:root {
  --bg-start: #f9fcff;
  --bg-end: #e9f4ff;
  --primary: #2e8ed9;
  --primary-dark: #1f75bd;
  --title: #0f2c4a;
  --text: #3a5a78;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: Inter, "Segoe UI", Roboto, Arial, sans-serif;
  background: linear-gradient(150deg, var(--bg-start), var(--bg-end));
  color: var(--text);
  overflow: hidden;
}

.hero {
  position: relative;
  isolation: isolate;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: clamp(24px, 6vw, 72px);
}

.hero::before,
.hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.hero::before {
  opacity: 0.75;
  background-image:
    linear-gradient(to right, rgba(53, 162, 243, 0.22) 2px, transparent 2px),
    linear-gradient(to bottom, rgba(53, 162, 243, 0.22) 2px, transparent 2px),
    linear-gradient(to right, rgba(37, 129, 214, 0.18) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(37, 129, 214, 0.18) 1px, transparent 1px);
  background-size: 48px 48px, 48px 48px, 12px 12px, 12px 12px;
  background-position: 0 0, 0 0, 2px 2px, 2px 2px;
}

.hero::after {
  background:
    radial-gradient(closest-side at 18% 24%, rgba(109, 191, 255, 0.28), transparent 70%),
    radial-gradient(closest-side at 84% 76%, rgba(64, 161, 243, 0.22), transparent 72%),
    radial-gradient(circle at 28% 68%, rgba(54, 152, 235, 0.18) 0 3px, transparent 3px),
    radial-gradient(circle at 74% 30%, rgba(54, 152, 235, 0.16) 0 2px, transparent 2px);
  background-size: auto, auto, 22px 22px, 18px 18px;
}

.content {
  position: relative;
  z-index: 1;
  width: min(980px, 100%);
  padding: clamp(14px, 2vw, 22px);
  text-align: center;
}

.tag {
  margin: 0 0 14px;
  color: var(--primary-dark);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  font-size: 0.82rem;
}

h1 {
  margin: 0;
  font-size: clamp(3rem, 10vw, 6rem);
  line-height: 1.02;
  color: var(--title);
  letter-spacing: 0.02em;
  text-shadow: 0 10px 28px rgba(38, 124, 194, 0.14);
}

.subtitle {
  margin: 16px auto 36px;
  max-width: 760px;
  font-size: clamp(1.02rem, 2.6vw, 1.34rem);
  line-height: 1.45;
  color: var(--text);
}

.overview {
  margin: 0 auto 30px;
  max-width: 860px;
  font-size: clamp(0.94rem, 1.8vw, 1.06rem);
  line-height: 1.6;
  color: #2f5374;
}

.download-group {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  justify-content: center;
}

.download-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  color: #fff;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  border-radius: 12px;
  padding: 13px 30px;
  box-shadow: 0 10px 24px rgba(46, 142, 217, 0.3);
  transition: transform 0.2s ease, box-shadow 0.2s ease, filter 0.2s ease;
}

.download-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px rgba(46, 142, 217, 0.38);
  filter: brightness(1.03);
}

.download-btn:active {
  transform: translateY(0);
}