:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --text: #111827;
  --muted: #667085;
  --line: #e5e7eb;
  --accent: #111827;
  --accent-2: #dff7eb;
  --dark: #0f172a;
  --radius: 24px;
  --shadow: 0 24px 80px rgba(15, 23, 42, 0.12);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  background: var(--bg);
  color: var(--text);
}

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

.container {
  width: min(1120px, calc(100% - 40px));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(14px);
  background: rgba(245, 247, 251, 0.82);
  border-bottom: 1px solid rgba(229, 231, 235, 0.8);
}

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

.brand {
  font-size: 1.35rem;
  font-weight: 800;
  letter-spacing: -0.04em;
}

.nav-cta {
  padding: 10px 16px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  font-weight: 600;
}

.hero {
  padding: 86px 0 72px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 48px;
  align-items: center;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 16px;
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #475467;
}

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

h1 {
  margin-bottom: 24px;
  font-size: clamp(3.4rem, 8vw, 6.8rem);
  line-height: 0.94;
  letter-spacing: -0.075em;
}

h2 {
  margin-bottom: 18px;
  font-size: clamp(2.2rem, 5vw, 4rem);
  line-height: 1;
  letter-spacing: -0.055em;
}

h3 {
  margin-bottom: 10px;
  font-size: 1.15rem;
}

.hero-text,
.card p,
.step p,
.signup p {
  color: var(--muted);
  line-height: 1.7;
}

.hero-text {
  max-width: 620px;
  margin-bottom: 30px;
  font-size: 1.1rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 26px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  padding: 0 22px;
  border-radius: 999px;
  font-weight: 700;
  transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.primary {
  color: white;
  background: var(--accent);
  box-shadow: 0 12px 30px rgba(17, 24, 39, 0.2);
}

.secondary {
  background: var(--surface);
  border: 1px solid var(--line);
}

.trust-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  color: #475467;
  font-size: 0.92rem;
  font-weight: 600;
}

.device-wrap {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 520px;
}

.device {
  position: relative;
  width: min(390px, 82vw);
  aspect-ratio: 1 / 1;
  border-radius: 44%;
  background:
    radial-gradient(circle at 35% 25%, rgba(255,255,255,.9), transparent 24%),
    linear-gradient(145deg, #e7e9ee, #b9bec8);
  box-shadow:
    inset 0 0 0 1px rgba(255,255,255,.65),
    inset 0 -22px 35px rgba(15,23,42,.11),
    var(--shadow);
  display: grid;
  place-items: center;
}

.device-ring {
  width: 78%;
  aspect-ratio: 1;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background:
    conic-gradient(from 20deg, #1f2937, #64748b, #111827, #94a3b8, #1f2937);
  box-shadow:
    inset 0 0 0 3px rgba(255,255,255,.14),
    0 10px 30px rgba(15,23,42,.18);
}

.device-screen {
  width: 84%;
  aspect-ratio: 1;
  border-radius: 50%;
  background:
    radial-gradient(circle at 35% 25%, rgba(255,255,255,.08), transparent 25%),
    #0b1220;
  color: white;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  box-shadow: inset 0 0 40px rgba(255,255,255,.03);
}

.device-screen strong {
  margin-top: 10px;
  font-size: 1.45rem;
  letter-spacing: -0.04em;
}

.device-screen small {
  margin-top: 6px;
  color: #a7f3d0;
}

.screen-logo {
  width: 54px;
  height: 54px;
  border-radius: 18px;
  display: grid;
  place-items: center;
  background: var(--accent-2);
  color: #111827;
  font-size: 1.35rem;
  font-weight: 800;
}

.usb-cable {
  position: absolute;
  left: 50%;
  bottom: -72px;
  width: 14px;
  height: 84px;
  transform: translateX(-50%);
  border-radius: 10px;
  background: linear-gradient(90deg, #0f172a, #334155, #0f172a);
}

.benefits,
.how,
.signup {
  padding: 92px 0;
}

.section-heading {
  max-width: 760px;
  margin-bottom: 36px;
}

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

.card {
  padding: 28px;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--line);
  box-shadow: 0 14px 40px rgba(15, 23, 42, 0.05);
}

.icon {
  width: 44px;
  height: 44px;
  margin-bottom: 28px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  background: var(--accent-2);
  font-size: 0.8rem;
  font-weight: 800;
}

.how-grid {
  display: grid;
  grid-template-columns: 0.8fr 1.2fr;
  gap: 72px;
  align-items: start;
}

.steps {
  display: grid;
  gap: 16px;
}

.step {
  display: grid;
  grid-template-columns: 52px 1fr;
  gap: 18px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
}

.step > span {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid var(--line);
  font-weight: 800;
}

.signup-box {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 50px;
  padding: 52px;
  border-radius: 32px;
  background: var(--dark);
  color: white;
}

.signup-box h2 {
  font-size: clamp(2rem, 4vw, 3.2rem);
}

.signup-box p {
  color: #cbd5e1;
}

.light {
  color: #a7f3d0;
}

.signup-form {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 12px;
}

.signup-form input {
  width: 100%;
  min-height: 56px;
  padding: 0 18px;
  border: 1px solid #334155;
  border-radius: 16px;
  background: #111827;
  color: white;
  font: inherit;
  outline: none;
}

.signup-form input:focus {
  border-color: #94a3b8;
}

.signup-form button {
  min-height: 56px;
  border: 0;
  border-radius: 16px;
  background: white;
  color: #111827;
  font: inherit;
  font-weight: 800;
  cursor: pointer;
}

.form-message {
  min-height: 24px;
  margin: 4px 0 0;
  font-size: 0.9rem;
}

footer {
  padding: 28px 0 40px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  color: var(--muted);
  font-size: 0.9rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 840px) {
  .hero {
    padding-top: 56px;
  }

  .hero-grid,
  .how-grid,
  .signup-box {
    grid-template-columns: 1fr;
  }

  .device-wrap {
    min-height: 440px;
  }

  .cards {
    grid-template-columns: 1fr;
  }

  .how-grid {
    gap: 30px;
  }

  .signup-box {
    padding: 34px 24px;
  }
}

@media (max-width: 560px) {
  .container {
    width: min(100% - 28px, 1120px);
  }

  .nav-cta {
    font-size: 0.85rem;
  }

  h1 {
    font-size: clamp(3rem, 17vw, 4.8rem);
  }

  .device-wrap {
    min-height: 370px;
  }

  .footer-inner {
    flex-direction: column;
  }
}