style.css

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
}

body {
    margin: 0;
    font-family: 'Roboto', sans-serif;
}

.header {
    background: #1F2229;
    width: 100%;
    height: 44px;
    color: #FFFFFF;
}

.header-container {
    width: 846px;
    margin: 0px auto;
    display: flex;
}

.header-heading {
    color: #FFFFFF;
    font-size: 14px;
    font-weight: 400;
    line-height: 16px;
    padding: 14px 20px;
}

.header-logo {
    padding: 12px 0 0;
}

.container {
    width: 716px;
    padding: 41px 42px 112px 42px;
    margin: 0px auto;
    background: #FAF6F6;
}

.container h1 {
    font-size: 36px;
    font-weight: 400;
    line-height: 42px;
    text-align: center;
    margin: 0 0 30px;
}

.main-description {
    font-size: 12px;
    font-weight: 400;
    line-height: 14px;
    text-align: justify;
    margin: 0 0 72px;
}

.calc-body {
    padding: 0 80px 0 72px;
}

.calc-body hr {
    border: none;
    border-top: 1px #000 solid;
    margin-bottom: 26px;
}

.main-form {
    margin-bottom: 28px;
}

.form-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    grid-gap: 37px 82px;
}

input[type='number'],
input[type="number"]:hover,
input[type="number"]:focus {
    appearance: none;
    -moz-appearance: textfield;
}

div.custom-input {
    display: flex;
    flex-direction: column-reverse;
    max-width: 20rem;
    margin: 0 auto;
    height: 54px;
}

.custom-input.hidden,
.hidden {
    display: none;
}

.custom-input input {
    padding: 29px 18px 9px;
    border: 1px solid #000;
    outline: none;
    width: 204px;
    height: 16px;
    font-size: 12px;
    font-weight: 400
}

.custom-input input.error {
    border: 1px solid #FF5A5F;
}

.custom-input label.error {
    order: 1;
    position: relative;
    color: #FF5A5F !important;
    top: 60px;
}

.custom-input label {
    padding-left: 1rem;
    color: #000000;
    font-size: 12px;
    font-weight: 400;
    transform: translateY(33px);
    transform-origin: left top;
    cursor: text;
    transition: all 0.3s;
}

.custom-input input:focus ~ .label-heading,
.custom-input input:not(:placeholder-shown) ~ .label-heading {
    padding: 0;
    color: #212121;
    transform: translate(15px, 23px);
}

.custom-checkbox {
    height: 54px;
}

.custom-checkbox input {
    display: none;
}

.custom-checkbox .custom__new-checkbox {
    display: inline-block;
    width: 25px;
    height: 25px;
    border: 1px solid #000000;
    background: #ffffff;
}

.custom-checkbox label {
    display: flex;
    margin-top: 13px;
}

.custom-checkbox label input:checked ~ .custom__new-checkbox {
    background: url("data:image/svg+xml;utf8, <svg width='16' height='14' viewBox='0 0 16 14' fill='none' xmlns='http://www.w3.org/2000/svg'> <line x1='0.290619' y1='8.59313' x2='7.29062' y2='13.5931' stroke='black'/> <line x1='6.5889' y1='13.7154' x2='15.5889' y2='0.715395' stroke='black'/> </svg>") no-repeat,
    #ffffff;
    background-position: 5px 5px;
}

.custom-checkbox-label {
    order: 2;
    font-size: 14px;
    font-weight: 400;
    white-space: nowrap;
    line-height: 25px;
    position: absolute;
    margin-left: 40px;
}

.custom-select {
    height: 54px;
    position: absolute;
    border: 1px solid #000000;
    margin-left: 181px;
    background: #ffffff;
    outline: 0px;
}

.form-submit {
    background: #33C4A0;
    color: #FFFFFF;
    padding: 19px 53px;
    border: none;
    margin-top: 64px;
    font-size: 12px;
    font-weight: 500;
    line-height: 14px;
    cursor: pointer;
}

.main-result-text {
    padding-left: 15px;
    font-size: 14px;
    font-weight: 400;
    margin-bottom: 12px;
}

.main-form-result {
    padding-left: 53px;
    font-weight: 700;
    font-size: 40px;
}