style.css

body {
    background-color: #000000;
    padding: 0 2rem;
    font-family: 'Work Sans', sans-serif;
    font-weight: 400;
}

h1 {
    font-family: 'Kanit', sans-serif;
    display: inline-block;
    border-bottom: 1px solid white;
    padding-bottom: 0.5rem;
    color: #ffffff;
}

button {
    background-color: #cb80a3;
    padding: 0.5rem 1.2rem;
    font-size: 1.1rem;
    font-family: 'Work Sans', sans-serif;
    font-weight: 500;
    border-radius: 0.3rem;
    margin: 0.5rem auto 1.5rem;
    border: 2px solid #cb80a3;
    border-radius: 0.5rem;
    line-height: 1.1rem;
    cursor: pointer;
    transition: all 0.15s ease-in-out;
}

button:hover {
    transition: all 0.15s ease-in-out;
    transform: translateY(-0.2rem);
}

button:active {
    background-color: #cb80a3;
    transition: all 0.15s ease-in-out;
    border: 2px solid #cb80a3;
}

button:focus {
    outline: none;
    border: 2px solid #cb80a3;
}

button:disabled {
    outline: none;
    transition: none;
    transform: none;
    cursor: not-allowed;
}

main {
    display: flex;
    justify-content: center;
    align-items: center;
    -webkit-perspective: 150rem;
    perspective: 150rem;
    -moz-perspective: 150rem;
    position: relative;
    margin: 0 auto;
}

.container {
    background-color: #ffffff;
    border-radius: 1rem;
    min-width: 350px;
    max-width: 500px;
    width: 50%;
    padding: 0 2rem;
    min-height: 700px;

    -webkit-transition: all 0.8s ease;
    transition: all 0.8s ease;
    position: absolute;
    top: 0;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    overflow: hidden;
    -webkit-box-shadow: 0 1.5rem 4rem rgba(0, 0, 0, 0.15);
    box-shadow: 0 1.5rem 4rem rgba(0, 0, 0, 0.15);
}

.container header {
    text-align: center;
    display: flex;
    align-items: center;
    flex-direction: column;
}

.container header h2 {
    margin-bottom: 0.2rem;
    font-weight: 500;
}

.container header h3 {
    margin-top: 0.2rem;
    font-weight: 200;
    font-size: 1rem;
    width: 80%;
}

.setting {
    margin: 1rem;
    display: flex;
    flex-direction: column;
}

input[type='color'] {
    appearance: none;
    -moz-appearance: none;
    -webkit-appearance: none;
    background: none;
    border: 1px solid #000000;
    cursor: pointer;
    height: 50px;
    padding: 0.2rem;
    width: 50px;
}

input[type='color']:focus {
    outline: none;
    border: 2px solid #cb80a3;
    border-radius: 2px;
}

::-webkit-color-swatch-wrapper {
    padding: 0;
}

::-webkit-color-swatch {
    border: 0;
}

::-moz-color-swatch {
    border: 1px solid #000000;
}

.colors {
    display: flex;
    justify-content: space-around;
}

.colors .setting {
    align-items: center;
    text-align: center;
}

.colors .setting span {
    font-weight: 200;
    font-size: 0.9rem;
}

.sub-label {
    font-weight: 200;
    font-size: 0.9rem;
}

input[type='text'] {
    border: 1px solid #000000;
    padding: 0.35rem 0.85rem 0.35rem 0.4rem;
    line-height: 1.2rem;
    font-size: 1rem;
    font-weight: 200;
    border-radius: 0.3rem;
    font-family: 'Work Sans', sans-serif;
}

input[type='text']:focus {
    outline: none;
    border: 1px solid #cb80a3;
}

input[type='range'] {
    -webkit-appearance: none;
    width: 100%;
    height: 5px;
    border-radius: 3px;
    background: #d9d9d9;
    outline: none;
    padding: 0;
    margin: 0;
}
input[type='range']::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #cb80a3;
    cursor: pointer;
    -webkit-transition: background 0.15s ease-in-out;
    transition: background 0.15s ease-in-out;
}
input[type='range']::-webkit-slider-thumb:hover {
    background: #cb80a3;
}
input[type='range']:active::-webkit-slider-thumb {
    background: #cb80a3;
}
input[type='range']::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border: 0;
    border-radius: 50%;
    background: #cb80a3;
    cursor: pointer;
    -moz-transition: background 0.15s ease-in-out;
    transition: background 0.15s ease-in-out;
}
input[type='range']::-moz-range-thumb:hover {
    background: #cb80a3;
}
input[type='range']:active::-moz-range-thumb {
    background: #cb80a3;
}
input[type='range']:focus::-webkit-slider-thumb {
    box-shadow: 0 0 0 3px #fff, 0 0 0 5px #cb80a3;
}

::-moz-range-track {
    background: #d7dcdf;
    border: 0;
}

input::-moz-focus-inner,
input::-moz-focus-outer {
    border: 0;
}

input[type='radio'] {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    display: inline-block;
    width: 15px;
    height: 15px;
    padding: 2px;
    background-clip: content-box;
    border: 1px solid #cb80a3;
    background-color: #ffffff;
    border-radius: 50%;
}

input[type='radio']:checked {
    background-color: #cb80a3;
}

input[type='radio']:focus {
    outline: none;
    border: 2px solid #cb80a3;
    background-color: #cb80a3;
}

fieldset {
    display: flex;
    flex-wrap: wrap;
    border: none;
    padding: 0;
    margin: 0;
    justify-content: space-between;
}

fieldset legend {
    margin-bottom: 0.5rem;
}

fieldset div {
    border: 1px solid #000000;
    border-radius: 0.3rem;
    display: flex;
    align-items: center;
    padding: 0.25rem 0.5rem;
    margin-right: 0.25rem;
    margin-bottom: 0.5rem;
}

fieldset div:last-child {
    margin-right: 0;
}

fieldset div input {
    margin-right: 0.5rem;
    cursor: pointer;
}

fieldset div label {
    cursor: pointer;
}

.cta {
    display: flex;
}

input.error {
    border: 2px solid #cd4218;
}

input.error:focus {
    border: 1px solid #cd4218;
}

.container-front.flipped {
    -webkit-transform: rotateY(-180deg);
    transform: rotateY(-180deg);
}

.container-back {
    -webkit-transform: rotateY(180deg);
    transform: rotateY(180deg);
}

.container-back.flipped {
    -webkit-transform: rotateY(0);
    transform: rotateY(0);
}

.setting img {
    width: 90%;
    margin: 0 auto;
}

.info {
    text-align: center;
    margin-top: 0.2rem;
    font-weight: 200;
    font-size: 1rem;
    width: 80%;
    margin: 0 auto;
}