styles.css

:root {
    --black: #000;
    --white: #fff;
    --yellow: #f7b600;

    --primary-color: var(--yellow);

    --bg-body: #e6e6e6;
    --bg-header: var(--primary-color);

    --shadow: 1px 1px 3px -1px var(--black);
}

* {
    margin: 0px;
    padding: 0px;
    outline: 0px;

    box-sizing: border-box;
}

body {
    font-size: 16px;
    font-family: "Trebuchet MS", "Lucida Sans Unicode", "Lucida Grande",
        "Lucida Sans", Arial, sans-serif;
    background: var(--bg-body);
}

/* Layout */

#area-cabecalho {
    background-color: var(--bg-header);
    padding: 15px;
    text-align: center;

    box-shadow: var(--shadow);
}

#area-logo,
#area-menu {
    padding: 10px;

    text-transform: uppercase;
}

#area-principal {
    width: 100%;
    max-width: 55.5rem;
    margin: 0px auto;
    padding: 1rem;

    display: flex;
    flex-direction: row-reverse;
}

@media (max-width: 960px) {
    #area-principal {
        flex-direction: column;
    }
}

#area-lateral {
    justify-content: space-between;
    width: 100%;
    max-width: 18.75rem;

    margin-left: 1rem;
}

#area-postagens {
    width: 100%;
    max-width: 41.25rem;
}

.postagem {
    padding: 1rem;
    margin-bottom: 1rem;
    background: white;
}

.postagem img {
    width: 100%;
    max-width: 620px;
}

.conteudo-lateral {
    background: white;
    padding: 1rem;
    margin-bottom: 1rem;
}

#rodape {
    background: green;
    clear: both;
    padding: 1rem;
    background: #ccc;
    text-align: center;
}

/* Formatação de menu */

a {
    text-decoration: none;
}

a:link,
a:visited {
    color: #f7b600;
}

a:hover {
    text-decoration: underline;
}

#area-cabecalho a:link,
#area-cabecalho a:visited {
    color: #fff;
    padding: 8px 12px;
}

#area-cabecalho a:hover {
    color: var(--primary-color);
    background: var(--white);

    transition: 0.2s;

    text-decoration: none;
}

/* Formatação em geral */

h1 {
    color: #4e4e4e;
    font-size: 2.5em;
}

.branco {
    color: white;
}

.data-postagem {
    font-size: 0.8em;
    border-bottom: 1px solid #f4f4f4;
    padding-bottom: 10px;
    margin-bottom: 10px;
    display: block;
}

h2 {
    color: #f7b600;
}

h3 {
    color: #565656;
    background: #ccc;
    padding: 5px;
}

.texto-lateral {
    font-size: 0.8em;
    padding: 5px;
}