/* 下载页面样式 */
:root {
    --primary-color: #0050a0;
    --text-dark: #2d3748;
    --text-light: #718096;
    --border-color: #e2e8f0;
    --bg-light: #f7fafc;
    --success-color: #48bb78;
    --warning-color: #ed8936;
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.15);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    background-color: #f5f5f5;
}

/* 主要内容区 */
.main-content {
    padding: 3rem 0;
    min-height: calc(100vh - 400px);
    background-color: #f5f5f5;
}

/* 下载页面头部 */
.download-header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInDown 0.6s ease-out;
}

.download-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.download-subtitle {
    font-size: 1.1rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto;
}

/* 下载区域 */
.download-section {
    background: #fff;
    border-radius: 8px;
    box-shadow: var(--shadow-md);
    overflow: hidden;
    animation: fadeInUp 0.6s ease-out 0.2s both;
}

/* 下载表格 */
.download-table-wrapper {
    overflow-x: auto;
}

.download-table {
    width: 100%;
    border-collapse: collapse;
    margin: 0;
}

.download-table thead {
    background-color: var(--primary-color);
    color: #fff;
}

.download-table th {
    padding: 1.25rem;
    font-weight: 600;
    text-align: left;
    font-size: 0.95rem;
    letter-spacing: 0.5px;
}

.download-table tbody tr {
    border-bottom: 1px solid var(--border-color);
}

.download-table tbody tr:hover {
    background-color: transparent;
}

.download-table td {
    padding: 1.25rem;
    vertical-align: middle;
    font-size: 0.95rem;
}

.filename-cell {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-dark);
    font-weight: 500;
}

.filename-cell i {
    color: var(--primary-color);
    font-size: 1.2rem;
}

.size-cell,
.date-cell {
    color: var(--text-light);
}

.action-cell {
    text-align: center;
}

/* 下载按钮 */
.btn-download-action {
    padding: 0.6rem 1.5rem;
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    border-radius: 4px;
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-download-action:hover {
    background-color: #003d7a;
}

.btn-download-action:active {
    background-color: #002d5a;
}

.btn-download-action:disabled {
    background-color: #999;
    cursor: not-allowed;
}

/* 无文件提示 */
.no-files-message {
    padding: 4rem 2rem;
    text-align: center;
    color: var(--text-light);
}

.no-files-icon {
    font-size: 4rem;
    color: var(--border-color);
    margin-bottom: 1rem;
}

.no-files-message p {
    font-size: 1.1rem;
    margin: 0;
}

/* 返回顶部按钮 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background-color: var(--primary-color);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    text-decoration: none;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s ease, background-color 0.3s ease;
    z-index: 999;
    box-shadow: var(--shadow-lg);
}

.back-to-top:hover {
    background-color: #003d7a;
}

/* 响应式设计 - 平板 */
@media (max-width: 991px) {
    .download-title {
        font-size: 2rem;
    }

    .download-table th,
    .download-table td {
        padding: 1rem;
        font-size: 0.9rem;
    }

    .filename-cell {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* 响应式设计 - 手机 */
@media (max-width: 767px) {
    .main-content {
        padding: 2rem 0;
    }

    .download-header {
        margin-bottom: 2rem;
    }

    .download-title {
        font-size: 1.75rem;
    }

    .download-subtitle {
        font-size: 1rem;
    }

    .download-table {
        font-size: 0.85rem;
    }

    .download-table th,
    .download-table td {
        padding: 0.75rem;
    }

    .download-table th {
        font-size: 0.8rem;
    }

    .filename-cell {
        gap: 0.5rem;
    }

    .filename-cell i {
        font-size: 1rem;
    }

    .btn-download-action {
        padding: 0.5rem 1rem;
        font-size: 0.85rem;
    }

    .back-to-top {
        width: 45px;
        height: 45px;
        bottom: 20px;
        right: 20px;
        font-size: 1rem;
    }
}

@media (max-width: 575px) {
    .download-title {
        font-size: 1.5rem;
    }

    .download-subtitle {
        font-size: 0.95rem;
    }

    .download-table-wrapper {
        border-radius: 0;
    }

    .download-table th,
    .download-table td {
        padding: 0.6rem;
    }

    .download-table th {
        font-size: 0.75rem;
    }

    .download-table td {
        font-size: 0.8rem;
    }

    .btn-download-action {
        padding: 0.4rem 0.8rem;
        font-size: 0.8rem;
    }

    .no-files-icon {
        font-size: 3rem;
    }

    .no-files-message p {
        font-size: 1rem;
    }
}

/* 动画效果 */
@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}