styles.css

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
}

html,
body {
    font-family: var(--roboto);
    font-size: 36px;
    background: rgb(129, 126, 126);
    overflow-y: hidden;
    
}

.container {
    width: 850px;
    height: 450px;
    margin: 200px auto;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-content: center;
    color: white;
    background: black;
    border-radius: 8px;
    border: 10px ridge white;
}
.intro {
    margin: auto .5rem;
    text-align: center;
}
.input-holder {
    height: auto;
    display: flex;
    flex-direction: column;
    text-align: center;
    justify-content: space-between;
}
.text-field {
    width: 400px;
    height: 40px;
    margin: .5rem auto;
    font-size: 20px;
    color: white;
    background: black;
    outline: none;
    border: none;
    border-bottom: 5px ridge white;
    border-radius: 5px;
    text-align: center;

}
.btn-check {
    width: 150px;
    height: 40px;
    margin: .5rem auto;
    font-size: 18px;
    font-weight: 600;
    color: white;
    background:black;
    border: 5px ridge white;;
    border-radius: 8px;
    padding-top: 4px;
}
/* STYLING RESPONSES */
.isoEval {
    text-align: center;
    margin: .4rem auto;
    color: orange;
}
.isoTrue {
    text-align: center;
    margin: .4rem auto;
    color: #00FF2A;
}
.isoFalse {
    text-align: center;
    margin: .4rem auto;
    color: #FF1919;
}

/* MAX-WIDTH 825PX*/
@media screen and (max-width: 825px) {
    .container {
        width: 80%;
        margin: auto; 
    }
    .intro,
    .isoEval,
    .isTrue,
    .isFalse {
        width: 80%;
        font-size: .8em;
        margin: 0 auto;
    }
    .input-holder {
        width: 100%;
    }
    .text-field {
        width: 70%;
    }
}

/* MAX-WIDTH 500PX */
@media screen and (max-width: 500px) {
    html,
    body {
        overflow-y: hidden;
        width: 100%;
    }
    body {
        position: relative;
    }
    .container {
        min-width: 340px;
        height: 420px;
    }
    .intro,
    .isoEval,
    .isTrue,
    .isFalse {
        font-size: .6em;
    }
}