body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
}
.tab-container {
  display: flex;
  flex-direction: row;
  min-height: 100vh;
}
.tab-menu {
  display: flex;
  flex-direction: column;
  background-color: #2c3e50;
  width: 250px;
  transition: width 0.3s;
}
.tab-link {
  padding: 15px;
  color: white;
  background: none;
  border: none;
  text-align: left;
  cursor: pointer;
  outline: none;
  transition: background 0.3s;
  display: flex;
  align-items: center;
  gap: 10px;
}
.tab-link:hover,
.tab-link.active {
  background-color: #34495e;
}
.tab-content {
  flex: 1;
  padding: 20px;
}
.tab-panel {
  display: none;
}
.tab-panel.active {
  display: block;
}
.toggle-btn {
  background-color: #1abc9c;
  color: white;
  border: none;
  padding: 15px;
  cursor: pointer;
  font-size: 16px;
  display: none;
  width: 100%;
}
/* Collapsed menu */
.tab-menu.collapsed {
  display: none;
}
/* Responsive */
@media (max-width: 768px) {
  .tab-container {
    flex-direction: column;
  }
  .tab-menu {
    width: 100%;
    flex-direction: column;
  }
  .toggle-btn {
    display: block;
  }
}
.chart {
  max-width: 900px;
  height: 350px;
  padding: 30px;
  margin: 0 auto;
}
.chart .chart_types {
    text-align: center;
    margin-bottom: 30px;
}
.char .char_types button {
    padding: 10px 25px;
}