/* LingDataWorks - Clean, professional, no AI fluff */

:root {
  --bg: #fff;
  --bg-secondary: #f8f9fa;
  --border: #e5e7eb;
  --text: #1a1a1a;
  --text-secondary: #6b7280;
  --text-muted: #9ca3af;
  --accent: #2563eb;
  --accent-hover: #1d4ed8;
  --radius: 6px;
  --max-width: 1080px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }
ul { list-style: none; }
img { max-width: 100%; display: block; }
h1, h2, h3, h4 { line-height: 1.3; font-weight: 600; }
h1 { font-size: 2.2rem; letter-spacing: -0.01em; }
h2 { font-size: 1.6rem; }
h3 { font-size: 1.15rem; }

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

/* ---- Nav ---- */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.navbar .container { display: flex; align-items: center; justify-content: space-between; height: 60px; }

.nav-logo { font-weight: 700; font-size: 1.1rem; color: var(--text); display: flex; align-items: center; gap: 8px; }
.nav-logo:hover { color: var(--text); }
.nav-logo .logo-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--accent); }

.nav-links { display: flex; gap: 32px; }
.nav-links a { color: var(--text-secondary); font-size: 0.92rem; font-weight: 500; transition: color 0.15s; }
.nav-links a:hover, .nav-links a.active { color: var(--text); }

.mobile-toggle { display: none; flex-direction: column; gap: 4px; cursor: pointer; background: none; border: none; padding: 4px; }
.mobile-toggle span { display: block; width: 22px; height: 2px; background: var(--text); transition: 0.2s; }

/* ---- Page header ---- */
.page-hero { padding: 120px 0 48px; text-align: center; }
.page-hero h1 { margin-bottom: 12px; }
.page-hero p { color: var(--text-secondary); font-size: 1.05rem; max-width: 560px; margin: 0 auto; }

/* ---- Hero ---- */
.hero { padding: 140px 0 80px; }
.hero .container { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; }
.hero h1 { margin-bottom: 20px; line-height: 1.25; }
.hero h1 span { color: var(--accent); }
.hero p { color: var(--text-secondary); font-size: 1.05rem; margin-bottom: 32px; max-width: 460px; line-height: 1.7; }
.hero-buttons { display: flex; gap: 12px; flex-wrap: wrap; }
.hero-right { display: flex; align-items: center; justify-content: center; }
.hero-right img { width: 100%; max-width: 520px; display: block; }

.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 10px 24px; border-radius: var(--radius);
  font-size: 0.92rem; font-weight: 500; cursor: pointer; border: none;
  transition: all 0.15s;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); color: #fff; }
.btn-outline { border: 1.5px solid var(--border); background: var(--bg); color: var(--text); }
.btn-outline:hover { border-color: var(--accent); color: var(--accent); }

/* ---- Section ---- */
.section { padding: 80px 0; }
.section-gray { background: var(--bg-secondary); }

.section-title { font-size: 1.6rem; text-align: center; margin-bottom: 12px; }
.section-subtitle { color: var(--text-secondary); text-align: center; max-width: 520px; margin: 0 auto 48px; font-size: 0.98rem; }

/* ---- Service Cards ---- */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 20px; }
#services .cards { grid-template-columns: repeat(2, 1fr); }

.card {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; transition: border-color 0.15s, transform 0.15s;
}
.card:hover { border-color: #cbd5e1; transform: translateY(-2px); }
.card-icon { font-size: 1.6rem; margin-bottom: 16px; }
.card h3 { margin-bottom: 8px; }
.card p { color: var(--text-secondary); font-size: 0.92rem; line-height: 1.7; }

/* ---- Feature grid ---- */
.feature-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; }
.feature-visual {
  border-radius: var(--radius);
  overflow: hidden; aspect-ratio: 4/3;
  padding: 7.25%;
}
.feature-visual img { width: 100%; height: 100%; object-fit: cover; display: block; border-radius: var(--radius); }
.feature-list { display: flex; flex-direction: column; gap: 20px; }
.feature-item { display: flex; gap: 14px; }
.feature-item .dot { width: 20px; height: 20px; min-width: 20px; border-radius: 50%; background: var(--accent); opacity: 0.12; display: flex; align-items: center; justify-content: center; margin-top: 2px; }
.feature-item h4 { font-size: 1rem; margin-bottom: 2px; }
.feature-item p { color: var(--text-secondary); font-size: 0.9rem; }

/* ---- Steps ---- */
.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 20px; }
.step {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 28px; text-align: center;
}
.step-num { width: 36px; height: 36px; border-radius: 50%; background: var(--text); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 600; font-size: 0.9rem; margin: 0 auto 16px; }
.step h3 { font-size: 1rem; margin-bottom: 6px; }
.step p { color: var(--text-secondary); font-size: 0.88rem; }

/* ---- Blog Cards ---- */
.blog-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.blog-card { border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; transition: border-color 0.15s; }
.blog-card:hover { border-color: #cbd5e1; }
.blog-tag { display: inline-block; padding: 2px 10px; border-radius: 100px; font-size: 0.78rem; font-weight: 500; background: var(--bg-secondary); color: var(--accent); margin-bottom: 10px; }
.blog-card h3 { margin-bottom: 6px; font-size: 1.2rem; }
.blog-card h3 a { color: var(--text); }
.blog-card h3 a:hover { color: var(--accent); }
.blog-card .excerpt { color: var(--text-secondary); font-size: 0.92rem; margin-bottom: 12px; line-height: 1.7; }
.blog-card .meta { color: var(--text-muted); font-size: 0.82rem; }

/* ---- Blog Toolbar ---- */
.blog-toolbar { display: flex; gap: 12px; margin-bottom: 32px; flex-wrap: wrap; align-items: center; }
.blog-search-wrap {
  flex: 1; min-width: 240px; position: relative; display: flex; align-items: center;
}
.blog-search-wrap::before {
  content: ''; position: absolute; left: 14px; width: 18px; height: 18px;
  background: currentColor; opacity: 0.35;
  mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Ccircle cx='11' cy='11' r='8'/%3E%3Cpath d='M21 21l-4.35-4.35'/%3E%3C/svg%3E") center/contain no-repeat;
  -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2'%3E%3Ccircle cx='11' cy='11' r='8'/%3E%3Cpath d='M21 21l-4.35-4.35'/%3E%3C/svg%3E") center/contain no-repeat;
  pointer-events: none;
}
.blog-search-wrap input {
  width: 100%; padding: 10px 16px 10px 42px; border-radius: 8px;
  border: 1px solid var(--border); font-size: 0.92rem; font-family: inherit;
  outline: none; background: var(--bg); transition: border-color 0.15s, box-shadow 0.15s;
}
.blog-search-wrap input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(37,99,235,0.08); }
.blog-search-wrap input::placeholder { color: var(--text-muted); }
.blog-toolbar select {
  padding: 10px 36px 10px 14px; border-radius: 8px; border: 1px solid var(--border);
  font-size: 0.9rem; font-family: inherit; background: var(--bg); cursor: pointer;
  outline: none; min-width: 130px; transition: border-color 0.15s, box-shadow 0.15s;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%236b7280' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 10px center; background-size: 16px;
}
.blog-toolbar select:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(37,99,235,0.08); }
.blog-result-count { color: var(--text-muted); font-size: 0.85rem; margin-bottom: 20px; }
.blog-empty { color: var(--text-secondary); text-align: center; padding: 60px 20px; }

/* ---- Blog Sidebar (archive) ---- */
.blog-archive { margin-top: 48px; border-top: 1px solid var(--border); padding-top: 28px; }
.blog-archive h3 { font-size: 1rem; margin-bottom: 16px; }
.blog-archive-list { display: flex; flex-wrap: wrap; gap: 8px; }
.blog-archive-list a {
  display: inline-block; padding: 4px 14px; border-radius: 100px;
  font-size: 0.85rem; border: 1px solid var(--border); color: var(--text-secondary);
  transition: all 0.15s;
}
.blog-archive-list a:hover, .blog-archive-list a.active { border-color: var(--accent); color: var(--accent); background: rgba(37,99,235,0.04); }

@media (max-width: 768px) {
  .blog-list { grid-template-columns: 1fr; }
}

/* ---- Blog Post ---- */
.blog-post-header { padding: 120px 0 40px; text-align: center; }
.blog-post-header h1 { max-width: 1125px; margin: 0 auto 12px; }
.blog-post-body { max-width: 1125px; margin: 0 auto; padding: 0 20px 80px; font-size: 1.05rem; }
.blog-post-body h2 { font-size: 1.4rem; margin: 40px 0 12px; }
.blog-post-body h3 { font-size: 1.1rem; margin: 28px 0 8px; }
.blog-post-body p { color: var(--text-secondary); margin-bottom: 18px; line-height: 1.8; }
.blog-post-body ul, .blog-post-body ol { color: var(--text-secondary); margin-bottom: 18px; padding-left: 22px; }
.blog-post-body li { margin-bottom: 6px; line-height: 1.7; }
.blog-post-body pre { background: var(--bg-secondary); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 20px; overflow-x: auto; margin-bottom: 20px; font-size: 0.88rem; line-height: 1.6; }
.blog-post-body code { font-family: "SF Mono", "Fira Code", "Cascadia Code", monospace; font-size: 0.88em; background: var(--bg-secondary); padding: 2px 5px; border-radius: 3px; }
.blog-post-body pre code { background: none; padding: 0; }
.blog-post-body blockquote { border-left: 3px solid var(--accent); padding: 8px 16px; margin-bottom: 18px; color: var(--text-secondary); background: var(--bg-secondary); border-radius: 0 var(--radius) var(--radius) 0; }
.blog-post-body .table-wrap { overflow-x: auto; margin-bottom: 24px; }
.blog-post-body table { width: 100%; border-collapse: collapse; font-size: 0.92rem; }
.blog-post-body thead { border-bottom: 2px solid var(--border); }
.blog-post-body th { padding: 10px 14px; text-align: left; font-weight: 600; color: var(--text); font-size: 0.88rem; white-space: nowrap; }
.blog-post-body td { padding: 10px 14px; border-bottom: 1px solid var(--border); color: var(--text-secondary); vertical-align: top; }
.blog-post-body tbody tr:nth-child(even) { background: var(--bg-secondary); }
.blog-post-body tbody tr:hover { background: rgba(37,99,235,0.04); }

/* ---- Related Posts ---- */
.related-posts { padding: 60px 0 80px; background: var(--bg-secondary); border-top: 1px solid var(--border); }
.related-posts h2 { text-align: center; margin-bottom: 32px; font-size: 1.3rem; }

/* ---- Contact ---- */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
.contact-info h2 { margin-bottom: 12px; }
.contact-info > p { color: var(--text-secondary); margin-bottom: 28px; }
.contact-method { display: flex; align-items: center; gap: 14px; margin-bottom: 18px; }
.contact-method .icon { font-size: 1.2rem; }
.contact-method h4 { font-size: 0.92rem; }
.contact-method p { color: var(--text-secondary); font-size: 0.9rem; }

.contact-form { background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; }
.contact-form h3 { margin-bottom: 20px; }
.form-group { margin-bottom: 16px; }
.form-group label { display: block; font-size: 0.88rem; font-weight: 500; margin-bottom: 6px; color: var(--text-secondary); }
.form-group input, .form-group textarea {
  width: 100%; padding: 10px 14px; border-radius: var(--radius); border: 1px solid var(--border);
  background: var(--bg); color: var(--text); font-size: 0.92rem; font-family: inherit;
  outline: none; transition: border-color 0.15s;
}
.form-group input:focus, .form-group textarea:focus { border-color: var(--accent); }
.form-group textarea { min-height: 110px; resize: vertical; }
.form-feedback { margin-top: 12px; font-size: 0.9rem; display: none; }
.form-feedback.success { color: #16a34a; display: block; }
.form-feedback.error { color: #dc2626; display: block; }

/* ---- CTA ---- */
.cta { padding: 80px 0; text-align: center; }
.cta h2 { margin-bottom: 12px; }
.cta p { color: var(--text-secondary); margin-bottom: 24px; font-size: 1rem; }

/* ---- Footer ---- */
.footer { background: var(--bg-secondary); border-top: 1px solid var(--border); padding: 48px 0 24px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 36px; margin-bottom: 36px; }
.footer-brand p { color: var(--text-secondary); font-size: 0.88rem; margin-top: 8px; max-width: 260px; }
.footer-col h4 { font-size: 0.9rem; margin-bottom: 14px; }
.footer-col ul { display: flex; flex-direction: column; gap: 8px; }
.footer-col a { color: var(--text-secondary); font-size: 0.88rem; }
.footer-col a:hover { color: var(--accent); }
.footer-bottom { padding-top: 20px; border-top: 1px solid var(--border); text-align: center; color: var(--text-muted); font-size: 0.82rem; }
.footer-bottom a { color: var(--text-muted); }
.footer-bottom a:hover { color: var(--accent); }

/* ---- Admin ---- */
.admin-header { border-bottom: 1px solid var(--border); margin-bottom: 28px; padding-bottom: 16px; display: flex; align-items: center; justify-content: space-between; }
.admin-header h1 { font-size: 1.3rem; }
.admin-nav { display: flex; gap: 20px; }
.admin-nav a { color: var(--text-secondary); font-size: 0.9rem; font-weight: 500; cursor: pointer; }
.admin-nav a.active { color: var(--accent); }
.admin-table { width: 100%; border-collapse: collapse; font-size: 0.9rem; }
.admin-table th, .admin-table td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--border); }
.admin-table th { font-weight: 600; color: var(--text-secondary); font-size: 0.82rem; }
.admin-table a { cursor: pointer; }
.admin-table .actions { display: flex; gap: 12px; }
.admin-panel { max-width: 800px; margin: 0 auto; }
.admin-panel textarea { min-height: 300px; font-family: monospace; }
.admin-login { max-width: 360px; margin: 120px auto; }

/* ---- Image Lightbox ---- */
.img-overlay {
  position: fixed; inset: 0; z-index: 9999;
  background: rgba(0,0,0,0.85);
  display: flex; align-items: center; justify-content: center;
  opacity: 0; pointer-events: none; transition: opacity 0.25s;
  cursor: zoom-out; padding: 40px;
}
.img-overlay.open { opacity: 1; pointer-events: auto; }
.img-overlay img { max-width: 90vw; max-height: 90vh; object-fit: contain; border-radius: 8px; }

/* ---- Responsive ---- */
@media (max-width: 768px) {
  h1 { font-size: 1.8rem; }
  h2 { font-size: 1.35rem; }

  .nav-links { display: none; position: absolute; top: 60px; left: 0; right: 0; background: var(--bg); border-bottom: 1px solid var(--border); flex-direction: column; padding: 20px; gap: 16px; }
  .nav-links.open { display: flex; }
  .mobile-toggle { display: flex; }

  .hero .container { grid-template-columns: 1fr; text-align: center; }
  .hero p { max-width: 100%; }
  .hero-buttons { justify-content: center; }
  .hero-right { order: -1; }

  .feature-grid { grid-template-columns: 1fr; gap: 32px; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .cards { grid-template-columns: 1fr; }
  #services .cards { grid-template-columns: 1fr; }
}

@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr; }
  .hero-buttons { flex-direction: column; }
  .btn { width: 100%; justify-content: center; }
}

/* ---- Back to top ---- */
.back-to-top {
  position: fixed; bottom: 28px; right: 28px; width: 40px; height: 40px;
  border-radius: 50%; background: var(--text); color: #fff; border: none;
  display: flex; align-items: center; justify-content: center; cursor: pointer;
  font-size: 1.1rem; opacity: 0; transform: translateY(8px);
  transition: opacity 0.2s, transform 0.2s; z-index: 99;
}
.back-to-top.visible { opacity: 1; transform: translateY(0); }
.back-to-top:hover { background: var(--accent); }