body {
    font-family: "Cascadia Code", sans-serif;
}

.content {
    max-width: 580px;
    width: 100%;
    margin: 0 auto;
    padding: 20px 0;
}

.section {
    margin-bottom: 20px;
}

.flex {
    display: flex;
}

.flex b {
    flex: 0 0 130px;
}

.input-container {
    position: relative;
    margin: 50px auto;
    width: 200px;
}

.input-container input[type="text"] {
    font-size: 20px;
    width: 100%;
    border: none;
    border-bottom: 2px solid #ccc;
    padding: 5px 0;
    background-color: transparent;
    outline: none;
}

.input-container .label {
    position: absolute;
    top: 0;
    left: 0;
    color: #ccc;
    transition: all 0.3s ease;
    pointer-events: none;
}

.input-container input[type="text"]:focus ~ .label,
.input-container input[type="text"]:valid ~ .label {
    top: -20px;
    font-size: 16px;
    color: #333;
}

.input-container .underline {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 2px;
    width: 100%;
    background-color: #333;
    transform: scaleX(0);
    transition: all 0.3s ease;
}

.input-container input[type="text"]:focus ~ .underline,
.input-container input[type="text"]:valid ~ .underline {
    transform: scaleX(1);
}