check > https://www.onphpid.com/belajar-membuat-template-web-menggunakan-bootstrap.html

index.css

body {
    background-color: #e5e5e5;
}

.meta-post {
    font-size: 12px;
    margin-bottom: 10px;
}

.header header {
    background-color: #fff;
    padding: 10px 20px;
}

nav.menus {
    background-color: #e74c3c;
    padding: 10px;
}

nav.menus ul {
    margin: 0;
    padding: 0;
}

nav.menus ul li {
    display: inline-block;
}

nav.menus ul li a {
    display: block;
    padding: 3px 7px;
    color: #fff;
}

nav.menus ul li a:hover, nav.menus ul li a:focus{
    text-decoration: none;
    background-color: #c0392b;
    color: #fff;
}

article.posts {
    padding: 10px 20px;
    background-color: #fff;
    margin-top: 20px;
}

aside.widgets {
    padding: 10px 20px;
    margin-top: 20px;
    background-color: #fff;
}
aside.widgets ul {
    margin:0;
    padding:0;
}
aside.widgets li {
    list-style: none;
    padding: 0;
    margin:0;
}

.widget-title {
  border-bottom: 4px solid #E74C3C;
  padding-bottom: 4px;
}

footer.copyright {
    padding: 10px 20px;
    font-size: 12px;
}