/* ============================================
   NewsHub 资讯聚合 - 全局样式
   支持亮色/暗色模式 + 响应式设计
   ============================================ */

/* ---------- CSS 变量 ---------- */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-card: #ffffff;
    --bg-hover: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --accent-light: #dbeafe;
    --border: #e2e8f0;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 25px -3px rgba(0, 0, 0, 0.1);
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --transition: all 0.25s ease;
}

/* 暗色模式变量 */
[data-theme="dark"] {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --bg-hover: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;
    --accent: #60a5fa;
    --accent-hover: #3b82f6;
    --accent-light: #1e3a5f;
    --border: #334155;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 25px -3px rgba(0, 0, 0, 0.5);
}

/* ---------- 基础重置 ---------- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                 "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    transition: var(--transition);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 16px;
}

.hidden {
    display: none !important;
}

/* ---------- 导航栏 ---------- */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
    gap: 16px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 22px;
    font-weight: 700;
    color: var(--accent);
    flex-shrink: 0;
}

.logo-icon {
    font-size: 26px;
}

.logo-text {
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* 搜索框 */
.search-box {
    flex: 1;
    max-width: 720px;
    position: relative;
    display: flex;
}

.search-box input {
    width: 100%;
    padding: 10px 44px 10px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 14px;
    outline: none;
    transition: var(--transition);
}

.search-box input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-light);
}

.search-box input::placeholder {
    color: var(--text-muted);
}

#searchBtn {
    position: absolute;
    right: 4px;
    top: 50%;
    transform: translateY(-50%);
    padding: 6px 12px;
    border: none;
    background: transparent;
    cursor: pointer;
    font-size: 16px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

#searchBtn:hover {
    background: var(--bg-hover);
}

/* 导航操作区 */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 8px;
}

.theme-toggle,
.mobile-menu-btn {
    width: 40px;
    height: 40px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    cursor: pointer;
    font-size: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
}

.theme-toggle:hover,
.mobile-menu-btn:hover {
    background: var(--bg-hover);
    border-color: var(--accent);
}

.theme-icon-light { display: inline; }
.theme-icon-dark { display: none; }
[data-theme="dark"] .theme-icon-light { display: none; }
[data-theme="dark"] .theme-icon-dark { display: inline; }

.mobile-menu-btn {
    display: none;
}

/* ---------- 分类标签 ---------- */
.categories {
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}

.categories-inner {
    display: flex;
    gap: 8px;
    padding: 12px 16px;
    overflow-x: auto;
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.categories-inner::-webkit-scrollbar {
    display: none;
}

.category-btn {
    flex-shrink: 0;
    padding: 8px 18px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    white-space: nowrap;
    transition: var(--transition);
}

.category-btn:hover {
    background: var(--bg-hover);
    color: var(--text-primary);
}

.category-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

[data-theme="dark"] .category-btn.active {
    color: #0f172a;
}

/* ---------- 主内容区 ---------- */
.main-content {
    padding: 24px 16px 80px;
    min-height: calc(100vh - 64px);
}

/* 状态栏 */
.status-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    margin-bottom: 20px;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    font-size: 13px;
    color: var(--text-secondary);
    flex-wrap: wrap;
    gap: 8px;
}

#lastUpdate {
    color: var(--accent);
    font-weight: 500;
}

/* 加载动画 */
.loading {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 80px 0;
    gap: 16px;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* 错误提示 */
.error-msg,
.empty-state {
    text-align: center;
    padding: 80px 20px;
    color: var(--text-secondary);
}

.error-msg p:first-child,
.empty-state p:first-child {
    font-size: 24px;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.empty-hint {
    font-size: 14px;
    color: var(--text-muted);
}

.btn-primary {
    margin-top: 20px;
    padding: 10px 28px;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

[data-theme="dark"] .btn-primary {
    color: #0f172a;
}

.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

/* ---------- 资讯卡片网格 ---------- */
.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.news-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.news-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent);
}

.card-image {
    position: relative;
    width: 100%;
    padding-top: 56.25%;
    background: linear-gradient(135deg, var(--accent-light), var(--bg-secondary));
    overflow: hidden;
}

.card-image img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.4s ease;
}

.news-card:hover .card-image img {
    transform: scale(1.05);
}

.card-image-placeholder {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    background: linear-gradient(135deg, var(--accent-light), var(--bg-secondary));
}

.card-category {
    position: absolute;
    top: 12px;
    left: 12px;
    padding: 4px 12px;
    background: rgba(59, 130, 246, 0.95);
    color: #fff;
    font-size: 12px;
    font-weight: 600;
    border-radius: 999px;
    backdrop-filter: blur(4px);
}

.card-body {
    padding: 16px;
    display: flex;
    flex-direction: column;
    flex: 1;
    gap: 10px;
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    line-height: 1.45;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.news-card:hover .card-title {
    color: var(--accent);
}

.card-description {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.55;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    flex: 1;
}

.card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 8px;
    border-top: 1px solid var(--border);
    margin-top: auto;
}

.card-source {
    font-size: 12px;
    color: var(--accent);
    font-weight: 500;
    max-width: 60%;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.card-date {
    font-size: 12px;
    color: var(--text-muted);
    flex-shrink: 0;
}

/* ---------- 分页 ---------- */
.pagination {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 8px;
    padding: 20px 0;
    flex-wrap: wrap;
}

.page-btn {
    padding: 8px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
}

.page-btn:hover:not(:disabled) {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

[data-theme="dark"] .page-btn:hover:not(:disabled) {
    color: #0f172a;
}

.page-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.page-numbers {
    display: flex;
    gap: 4px;
    flex-wrap: wrap;
    justify-content: center;
}

.page-num {
    min-width: 38px;
    height: 38px;
    padding: 0 10px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.page-num:hover {
    background: var(--bg-hover);
}

.page-num.active {
    background: var(--accent);
    color: #fff;
    border-color: var(--accent);
}

[data-theme="dark"] .page-num.active {
    color: #0f172a;
}

.page-ellipsis {
    padding: 0 8px;
    color: var(--text-muted);
    display: flex;
    align-items: center;
}

/* ---------- 页脚 ---------- */
.footer {
    background: var(--bg-primary);
    border-top: 1px solid var(--border);
    padding: 24px 0;
    transition: var(--transition);
}

.footer-inner {
    text-align: center;
    color: var(--text-secondary);
    font-size: 13px;
}

.footer-inner p {
    margin: 4px 0;
}

.footer-hint {
    color: var(--text-muted);
    font-size: 12px;
}

/* ---------- 返回顶部 ---------- */
.back-to-top {
    position: fixed;
    right: 20px;
    bottom: 24px;
    width: 44px;
    height: 44px;
    border: none;
    border-radius: 50%;
    background: var(--accent);
    color: #fff;
    font-size: 20px;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    z-index: 99;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
}

[data-theme="dark"] .back-to-top {
    color: #0f172a;
}

.back-to-top:not(.hidden) {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
}

/* ============================================
   响应式适配 - 平板 (≤900px)
   ============================================ */
@media (max-width: 900px) {
    .news-grid {
        grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
        gap: 16px;
    }
}

/* ============================================
   响应式适配 - 手机 (≤640px)
   ============================================ */
@media (max-width: 640px) {
    .nav-inner {
        height: 56px;
        gap: 10px;
    }

    .search-box {
        max-width: none;
    }

    .search-box input {
        padding: 8px 40px 8px 12px;
        font-size: 14px;
    }

    .mobile-menu-btn {
        display: none;
    }

    .main-content {
        padding: 16px 12px 60px;
    }

    .status-bar {
        padding: 10px 12px;
        font-size: 12px;
        flex-direction: column;
        align-items: flex-start;
    }

    .news-grid {
        grid-template-columns: 1fr;
        gap: 14px;
    }

    .card-title {
        font-size: 15px;
    }

    .card-description {
        font-size: 13px;
        -webkit-line-clamp: 2;
    }

    .card-body {
        padding: 14px;
    }

    .page-btn {
        padding: 6px 12px;
        font-size: 13px;
    }

    .page-num {
        min-width: 34px;
        height: 34px;
        font-size: 13px;
    }

    .back-to-top {
        right: 14px;
        bottom: 16px;
        width: 40px;
        height: 40px;
        font-size: 18px;
    }
}

/* 超小屏幕 */
@media (max-width: 380px) {
    .category-btn {
        padding: 6px 14px;
        font-size: 13px;
    }

    .card-title {
        font-size: 14px;
    }
}