* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  background: #f4f4f4;
  font-family: sans-serif;
  overflow: hidden;
}

.toolbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 50px;
  background: #1e1e1e;
  display: flex;
  align-items: center;
  padding: 0 10px;
  gap: 10px;
  z-index: 10; /* IMPORTANT */
}


.toolbar button {
  background: #333;
  border: none;
  color: white;
  font-size: 16px;
  padding: 6px 10px;
  cursor: pointer;
}

.toolbar button:hover {
  background: #555;
}

.toolbar input[type="range"] {
  width: 100px;
}

.toolbar button.active {
  background: #6a5acd;
}


/* in whiteboard.css */
#board {
  width: 100%;
  height: 500px;
  cursor: crosshair;
  display: block;
}