body {
  background: #111;
  color: #eee;
  font-family: system-ui;
}

nav {
  background: #222;
  padding: 10px 20px;
  display: flex;
  gap: 20px;
  border-bottom: 1px solid #444;
}

nav a {
  color: #ddd;
  text-decoration: none;
}

.container {
  padding: 20px;
  max-width: 900px;
  margin: auto;
}

input[type="text"] {
  width: 300px;
  padding: 8px;
  background: #222;
  border: 1px solid #444;
  color: #eee;
}

.card-details {
  background: #181818;
  margin: 15px 0;
  padding: 15px;
  border-radius: 6px;
  border: 1px solid #333;
}

.chart-legend span {
  margin-right: 20px;
  cursor: pointer;
  font-size: 13px;
}

.error-box {
  color: #ff5555;
  font-weight: bold;
  margin-top: 10px;
}