style.css

*{
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #E7E8D1;
}

.converter-container {
    background-color: #A7BEAE;
    border-radius: 5px;
    padding: 20px 30px;
    box-shadow: 0px 5px 8px rgba(0, 0, 0, 0.5);
    text-align: center;
}

.converter-container h1 {
    font-size: 2.5rem;
    margin-bottom: 40px;
}

.converter-container .input-container {
    display: flex;
    margin-block: 20px;
}

.converter-container .input-container input {
    flex: 1;
    outline: none;
    border: none;
    font-size: 15px;
    padding: 8px;
    overflow: hidden;
    margin-right: 5px;
    border-radius: 5px;
    background-color: #fff;
}

.converter-container .input-container select {
    width: 150px;
    outline: none;
    border: none;
    font-size: 15px;
    padding: 8px;
    overflow: hidden;
    border-radius: 5px;
}

.converter-container .arrow {
    transform: rotate(90deg);
    font-size: 2rem;
}

.converter-container .result {
    font-size: 1.8rem;
    font-weight: 600;
    margin-top: 40px;
}

/* Responsive for small screen */

@media screen and (max-width: 540px) {
    .converter-container {
        width: 80%;
        margin: auto;
    }

    .converter-container h1 {
        font-size: 1.5rem;
    }

    .converter-container .input-container select {
        width: 100px;
    }

    .converter-container .result {
        font-size: 1.4rem;
        font-weight: 600;
        margin-top: 40px;
    }
}