:root {
  --sky: #7ec8e3;
  --sky-deep: #4aa3c7;
  --gold: #f4c430;
  --ink: #1f2d3a;
  --ink-soft: #34495e;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: radial-gradient(120% 60% at 50% -10%, #aee2f2 0%, var(--sky) 40%, var(--sky-deep) 100%);
  background-attachment: fixed;
  min-height: 100vh;
  line-height: 1.6;
}
.wrap { max-width: 760px; margin: 0 auto; padding: 28px 24px 80px; }
.topnav {
  display: flex; align-items: center; gap: 18px;
  max-width: 760px; margin: 0 auto; padding: 22px 24px;
  font-weight: 600;
}
.topnav .brand { font-size: 20px; letter-spacing: -0.02em; margin-right: auto; text-decoration: none; color: var(--ink); }
.topnav a { color: var(--ink-soft); text-decoration: none; font-size: 15px; }
.topnav a:hover { color: var(--ink); }
.sheet {
  background: rgba(255,255,255,0.7);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,0.6);
  border-radius: 22px;
  padding: 40px 36px;
}
.sheet h1 { font-size: clamp(30px, 5vw, 44px); letter-spacing: -0.03em; margin-bottom: 6px; }
.sheet .updated { color: var(--ink-soft); font-size: 14px; margin-bottom: 28px; }
.sheet h2 { font-size: 20px; margin: 28px 0 8px; }
.sheet p, .sheet li { color: var(--ink-soft); margin-bottom: 10px; }
.sheet ul { padding-left: 22px; margin-bottom: 12px; }
.sheet a { color: var(--ink); font-weight: 600; }
.btn {
  display: inline-flex; align-items: center; gap: 10px;
  background: var(--ink); color: #fff; text-decoration: none;
  padding: 13px 22px; border-radius: 14px; font-weight: 600;
  margin-top: 8px;
  box-shadow: 0 10px 24px rgba(31,45,58,0.22);
}
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px,1fr)); gap: 16px; margin-top: 22px; }
.card { background: rgba(255,255,255,0.55); border-radius: 16px; padding: 22px; border: 1px solid rgba(255,255,255,0.55); }
.card h3 { font-size: 17px; margin-bottom: 6px; }
.card p { font-size: 15px; }
footer { text-align: center; padding: 24px; color: var(--ink-soft); font-size: 14px; }
footer a { color: var(--ink); }