.flex-container {
    display: flex;
    flex-wrap: wrap;
  }
  body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

header {
    background-color: #333;
    text-align: center;
    padding: 1px;
}

h1 {
    font-size: 36px;
    color: #fff;
}

.header-image {
    max-width: 100px;
}

nav {
    background-color: #333;
    text-align: center;
}

.nav-tabs {
    list-style-type: none;
    padding: 0;
}

.nav-tabs li {
    display: inline;
    margin: 0 10px;
}

.nav-tabs a {
    color: #fff;
    text-decoration: none;
}


.category {
    display: flex;
}

.container {
    margin: 0 auto;
    max-width: 800px;
    padding: 0 15px;
}

.text-column {
    padding: 20px;
    background-color: #fff;
    box-shadow: 0 0 5px rgba(0,0,0,0.2);
}