style.css

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background-color: #f5f5f5;
}

/* Sidebar styles */
.sidebar {
  list-style-type: none;
  margin: 0;
  padding: 0;
  width: 250px;
  background-color: #212529; /* Dark background color */
  color: #ffffff; /* Text color */
  position: fixed;
  height: 100%;
  overflow: auto;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
  transition: width 0.3s ease;
}

.sidebar li a {
  display: block;
  color: #ffffff;
  padding: 16px;
  text-decoration: none;
  border-bottom: 1px solid #444; /* Separator color */
  transition: background-color 0.3s ease;
}

.sidebar li a.active {
  background-color: #17a2b8; /* Active link color */
}

.sidebar li a:hover:not(.active) {
  background-color: #343a40; /* Hovered link color */
}

/* Content styles */
.content {
  margin-left: 250px;
  padding: 20px;
  height: 1000px;
  background-color: #ffffff; /* Content background color */
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1); /* Content shadow */
  border-radius: 4px; /* Rounded corners */
  transition: margin-left 0.3s ease, box-shadow 0.3s ease;
}

/* Media queries */
@media screen and (max-width: 900px) {
  .sidebar {
    width: 100px;
  }

  .content {
    margin-left: 100px;
  }

  .sidebar li a {
    padding: 8px;
    font-size: 14px;
  }
}

@media screen and (max-width: 400px) {
  .sidebar {
    width: 100%;
    height: auto;
    position: relative;
  }

  .content {
    margin-left: 0;
  }

  .sidebar li a {
    text-align: center;
    float: none;
    border-bottom: none;
    padding: 16px;
    font-size: 16px;
  }
}