:root {
  --primary-color: #2c3e50;
  --secondary-color: #27ae60;
  --bg-color: #f4f7f6;
  --text-color: #333;
  --card-bg: #ffffff;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  margin: 0;
  padding: 20px;
}

.container {
  max-width: 600px;
  margin: 0 auto;
  background: var(--card-bg);
  padding: 30px;
  border-radius: 12px;
  box-shadow: 0 8px 16px rgba(0,0,0,0.05);
}

h1, h2 {
  color: var(--primary-color);
  text-align: center;
}

.auth-box form {
  display: flex;
  flex-direction: column;
  gap: 15px;
  margin-top: 20px;
}

input[type="email"], input[type="file"] {
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: 6px;
  font-size: 16px;
}

button {
  background-color: var(--secondary-color);
  color: white;
  border: none;
  padding: 14px;
  border-radius: 6px;
  font-size: 16px;
  font-weight: bold;
  cursor: pointer;
  transition: background 0.3s;
}

button:hover {
  background-color: #219653;
}

.dashboard-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid #eee;
}

.btn-secondary {
  background-color: #e74c3c;
  padding: 8px 16px;
}

.btn-secondary:hover {
  background-color: #c0392b;
}

.chart-container {
  margin-top: 30px;
  position: relative;
}

#feedback-msg {
  margin-top: 15px;
  text-align: center;
  font-weight: bold;
  color: var(--secondary-color);
}