html {
    font-size: 10px;
}
body {
    font-family: Arial, Helvetica, sans-serif;
    font-style: normal;
    font-size: 2rem;
    line-height: 1;
    background-color: #ececec;
}
.container {
    width: 1000px;
    background-color: #fff;
    margin: 5rem auto;
    padding: 5rem;
    text-align: center;
}
h1 {
    text-align: center;
    margin: 0 0 5rem;
}
form {
    display: inline-block;
    text-align: start;
}
form > label,
form > div.custom {
    display: flex;
    margin-bottom: 2.5rem;

}
form > label > span,
form > div.custom > span{
    width: 350px;
    flex: 0 0 350px;
    font-size: 1.8rem;
}
.err,
form small {
    font-size: 1.3rem;
    display: block;
}
form small {
    opacity: .5;
    margin-top: 4px;
}
.err {
    color: red;
    margin-top: 1rem;
}
.err:empty {
    display: none;
}
form > label > span > small::before {
    content: "(";
}
form > label > span > small::after {
    content: ")";
}
form input {
    width: 300px;
    flex: 0 0 300px;
    border-radius: 3px;
    border: 1px solid gray;
    font-size: 1.5rem;
    height: 3rem;
    padding: 0 10px;
    box-sizing: border-box;
    box-shadow: none !important;
    outline: none !important;
}
form input:focus {
    border-color: #58a0fd;
}
form .parameter {
     display: flex;
     gap: 10px;
     align-items: center;
     margin-top: 1.5rem;
}
form .parameter:first-child {
    margin: 0;
}
form .parameter input {
    width: 145px;
    flex: 0 0 145px;
}
.actions {
    margin-top: 1.5rem;
}
.test,
.copy,
.add {
    text-decoration: none;
    border: 1px solid gray;
    background-color: #ececec;
    padding: 5px 10px;
    font-size: 1.5rem;
    color: #000;
    border-radius: 3px;
}
textarea:placeholder-shown ~ .test,
textarea:placeholder-shown + .copy {
    display: none;
}
.test,
.copy {
    margin-top: 1rem;
    display: inline-block;
}
.remove {
    color: red;
    font-weight: 700;
    text-decoration: none;
    font-size: 1.7rem;
    margin-inline-start: 6px;
    padding: 4px;
}
form .parameter:first-child .remove {
    visibility: hidden;
    pointer-events: none;
}
button {
    background-color: #000;
    color: #fff;
    border: none;
    padding: 8px 14px;
    border-radius: 3px;
    font-weight: 700;
    cursor: pointer;
}
.result {
    margin-top: 3rem;
    padding-top: 3rem;
    border-top: 1px solid lightgray;
}
.result b {
    display: block;
    margin-bottom: 10px;
}
.result textarea {
    width: 100%;
    border-radius: 3px;
    border: 1px solid gray;
    font-size: 1.5rem;
    line-height: 1.3;
    padding: 10px;
    box-sizing: border-box;
    box-shadow: none !important;
    outline: none !important;
    background-color: #efefef;
    -webkit-user-select: all;
     user-select: all;
}