body {
  margin:0;
  font-family: 'Segoe UI', sans-serif;
  background:#f4f6f9;
  color:#222;
}

header {
  background:#0f172a;
  padding:15px 0;
}

.container {
  width:90%;
  margin:auto;
  display:flex;
  justify-content:space-between;
  align-items:center;
}

.logo {
  color:#fff;
  font-size:22px;
  font-weight:600;
}

nav a {
  color:#fff;
  margin-left:20px;
  text-decoration:none;
}

.hero {
  text-align:center;
  padding:80px 20px;
  background:linear-gradient(135deg,#2563eb,#1e3a8a);
  color:white;
}

.tools-grid {
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(220px,1fr));
  gap:25px;
  padding:50px;
}

.card {
  background:white;
  padding:30px;
  border-radius:12px;
  text-align:center;
  text-decoration:none;
  color:#222;
  box-shadow:0 10px 30px rgba(0,0,0,0.08);
  transition:.3s;
}

.card:hover {
  transform:translateY(-6px);
}

.calculator-box {
  max-width:500px;
  margin:40px auto;
  background:white;
  padding:30px;
  border-radius:12px;
  box-shadow:0 10px 30px rgba(0,0,0,0.1);
}

input, button {
  width:100%;
  padding:12px;
  margin-top:10px;
  border-radius:8px;
  border:1px solid #ccc;
}

button {
  background:#2563eb;
  color:white;
  border:none;
  cursor:pointer;
}

.result {
  margin-top:20px;
  font-weight:bold;
  font-size:18px;
}

footer {
  background:#0f172a;
  color:white;
  text-align:center;
  padding:20px;
}