/* カスタム CSS をここに入力してください */
.color__site-header, .color__site-title, .color__site-title:hover {
    color: #ffffff;
}

.color__nav-bg--pc, .global-nav__sub-menu li {
    background-color: #626a6b;
}

.color__nav-font--pc {
    color: #ffffff;
}

.site__footer, .site__footer a, .site__footer a:hover {
    color: #a7a7a7;
}

button, input[type=button], input[type=reset], input[type=submit] {
    padding: .5em 2em;
    background-color: #878e92;
    border: 1px solid #46494a;
    color: #fff;
    transition: all .3s;
}







子テーマのstyle.cssに追記

.wpcf7 input[name="your-name"],
.wpcf7 input[name="your-email"],
.wpcf7 input[name="your-conpany"],
.wpcf7 input[name="your-subject"] {

        width: 60%;
        height: 35px !important;
}