:root {
  --cyan: #31d7ff;
  --cyan-2: #008cff;
  --white: #f6fbff;
  --muted: rgba(236, 249, 255, 0.72);
  --line: rgba(117, 224, 255, 0.28);
  --dark: #020713;
  --font-ui: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-display: Georgia, "Times New Roman", serif;
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--dark);
  color: var(--white);
  font-family: var(--font-ui);
}
a { color: inherit; text-decoration: none; }

.hero {
  min-height: 100vh;
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-rows: auto 1fr auto;
  background:
    linear-gradient(90deg, rgba(1, 4, 14, 0.92) 0%, rgba(1, 8, 23, 0.62) 34%, rgba(1, 7, 20, 0.14) 100%),
    url("../assets/proof-of-water-droplet-dimmed.png") center center / cover no-repeat;
  isolation: isolate;
}

/* Extra screen/tint layer for readable text. Adjust opacity here. */
.screen {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    radial-gradient(circle at 68% 50%, rgba(0, 212, 255, 0.10), transparent 28%),
    linear-gradient(180deg, rgba(0, 0, 0, 0.18) 0%, rgba(0, 0, 0, 0.42) 100%);
  pointer-events: none;
}

.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.035) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: linear-gradient(90deg, black, transparent 78%);
  opacity: 0.24;
}

.topbar {
  min-height: 86px;
  padding: 22px clamp(22px, 5vw, 72px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 1px solid rgba(117, 224, 255, 0.16);
  background: rgba(0, 8, 22, 0.42);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 14px;
  text-transform: uppercase;
}
.brand strong {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 2vw, 2rem);
  font-weight: 500;
  letter-spacing: 0.12em;
  line-height: 1;
  text-shadow: 0 0 22px rgba(111, 230, 255, 0.28);
}
.brand em {
  display: block;
  margin-top: 5px;
  color: var(--cyan);
  font-style: normal;
  font-size: 0.78rem;
  letter-spacing: 0.26em;
  text-transform: lowercase;
}
.drop-mark {
  width: 42px;
  height: 54px;
  flex: 0 0 auto;
  background:
    radial-gradient(circle at 50% 70%, rgba(255,255,255,0.88), transparent 12%),
    linear-gradient(180deg, rgba(52, 220, 255, 0.95), rgba(0, 114, 255, 0.52));
  clip-path: path("M21 0 C9 17 2 28 2 38 C2 49 10 54 21 54 C32 54 40 49 40 38 C40 28 33 17 21 0 Z");
  filter: drop-shadow(0 0 18px rgba(49, 215, 255, 0.55));
}

.nav {
  display: flex;
  gap: clamp(16px, 3vw, 44px);
  color: rgba(246, 251, 255, 0.78);
  font-size: 0.84rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}
.nav a:hover { color: var(--cyan); text-shadow: 0 0 18px rgba(49, 215, 255, 0.65); }

.hero-copy {
  width: min(720px, calc(100% - 44px));
  margin-left: clamp(22px, 7vw, 112px);
  align-self: center;
  padding: clamp(36px, 6vw, 92px) 0;
}
.eyebrow {
  margin: 0 0 24px;
  color: rgba(249, 253, 255, 0.88);
  font-size: clamp(0.95rem, 1.55vw, 1.35rem);
  line-height: 1.55;
  letter-spacing: 0.32em;
  text-transform: uppercase;
}
h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(5rem, 11vw, 13rem);
  font-weight: 400;
  line-height: 0.84;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: #fff;
  text-shadow:
    0 0 6px rgba(255, 255, 255, 0.86),
    0 0 28px rgba(101, 220, 255, 0.88),
    0 0 84px rgba(0, 143, 255, 0.55);
}
.summary {
  width: min(560px, 100%);
  margin: 30px 0 0;
  color: var(--muted);
  font-size: clamp(1rem, 1.5vw, 1.24rem);
  line-height: 1.7;
}
.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 34px;
}
.button {
  min-height: 58px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 26px;
  border-radius: 9px;
  border: 1px solid var(--line);
  background: rgba(0, 13, 32, 0.48);
  color: #fff;
  font-weight: 900;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-size: 0.86rem;
  box-shadow: inset 0 0 20px rgba(90, 206, 255, 0.06);
  transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
}
.button:hover {
  transform: translateY(-2px);
  border-color: rgba(125, 232, 255, 0.92);
  box-shadow: 0 0 34px rgba(42, 205, 255, 0.32), inset 0 0 20px rgba(90, 206, 255, 0.12);
}
.primary {
  border-color: rgba(111, 230, 255, 0.72);
  background: linear-gradient(180deg, rgba(23, 197, 255, 0.95), rgba(0, 86, 195, 0.92));
  box-shadow: 0 0 28px rgba(38, 203, 255, 0.44), inset 0 0 22px rgba(255, 255, 255, 0.18);
}
.note {
  margin-top: 22px;
  color: rgba(236, 249, 255, 0.54);
  font-size: 0.82rem;
  line-height: 1.5;
}
.note code {
  color: rgba(255,255,255,0.88);
  background: rgba(255,255,255,0.08);
  padding: 0.15em 0.35em;
  border-radius: 4px;
}
.bottomline {
  padding: 20px clamp(22px, 5vw, 72px);
  display: flex;
  justify-content: space-between;
  gap: 16px;
  border-top: 1px solid rgba(117, 224, 255, 0.16);
  background: rgba(0, 8, 22, 0.48);
  color: rgba(236, 249, 255, 0.68);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  backdrop-filter: blur(14px);
}

@media (max-width: 760px) {
  .hero {
    background-position: 62% center;
    background-image:
      linear-gradient(180deg, rgba(1, 4, 14, 0.18) 0%, rgba(1, 4, 14, 0.40) 36%, rgba(1, 4, 14, 0.96) 78%),
      url("../assets/proof-of-water-droplet-dimmed.png");
  }
  .topbar { padding: 18px 20px; }
  .nav { display: none; }
  .brand strong { font-size: 1.15rem; }
  .brand em { font-size: 0.64rem; letter-spacing: 0.18em; }
  .drop-mark { width: 34px; height: 44px; }
  .hero-copy {
    width: calc(100% - 40px);
    margin: 0 20px;
    align-self: end;
    padding: 42vh 0 42px;
  }
  .eyebrow { font-size: 0.82rem; letter-spacing: 0.2em; }
  h1 { font-size: clamp(3.4rem, 18vw, 6.5rem); letter-spacing: 0.06em; }
  .summary { font-size: 0.95rem; }
  .button { width: 100%; min-height: 54px; font-size: 0.78rem; }
  .bottomline { flex-direction: column; padding: 18px 20px; }
}