style.css

* {
    font-family: Poppins;
}


body {
    background-image: linear-gradient(90deg,#66a6ff,#89f7fe);
    color: #1a263f;
}

.container {
    width: 360px;
    height: 470px;
    padding: 10px 40px;

    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);

    background-color: #fefeff;    
    border-radius: 10px;
    box-shadow: 0 20px 30px rgba(0,0,0,0.2);
}


.titulo-contato, .subtitulo {
    text-align: center;
    margin-bottom: -10px;
}

.grupo {
    margin-top: 1.5em;
    border: #ffffff;
    border-top: 1px solid #b3b3b3;
}

.campo {
    float:  left;
    margin-right: 3px;
    margin-top: 10px;
    margin-bottom: 10px;
    border: #ffffff;
}

.email input {
    width: 96.6%;
    padding: .2em;
}

.campo input[type="text"], .email input[type="email"], .campo-texto textarea {
    padding: .2em;
    border: 1px solid #b3b3b3;
    display: block;
}

textarea {
    resize: none; /*Para retirar o redimensionamento da area de texto*/
    width: 357px; 
    margin: 0px -2px 0px 0px; 
    height: 120px;  
}
  
.botao:active {
    background: #0a0a0a;
    transform: translateY(4px);
} 
  
.botao {
    padding: 20px;
    width: 200px;
    font-size: 1.2em;
    border: none;
    color: #ffffff;
    background: #090a14;
    background-size: 200%;

    margin-top: 20px;
    padding: 0.2em 0.6em;

    position: relative;
    left: 22%;

    border-radius: 4px;
    box-shadow: 2px 5px #b3b3b3;

    transition: all 0.5s;
    cursor: pointer;
}
  
.botao span {
    cursor: pointer;
    display: inline-block;
    position: relative;
    transition: 0.5s;
}
  
.botao span:after {
    content: '\00bb';
    position: absolute;
    opacity: 0;
    top: 0;
    right: -20px;
    transition: 0.5s;
}
  
.botao:hover span {
    padding-right: 25px;
}
  
.botao:hover span:after {
    opacity: 1;
    right: 0;
}

/* referencia para os botões -
https://www.w3schools.com/css/tryit.asp?filename=trycss_buttons_animate1

https://www.w3schools.com/css/tryit.asp?filename=trycss_buttons_animate3
*/


/*media query*/
@media (max-width: 991px) { 
    html {
        font-size: 100%;
    }
}

@media (max-width: 425px) { /*pc*/
    .container {
        width: 290px;
        height: 520px;
    }
    .campo {
        float:  none;
        width: 96.6%;
    }
    
    .campo input {
        width: 96.6%;
    }

    textarea {
        width: 280px;
        margin: 0px 5.6875px 0px 0px; 
        height: 103px;
    }

    .botao {
        left: 20%;
        }
}

@media (max-width: 375px) { 
    .container {
        width: 250px;
        height: 520px;
    }

    textarea {
        width: 251px;
    }

    .botao {
        left: 10%;
        }
    
}

@media (max-width: 320px) { /*celular*/
    html {
        font-size: 14px;
    }
        .container {
        width: 200px;
    }

    textarea {
        width: 205px;
        height: 69px;
    }

    .botao {
    left: 0;
    }
}