* {
    box-sizing: border-box;
}
body {
    background-color: lightgray;
    font-family: Arial, Helvetica, sans-serif;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100vh;
    margin: 0;
    padding: 20px;
}
h1 {
    color:yellowgreen;
}
p {
    text-align: center;
}
.btn {
    color: white;
    background-color: yellowgreen;
    cursor: pointer;
    border-radius: 5px;
    font-size: 12px;
    padding: 5px 10px;
}
.currency {
    padding: 40px 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.currency select {
    padding: 10px 20px 10px;
    border: 1px solid gray;
    font-size: 16px;
    background: transparent;
}
.currency input {
    border: 0;
    background: transparent;
    font-size: 24px;
    text-align: right;
}
.swap-rate-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.rate {
    color: yellowgreen;
    font-size: 16px;
    padding: 0 10px;
}
select:focus, input:focus, button:focus {
    outline: 0;
}