/* 响应式布局 */
/* 响应式断点更新 - Tablet */
@media (max-width: 1024px) {
    :root {
        --nav-width: 240px; /* 平板设备侧边栏宽度 */
    }
     /* 平板上可能也需要调整内容区左边距 */
    .content-container {
        margin-left: var(--nav-width);
    }
    /* 平板上时间块列数可能需要调整 */
    .playlist-section {
        grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); /* 调整最小宽度 */
    }
}


/* --- MOBILE OPTIMIZATIONS START --- */
@media (max-width: 768px) {
    :root {
        /* --- 显著减小移动端头部高度 --- */
        --header-height: 70px;
        --nav-width: 100%; /* 导航变为底部栏，宽度占满 */
        --bottom-nav-height: 65px; /* 定义底部导航高度变量 */
    }

    .main-header {
        /* --- 调整移动端头部内边距 --- */
        padding: 0.8rem 1rem; /* 稍微减小垂直内边距 */
        z-index: 1002;
    }

    .glowing-title {
        /* --- 调整移动端标题字体大小 --- */
        font-size: clamp(1.6rem, 4vw, 2rem);
    }

    .header-sub {
       /* --- 调整移动端副标题字体大小和边距 --- */
        font-size: clamp(0.8rem, 2vw, 0.9rem);
        margin-top: 0.2rem; /* 减小与主标题的间距 */
    }

    .side-nav {
        /* --- 将导航栏移至底部 --- */
        position: fixed;
        bottom: 0;
        left: 0;
        top: auto;
        width: 100%;
        height: var(--bottom-nav-height); /* 使用变量设置高度 */
        padding: 0.4rem 0.5rem;
        background: rgba(10, 10, 20, 0.95); /* 使用更不透明的背景 */
        backdrop-filter: blur(8px);
       -webkit-backdrop-filter: blur(8px);
        display: flex;
        justify-content: space-around;
        align-items: center;
        transform: translateY(0);
        border-top: 1px solid var(--border-color);
        border-right: none;
        z-index: 9999; /* 提高 z-index */
        overflow-y: hidden;
        box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.3); /* 添加顶部阴影 */
    }

    .nav-item {
        margin: 0 0.2rem;
        padding: 0.4rem 0.3rem;
        flex: 1;
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        min-width: auto;
        border-radius: 8px;
        transform: none !important;
        border: none;
        background: transparent;
        position: static;
        overflow: visible;
        animation: none;
    }
    .nav-item::before, .nav-item::after {
         display: none;
    }

     .nav-item:hover {
        background: rgba(255, 255, 255, 0.1);
    }

     .nav-item.active {
        background: rgba(0, 180, 216, 0.15);
        border-left: none;
        border-top: 3px solid var(--primary);
        transform: none !important;
        box-shadow: none;
        color: var(--primary);
     }
     .nav-item.active .nav-icon {
         color: var(--secondary);
     }
     .nav-item.active .nav-text {
         color: var(--text-primary);
         font-weight: 600;
     }


    .nav-icon {
        font-size: 1.1rem;
        margin-right: 0;
        margin-bottom: 0.1rem;
        color: var(--text-secondary);
    }

    .nav-text {
        font-size: 0.65rem;
        letter-spacing: 0.3px;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
        max-width: 100%;
        font-weight: 400;
        color: var(--text-secondary);
    }

    .content-container {
        margin-left: 0;
        padding: 1.5rem 1rem;
        margin-top: var(--header-height);
        /* --- 确保内容不会被底部导航遮挡 --- */
        padding-bottom: calc(var(--bottom-nav-height) + 1.5rem); /* 底部内边距等于导航高度加上一些额外空间 */
        min-height: calc(100vh - var(--header-height) - var(--bottom-nav-height)); /* 调整最小高度计算 */
    }

    .playlist-section {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    /* --- 调整卡片和列表项的内边距适应较小屏幕 --- */
    .content-card {
        padding: 1.5rem 1rem;
        border-radius: 15px;
    }
    .playlist-period {
         padding: 1.5rem 1rem;
         margin: 1.5rem 0;
         border-radius: 20px;
    }
     .period-title {
        font-size: 1.4rem;
        padding-bottom: 0.6rem;
        margin-bottom: 1rem;
     }
     .period-number {
         width: 35px;
         height: 35px;
         font-size: 1rem;
         margin-right: 0.8rem;
     }
     .time-block {
        padding: 1.5rem 1rem;
        border-radius: 15px;
     }
    .song-list li {
         padding: 1rem;
         border-radius: 12px;
         margin: 0.6rem 0;
         flex-direction: row;
         align-items: center;
    }
}

/* Further adjustments for very small screens */
@media (max-width: 480px) {
    :root {
        --header-height: 60px;
        --bottom-nav-height: 55px; /* 极小屏幕下稍微减小底部导航高度 */
    }

     .main-header {
        padding: 0.6rem 0.8rem;
    }

    .glowing-title {
        font-size: 1.4rem;
    }
     .header-sub {
        font-size: 0.7rem;
        letter-spacing: 1px;
     }

    .content-container {
        padding: 1rem 0.8rem;
        /* 确保内容不会被底部导航遮挡 */
        padding-bottom: calc(var(--bottom-nav-height) + 1rem); /* 根据新的导航高度调整底部内边距 */
        min-height: calc(100vh - var(--header-height) - var(--bottom-nav-height)); /* 调整最小高度计算 */
    }

    .nav-icon {
        font-size: 1rem;
    }
    .nav-text {
        font-size: 0.6rem;
    }
     .nav-item.active {
         border-top-width: 2px;
     }

    .content-card, .playlist-period, .time-block {
        padding: 1rem 0.8rem;
        border-radius: 12px;
    }
    .song-list li {
        padding: 0.8rem;
        border-radius: 10px;
    }
     .period-title {
        font-size: 1.2rem;
     }
     .period-number {
         width: 30px;
         height: 30px;
         font-size: 0.9rem;
     }

     .song-title {
         font-size: 0.95rem;
     }
     .duration {
         font-size: 0.8rem;
     }
     .recommend-tag {
         font-size: 0.8rem;
         padding: 0.2rem 0.6rem;
     }
}

/* 触摸设备优化 */
@media (hover: none) and (pointer: coarse) {
    .nav-item:hover,
    .content-card:hover,
    .time-block:hover,
    .song-list li:hover {
        transform: none;
        box-shadow: none;
        filter: none;
    }
     .nav-item:hover {
         background: rgba(255, 255, 255, 0.1);
     }
     .content-card:hover {
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
     }
      .time-block:hover {
         box-shadow: none;
     }
     .song-list li:hover {
         background: rgba(255,255,255,0.04);
         transform: none !important;
         box-shadow: none;
     }
}