* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html,
body {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-family: Arial, Helvetica, sans-serif;
    background-color: #ffffff;
    flex-direction: column;
}

h1 {
    font-size: 50px;
    margin-bottom: 30px;
    font-weight: 800;
}

.box {
    background-color: rgb(158, 8, 8);
    width: 500px;
    padding: 30px 0;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    border: none;
    border-radius: 50px;
    box-shadow: 0px 0px 20px rgba(0, 0, 0, 0.247);
}

.categories {
    width: 80%;
}

.categories select {
    width: 100%;
    margin: 10px 0;
    font-size: 30px;
    text-align: center;
    border-radius: 20px;
    border: none;
    background-color: rgb(219, 86, 71);
    color: white;
    box-shadow: 0px 0px 5px rgba(56, 1, 1, 0.616);
    padding: 5px 0;
}
.categories select:focus{
    outline: none;
}
.display {
    width: 80%;
}

.display input {
    width: 100%;
    margin: 10px 0;
    font-size: 35px;
    text-align: center;
    border-radius: 20px;
    border: none;
    background-color: transparent;
    color: white;
    box-shadow: 0px 0px 5px rgba(56, 1, 1, 0.616);
    padding: 5px 0;
    border: 2px solid white;
}

input:focus {
    outline: none;
}

.converter {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 80%;
    text-align: center;
}

.converter select {
    width: 50%;
    margin: 10px;
    font-size: 30px;
    border-radius: 20px;
    padding: 3px 10px;
    background-color: rgb(219, 86, 71);
    color: white;
    border: none;
    box-shadow: 0px 0px 5px rgba(56, 1, 1, 0.616);
}

h4 {
    color: white;
    font-size: 25px;
    margin: 20px 0;
}

.result {
    width: 80%;
    text-align: center;
}

button {
    width: 100%;
    font-size: 25px;
    border-radius: 20px;
    padding: 8px 0px;
    border: none;
    background-color: rgb(214, 7, 7);
    color: white;
    box-shadow: 0px 0px 5px rgba(56, 1, 1, 0.5);
    cursor: pointer;
}

button:active {
    scale: .9;
}

@media screen and (max-width: 510px) {
    .box {
        width: 90%;
    }
}

@media screen and (max-width: 450px) {
    h1 {
        font-size: 35px;
    }
}

@media screen and (max-width: 380px) {
    .converter select {
        font-size: 20px;
    }

    h4 {
        font-size: 20px;
    }
}