/* ============================================
   PC端适配样式 (屏幕宽度 > 992px)
   ============================================ */
@media screen and (min-width: 992px) {
    /* 全局背景 */
    body {
        background-color: #f5f7fa;
    }

    /* 主容器宽度限制 */
    .container,
    .main-content,
    .study-record,
    .thematic-details,
    .user-page,
    .login-container,
    .collect-page {
        max-width: 1200px;
        margin: 0 auto;
        background-color: #fff;
        box-shadow: 0 0 20px rgba(0, 0, 0, 0.05);
    }

    /* ========== 顶部导航 ========== */
    header {
        max-width: 1200px;
        margin: 0 auto;
        padding: 15px 20px;
        background: #fff;
        border-bottom: 1px solid #e5e5e5;
        display: flex;
        align-items: center;
        justify-content: space-between;
    }

    header .image {
        flex-shrink: 0;
    }

    header .image .img {
        height: 40px;
    }

    header form {
        width: 300px;
        position: relative;
    }

    header form input {
        width: 100%;
        padding: 10px 15px 10px 40px;
        border: 1px solid #e5e5e5;
        border-radius: 30px;
        font-size: 14px;
        background-color: #f8f9fa;
    }

    header form img {
        position: absolute;
        left: 12px;
        top: 50%;
        transform: translateY(-50%);
        width: 18px;
        opacity: 0.5;
    }

    /* ========== 课程网格布局 ========== */
    .goods,
    .collect-list,
    .grade-list {
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        gap: 20px;
        padding: 20px;
    }

    /* 课程卡片样式 */
    .item,
    .collect-item,
    .grade-item {
        border-radius: 12px;
        overflow: hidden;
        transition: transform 0.3s, box-shadow 0.3s;
        background: #fff;
        border: 1px solid #eef2f6;
        cursor: pointer;
    }

    .item:hover,
    .collect-item:hover,
    .grade-item:hover {
        transform: translateY(-5px);
        box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    }

    /* 封面图片 */
    .item .image img,
    .collect-item .cover,
    .grade-item .cover {
        width: 100%;
        height: 160px;
        object-fit: cover;
    }

    /* 文字区域 */
    .item .text,
    .collect-item .info,
    .grade-item .info {
        padding: 12px;
    }

    /* 标题 */
    .item .name,
    .collect-item .title,
    .grade-item .title {
        font-size: 16px;
        font-weight: 500;
        line-height: 1.4;
        color: #333;
        display: -webkit-box;
        -webkit-line-clamp: 2;
        -webkit-box-orient: vertical;
        overflow: hidden;
        margin-bottom: 8px;
    }

    /* 标签 */
    .item .label .cell {
        display: inline-block;
        font-size: 12px;
        color: #999;
        background: #f5f5f5;
        padding: 2px 8px;
        border-radius: 4px;
        margin-right: 5px;
    }

    /* 价格区域 */
    .price {
        margin-top: 12px;
        padding-top: 12px;
        border-top: 1px solid #f0f0f0;
        display: flex;
        align-items: center;
        justify-content: space-between;
    }

    .price .free {
        color: #2C8EFF;
        font-size: 14px;
    }

    .price .money {
        color: #ff4d4f;
        font-size: 18px;
        font-weight: 600;
    }

    .price .total {
        font-size: 12px;
        color: #999;
    }

    /* ========== 专题详情页 ========== */
    .swiper-conter {
        max-width: 800px;
        margin: 0 auto;
    }

    /* banner轮播 */
    .banner.slider-banner {
        max-width: 800px;
        margin: 0 auto;
        border-radius: 12px;
        overflow: hidden;
    }

    /* 专题标题 */
    .swiper .name {
        max-width: 800px;
        margin: 20px auto 0;
        font-size: 24px !important;
        font-weight: 600 !important;
    }

    /* 详情内容 */
    .content {
        max-width: 800px;
        margin: 0 auto;
        padding: 30px;
        font-size: 16px;
        line-height: 1.8;
        color: #555;
    }

    /* 目录列表 */
    .video_list {
        max-width: 800px;
        margin: 0 auto;
    }

    .catalogue li {
        padding: 15px;
        border-bottom: 1px solid #f0f0f0;
        display: flex;
        align-items: center;
        cursor: pointer;
        transition: background 0.2s;
    }

    .catalogue li:hover {
        background-color: #f8f9fa;
    }

    /* ========== 会员中心 ========== */
    .user-page {
        padding: 20px;
    }

    .user-section {
        background: linear-gradient(135deg, #2C8EFF 0%, #1a6fd9 100%);
        border-radius: 16px;
        padding: 30px;
        margin-bottom: 20px;
    }

    .tool-section,
    .serve-section {
        background: #fff;
        border-radius: 16px;
        padding: 20px;
        margin-bottom: 20px;
        border: 1px solid #eef2f6;
    }

    .tool-section .list,
    .serve-section .list {
        display: flex;
        flex-wrap: wrap;
        gap: 15px;
    }

    .tool-section .item,
    .serve-section .item {
        width: calc(25% - 15px);
        text-align: center;
        padding: 15px;
        border-radius: 12px;
        transition: background 0.2s;
    }

    .tool-section .item:hover,
    .serve-section .item:hover {
        background-color: #f8f9fa;
    }

    /* ========== 登录页 ========== */
    .login-container {
        max-width: 450px;
        margin: 50px auto;
        border-radius: 24px;
        padding: 40px;
        box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    }

    /* ========== 底部菜单 ========== */
    .store-menu {
        max-width: 1200px;
        margin: 0 auto;
        background: #fff;
        border-top: 1px solid #e5e5e5;
        padding: 20px;
        text-align: center;
    }

    /* ========== 右侧悬浮菜单 ========== */
    .quick {
        right: 30px !important;
        top: 50% !important;
        transform: translateY(-50%);
    }

    .quick .main {
        width: 50px;
        height: 50px;
        background: #2C8EFF;
        border-radius: 50%;
        display: flex;
        align-items: center;
        justify-content: center;
        cursor: pointer;
        box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    }

    .quick .main img {
        width: 30px;
    }
}

/* ============================================
   超大屏幕 (1440px以上)
   ============================================ */
@media screen and (min-width: 1440px) {
    .container,
    .main-content,
    .study-record,
    .thematic-details,
    .user-page {
        max-width: 1400px;
    }

    .goods,
    .collect-list,
    .grade-list {
        grid-template-columns: repeat(5, 1fr);
        gap: 24px;
    }
}

/* ============================================
   平板适配 (768px - 991px)
   ============================================ */
@media screen and (min-width: 768px) and (max-width: 991px) {
    .goods,
    .collect-list,
    .grade-list {
        grid-template-columns: repeat(3, 1fr);
        gap: 15px;
    }
}

/* ============================================
   小屏PC (992px - 1199px)
   ============================================ */
@media screen and (min-width: 992px) and (max-width: 1199px) {
    .goods,
    .collect-list,
    .grade-list {
        grid-template-columns: repeat(3, 1fr);
    }
}