/* ==================== GossHub 公共基础样式 ==================== */
/* #1 CSS外置 + #2 统一CSS变量 + #8 暗色模式 */

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

:root {
    --primary: #1E40AF;
    --primary-light: #3B82F6;
    --primary-lighter: #DBEAFE;
    --primary-dark: #1E3A8A;
    --bg: #F8FAFC;
    --white: #FFFFFF;
    --text: #1E293B;
    --text-secondary: #64748B;
    --border: #E2E8F0;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.05), 0 2px 4px rgba(0,0,0,0.03);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.06), 0 4px 6px rgba(0,0,0,0.04);
    --radius: 12px;
    --radius-sm: 8px;
    --container: 1260px;
    --gutter: 20px;
    --success: #10B981;
    --warning: #F59E0B;
    --danger: #EF4444;
    --wechat: #07C160;
    --highlight: #FEF08A;
    --highlight-dark: #854D0E;
}

/* #8 暗色模式 — 优化对比度与层次感 */
[data-theme="dark"] {
    --primary: #60A5FA;
    --primary-light: #93C5FD;
    --primary-lighter: #1E3A5F;
    --primary-dark: #3B82F6;
    --bg: #0B1120;
    --white: #1A2332;
    --text: #E2E8F0;
    --text-secondary: #94A3B8;
    --border: #2D3B4F;
    --shadow: 0 1px 3px rgba(0,0,0,0.4), 0 1px 2px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.4), 0 2px 4px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.4), 0 4px 6px rgba(0,0,0,0.3);
    --success: #34D399;
    --warning: #FBBF24;
    --danger: #F87171;
    --wechat: #07C160;
    --highlight: #854D0E;
    --highlight-dark: #FEF08A;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

/* ========== 主题切换按钮 ========== */
.theme-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 10px;
    border: 1.5px solid var(--border);
    background: var(--white);
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 16px;
    transition: all 0.2s;
}
.theme-toggle:hover {
    border-color: var(--primary-light);
    color: var(--primary-light);
    background: var(--primary-lighter);
}

/* ========== 页脚 (#7 完善) ========== */
.site-footer {
    background: var(--white);
    border-top: 1px solid var(--border);
    padding: 32px 0 24px;
    margin-top: 40px;
    color: var(--text-secondary);
    font-size: 13px;
}
[data-theme="dark"] .site-footer {
    background: #0E1525;
    border-top-color: rgba(96,165,250,0.08);
}
.site-footer a { color: var(--primary-light); text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }
.footer-inner {
    max-width: var(--container);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}
.footer-links {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
    justify-content: center;
}
.footer-links a {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    font-size: 13px;
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}
.footer-links a:hover { color: var(--primary-light); }
.footer-copy {
    font-size: 12px;
    color: var(--text-secondary);
    opacity: 0.7;
}

/* ========== 标签 ========== */
.tag-list {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-top: 8px;
}
.tag-item {
    font-size: 11px;
    background: var(--primary-lighter);
    color: var(--text-secondary);
    padding: 2px 8px;
    border-radius: 4px;
}

/* ========== 空状态 ========== */
.empty-state {
    text-align: center;
    padding: 60px 24px;
    color: var(--text-secondary);
}
.empty-state i {
    font-size: 48px;
    margin-bottom: 16px;
    opacity: 0.4;
}
.empty-state h3 {
    font-size: 18px;
    margin-bottom: 8px;
    color: var(--text);
}

/* ========== #25 可访问性 ========== */

/* Skip Link — 键盘用户跳过导航直达主内容 */
.skip-link {
    position: absolute;
    top: -100px;
    left: 16px;
    z-index: 10000;
    background: var(--primary);
    color: #fff;
    padding: 10px 20px;
    border-radius: 0 0 8px 8px;
    font-size: 14px;
    font-weight: 600;
    text-decoration: none;
    transition: top 0.2s;
}
.skip-link:focus {
    top: 0;
    outline: 3px solid var(--primary-light);
    outline-offset: 2px;
}

/* 屏幕阅读器专用隐藏 */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    border: 0;
}

/* #25 键盘焦点可见性 — 仅键盘操作时显示焦点框 */
:focus {
    outline: 3px solid var(--primary-light);
    outline-offset: 2px;
}
/* 鼠标点击时隐藏焦点框，避免视觉干扰 */
body.using-mouse :focus {
    outline: none;
}
/* 始终为跳转链接保留焦点 */
.skip-link:focus {
    outline: 3px solid var(--primary-light);
    outline-offset: 2px;
}

/* #25 高对比度焦点环 — 适用于交互元素 */
a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible,
textarea:focus-visible,
[tabindex]:focus-visible {
    outline: 3px solid var(--primary-light);
    outline-offset: 2px;
    border-radius: 4px;
}
body.using-mouse a:focus-visible,
body.using-mouse button:focus-visible,
body.using-mouse input:focus-visible,
body.using-mouse select:focus-visible,
body.using-mouse textarea:focus-visible {
    outline: none;
}

/* #25 暗色模式下增强文本对比度 */
[data-theme="dark"] .site-footer,
[data-theme="dark"] .footer-copy {
    color: #94A3B8;
}
[data-theme="dark"] .tag-item {
    color: #CBD5E1;
    background: rgba(96, 165, 250, 0.12);
}
[data-theme="dark"] .empty-state p {
    color: #94A3B8;
}
/* 暗色模式主题切换按钮 */
[data-theme="dark"] .theme-toggle {
    background: rgba(96, 165, 250, 0.1);
    border-color: rgba(96, 165, 250, 0.25);
    color: #FBBF24;
}
[data-theme="dark"] .theme-toggle:hover {
    background: rgba(96, 165, 250, 0.2);
    border-color: var(--primary);
    color: #FCD34D;
}

/* ========== 响应式通用 ========== */
@media (max-width: 1280px) {
    .container { padding-left: 24px; padding-right: 24px; }
}
@media (max-width: 768px) {
    .footer-inner { padding: 0 16px; }
}