.a_link,
.a_link:link,
.a_link:hover {
    color: #ffffff;
    text-decoration: none;
    display: block;
}

/* 移除原本在 <a> 上的 outline，改為對內層套用 box-shadow */
.a_link:focus,
.a_link:focus-visible {
    outline: none;
}

.a_link:focus .R_menu_bg,
.a_link:focus-visible .R_menu_bg {
    box-shadow:
        0 0 0 2px #ffffff,   /* 內層：白色 */
        0 0 0 5px #2873ff;   /* 外層：藍色 */
    border-radius: 0.625rem;
}

.R_menu_bg {
    width: 100%;
    height: 2.8125rem; /* 45px */
    line-height: 2.8125rem;
    position: relative;
    overflow: hidden;
    margin-bottom: 0.3125rem; /* 5px */
}

.R_menu_bot {
    width: 100%;
    height: 2.8125rem; /* 45px */
    position: relative;
    border-top-right-radius: 0.625rem; /* 10px */
    border-bottom-right-radius: 0.625rem; /* 10px */
    left: 0rem;
    transition: 0.2s;
}

.R_menu_bot:hover {
    left: -2.25rem; /* -36px */
    transition: 0.2s;
    border: 3px solid #2873ff;
}

.R_menu_bot>.shadow {
    width: 4.875rem; /* 78px */
    height: 2.8125rem; /* 45px */
    left: -1.6875rem; /* -27px */
    background-color: #000;
    transform: rotate(-60deg);
    position: relative;
    opacity: 0.2;
}

.R_menu_bot>.icon {
    width: 100%;
    height: 2.8125rem; /* 45px */
    top: -2.8125rem; /* -45px */
    left: 0.25rem; /* 4px */
    position: relative;
    font-size: 1.75rem;
    color: #fff;
    text-shadow: 0.0625rem 0.0625rem 0.125rem #000000;
}

.R_menu_bot .fa {
    display: inline-block;
    font: normal normal normal 0.875rem/1 FontAwesome;
    font-size: inherit;
    text-rendering: auto;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.R_menu_bot>.word {
    width: 100%;
    height: 2.8125rem; /* 45px */
    top: -5.625rem; /* -90px */
    position: relative;
    font-family: 'Microsoft JhengHei';
    color: #fff;
    text-shadow: 0.0625rem 0.0625rem 0.125rem #000000;
}