:root {
      --color-primary: #1a56db;
      --color-primary-dark: #1e3a8a;
      --color-primary-light: #3b82f6;
      --color-primary-50: #eff6ff;
      --color-primary-100: #dbeafe;
      --color-accent: #f59e0b;
      --color-accent-light: #fbbf24;
      --color-danger: #ef4444;
      --color-bg: #f1f5f9;
      --color-bg-card: #ffffff;
      --color-bg-dark: #0f172a;
      --color-text: #1e293b;
      --color-text-secondary: #64748b;
      --color-text-muted: #94a3b8;
      --color-text-inverse: #ffffff;
      --color-border: #e2e8f0;
      --color-border-light: #f1f5f9;
      --shadow-sm: 0 1px 2px 0 rgba(0,0,0,.05);
      --shadow-md: 0 4px 6px -1px rgba(0,0,0,.07), 0 2px 4px -2px rgba(0,0,0,.05);
      --radius-sm: 6px;
      --radius-md: 10px;
      --radius-lg: 16px;
      --transition-fast: all .15s ease;
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Microsoft YaHei", sans-serif;
      --font-size-xs: 12px;
      --font-size-sm: 13px;
      --font-size-base: 14px;
      --font-size-lg: 18px;
      --font-size-xl: 22px;
      --font-size-2xl: 28px;
      --space-2: 8px; --space-3: 12px; --space-4: 16px; --space-5: 20px; --space-6: 24px; --space-8: 32px; --space-10: 40px;
      --max-width: 1240px;
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { overflow-x: hidden; }
    body { font-family: var(--font-sans); font-size: var(--font-size-base); line-height: 1.6; color: var(--color-text); background: var(--color-bg); overflow-x: hidden; }
    a { color: var(--color-text); text-decoration: none; transition: var(--transition-fast); }
    a:hover { color: var(--color-primary); }
    .container { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--space-5); }
    .header { position: sticky; top: 0; z-index: 100; background: var(--color-bg-card); border-bottom: 1px solid var(--color-border); box-shadow: var(--shadow-sm); }
    .header-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; gap: var(--space-6); }
    .logo { display: flex; align-items: center; gap: var(--space-3); flex-shrink: 0; }
    .logo-icon { width: 38px; height: 38px; background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light)); border-radius: var(--radius-md); display: flex; align-items: center; justify-content: center; color: var(--color-text-inverse); font-weight: 800; font-size: var(--font-size-lg); }
    .logo-text { font-size: var(--font-size-lg); font-weight: 700; color: var(--color-text); }
    .logo-text span { color: var(--color-primary); }
    .search-area { flex: 1; max-width: 520px; }
    .search-box { display: flex; border: 2px solid var(--color-border); border-radius: var(--radius-md); overflow: hidden; }
    .search-input { flex: 1; padding: var(--space-2) var(--space-4); border: none; outline: none; font-size: var(--font-size-base); background: transparent; }
    .search-btn { padding: var(--space-2) var(--space-6); background: var(--color-primary); color: var(--color-text-inverse); border: none; font-size: var(--font-size-base); font-weight: 600; cursor: pointer; }
    .auth-area { display: flex; align-items: center; gap: var(--space-3); flex-shrink: 0; }
    .btn-login, .btn-register { padding: var(--space-2) var(--space-5); border-radius: var(--radius-md); font-size: var(--font-size-sm); font-weight: 600; cursor: pointer; border: none; white-space: nowrap; }
    .btn-login { background: transparent; color: var(--color-text-secondary); border: 1px solid var(--color-border); }
    .btn-login:hover { border-color: var(--color-primary); color: var(--color-primary); }
    .btn-register { background: var(--color-primary); color: var(--color-text-inverse); }

    .breadcrumb { padding: 10px 0; font-size: var(--font-size-sm); color: var(--color-text-muted); }
    .breadcrumb-inner { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--space-5); }
    .breadcrumb a { color: var(--color-text-muted); }
    .breadcrumb a:hover { color: var(--color-primary); }
    .breadcrumb-sep { margin: 0 8px; color: #94a3b8; }
    .breadcrumb-current { color: var(--color-text-secondary); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; max-width: 400px; display: inline-block; vertical-align: middle; }

    .main-content { padding: var(--space-8) 0; }
    .content-grid { display: grid; grid-template-columns: 1fr 280px; gap: var(--space-6); align-items: start; }
    .main-column { display: flex; flex-direction: column; gap: var(--space-6); }
    .content-section { background: var(--color-bg-card); border-radius: var(--radius-lg); box-shadow: var(--shadow-md); padding: var(--space-6); }
    .section-title { display: flex; align-items: center; gap: var(--space-3); margin-bottom: var(--space-5); padding-bottom: var(--space-3); border-bottom: 2px solid var(--color-border-light); }
    .section-title-bar { width: 4px; height: 22px; border-radius: 2px; background: linear-gradient(180deg, var(--color-primary), var(--color-primary-light)); flex-shrink: 0; }
    .section-title h2 { font-size: var(--font-size-lg); font-weight: 700; color: var(--color-text); }
    .video-title { font-size: 22px; font-weight: 700; color: #333; margin-bottom: 24px; text-align: center; }
    .video-player { display: flex; justify-content: center; }
    .video-player video { width: 100%; max-width: 800px; border-radius: 12px; }
    .vid-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
    .vid-card { background: var(--color-bg-card); border: 1px solid var(--color-border); border-radius: var(--radius-md); overflow: hidden; transition: var(--transition-fast); }
    .vid-card:hover { border-color: var(--color-primary-light); box-shadow: 0 4px 12px rgba(0,0,0,.08); transform: translateY(-2px); }
    .vid-card-tt { font-size: 13px; color: var(--color-text); padding: 10px; text-align: center; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
    .side-column { display: flex; flex-direction: column; gap: var(--space-6); position: sticky; top: 80px; }
    .side-consult { background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light)); border-radius: var(--radius-md); padding: 20px; text-align: center; margin-bottom: var(--space-6); }
    .side-consult p { color: rgba(255,255,255,.9); font-size: 13px; margin-bottom: 12px; }
    .side-consult-btn { display: block; padding: 10px 0; background: #fff; color: var(--color-primary); border-radius: var(--radius-sm); font-size: 15px; font-weight: 700; transition: var(--transition-fast); }
    .side-consult-btn:hover { background: var(--color-primary-50); color: var(--color-primary); transform: translateY(-1px); }
    .side-card { background: var(--color-bg-card); border-radius: var(--radius-lg); box-shadow: var(--shadow-md); padding: var(--space-5); }
    .side-card-hd { display: flex; align-items: center; gap: var(--space-3); margin-bottom: 16px; padding-bottom: 12px; border-bottom: 1px solid var(--color-border); }
    .side-card-icon { width: 36px; height: 36px; border-radius: var(--radius-md); background: linear-gradient(135deg, var(--color-primary), var(--color-primary-light)); display: flex; align-items: center; justify-content: center; flex-shrink: 0; }
    .side-card-icon svg { width: 18px; height: 18px; color: var(--color-text-inverse); }
    .side-card-title { font-size: 15px; font-weight: 700; color: var(--color-text); }
    .brand-detail { display: flex; flex-direction: column; gap: 6px; }
    .brand-row { display: flex; align-items: flex-start; gap: 8px; font-size: 13px; line-height: 1.6; }
    .brand-row-label { font-weight: 600; color: var(--color-text); white-space: nowrap; flex-shrink: 0; min-width: 68px; }
    .brand-row-value { color: var(--color-text-secondary); word-break: break-all; }
    .brand-row-value a { color: var(--color-primary); }
    .brand-row-value a:hover { text-decoration: underline; }

    .side-news-list { display: flex; flex-direction: column; }
    .side-news-item { display: flex; align-items: flex-start; gap: 8px; padding: 8px 0; border-bottom: 1px dashed var(--color-border); font-size: 13px; color: var(--color-text-secondary); }
    .side-news-item:last-child { border-bottom: none; }
    .side-news-item:hover { color: var(--color-primary); }
    .side-news-dot { width: 5px; height: 5px; border-radius: 50%; background: var(--color-primary-light); flex-shrink: 0; margin-top: 6px; }
    .side-prod-list { display: flex; flex-direction: column; gap: 8px; }
    .side-prod-item { display: flex; align-items: center; gap: 10px; padding: 8px 0; border-bottom: 1px dashed var(--color-border); transition: var(--transition-fast); }
    .side-prod-item:last-child { border-bottom: none; }
    .side-prod-item:hover { color: var(--color-primary); }
    .side-prod-img { width: 50px; height: 50px; border-radius: var(--radius-sm); object-fit: cover; flex-shrink: 0; }
    .side-prod-name { flex: 1; font-size: 13px; color: var(--color-text); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
    .footer { background: var(--color-bg-dark); color: rgba(255,255,255,.65); padding: var(--space-10) 0 var(--space-6); }
    .footer-top { display: flex; justify-content: space-between; gap: var(--space-8); padding-bottom: var(--space-8); border-bottom: 1px solid rgba(255,255,255,.1); flex-wrap: wrap; }
    .footer-brand { max-width: 320px; }
    .footer-brand-name { font-size: var(--font-size-lg); font-weight: 700; color: var(--color-text-inverse); margin-bottom: var(--space-3); }
    .footer-brand-desc { font-size: var(--font-size-sm); line-height: 1.7; }
    .footer-links-section h4 { color: var(--color-text-inverse); font-size: var(--font-size-base); font-weight: 600; margin-bottom: var(--space-4); }
    .footer-links-list { display: flex; flex-wrap: wrap; gap: var(--space-2) var(--space-4); }
    .footer-links-list a { font-size: var(--font-size-sm); color: rgba(255,255,255,.55); }
    .footer-links-list a:hover { color: var(--color-text-inverse); }
    .footer-bottom { padding-top: var(--space-5); text-align: center; font-size: var(--font-size-xs); color: rgba(255,255,255,.35); }
    @media (max-width: 1024px) {
      .content-grid { grid-template-columns: 1fr 240px; }
    }
    @media (max-width: 768px) {
      .header-inner { height: 56px; }
      .search-area, .auth-area { display: none; }
      .breadcrumb { display: none; }
      .content-grid { grid-template-columns: 1fr; }
      .side-column { position: static; }
      .vid-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-top { flex-direction: column; }
    }