: var(--brand);
  background: #fff;
  border-color: var(--border);
}

.hero-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 30px;
  box-shadow: var(--shadow);
  padding: 30px;
  min-height: 390px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  overflow: hidden;
  position: relative;
}

.product-visual {
  position: absolute;
  inset: 24px 24px auto 24px;
  height: 210px;
  background: linear-gradient(135deg, #f8fafc, #e5eaf2);
  border: 1px solid var(--border);
  border-radius: 24px;
  overflow: hidden;
}

.battery {
  position: absolute;
  width: 132px;
  height: 132px;
  border-radius: 999px;
  background: linear-gradient(135deg, #111827, #3b4658);
  box-shadow: inset 0 0 0 10px #e5e7eb, 0 24px 40px rgba(15,23,42,.16);
}

.battery::after {
  content: "";
  position: absolute;
  inset: 38px;
  border-radius: 999px;
  background: #f9fafb;
}

.battery-one { left: 34px; top: 42px; }
.battery-two { right: 42px; top: 28px; transform: scale(.84); }
.battery-three { left: 42%; bottom: 22px; transform: scale(.7); }

.hero-card h2 {
  font-size: 2rem;
  letter-spacing: -0.05em;
  margin-bottom: 4px;
}

.hero-card p {
  color: var(--muted);
  margin-bottom: 0;
}

.section { padding: 64px 0; }

.section-heading {
  max-width: 720px;
  margin-bottom: 28px;
}

.section-heading h2,
.support-box h2 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  line-height: 1.05;
  letter-spacing: -0.055em;
  margin-bottom: 14px;
}

.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 22px;
  padding: 26px;
  box-shadow: 0 10px 35px rgba(15, 23, 42, 0.05);
}

.icon {
  width: 48px;
  height: 48px;
  border-radius: 16px;
  display: grid;
  place-items: center;
  background: var(--surface-soft);
  margin-bottom: 22px;
  font-size: 1.4rem;
}

.card h3 {
  font-size: 1.25rem;
  margin-bottom: 8px;
}

.card p {
  color: var(--muted);
  margin-bottom: 0;
}

.support-section { padding-top: 24px; }

.support-box {
  background: var(--brand);
  color: #fff;
  border-radius: 30px;
  padding: 36px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 26px;
}

.support-box .eyebrow { color: #93c5fd; }

.support-box p {
  color: #cbd5e1;
  max-width: 640px;
  margin-bottom: 0;
}

.support-box .button {
  background: #fff;
  color: var(--brand);
  white-space: nowrap;
}

.site-footer {
  padding: 26px 0;
  color: var(--muted);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  border-top: 1px solid var(--border);
  padding-top: 22px;
}

.footer-inner p { margin: 0; }

@media (max-width: 820px) {
  nav { gap: 12px; font-size: 0.9rem; }
  .hero { padding-top: 48px; }
  .hero-grid { grid-template-columns: 1fr; }
  .hero-card { min-height: 330px; }
  .cards { grid-template-columns: 1fr; }
  .support-box { align-items: flex-start; flex-direction: column; }
  .support-box .button { width: 100%; }
}

@media (max-width: 560px) {
  .container { width: min(100% - 24px, 1120px); }
  .nav { min-height: 64px; }
  .logo { font-size: 1.3rem; }
  nav a:not(.nav-button) { display: none; }
  h1 { font-size: 2.7rem; }
  .lead { font-size: 1.05rem; }
  .hero-actions .button { width: 100%; }
  .hero-card, .support-box { border-radius: 22px; }
  .section { padding: 46px 0; }
  .footer-inner { flex-direction: column; }
}