:root {
    --bg: #f5f7fb;
    --bg-strong: #e3edff;
    --card: #ffffff;
    --nav-bg: rgba(255, 255, 255, 0.95);
    --muted: #475569; 
    --text: #0b3858;
    --accent: #2998ff;
    --accent-soft: rgba(41, 152, 255, 0.12);
    --accent-dark: #0054c7;
    --danger: #ef4444;
    --radius-pill: 999px;
    --radius-lg: 20px;
    --radius-xl: 26px;
    --shadow-soft: 0 24px 60px rgba(15, 23, 42, 0.08);
    --shadow-sm: 0 14px 35px rgba(15, 23, 42, 0.06);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --border: rgba(11, 56, 88, 0.08);
  }

  * { box-sizing: border-box; }
  html { scroll-behavior: smooth; }
  body {
    margin: 0;
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
  }

  a { text-decoration: none; color: inherit; transition: var(--transition); }
  ul, ol { padding-left: 20px; }
  
  
  .flex-center { display: flex; align-items: center; justify-content: center; }

  .hc-hero {
    background: linear-gradient(135deg, var(--bg-strong) 0%, var(--bg) 100%);
    padding: 80px 0 60px;
    text-align: center;
    border-bottom: 1px solid var(--border);
    position: relative;
    overflow: hidden;
  }
  
  .hc-hero::before {
    content: ''; position: absolute; top: -50px; left: -50px;
    width: 300px; height: 300px; background: var(--accent-soft);
    border-radius: 50%; filter: blur(80px); opacity: 0.6;
  }
  .hc-hero::after {
    content: ''; position: absolute; bottom: -50px; right: -50px;
    width: 250px; height: 250px; background: #dbeafe;
    border-radius: 50%; filter: blur(60px); opacity: 0.5;
  }

  .hc-badge {
    display: inline-block;
    background: var(--accent-soft);
    color: var(--accent-dark);
    font-size: 13px; font-weight: 600;
    padding: 6px 16px; border-radius: var(--radius-pill);
    margin-bottom: 16px; letter-spacing: 0.5px;
    border: 1px solid rgba(41, 152, 255, 0.2);
  }

  .hc-title { font-size: 42px; font-weight: 800; margin: 0; letter-spacing: -1px; color: var(--text); }
  .hc-sub { font-size: 18px; color: var(--muted); margin-top: 12px; max-width: 600px; margin-left: auto; margin-right: auto; }

  .hc-search-wrap {
    position: relative; max-width: 680px; margin: 40px auto 0;
    z-index: 10;
  }
  .hc-search {
    background: var(--card);
    display: flex; align-items: center;
    padding: 8px; border-radius: var(--radius-xl);
    box-shadow: var(--shadow-soft);
    border: 1px solid var(--border);
    transition: var(--transition);
  }
  .hc-search:focus-within {
    transform: translateY(-2px);
    box-shadow: 0 20px 40px rgba(41, 152, 255, 0.15);
    border-color: var(--accent);
  }
  .hc-search i { font-size: 18px; color: var(--accent); margin-left: 16px; }
  .hc-search input {
    border: 0; outline: 0; width: 100%;
    padding: 16px; font-size: 16px; color: var(--text);
    background: transparent;
  }
  .hc-search input::placeholder { color: #94a3b8; }
  .hc-search button {
    background: var(--accent); color: white; border: 0;
    padding: 12px 28px; border-radius: var(--radius-lg);
    font-weight: 600; cursor: pointer; transition: var(--transition);
  }
  .hc-search button:hover { background: var(--accent-dark); }

  .hc-layout {
    display: grid;
    grid-template-columns: 280px 1fr; 
    gap: 40px;
    margin-top: 60px;
    padding-bottom: 80px;
  }

  .hc-sidebar {
    position: sticky; top: 40px;
    height: fit-content;
    background: var(--card);
    padding: 24px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
    display: flex; flex-direction: column; gap: 8px;
  }
  .nav-label {
    font-size: 12px; text-transform: uppercase; letter-spacing: 1px;
    color: var(--muted); font-weight: 700; margin-bottom: 8px; padding-left: 12px;
  }
  .nav-item {
    display: flex; align-items: center; gap: 12px;
    padding: 12px 16px; border-radius: 12px;
    font-weight: 500; font-size: 14px;
    color: var(--text);
    transition: var(--transition);
    cursor: pointer;
  }
  .nav-item:hover { background: var(--bg); color: var(--accent); }
  .nav-item.active { background: var(--accent-soft); color: var(--accent-dark); font-weight: 600; }
  .nav-item i { width: 20px; text-align: center; }

  .section-header { margin-bottom: 24px; border-bottom: 1px solid var(--border); padding-bottom: 16px; }
  .section-header h2 { font-size: 26px; margin: 0; display: flex; align-items: center; gap: 12px; }
  .section-header i { color: var(--accent); }
  
  .quick-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 20px; margin-bottom: 40px;
  }
  .quick-card {
    background: var(--card); padding: 24px; border-radius: var(--radius-lg);
    border: 1px solid var(--border); box-shadow: 0 4px 6px rgba(0,0,0,0.02);
    transition: var(--transition); cursor: pointer; text-align: center;
  }
  .quick-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-sm); border-color: var(--accent-soft); }
  .quick-card .icon-box {
    width: 50px; height: 50px; background: var(--accent-soft); color: var(--accent);
    border-radius: 14px; display: flex; align-items: center; justify-content: center;
    font-size: 20px; margin: 0 auto 16px;
  }
  .quick-card h3 { font-size: 16px; margin: 0 0 8px; }
  .quick-card p { font-size: 13px; color: var(--muted); margin: 0; }

  .acc-group { margin-bottom: 50px; scroll-margin-top: 100px; }
  .accordion { display: flex; flex-direction: column; gap: 12px; }
  
  .acc-item {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 16px;
    overflow: hidden;
    transition: var(--transition);
  }
  .acc-item:hover { border-color: var(--accent); box-shadow: 0 4px 12px rgba(41, 152, 255, 0.08); }
  
  .acc-trigger {
    padding: 18px 24px; cursor: pointer;
    display: flex; align-items: center; justify-content: space-between;
    background: white; z-index: 2; position: relative;
  }
  .acc-left { display: flex; align-items: center; gap: 16px; }
  .acc-icon {
    width: 36px; height: 36px; border-radius: 10px;
    background: var(--bg); color: var(--text);
    display: flex; align-items: center; justify-content: center; font-size: 15px;
    transition: var(--transition);
  }
  .acc-item:hover .acc-icon { background: var(--accent); color: white; }
  
  .acc-info h4 { margin: 0; font-size: 16px; font-weight: 600; }
  .acc-info span { font-size: 13px; color: var(--muted); }
  .acc-chevron { color: #cbd5e1; transition: transform 0.3s ease; }
  
  .acc-body {
    max-height: 0; overflow: hidden;
    transition: max-height 0.4s ease-out;
    background: linear-gradient(to bottom, #ffffff, var(--bg));
  }
  .acc-content { padding: 20px 24px 30px; border-top: 1px dashed var(--border); }
  
  .acc-content h3 { font-size: 18px; color: var(--accent-dark); margin-top: 0; }
  .acc-content ul, .acc-content ol { color: var(--muted); margin-bottom: 20px; }
  .acc-content li { margin-bottom: 8px; }
  .acc-content p { color: var(--muted); }
  
  .tag { 
    display: inline-block; padding: 4px 10px; border-radius: 6px; 
    font-size: 11px; font-weight: 600; text-transform: uppercase; 
    margin-bottom: 12px;
  }
  .tag.setup { background: #d1fae5; color: #047857; }
  .tag.trouble { background: #fee2e2; color: #b91c1c; }
  .tag.info { background: #e0f2fe; color: #0369a1; }

  

  @media (max-width: 992px) {
    .hc-layout { grid-template-columns: 1fr; margin-top: 30px; }
    .hc-sidebar { display: none;  }
    .hc-title { font-size: 32px; }
    .quick-grid { grid-template-columns: 1fr 1fr; }
  }
  @media (max-width: 600px) {
    .quick-grid { grid-template-columns: 1fr; }
    .acc-trigger { padding: 16px; }
    .acc-info span { display: none; } 
  }