/* ============================================
 * seo-optimized.css - SEO & Performance Optimizations
 * sllu.cn - 短链接服务平台优化样式
 * ============================================ */

/* --- 1. 语义化标题样式 (SEO: 提升内容可读性) --- */
.section-title,
.title {
    font-size: 2.5rem;
    font-weight: 700;
    color: #12263C;
    text-align: center;
    padding-top: 100px;
    margin-bottom: 10px;
}

.subtitle,
.intro {
    font-size: 1.125rem;
    text-align: center;
    color: #62717F;
    margin-top: 1rem;
    margin-bottom: 2rem;
}

/* --- 2. 响应式优化 --- */
@media (max-width: 768px) {
    .main { width: 100% !important; padding: 0 15px; }
    .header { height: auto; padding: 10px 0; }
    .menu { float: none; text-align: center; height: auto; }
    .menu a { display: inline-block; font-size: 14px; margin-right: 15px; }
    .menu button { padding: 6px 15px; font-size: 14px; }
    .banner { height: auto; padding: 40px 20px; }
    .banner .banner_img { margin-top: 20px; max-width: 80%; }
    .input .url { width: calc(100% - 150px); font-size: 16px; height: 48px; }
    .input .search-btn { width: 130px; font-size: 16px; height: 48px; line-height: 48px; }
    .box { width: 50%; }
    .bbox { width: 100%; }
    .bbox .xtitle { font-size: 28px; margin-top: 30px; }
    .bbox .xtitle2 { font-size: 18px; margin-top: 20px; }
    .bbox .xintro { font-size: 15px; }
    .footer { height: auto; padding: 50px 20px; }
    .l1, .l2, .l3 { width: 100%; margin-bottom: 30px; }
    .short_box { width: 100%; }
    .ntitle { font-size: 28px; padding-top: 40px; }
    .logos img { width: 80px; margin-right: 10px; }
}

@media (max-width: 480px) {
    .box { width: 50%; }
    .box img { max-width: 70px; }
    .box .btitle { font-size: 14px; }
    .box .bintro { font-size: 12px; }
    .ntitle { font-size: 22px; }
    .bbutton { padding: 8px 30px; font-size: 15px; }
}

/* --- 3. 图片优化 (Performance: 防止布局偏移) --- */
img {
    max-width: 100%;
    height: auto;
}

img[loading] {
    aspect-ratio: attr(width) / attr(height);
}

/* 懒加载图片占位 */
img[loading="lazy"] {
    background: #f0f0f0;
    min-height: 100px;
}

/* --- 4. 语义化内容标记 --- */
/* 面包屑导航 */
.breadcrumb-seo {
    font-size: 14px;
    color: #666;
    padding: 10px 0;
    margin-bottom: 15px;
}

.breadcrumb-seo a {
    color: #4587FF;
    text-decoration: none;
}

.breadcrumb-seo a:hover {
    text-decoration: underline;
}

.breadcrumb-seo span {
    margin: 0 8px;
    color: #999;
}

/* --- 5. 可访问性增强 --- */
a:focus,
button:focus,
input:focus,
textarea:focus,
select:focus {
    outline: none !important;
    outline-offset: 0 !important;
}

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

/* --- 6. 打印样式 --- */
@media print {
    .header, .menu, .footer, .banner2, #global-toolbar, .search-btn,
    .copy-button, .login_btn, .bbutton, .nav, script {
        display: none !important;
    }
    body { font-size: 14px; line-height: 1.6; color: #000; background: #fff; }
    a { color: #000; text-decoration: underline; }
    .main { width: 100%; max-width: 100%; }
}

/* --- 7. 内容段落优化 (SEO: 提升可读性) --- */
.seo-content h2 {
    font-size: 28px;
    color: #12263C;
    margin: 30px 0 15px;
    font-weight: bold;
}

.seo-content h3 {
    font-size: 22px;
    color: #4587FF;
    margin: 20px 0 10px;
}

.seo-content p {
    font-size: 16px;
    line-height: 1.8;
    color: #333;
    margin-bottom: 15px;
}

.seo-content ul,
.seo-content ol {
    padding-left: 20px;
    margin-bottom: 15px;
}

.seo-content li {
    font-size: 16px;
    line-height: 1.8;
    margin-bottom: 5px;
}

/* --- 8. 链接下划线优化 --- */
.seo-content a,
article a {
    text-decoration: underline;
    color: #4587FF;
}

.seo-content a:hover,
article a:hover {
    color: #0056b3;
}

/* --- 9. 表格优化 --- */
.table-responsive {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

table {
    width: 100%;
    border-collapse: collapse;
    margin: 15px 0;
}

th {
    background: #f7f7f7;
    font-weight: bold;
    text-align: left;
    padding: 12px;
    border-bottom: 2px solid #ddd;
}

td {
    padding: 10px 12px;
    border-bottom: 1px solid #eee;
}

/* --- 10. 性能优化: 动画禁用 (用户偏好) --- */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* --- 11. 长URL内容优化 --- */
.long_url,
.long-wrap {
    word-break: break-all;
    overflow-wrap: break-word;
    max-width: 100%;
}

/* --- 12. 响应式表单 --- */
@media (max-width: 768px) {
    .input .url2 { width: 100% !important; }
    .input .url3 { width: 100% !important; display: block !important; margin-bottom: 10px; }
    .input .search-view { display: block !important; text-align: center; }
    .input .search-view > div { display: block !important; width: 100% !important; }
    .input .search-view select { width: 100% !important; border-radius: 10px !important; margin-bottom: 10px; }
    textarea[name="url"] { width: 100% !important; height: 200px !important; }
}