#contact_form {display: flex; flex-direction: column; align-items: center;
    max-width: min(90vw, 450px); margin: auto; margin-top: 15px; padding: 10px; background: var(--col_bg3);
    border-radius: 10px; box-shadow: 0 0 10px 5px var(--col_bg3);
}
    #contact_form #contact_msg {margin-top: 0px;}
    #contact_form #contact_error_msg {color: red; font-weight: 700;}
    #contact_form label {display: block; width: 100%; margin-bottom: 10px;}
        #contact_form .label_text {display: block; margin-bottom: 5px; font-family: var(--font_2); font-size: 95%;}
        #contact_form label input:not(input[type="checkbox"]), #contact_form textarea, #contact_form select {
            box-sizing: border-box; /* avoid overflow due to padding / border */
            width: 100%; outline: none; /* avoid blue border when selected on firefox */
            background: var(--col_action2);
        }
        #contact_form label input:not(input[type="checkbox"]):focus, #contact_form textarea:focus, #contact_form select:focus {
            box-sizing: border-box; /* avoid overflow due to padding / border */
            width: 100%; outline: none; /* avoid blue border when selected on firefox */
            background: var(--col_action);
        }    
    #contact_form input[type="submit"] {margin: auto; font-size: 90%;}
    #contact_form #_robot {display: none;}
    #contact_form textarea {resize: vertical;}
    #contact_form #robot_message {margin-left: 4px; text-shadow: 0 0 7px green;}
    #contact_form #msg_remaining_characters {font-weight: 700;}
    #contact_form #robot {display: flex; align-items: center; width: fit-content; margin-right: auto;}
    #contact_form input:not(input[type="submit"]):invalid, #contact_form textarea:invalid {
        border-radius: 4px; border: 1px solid red; box-shadow: 0 0 7px red; color: black/*SEO*/;}
    #contact_form input[name="robot"]:invalid + #robot_message {text-shadow: 0 0 7px red;}
    #contact_form input:not(input[type="submit"]):valid, #contact_form textarea:valid, #contact_form select:valid {
        border-radius: 4px; border: 1px solid green; box-shadow: 0 0 7px green; accent-color: var(--col_action); /*checkbox*/
    }
    #contact_form input::placeholder, #contact_form textarea::placeholder {font-style: italic; color: #333333;}