/* ===== CSS Variables ===== */
:root {
    --bg: #F0F4F5;
    --white: #FFFFFF;
    --red: #F44336;
    --red-hover: #D32F2F;
    --text: #2C3E50;
    --text-secondary: #64748B;
    --text-light: #94A3B8;
    --border: #E2E8F0;
    --card-shadow: 0 4px 12px 0 rgba(52,73,94,.1);
    --card-shadow-hover: 0 8px 24px 0 rgba(52,73,94,.16);
    --nav-height: 60px;
    --mobile-bottom-height: 56px;
    --max-width: 1280px;
    --radius: 10px;
    --radius-sm: 6px;
    --transition: 0.25s ease;
}

/* ===== Reset ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
    padding-top: var(--nav-height);
    padding-bottom: 80px;
}
a { text-decoration: none; color: inherit; }
ul, ol { list-style: none; }
img { max-width: 100%; display: block; }
input, button, select { font-family: inherit; font-size: inherit; outline: none; border: none; }

/* ===== Container ===== */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 20px; }

/* ===== Top Navigation ===== */
.top-nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    height: var(--nav-height); background: var(--white);
    box-shadow: 0 2px 8px rgba(0,0,0,.06);
    display: flex; align-items: center;
}
.nav-inner {
    max-width: var(--max-width); width: 100%; margin: 0 auto;
    padding: 0 20px; display: flex; align-items: center; gap: 0;
    height: 100%;
}
.nav-logo {
    font-size: 1.25rem; font-weight: 700; color: var(--red);
    white-space: nowrap; margin-right: 24px;
    display: flex; align-items: center; gap: 6px;
}
.nav-logo .logo-icon { font-size: 1.5rem; }
.nav-links { display: flex; align-items: center; gap: 4px; flex: 1; }
.nav-links a {
    padding: 8px 14px; border-radius: var(--radius-sm);
    font-size: 0.9rem; color: var(--text-secondary);
    transition: var(--transition); white-space: nowrap;
}
.nav-links a:hover, .nav-links a.active { color: var(--red); background: #FFF5F5; }
.nav-dropdown { position: relative; }
.nav-dropdown > a::after { content: '▼'; font-size: 0.6rem; margin-left: 4px; }
.nav-dropdown-menu {
    position: absolute; top: 100%; left: 0; min-width: 150px;
    background: var(--white); border-radius: var(--radius-sm);
    box-shadow: var(--card-shadow); opacity: 0; visibility: hidden;
    transform: translateY(8px); transition: var(--transition); z-index: 1001;
    padding: 6px 0;
}
.nav-dropdown:hover .nav-dropdown-menu { opacity: 1; visibility: visible; transform: translateY(0); }
.nav-dropdown-menu a { display: block; padding: 10px 18px; font-size: 0.85rem; }
.nav-search {
    display: flex; align-items: center; background: var(--bg);
    border-radius: 20px; padding: 0 14px; height: 36px; width: 200px;
    margin: 0 12px;
}
.nav-search input { background: transparent; width: 100%; font-size: 0.85rem; color: var(--text); }
.nav-search input::placeholder { color: var(--text-light); }
.nav-search button { background: none; cursor: pointer; color: var(--text-light); font-size: 1rem; padding: 0 4px; }
.nav-login { margin-left: 8px; }
.nav-login a {
    padding: 7px 18px; background: var(--red); color: #fff;
    border-radius: 20px; font-size: 0.85rem; font-weight: 500;
    transition: var(--transition); white-space: nowrap;
}
.nav-login a:hover { background: var(--red-hover); }
.nav-toggle { display: none; font-size: 1.5rem; cursor: pointer; color: var(--text); padding: 4px; }

/* ===== Hero Section ===== */
.hero {
    background: linear-gradient(135deg, #F44336 0%, #E53935 50%, #C62828 100%);
    color: #fff; padding: 50px 0 40px; text-align: center;
}
.hero h1 { font-size: 2rem; font-weight: 700; margin-bottom: 10px; }
.hero p { font-size: 1.05rem; opacity: 0.9; max-width: 640px; margin: 0 auto 20px; }
.hero-tags { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.hero-tags span {
    padding: 6px 16px; background: rgba(255,255,255,.2); border-radius: 20px;
    font-size: 0.85rem; cursor: pointer; transition: var(--transition);
}
.hero-tags span:hover { background: rgba(255,255,255,.35); }

/* ===== Dynamic Scroll Bar ===== */
.dynamic-scroll {
    background: var(--white); padding: 12px 20px;
    border-radius: var(--radius); margin: 20px auto; max-width: var(--max-width);
    box-shadow: var(--card-shadow); overflow: hidden; position: relative;
}
.dynamic-scroll-inner {
    display: flex; gap: 40px; white-space: nowrap;
    animation: scrollLeft 40s linear infinite;
}
.dynamic-scroll-inner .item { font-size: 0.85rem; color: var(--text-secondary); display: flex; align-items: center; gap: 6px; }
.dynamic-scroll-inner .item .dot { width: 6px; height: 6px; background: var(--red); border-radius: 50%; flex-shrink: 0; }
@keyframes scrollLeft {
    0% { transform: translateX(0); }
    100% { transform: translateX(-50%); }
}

/* ===== Section Title ===== */
.section-header {
    display: flex; align-items: center; justify-content: space-between;
    margin: 32px 0 18px;
}
.section-header h2 { font-size: 1.35rem; font-weight: 700; position: relative; padding-left: 14px; }
.section-header h2::before { content: ''; position: absolute; left: 0; top: 4px; bottom: 4px; width: 4px; background: var(--red); border-radius: 2px; }

/* ===== Filter Bar ===== */
.filter-bar {
    display: flex; align-items: center; flex-wrap: wrap; gap: 10px;
    margin-bottom: 18px; padding: 14px 18px; background: var(--white);
    border-radius: var(--radius); box-shadow: var(--card-shadow);
}
.filter-tags { display: flex; gap: 6px; flex-wrap: wrap; }
.filter-tag {
    padding: 6px 16px; border-radius: 20px; font-size: 0.85rem;
    cursor: pointer; background: var(--bg); color: var(--text-secondary);
    transition: var(--transition); border: 1px solid transparent;
}
.filter-tag:hover { color: var(--red); border-color: var(--red); }
.filter-tag.active { background: var(--red); color: #fff; border-color: var(--red); }
.filter-sort { display: flex; gap: 6px; margin-left: auto; }
.filter-sort .sort-btn {
    padding: 6px 14px; border-radius: 20px; font-size: 0.85rem;
    cursor: pointer; background: var(--bg); color: var(--text-secondary);
    transition: var(--transition);
}
.filter-sort .sort-btn:hover, .filter-sort .sort-btn.active { background: var(--red); color: #fff; }

/* ===== Service Cards Grid ===== */
.service-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 18px;
}
.service-card {
    background: var(--white); border-radius: var(--radius);
    box-shadow: var(--card-shadow); overflow: hidden;
    transition: var(--transition); cursor: pointer; position: relative;
    display: flex; flex-direction: column;
}
.service-card:hover { box-shadow: var(--card-shadow-hover); transform: translateY(-3px); }
.service-card .card-badge {
    position: absolute; top: 10px; right: 10px; z-index: 2;
    padding: 3px 10px; border-radius: 12px; font-size: 0.72rem;
    color: #fff; font-weight: 500;
}
.badge-hot { background: #FF6D00; }
.badge-free { background: #4CAF50; }
.badge-paid { background: var(--red); }
.badge-vip { background: #7C4DFF; }
.badge-new { background: #2196F3; }
.service-card .card-icon {
    height: 120px; display: flex; align-items: center; justify-content: center;
    font-size: 3rem; color: var(--red);
}
.card-icon-tech { background: linear-gradient(135deg, #E3F2FD, #BBDEFB); }
.card-icon-design { background: linear-gradient(135deg, #FCE4EC, #F8BBD0); }
.card-icon-marketing { background: linear-gradient(135deg, #FFF3E0, #FFE0B2); }
.card-icon-data { background: linear-gradient(135deg, #E8F5E9, #C8E6C9); }
.card-icon-tools { background: linear-gradient(135deg, #F3E5F5, #E1BEE7); }
.card-icon-edu { background: linear-gradient(135deg, #E0F7FA, #B2EBF2); }
.service-card .card-body { padding: 16px 18px; flex: 1; display: flex; flex-direction: column; }
.service-card .card-cat {
    font-size: 0.75rem; color: var(--red); font-weight: 500; margin-bottom: 6px;
}
.service-card .card-title { font-size: 1.05rem; font-weight: 600; margin-bottom: 6px; }
.service-card .card-desc { font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 12px; flex: 1; }
.service-card .card-footer {
    display: flex; align-items: center; justify-content: space-between;
    padding-top: 10px; border-top: 1px solid var(--border);
}
.service-card .card-price { font-size: 1.1rem; font-weight: 700; color: var(--red); }
.service-card .card-price.free { color: #4CAF50; }
.service-card .card-stats { font-size: 0.78rem; color: var(--text-light); display: flex; gap: 10px; }

/* ===== Pagination ===== */
.pagination {
    display: flex; justify-content: center; align-items: center; gap: 6px;
    margin: 30px 0 20px;
}
.pagination a, .pagination span {
    width: 38px; height: 38px; display: flex; align-items: center; justify-content: center;
    border-radius: var(--radius-sm); font-size: 0.9rem; cursor: pointer;
    background: var(--white); color: var(--text-secondary);
    box-shadow: 0 1px 3px rgba(0,0,0,.06); transition: var(--transition);
}
.pagination a:hover { color: var(--red); }
.pagination a.active { background: var(--red); color: #fff; }
.pagination .page-dots { background: transparent; box-shadow: none; cursor: default; }

/* ===== Footer ===== */
.footer {
    background: #1a1a2e; color: #ccc; padding: 40px 0 20px; margin-top: 40px;
}
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 30px; margin-bottom: 30px; }
.footer h3 { color: #fff; font-size: 1rem; margin-bottom: 14px; }
.footer p { font-size: 0.85rem; line-height: 1.8; }
.footer a { font-size: 0.85rem; display: block; padding: 4px 0; color: #aaa; transition: var(--transition); }
.footer a:hover { color: var(--red); }
.footer-bottom {
    border-top: 1px solid rgba(255,255,255,.1); padding-top: 18px;
    text-align: center; font-size: 0.8rem; color: #888;
}

/* ===== Floating Button ===== */
.float-promo {
    position: fixed; bottom: 100px; right: 24px; z-index: 999;
    width: 56px; height: 56px; border-radius: 50%; background: var(--red);
    color: #fff; display: flex; align-items: center; justify-content: center;
    box-shadow: 0 4px 16px rgba(244,67,54,.4); cursor: pointer;
    animation: floatPulse 2s ease-in-out infinite; font-size: 0.75rem;
    font-weight: 600; text-align: center; line-height: 1.2;
}
@keyframes floatPulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.08); }
}

/* ===== Mobile Bottom Bar ===== */
.mobile-bottom-bar {
    display: none; position: fixed; bottom: 0; left: 0; right: 0; z-index: 1000;
    height: var(--mobile-bottom-height); background: var(--white);
    box-shadow: 0 -2px 8px rgba(0,0,0,.08);
    padding: 0 8px;
}
.mobile-bottom-bar .mb-inner { display: flex; align-items: center; height: 100%; }
.mobile-bottom-bar a {
    flex: 1; display: flex; flex-direction: column; align-items: center;
    font-size: 0.68rem; color: var(--text-light); padding: 4px 0;
}
.mobile-bottom-bar a .mb-icon { font-size: 1.2rem; margin-bottom: 2px; }
.mobile-bottom-bar a.active { color: var(--red); }

/* ===== Overlay ===== */
.nav-overlay { display: none; position: fixed; inset: 0; z-index: 998; background: rgba(0,0,0,.4); }

/* ===== Login Page ===== */
.login-page { display: flex; justify-content: center; align-items: center; min-height: calc(100vh - var(--nav-height) - 80px); padding: 40px 20px; }
.login-card {
    background: var(--white); border-radius: var(--radius); box-shadow: var(--card-shadow);
    width: 100%; max-width: 420px; padding: 36px 32px;
}
.login-card h2 { text-align: center; font-size: 1.5rem; margin-bottom: 6px; }
.login-card .login-sub { text-align: center; color: var(--text-secondary); font-size: 0.85rem; margin-bottom: 24px; }
.form-group { margin-bottom: 18px; }
.form-group label { display: block; font-size: 0.85rem; font-weight: 500; margin-bottom: 6px; color: var(--text); }
.form-group input {
    width: 100%; padding: 10px 14px; border: 1px solid var(--border); border-radius: var(--radius-sm);
    font-size: 0.9rem; transition: var(--transition);
}
.form-group input:focus { border-color: var(--red); box-shadow: 0 0 0 3px rgba(244,67,54,.1); }
.form-options { display: flex; justify-content: space-between; align-items: center; font-size: 0.8rem; margin-bottom: 18px; }
.form-options a { color: var(--red); }
.btn-primary {
    width: 100%; padding: 12px; background: var(--red); color: #fff;
    border-radius: var(--radius-sm); font-size: 0.95rem; font-weight: 600;
    cursor: pointer; transition: var(--transition);
}
.btn-primary:hover { background: var(--red-hover); }
.login-switch { text-align: center; margin-top: 16px; font-size: 0.85rem; color: var(--text-secondary); }
.login-switch a { color: var(--red); font-weight: 500; }
.login-tabs { display: flex; margin-bottom: 24px; border-bottom: 2px solid var(--border); }
.login-tab {
    flex: 1; text-align: center; padding: 10px; cursor: pointer; font-weight: 500;
    color: var(--text-secondary); transition: var(--transition); font-size: 0.95rem;
}
.login-tab.active { color: var(--red); border-bottom: 2px solid var(--red); margin-bottom: -2px; }
.social-login { display: flex; gap: 12px; margin-top: 18px; justify-content: center; }
.social-btn {
    width: 44px; height: 44px; border-radius: 50%; border: 1px solid var(--border);
    display: flex; align-items: center; justify-content: center; cursor: pointer;
    font-size: 1.2rem; transition: var(--transition); background: var(--white);
}
.social-btn:hover { border-color: var(--red); color: var(--red); }

/* ===== Tutorial / Updates Page ===== */
.page-header {
    background: var(--white); padding: 28px 0; margin-bottom: 20px;
    box-shadow: var(--card-shadow);
}
.page-header h1 { font-size: 1.5rem; color: var(--text); }
.page-header .breadcrumb { font-size: 0.8rem; color: var(--text-light); margin-top: 4px; }
.page-header .breadcrumb a { color: var(--red); }
.content-card {
    background: var(--white); border-radius: var(--radius);
    box-shadow: var(--card-shadow); padding: 24px 28px; margin-bottom: 18px;
}
.content-card h3 { font-size: 1.1rem; margin-bottom: 10px; color: var(--text); }
.content-card p, .content-card li { font-size: 0.9rem; color: var(--text-secondary); line-height: 1.8; }
.content-card ul { padding-left: 20px; }
.content-card ul li { list-style: disc; margin-bottom: 6px; }
.steps { counter-reset: step; padding-left: 0; }
.steps li {
    counter-increment: step; list-style: none; padding: 16px 0 16px 44px;
    position: relative; border-bottom: 1px solid var(--border);
}
.steps li::before {
    content: counter(step);
    position: absolute; left: 0; top: 14px;
    width: 28px; height: 28px; border-radius: 50%; background: var(--red);
    color: #fff; display: flex; align-items: center; justify-content: center;
    font-size: 0.8rem; font-weight: 700;
}
.steps li h4 { font-size: 1rem; margin-bottom: 4px; }
.steps li p { font-size: 0.85rem; color: var(--text-secondary); }
.update-item { padding: 14px 0; border-bottom: 1px solid var(--border); }
.update-item:last-child { border: none; }
.update-item .update-date { font-size: 0.8rem; color: var(--red); font-weight: 500; }
.update-item .update-ver { display: inline-block; padding: 2px 8px; background: var(--red); color: #fff; border-radius: 4px; font-size: 0.72rem; margin-left: 8px; }
.update-item h4 { font-size: 1rem; margin: 6px 0; }
.update-item ul { padding-left: 18px; }
.update-item ul li { list-style: disc; font-size: 0.85rem; color: var(--text-secondary); margin-bottom: 3px; }

/* ===== No Results ===== */
.no-results { text-align: center; padding: 60px 20px; color: var(--text-light); }
.no-results .no-icon { font-size: 4rem; margin-bottom: 12px; }

/* ===== Responsive ===== */
@media (max-width: 992px) {
    .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
    :root { --nav-height: 52px; }
    body { padding-top: var(--nav-height); padding-bottom: calc(var(--mobile-bottom-height) + 20px); }
    .nav-links { display: none; }
    .nav-search { display: none; }
    .nav-login { margin-left: auto; }
    .nav-toggle { display: block; }
    .nav-links.mobile-open {
        display: flex; flex-direction: column; position: fixed;
        top: var(--nav-height); left: 0; right: 0; background: var(--white);
        padding: 10px 20px; box-shadow: 0 4px 12px rgba(0,0,0,.1);
        z-index: 999; gap: 0;
    }
    .nav-links.mobile-open a { padding: 12px 0; border-bottom: 1px solid var(--border); border-radius: 0; }
    .nav-links.mobile-open .nav-dropdown-menu { position: static; opacity: 1; visibility: visible; transform: none; box-shadow: none; padding: 0 0 0 16px; }
    .nav-links.mobile-open .nav-dropdown-menu a { border: none; font-size: 0.85rem; }
    .nav-overlay.show { display: block; }
    .hero { padding: 30px 0 24px; }
    .hero h1 { font-size: 1.35rem; }
    .hero p { font-size: 0.9rem; }
    .service-grid { grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 12px; }
    .filter-bar { flex-direction: column; align-items: flex-start; }
    .filter-sort { margin-left: 0; }
    .mobile-bottom-bar { display: block; }
    .float-promo { bottom: 80px; right: 14px; width: 46px; height: 46px; font-size: 0.65rem; }
    .footer-grid { grid-template-columns: 1fr; gap: 20px; }
    .login-card { padding: 24px 20px; }
    .content-card { padding: 18px 16px; }
}

@media (max-width: 480px) {
    .service-grid { grid-template-columns: 1fr; }
    .hero h1 { font-size: 1.15rem; }
    .pagination a, .pagination span { width: 32px; height: 32px; font-size: 0.8rem; }
}
（内容由AI生成，仅供参考）