/* === CSS 文件 === */
/* #nav-intro {
    position: fixed;
    top: 50%;
    left: 20px;
    transform: translateY(-50%);
    z-index: 1000;
}

.navbox {
    display: block;
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

#nav-intro button {
    display: block;
    width: 100%;
    padding: 12px 20px;
    margin: 8px 0;
    border: none;
    border-radius: 4px;
    background: #f8f9fa;
    color: #333;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 14px;
    text-align: left;
}

#nav-intro button:hover {
    background: #e9ecef;
    transform: translateX(5px);
}

#nav-intro button:active {
    background: #dee2e6;
} */

/* 方案1 */
/* ===== 导航栏样式 ===== */
#nav-intro {
    position: fixed;
    top: 50%;
    left: 30px;
    transform: translateY(-50%);
    z-index: 1000;
    background: rgba(255, 255, 255, 0.15);
    border-radius: 15px;
    padding: 20px 15px;
    backdrop-filter: blur(4px);
    border: 1px solid rgba(0, 0, 0, 0.1);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.navbox {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

#nav-intro button {
    padding: 12px 25px;
    border: none;
    border-radius: 8px;
    /* background: rgba(94, 80, 63, 0.9); /* 深咖啡色 */ 
    color: #f3e9d2;
	/* background: rgba(46, 64, 56, 0.9); */ /* 深墨绿 */ 
	background: rgba(134, 60, 60, 0.9); /* 陶土红 */
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-family: 'Arial', sans-serif;
    font-size: 15px;
    text-align: left;
    position: relative;
    overflow: hidden;
    min-width: 120px;
}

/* 悬停效果 */
#nav-intro button:hover {
    /* background: rgba(74, 62, 48, 0.95);/* 深咖啡色 */ 
	/* background: rgba(34, 49, 42, 0.95); *//* 墨绿色系 */
	background: rgba(109, 48, 48, 0.95); /* 砖红色系 */
    transform: translateX(10px);
    box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.15);
}

/* 激活状态 */
#nav-intro button.active {
    background: rgba(114, 92, 70, 0.95);
    font-weight: 600;
    transform: translateX(15px);
}

/* 点击涟漪效果 */
#nav-intro button::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    transform: translate(-50%, -50%);
    transition: width 0.3s, height 0.3s;
}

#nav-intro button:active::after {
    width: 150px;
    height: 150px;
}

/* 内容区块滚动边距 */
#intro, #chpt1, #chpt2, #chpt3, #methods {
    scroll-margin-top: 80px;
}