Edit in JSFiddle

<label for="email">Email *</label>
<input placeholder="Inserisci la tua email" type="email" name="email" value="">

::-webkit-input-placeholder { /* WebKit browsers */
    color:    #555;
}
:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
    color:    #555;
}
::-moz-placeholder { /* Mozilla Firefox 19+ */
    color:    #555;
}
:-ms-input-placeholder { /* Internet Explorer 10+ */
    color:    #555;
}
label {
    box-sizing: border-box;
    font-family: sans-serif;
    font-size: 15px;
    font-weight: 400;
    line-height: 1;
    color: #000;
    margin:0 10px;
}
input {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    border: 1px solid #999;
    height: 30px;
    line-height: 1;
    font-size: 15px;
    border-radius: 0px;
    text-indent: 10px;
}