/* vertical-nav.css */
.vertical-nav {
    position: absolute;
    left: 30px;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    z-index: 100;
    width: 60px;
    height: 360px;
    justify-content: center;
    padding: 10px;
    border-radius: 0 30px 30px 0;
}

.vertical-nav a {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: transparent;
    color: #fcc0c5;
    font-size: 14px;
    font-weight: bold;
    text-decoration: none;
    position: relative;
    overflow: hidden;
    border: none;
}

.vertical-nav a span {
    position: relative;
    z-index: 2;
    transition: color 0.3s ease;
    text-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}

.vertical-nav a svg {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.vertical-nav a svg circle {
    stroke: #b3e87d;
    stroke-width: 2;
    fill: none;
    stroke-dasharray: 188.4;
    stroke-dashoffset: 188.4;
    transition: none;
    opacity: 0;
}

.vertical-nav a.active span {
    color: #fcc0c5; /* アクティブ時のテキスト色 */
}

.vertical-nav a.active svg circle {
    opacity: 1;
    animation: drawCircle 4s linear infinite;
}

.vertical-nav a:not(.active) svg circle {
    stroke-dashoffset: 188.4;
    opacity: 0;
}

@keyframes drawCircle {
    0% {
        stroke-dashoffset: 188.4;
    }
    100% {
        stroke-dashoffset: -188.4;
    }
}

/* ホバー効果を無効化 */
.vertical-nav a:hover {
    background-color: transparent;
}

/* レスポンシブ設定 */
@media (max-width: 768px) {
    .vertical-nav {
        left: 15px;
        width: 50px;
        gap: 15px;
    }
    
    .vertical-nav a {
        width: 35px;
        height: 35px;
        font-size: 12px;
    }
}

@media (max-width: 480px) {
    .vertical-nav {
        left: 10px;
        width: 45px;
        gap: 12px;
    }
    
    .vertical-nav a {
        width: 30px;
        height: 30px;
        font-size: 10px;
    }
}