style.css

@import url('https://fonts.googleapis.com/css2?family=Montserrat:wght@300&display=swap');
/* the bellow root components defines varriables that contain the error 
color  and success color that are used in the document*/
:root{
    --success-color:#2ecc2e;;
    --error-color: #cc2e2e;;
}

*{
    box-sizing: border-box;
}

body {
    background-color: bisque;
    font-family: 'Montserrat', sans-serif; 
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
   margin: 0; 
}

.container{
    background-color: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 10px rgba(0,0, 0, 0.3);
    width: 400px;

}

h2{
    text-align: center;
    margin: 0 0 20px;

}

.form{
    padding: 30px 40px;

}

.form-control {
    margin-bottom: 10px;
    padding-bottom: 20px;
    position: relative;

}

.form-control label {
    color: #777;
    display: block;
    margin-bottom: 5px;
}

.form-control input {
    border: 2px solid #f0f0ff;
    border-radius: 2px;
    display: block;
    width: 100%;
    padding: 10px;
    font-size: 14px;
}

.form-control input:focus {
    outline: 0;
    border-color: #777;

}

.form-control.success input {
    border-color: var(--success-color);
}

.form-control.error input {
    border-color: var(--error-color);
}

.form-control small {
    color: var(--error-color);
    position: absolute;
    bottom: 0;
    left: 0;
    visibility: hidden;
}

.form-control.error small {
    visibility: visible;
    position: absolute;
}

.form button{
    cursor: pointer;
    background-color: #3498db;
    border: 2px solid #3498db;
    border-radius: 4px;
    color: #f0f0ff;
    display: block;
    font-size: 16px;
    padding: 10px;
    margin-top: 20px;
    width: 100%;
}