body {
  background-color: #f4f6f9;
  font-family: "Segoe UI", sans-serif;
}
.header-banner {
  background-color: #003366;
  color: #fff;
  text-align: center;
  padding: 1.8rem 0 1.2rem;
  border-bottom: 6px solid #0d6efd;
}
.header-banner h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: 1px;
  margin: 0;
}
.header-banner .date {
  font-size: 1rem;
  font-weight: 400;
  opacity: 0.9;
}
.category-card {
  border: none;
  border-radius: 0.75rem;
  box-shadow: 0 .25rem .5rem rgba(0,0,0,.08);
  margin-bottom: 2rem;
}
.category-card .card-header {
  background-color: #003366;
  color: #fff;
  font-weight: 600;
  font-size: 1.1rem;
  border-top-left-radius: .75rem;
  border-top-right-radius: .75rem;
}
.mineral-card {
  background: #fff;
  border: 1px solid #e1e5eb;
  border-radius: 0.75rem;
  text-align: center;
  padding: 1rem;
  transition: all .2s ease-in-out;
}
.mineral-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 .5rem 1rem rgba(0,0,0,.1);
}
.mineral-title {
  font-weight: 600;
  color: #003366;
}
.change-up { color: #198754; font-weight: 600; }
.change-down { color: #dc3545; font-weight: 600; }
.change-na { color: #6c757d; }
.trend-icon { font-weight: bold; font-size: 1rem; vertical-align: middle; }
footer {
  background: #003366;
  color: #fff;
  text-align: center;
  padding: 1rem 0;
  margin-top: 2rem;
}
footer img {
  height: 48px;
  margin-left: 10px;
  vertical-align: middle;
}