:root{
  --bg:#f4f7fb;
  --card:#ffffff;
  --accent:#0b6efd;
  --muted:#6b7280;
  --glass: rgba(255,255,255,0.6);
}

*{box-sizing:border-box;font-family:Arial, sans-serif;}
body{
  margin:0;
  background: linear-gradient(180deg, #e6f0ff 0%, var(--bg) 100%);
  min-height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  padding:30px;
  color:#111827;
}

.card{
  width:100%;
  max-width:720px;
  background:var(--card);
  border-radius:14px;
  box-shadow: 0 8px 30px rgba(11, 92, 204, 0.08);
  padding:28px;
  border: 1px solid rgba(11, 110, 255, 0.06);
}

h1{margin:0 0 8px;font-size:24px;color:var(--accent)}
.nav{display:flex;gap:10px;flex-wrap:wrap;margin:12px 0}
a{
  text-decoration:none;
  background:linear-gradient(90deg,var(--accent),#3aa0ff);
  color:white;
  padding:10px 14px;
  border-radius:10px;
  box-shadow:0 6px 18px rgba(11,110,255,0.12);
  transition:transform .12s ease, box-shadow .12s ease;
}
a:hover{transform:translateY(-4px);box-shadow:0 12px 30px rgba(11,110,255,0.18);}

form.calc{
  display:grid;
  grid-template-columns:1fr auto;
  gap:12px;
  align-items:center;
  margin-top:12px;
}
.input, select{
  width:100%;
  padding:12px 14px;
  border-radius:10px;
  border:1px solid #e6eefb;
  background:var(--glass);
  outline:none;
  font-size:16px;
}
.btn{
  padding:12px 18px;border-radius:10px;border:0;background:var(--accent);color:#fff;font-weight:600;cursor:pointer;
  box-shadow:0 8px 18px rgba(11,110,255,0.12);
}
.result{
  margin-top:16px;
  padding:14px;border-radius:8px;background:#f8fbff;border:1px solid #e6f0ff;color:#0b4db8;font-weight:700;
}