a {
    color: #017acd;
}

/* コンテナ */
.container {
    width: 860px;
    margin-left: auto;
    margin-right: auto;
    display: grid;
    grid-template-columns: 170px 670px;
    /* grid-template-rows: 1fr 1fr 1fr; */
    grid-template-areas: 
        "header header"
        "aside content"
        "footer footer";
}

.header{
    grid-area: header;
}

.sidebar{
    grid-area: aside;
    width: 95%;
    margin-top: 0 auto auto;
}

.content{
    grid-area: content;
    width: 95%;
    margin-left: auto;
    margin-right: auto;
    margin-bottom: 25px
}

.footer{
    grid-area: footer;
}