body {
  background: #111;
  color: #fff;
  font-family: Arial, sans-serif;
  margin: 0;
}

/* Tool blocks */
.tool-block {
  background: #222;
  padding: 20px;
  border-radius: 8px;
  box-shadow: 0 0 10px rgba(0,0,0,0.5);
  min-height: 100%;
}

/* Headings */
h2 {
  color: #fff;
  font-size: 1.5rem;
  margin-top: 0;
  margin-bottom: 1rem;
}

/* Input fields */
input[type="number"],
input[type="text"],
select {
  background: #fff;
  color: #000;
  border: none;
  border-radius: 5px;
  padding: 10px;
  font-size: 1rem;
  width: 100%;
  margin-bottom: 1rem;
  box-sizing: border-box;
}

/* Labels */
label,
.form-label {
  font-weight: bold;
  font-size: 0.95rem;
  margin-bottom: 0.5rem;
  display: block;
  color: #fff;
}

/* Buttons */
button,
.btn-custom {
  background: #28a745;
  color: #fff;
  font-weight: bold;
  border: none;
  border-radius: 5px;
  padding: 12px 20px;
  width: 100%;
  font-size: 1rem;
  cursor: pointer;
  margin-top: 1rem;
}

/* Helper text */
.helper {
  font-size: 0.9rem;
  color: #aaa;
  line-height: 1.5;
  margin-bottom: 1.5rem;
}

/* Result block */
.result {
  background: #333;
  padding: 15px;
  border-radius: 6px;
  font-size: 1rem;
  line-height: 1.5;
  margin-top: 1rem;
}

/* Chart container */
.chart-container {
  background: #1b1b1b;
  margin-top: 1.5rem;
  padding: 1.5rem;
  border-radius: 8px;
}

.chart-note {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: #bbb;
  font-style: italic;
}

canvas {
  max-width: 100%;
}