.btn_style02 {
 width: 100%;
 max-width: 300px;
}

.btn_style02 a {
 display: block;
 width: 100%;
 padding: 15px 0;
 text-align: center;
 color: #fff;
 text-decoration: none;
 font-weight: normal;
 background: var(--main-color);
 border-width: 1px 1px 1px 1px;
 border-style: solid;
 border-color: var(--main-color);
 position: relative;
}

.btn_style02 a:hover { 
 color: var(--main-color);
 background: #fff;
}

.btn_style02 a .mail_icon {
 padding: 0 0 0 25px;
 position: relative;
}

.btn_style02 a .mail_icon::before {
 content: '';
 display: inline-block;
 position: absolute;
 left: 0;
 top: 50%;
 transform: translateY(-50%);
 -webkit-mask-image: url(../img/common/mail_icon.svg);
 mask-image: url(../img/common/mail_icon.svg);
 -webkit-mask-repeat: no-repeat;
 mask-repeat: no-repeat;
 width: 18px;
 height: 13px;
 -webkit-mask-size: 100% auto;
 mask-size: 100% auto;
 background-color: #fff;
}

.btn_style02 a:hover .mail_icon::before {
 background-color: var(--main-color);
}