body {
  background: linear-gradient(to bottom right, #001f3f, #0074D9);
  font-family: 'Segoe UI', sans-serif;
}

.ipv6-container {
  background: #ffffff;
  max-width: 960px;
  margin: 30px auto;
  border-radius: 16px;
  padding: 30px;
  box-shadow: 0 12px 30px rgba(0, 0, 0, 0.2);
}

.ipv6-container h2 {
  text-align: center;
  font-size: 30px;
  color: #0074D9;
  margin-bottom: 30px;
  text-shadow: 0 2px 3px rgba(0, 0, 0, 0.1);
}

.ipv6-box {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
}

.ipv6-left,
.ipv6-right {
  flex: 1 1 420px;
  background: #f0f8ff;
  padding: 20px;
  border-radius: 14px;
  box-shadow: inset 0 0 6px rgba(0, 0, 0, 0.05);
}

.ipv6-left h3,
.ipv6-right h3 {
  color: #0050a0;
  margin-bottom: 20px;
}

.ipv6-left label {
  display: block;
  margin-top: 15px;
  font-weight: 600;
  color: #003366;
}

.ipv6-left input[type="text"] {
  width: 100%;
  padding: 10px;
  margin-top: 5px;
  border: 2px solid #0074D9;
  border-radius: 8px;
  font-size: 15px;
  outline: none;
}

input[type="range"] {
  width: 100%;
  margin-top: 10px;
}

button {
  margin-top: 25px;
  padding: 12px 25px;
  background: linear-gradient(to right, #0074D9, #00bfff);
  color: white;
  border: none;
  border-radius: 10px;
  font-size: 16px;
  cursor: pointer;
  transition: background 0.3s ease;
  width: 100%;
}

button:hover {
  background: linear-gradient(to right, #00bfff, #0074D9);
}

.result-card {
  background: #ffffff;
  padding: 15px;
  border-left: 6px solid #0074D9;
  border-radius: 10px;
  margin-bottom: 15px;
  box-shadow: 0 4px 12px rgba(0, 116, 217, 0.1);
}

.result-card p {
  margin: 5px 0 0;
  color: #111;
  font-family: monospace;
  font-size: 14px;
}