/* Reset */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0;}
body {
  font-family: Arial, sans-serif;
  background: #f5f5f5;
  margin: 0;
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  line-height: 1.6;
  color: #333;
}
.container{max-width:1200px;margin:0 auto;padding:0 20px;}

/* Header */
header {
  background: linear-gradient(135deg,#1a365d 0%,#2d5c8a 100%);
  color: #fff;
  padding: 1rem 0;
  position: fixed;
  width: 100%;
  top: 0;
  z-index: 1000;
}
header .logo {
  font-size: 1.8rem;
  font-weight: bold;
  background: linear-gradient(45deg,#4fd1c7,#81e6d9);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}
.nav-links {
  display: flex;
  list-style: none;
  gap: 2rem;
}
.nav-links a {
  color: #fff;
  text-decoration: none;
  transition: color .3s;
}
.nav-links a:hover {
  color: #4fd1c7;
}

/* Card / Tool Layout */
.card {
  background: #fff;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  width: 100%;
  max-width: 600px;
  margin-top: 20px;
}
h1 {
  text-align: center;
  margin-bottom: 20px;
}
.input-group {
  margin-bottom: 15px;
}
label {
  display: block;
  margin-bottom: 5px;
}
input, select {
  width: 100%;
  padding: 8px;
  box-sizing: border-box;
  border: 1px solid #ccc;
  border-radius: 4px;
}
.row {
  display: flex;
  gap: 10px;
}
.row .input-group {
  flex: 1;
}
button,
.btn {
  display: inline-block;
  width: 100%;
  padding: 10px 24px;
  background: linear-gradient(45deg, #f56565, #ed8936);
  color: #fff;
  border: none;
  border-radius: 8px;
  font-weight: bold;
  font-size: 16px;
  cursor: pointer;
  transition: transform .3s, box-shadow .3s;
}
button:hover,
.btn:hover {
  background: #0056b3;
  transform: translateY(-2px);
  box-shadow: 0 10px 25px rgba(245,101,101,.3);
}
.result-range h2,
.comps h2 {
  margin-top: 0;
}
.comp-card {
  background: #e9ecef;
  padding: 10px;
  border-radius: 6px;
  margin-top: 10px;
}
.hidden {
  display: none;
}

/* Responsive */
@media (max-width:768px){
  .nav-links{flex-direction:column;gap:1rem;}
  .container{padding:0 1rem;}
}