d {
    width: 4em;
}

body {
    display: block;
}

li + li {
    margin-top: 8px;
}

.post-list {
    display: flex;
    margin: 0.25em;
}

.center {
    max-width: 670px;
    margin: 0 auto;
    padding: 0 15px;
    display: block;
}

form {
    box-sizing: border-box;
}

input {
    width: 100%;
    padding: 5px;
    margin-bottom: 10px;
    box-sizing: border-box;
}

textarea {
    width: 100%;
    margin-bottom: 10px;
    height: 25ch;
    box-sizing: border-box;
}

input[type="submit"] {
    display: block;
    width: 120px;
    margin-left: auto;
    margin-right: 0px;
}