body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  margin: 0;
  font-family: Arial, sans-serif;
  background-color: #fefefe;
  color: #333;
}

header, footer {
  flex-shrink: 0;
  background-color: #fff;
  border-bottom: 1px solid #ddd;
  padding: 0.5rem 1rem;
}

header img { height: 50px; vertical-align: middle; }

.nav-wrapper { display: inline-block; margin-left: 1rem; }

nav a { margin-right: 1rem; text-decoration: none; color: #333; font-weight: 500; }
nav a:hover { text-decoration: underline; }

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: left;
  align-items: left;
  padding: 1rem;
  text-align: center;
}

.matrix-wrapper { display: flex; flex-direction: column; gap: 1rem; width: 100%; max-width: 600px; }

.filter-form { margin-bottom: 0.5rem; }
.filter-form select { padding: 0.25rem 0.5rem; font-size: 1rem; }

.matrix table { border-collapse: collapse; margin: auto; }
.matrix td { width: 40px; height: 40px; text-align: center; vertical-align: middle; border: 1px solid #ccc; }
.matrix td a { display: block; width: 100%; height: 100%; text-decoration: none; color: #333; }
.matrix td a:hover { background-color: rgba(0,0,0,0.05); }

.unit-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 0.75rem;
  justify-items: center;
  width: 100%;
}

.unit-card {
  padding: 0.5rem 0.75rem;
  border: 1px solid #ccc;
  border-radius: 6px;
  background-color: #fafafa;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
  text-align: center;
  transition: transform 0.1s ease, box-shadow 0.1s ease;
}

.unit-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0,0,0,0.1);
}

.unit-card a { text-decoration: none; color: #333; font-weight: 500; }
.unit-card a:hover { text-decoration: underline; }

footer {
  text-align: center;
  padding: 1rem;
  border-top: 1px solid #ddd;
  background-color: #fff;
  font-size: 0.9rem;
  color: #666;
}

@media (max-width: 600px) {
  .matrix td { width: 30px; height: 30px; }
  .unit-grid { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); }
}

@media (max-width: 400px) {
  .matrix td { width: 25px; height: 25px; }
  .unit-card { padding: 0.4rem 0.5rem; }
}