index.css

body {
    margin: 0;
    text-align: center;
}

@font-face {
    font-family: 'Inter';
    src: url(Inter[wght].ttf);
}

/*Main Container of the app*/
.main-container {
    width: 550px;
    height: 729px;
    background: #1F2937;
    margin: 0 auto;
}

/*Head Container*/
.head-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-around;
    width: 550px;
    height: 285px;
    background: #6943FF;
}

#title {
    font-family: 'Inter';
    font-style: normal;
    font-weight: 800;
    font-size: 28px;
    line-height: 38px;
    letter-spacing: -0.03em;
    color: #FFFFFF;
    margin-bottom: 0px;
}

#value {
    width: 300px;
    height: 83px;
    border: 2px solid #B295FF;
    border-radius: 5px;
    box-sizing: border-box;
    background: #6943FF;
    font-family: 'Inter';
    font-style: normal;
    font-weight: 800;
    font-size: 58px;
    line-height: 24px;
    color: #FFFFFF;
    text-align: center;
    margin-bottom: 0px;
}

/* Chrome, Safari, Edge, Opera */
input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Firefox */
input[type=number] {
  -moz-appearance: textfield;
}

button {
    width: 117px;
    height: 42px;
    background: #FFFFFF;
    box-shadow: 0px 1px 2px rgba(0, 0, 0, 0.05);
    border: none;
    border-radius: 5px;
    font-family: 'Inter';
    font-style: normal;
    font-weight: 500;
    font-size: 16px;
    line-height: 24px;
    color: #3D3D3D;
    margin-bottom: 0px;
}

/*Group Container with the 3 groups*/
.conversion-groups {
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    align-items: center;
}

.group {
    display: flex;
    flex-direction: column;
    justify-content: center;
    width: 500px;
    height: 108.57px;
    background: #273549;
    border-radius: 4.68077px 0px 0px 0px;
    margin-top: 25px;
}

.group-title {
    font-family: 'Inter';
    font-style: normal;
    font-weight: 600;
    font-size: 20px;
    line-height: 20px;
    color: #CCC1FF;
    margin-bottom: 0px;
}

.conversion-style {
    font-family: 'Inter';
    font-style: normal;
    font-weight: 400;
    font-size: 14px;
    line-height: 20px;
    color: #FFFFFF;
}