* { margin: 0; padding: 0; box-sizing: border-box; }
body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #0f172a;
  color: #e2e8f0;
  font-family: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
}
main { text-align: center; padding: 40px 24px; }
.logo { font-size: 14px; letter-spacing: 4px; color: #38bdf8; margin-bottom: 26px; font-weight: 600; }
h1 { font-size: 32px; margin-bottom: 16px; font-weight: 600; }
p { color: #94a3b8; font-size: 15px; margin-bottom: 8px; }
.sub { font-size: 13px; color: #64748b; }
.btn {
  display: inline-block;
  margin-top: 30px;
  padding: 10px 30px;
  border: 1px solid #38bdf8;
  color: #38bdf8;
  text-decoration: none;
  border-radius: 6px;
  font-size: 14px;
  transition: all .2s;
}
.btn:hover { background: #38bdf8; color: #0f172a; }