body {
  font-family: Arial, sans-serif;
  background: #f4f6f9;
  margin: 0;
  padding: 0;
}

.tool-wrapper {
  max-width: 520px;
  margin: 50px auto;
  background: #ffffff;
  padding: 30px;
  border-radius: 10px;
  box-shadow: 0 8px 20px rgba(0,0,0,0.08);
}

.tool-wrapper h1 {
  text-align: center;
  margin-bottom: 5px;
  font-size: 24px;
}

.subtitle {
  text-align: center;
  font-size: 14px;
  color: #666;
  margin-bottom: 25px;
}

.input-group {
  margin-bottom: 18px;
}

.input-group label {
  display: block;
  font-size: 13px;
  margin-bottom: 6px;
  color: #333;
}

.input-group input,
.input-group select {
  width: 100%;
  padding: 10px;
  border-radius: 6px;
  border: 1px solid #ccc;
  font-size: 14px;
}

.analyze-btn {
  width: 100%;
  background: #007bff;
  color: #fff;
  border: none;
  padding: 12px;
  font-size: 15px;
  border-radius: 6px;
  cursor: pointer;
}

.analyze-btn:hover {
  background: #0056b3;
}

.result-box {
  margin-top: 25px;
  padding: 15px;
  background: #f8f9fb;
  border-radius: 6px;
  font-size: 14px;
  display: none;
}
.kd-bar {
  width: 100%;
  height: 14px;
  background: #e0e0e0;
  border-radius: 20px;
  margin: 8px 0 15px 0;
  overflow: hidden;
}

.kd-fill {
  height: 100%;
  border-radius: 20px;
}

.kd-easy {
  background: #28a745;
}

.kd-medium {
  background: #ffc107;
}

.kd-hard {
  background: #dc3545;
}