grav-ouidade.com/user/plugins/admin/themes/grav/scss/template/_login.scss

#admin-login {
    @extend %vertical-align;
    background: $accent-bg;
    max-width: 24rem;
    margin: 0 auto;

    .form-field {
        padding-left: 0;
        margin-bottom: 0;
    }

    .form-label {
        display: none;
    }

    .form-data {
        padding-right: 0;
    }

    h1 {
        background: $darker-accent-bg url(../images/logo.png) 50% 50% no-repeat;
        font-size: 0;
        color: transparent;
        height: 216px;
        margin: 0;
    }

    form {
        padding: 2rem 3rem;
        input {
            margin-bottom: 2rem;
            background: $page-bg;
            color: $core-text;
            font-size: 1.4rem;
            line-height: 1.5;
            text-align: center;
            font-weight: 300;
            -webkit-font-smoothing: auto;
            border: 1px solid shade($accent-bg, 20%);
            @include placeholder {
                color: tint($page-bg,40%);
            }
        }

        .form-actions {
            text-align: center;
            margin: 0 -3rem -3rem -3rem;
            padding: 1.5rem 3rem;

            button:first-child {
                margin-right: 1rem;
            }
        }
    }

    .alert {
        text-align: center;
        padding: 1rem 3rem;
    }
}