body {
  font-family: 'Inter', sans-serif;
  background: #f9f9f9;
  margin: 0;
  padding: 40px;
}

.container {
  max-width: 800px;
  margin: auto;
  color: #333;
}

h1 {
  margin-bottom: 20px;
}

.section {
  background: white;
  border-radius: 8px;
  padding: 20px;
  margin-bottom: 30px;
  box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}

label {
  display: block;
  margin-top: 12px;
  font-weight: 600;
}

select, input[type="number"] {
  width: 100%;
  padding: 8px;
  font-size: 14px;
  border: 1px solid #ccc;
  border-radius: 4px;
  margin-top: 4px;
}

.unit-toggle {
  margin-top: 8px;
}

.unit-toggle label {
  font-weight: normal;
  margin-right: 10px;
}

button {
  background: #1976d2;
  color: white;
  border: none;
  padding: 10px 20px;
  font-size: 14px;
  border-radius: 4px;
  cursor: pointer;
  margin-top: 20px;
}

button:hover {
  background: #145aa9;
}

.spinner {
  border: 6px solid #eee;
  border-top: 6px solid #1976d2;
  border-radius: 50%;
  width: 40px;
  height: 40px;
  margin: 20px auto;
  animation: spin 0.9s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 20px;
}

th {
  text-align: left;
  background: #efefef;
  padding: 10px;
  font-weight: 600;
}

td {
  padding: 8px 10px;
  border-bottom: 1px solid #eee;
}

#loading p {
  text-align: center;
  color: #555;
}

footer {
  text-align: center;
  padding: 30px 0 10px;
  font-size: 13px;
  color: #888;
}

footer a {
  color: #1976d2;
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}