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

.header{
    background-color: #4CAF50;
    width: 100%;
    color: white;
    text-align: center;
    padding: 10px;
    margin: 0;
}

.menu{
    float: left;
    height: 90px; 
    width: 100%;
    background: #ccc;
    padding: 20px;
}

.menu {
      background: #929292;
    }

.menu ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    justify-content: center;
}

.menu ul li {
    margin: 0;
}

.menu ul li a {
    display: block;
    padding: 15px 25px;
    color: white;
    text-decoration: none;
    transition: 0.3s;
}

.menu ul li a:hover {
    background: #666;
}

.container {
    display: flex;
    align-items: stretch; 
    gap: 20px;
    padding: 20px;
}

.leftbar {
    flex: 1;
    height: 500px;
    background: #f0f0f0;
}

.content {
    flex: 3;
    background: #fff;
    padding: 20px;
    box-shadow: 0 0 5px rgba(0,0,0,0.1);
    height: 500px;
}

.footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 15px;
    margin-top: 20px;
    height: 100px;
}