:root {
  --bg: #0b1020;
  --bg-soft: #121a2d;
  --panel: rgba(18, 26, 45, 0.82);
  --panel-border: rgba(148, 163, 184, 0.18);
  --text: #e5eefb;
  --muted: #b6c0d6;
  --primary: #62d0ff;
  --primary-strong: #3aa9f5;
  --accent: #8ef0b9;
  --warning: #ffcd70;
  --shadow: rgba(0, 0, 0, 0.22);
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: Arial, Helvetica, sans-serif;
  background: radial-gradient(circle at top, #16213d 0%, #0b1020 40%, #070c16 100%);
  color: var(--text);
  line-height: 1.6;
}

img {
  max-width: 100%;
  display: block;
}

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

.container {
  width: min(1100px, calc(100% - 2rem));
  margin: 0 auto;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(12px);
  background: rgba(11, 16, 32, 0.72);
  border-bottom: 1px solid var(--panel-border);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 74px;
}

.brand {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.nav-links a {
  color: var(--muted);
  font-weight: 600;
  padding: 0.5rem 0.8rem;
  border-radius: 999px;
  transition: 0.2s ease;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  background: rgba(98, 208, 255, 0.12);
}

.hero {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 2rem;
  align-items: center;
  padding: 4.5rem 0 3rem;
}

.eyebrow {
  display: inline-block;
  margin: 0 0 0.7rem;
  color: var(--primary);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.76rem;
}

.hero-copy h1,
.page-card h1,
.section-heading h2 {
  margin: 0 0 1rem;
  line-height: 1.15;
}

.hero-copy h1 {
  font-size: clamp(2.5rem, 4vw, 4.2rem);
}

.lead {
  font-size: 1.08rem;
  color: var(--muted);
  max-width: 620px;
}

.hero-actions,
.app-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-top: 1.5rem;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0.8rem 1.3rem;
  border-radius: 12px;
  border: 1px solid transparent;
  font-weight: 700;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button.primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-strong));
  color: #05121d;
}

.button.secondary {
  border-color: var(--panel-border);
  background: rgba(148, 163, 184, 0.06);
  color: var(--text);
}

.hero-panel,
.page-card,
.feature-card,
.info-box {
  border: 1px solid var(--panel-border);
  background: var(--panel);
  border-radius: 22px;
  box-shadow: 0 18px 45px var(--shadow);
}

.hero-panel {
  padding: 1.5rem;
}

.board-demo {
  display: grid;
  grid-template-columns: repeat(4, minmax(52px, 1fr));
  gap: 0.55rem;
  padding: 0.5rem;
}

.cell {
  display: grid;
  place-items: center;
  min-height: 64px;
  border-radius: 12px;
  font-weight: 800;
  color: var(--text);
  background: rgba(148, 163, 184, 0.08);
}

.cell.hidden {
  background: linear-gradient(135deg, #1b2d4d, #12233e);
  color: #cfe9ff;
}

.cell.revealed {
  background: rgba(142, 240, 185, 0.12);
  color: var(--accent);
}

.cell.mine {
  background: rgba(255, 205, 112, 0.14);
  color: var(--warning);
}

.cell.flag {
  background: rgba(255, 120, 120, 0.12);
  color: #ff8f8f;
}

.features {
  padding: 1rem 0 4rem;
}

.section-heading {
  margin-bottom: 1.5rem;
}

.feature-grid,
.info-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1.25rem;
}

.feature-card,
.info-box {
  padding: 1.5rem;
}

.feature-card h3,
.info-box h3 {
  margin-top: 0;
  margin-bottom: 0.75rem;
}

.feature-card p,
.info-box p,
.page-card p,
.page-card li {
  color: var(--muted);
}

.page-shell {
  padding: 3rem 0 4rem;
}

.page-card {
  padding: 2rem;
}

.page-card h2 {
  margin-top: 2rem;
}

.info-box ul {
  margin: 0;
  padding-left: 1.1rem;
}

.site-footer {
  border-top: 1px solid var(--panel-border);
  background: rgba(11, 16, 32, 0.75);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 72px;
  color: var(--muted);
}

@media (max-width: 760px) {
  .hero {
    grid-template-columns: 1fr;
    padding-top: 3rem;
  }

  .feature-grid,
  .info-grid {
    grid-template-columns: 1fr;
  }

  .nav {
    flex-direction: column;
    justify-content: center;
    padding: 1rem 0;
    gap: 0.75rem;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }

  .footer-inner {
    flex-direction: column;
    justify-content: center;
    padding: 1rem 0;
  }
}