app/web/sidebar.css

/* Sidebar placed on the left bottom */
#sidebar {
  position: fixed; /* stay in place when scrolling */
  left: 0; /* stick to left edge */
  bottom: 0; /* stick to bottom edge */
  width: 140px; /* fixed width of a sidebar */

  /* look & feel */
  background: #202124; /* dark gray background */
  color: #fff; /* white text */
  padding: 12px 8px; /* inner padding */
  box-sizing: border-box; /* include padding in width */

  display: flex; /* flex container */
  flex-direction: column; /* stack items vertically */
  gap: 8px; /* space between items */
}

/* buttons inside the bar */
#sidebar a {
  display: block; /* make links block-level */
  padding: 8px 4px; /* inner padding */
  border-radius: 4px; /* rounded corners */
  color: #fff; /* white text */
  text-decoration: none; /* no underline */
  text-align: center; /* center text */
  background: #3d4043; /* slightly lighter bg */
  font-weight: 600; /* semi-bold text */
  font-size: 14px; /* slightly larger text */
}
#sidebar a:hover {
  background: #5f6368; /* background of a button when hover */
}

/* keep main app shifted right so it doesn’t sit under the bar */
body {
  margin-left: 140px !important; /* move main content to the reight to not cover with sidebar */
}