contact.css

header.content {
    text-align: center;
    justify-content: center;
    padding: 0;
}

h1 {
    font-size: 6rem;
}

h2, .subline {
    text-align: center;
}

/* Form */

#message-form {
    box-sizing: border-box;
    width: 50%;
    height: 100%;
    margin: 2% 0;
}

input {
    box-sizing: border-box;
    padding: 1rem;
    border-radius: 5rem;
    min-width: 13rem;
    width: 100%;
    font-family: din-2014;
    font-size: .8rem;
    font-weight: 500;
    outline: none;
    color: var(--dark);
    background-color: rgba(242, 242, 242, 0.8);
    border: 1px solid rgba(242, 242, 242, 0.8);
    transition: border .15s ease-in;
}

input:active, input:focus, textarea:active, textarea:focus {
    border: 1px solid var(--grey30);
}

textarea {
    display: block;
    box-sizing: border-box;
    padding: 1rem;
    border-radius: 1rem;
    width: 100%;
    font-family: din-2014;
    font-size: .8rem;
    font-weight: 500;
    outline: none;
    color: var(--dark);
    background-color: rgba(242, 242, 242, 0.8);
    border: 1px solid rgba(242, 242, 242, 0.8);
    transition: border .15s ease-in;
}

label {
    display: block;
    margin-left: 1.5rem;
    margin-bottom: .5rem;
    color: var(--grey10);
    font-weight: 600;
}

#input__personal-details {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-content: space-between;
    width: 100%;
}

#input__personal-details div {
    flex-basis: 48%;
}

#input__message {
    margin: 5% 0;
}

.buttons {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    margin-top: unset;
    width: 100%;
}

button, .button {
    width: 46%;
    margin: unset;
}

@media only screen and (max-width: 768px) {
    header.content {
        justify-content: center;
    }

    article:last-of-type {
        padding: 15% 10% 0;
        justify-content: center;
    }

    article:last-of-type .copy {
        height: auto;
    }

    #message-form {
        height: auto;
        width: 100%;
    }

    .buttons, #input__personal-details {
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;

    }

    button, .button {
        box-sizing: border-box;
        width: 100%;
        margin: 1% 0;
    }

    button {
        order: 1;
    }
    
    .button {
        order: 2;
    }

    .input {
        margin: 2.5% 0;
    }

    #input__personal-details div {
        width: 100%;
    }
}