style.css

body {
    position: relative;
    width: auto;
    height: 100%;
    font-family: Arial, Helvetica, sans-serif;
    background-color:goldenrod;
    color: aliceblue;
}

h2 {
    font-family: 'Courier New', Courier, monospace;
    text-align: center;
    font-size: xx-large;
}

#div1 {
    position: relative;
    top: 30px;
    left: 30%;
    margin: 20px;
    padding: 23px;
    height: 50%;
    width: 370px;
    border-radius: 10px;
    background-color: rgb(224, 236, 161);
    color: rgb(0, 0, 0);
}

.input_sec {
    position: relative;
    top: auto;
    left: 150px;
    margin-top: 10px;
    border: 1px solid transparent;
    border-radius: 5px;
    padding: 5px;
}

.input_sec:hover,
.input_sec:focus {
    background: #e5f6f2;
    outline: none;
    font-weight: 200;
}

.let {
    position: absolute;
    top: auto;
    margin: 15px;
    left: 15px;
}

button {
    width: 100px;
    height: 40px;
    margin: 35px 40px;
    border: none;
    border-radius: 5px;
    font-size: medium;
    cursor: pointer;
    opacity: 0.9;
}

#cancelbtn {
    background-color: red;
}

#submitbtn {
    background-color: #04AA6D;
}

button:hover {
    color: white;
    opacity: 0.7;
}

button:focus {
    background-color: rgb(134, 143, 119);
}

@media screen and (max-width: 300px) {

    .cancelbtn,
    .submitbtn {
        width: 100%;
    }
}