:root {
    --color__background: #f6f4f3;
    --color__gray: #ccc;
}

* {
    font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
    box-sizing: border-box;
}

body {
    margin: 0;
    background-color: var(--color__background);
}

.container {
    margin: 0 auto;
    padding: 1rem;
    max-width: 40rem;
}

.button {
    display: inline-block;
    padding: 0.5rem 1rem;
    background-color: var(--color__gray);
    border: 0;
    cursor: pointer;
    text-decoration: none;
}

.button:hover {
    filter: brightness(90%);
}

.message-form__author, .message-form__text {
    display: block;
    width: 100%;
    outline: none;
    padding: .5rem;
    resize: none;
    border: 1px solid var(--color__gray);
    box-sizing: border-box;
}

.message-form__submit {
    display: block;
    width: 100%;
    outline: none;
    padding: .5rem;
    background-color: var(--color__gray);
    border: none;
    cursor: pointer;
    font-weight: bold;
}

.message-form__submit:hover {
    filter: brightness(90%);
}

.message {
    border: 1px solid var(--color__gray);
    border-top: 0;
    padding: .5rem;
    border-radius: .5rem;
}

.message__author {
    font-size: 1rem;
}

.message__created_at {
    color: var(--color__gray);
}

.message__footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}