/* ==========================================
       全局变量与重置 (高端科技感深色主题)
       ========================================== */
    :root {
      --color-primary: #dc9700;
      --bg-header-footer: #3f2814;
      --bg-hf-hover: #482d19;
      --btn-normal: #dd9800;
      --btn-hover: #fed107;
      --bg-body: #0d0805;
      --bg-card: #18100a;
      --bg-card-hover: #22170f;
      --text-main: #e8ddd0;
      --text-muted: #a39587;
      --border-color: #352211;
      
      --color-success: #22c55e;
      --color-vultr: #3b82f6;
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Helvetica Neue", STHeiti, "Microsoft Yahei", sans-serif;
      background-color: var(--bg-body);
      color: var(--text-main);
      line-height: 1.8;
      -webkit-font-smoothing: antialiased;
    }

    a { text-decoration: none; color: var(--color-primary); transition: all 0.3s ease; }

    /* 居中核心容器，严格限制 1200px */
    .container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 20px; }

    /* ==========================================
       UI细节：按钮与交互
       ========================================== */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 10px 24px;
      border-radius: 6px;
      font-size: 16px;
      font-weight: 600;
      cursor: pointer;
      border: none;
      transition: all 0.3s ease;
      box-shadow: 0 4px 6px rgba(0, 0, 0, 0.2);
    }

    .btn-sm { padding: 8px 20px; font-size: 14px; }
    .btn-large { padding: 14px 32px; font-size: 18px; }

    .btn-primary, .nav-cta, .btn-buy, .btn-green {
      background: linear-gradient(135deg, var(--btn-normal) 0%, #c28500 100%);
      color: #fff !important;
      text-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
    }

    .btn-primary:hover, .nav-cta:hover, .btn-buy:hover, .btn-green:hover {
      background: linear-gradient(135deg, var(--btn-hover) 0%, var(--btn-normal) 100%);
      color: #111 !important;
      text-shadow: none;
      box-shadow: 0 6px 15px rgba(221, 152, 0, 0.4);
      transform: translateY(-2px);
    }

    .btn-outline {
      border: 1px solid var(--color-primary);
      color: var(--color-primary);
      background: transparent;
    }

    .btn-outline:hover {
      background: var(--color-primary);
      color: #fff !important;
      box-shadow: 0 6px 15px rgba(220, 151, 0, 0.3);
    }

    .btn-vultr {
      border: 1px solid var(--color-vultr);
      color: var(--color-vultr);
      background: transparent;
    }

    .btn-vultr:hover {
      background: var(--color-vultr);
      color: #fff !important;
      box-shadow: 0 6px 15px rgba(59, 130, 246, 0.3);
    }

    /* ==========================================
       导航栏 (Header)
       ========================================== */
    .nav {
      background-color: var(--bg-header-footer);
      position: sticky;
      top: 0;
      z-index: 999;
      box-shadow: 0 2px 20px rgba(0, 0, 0, 0.6);
      height: 70px;
      display: flex;
      align-items: center;
    }

    .nav .container { display: flex; justify-content: space-between; align-items: center; }
    .nav-logo { font-size: 24px; font-weight: 700; color: var(--color-primary); letter-spacing: 1px; }
    .nav-logo span { color: #fff; font-weight: 400; margin-left: 4px; }
    .nav-links { list-style: none; display: flex; gap: 10px; }
    .nav-links a { color: #e8ddd0; padding: 8px 16px; border-radius: 6px; font-size: 15px; }
    .nav-links a:hover, .nav-links a.active { background-color: var(--bg-hf-hover); color: var(--color-primary); }
    .nav-toggle { display: none; background: transparent; border: none; color: var(--color-primary); font-size: 28px; cursor: pointer; }

    /* ==========================================
       内页首屏 Hero & 目录
       ========================================== */
    .hero-sm {
      padding: 60px 0;
      text-align: center;
      background: radial-gradient(circle at top, var(--bg-header-footer) 0%, var(--bg-body) 80%);
      border-bottom: 1px solid var(--border-color);
    }

    .hero-sm h1 { font-size: 40px; color: #fff; margin-bottom: 16px; letter-spacing: 1px; }
    .hero-sm p { font-size: 18px; color: var(--text-muted); margin: 0; }

    .toc-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 32px;
      margin: 40px 0;
      box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    }

    .toc-card h4 { color: var(--color-primary); font-size: 20px; margin-bottom: 20px; }
    .toc-card ol {
      padding-left: 20px;
      line-height: 2.2;
      color: var(--text-muted);
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 0 40px;
    }
    .toc-card ol a { color: var(--text-main); font-size: 16px; }
    .toc-card ol a:hover { color: var(--color-primary); padding-left: 4px; }

    /* ==========================================
       通用排版与组件
       ========================================== */
    .section { padding: 60px 0; border-bottom: 1px solid var(--border-color); }
    .section h2 { font-size: 28px; color: #fff; margin-bottom: 24px; text-align: center; }
    .section h3 { font-size: 20px; color: var(--color-primary); margin: 32px 0 16px; }
    .section p { margin-bottom: 16px; color: var(--text-muted); }

    .alert {
      border-radius: 8px;
      padding: 20px 24px;
      margin: 24px 0;
      display: flex;
      align-items: center;
      font-size: 16px;
      line-height: 1.8;
      text-align: justify;
    }
    .alert.success { background: rgba(34, 197, 94, 0.05); border-left: 4px solid var(--color-success); color: var(--text-main); }
    .alert.info { background: rgba(220, 151, 0, 0.05); border-left: 4px solid var(--color-primary); color: var(--text-main); }

    /* 场景卡片 (对称 3 列) */
    .usecase-cards {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin: 32px 0;
    }

    .usecase-card {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 32px 24px;
      text-align: center;
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
      align-items: center;
      position: relative;
      overflow: hidden;
    }

    .usecase-card:hover {
      border-color: var(--color-primary);
      transform: translateY(-5px);
      box-shadow: 0 12px 24px rgba(0,0,0,0.3);
    }
    
    .usecase-card.hot::before {
      content: "";
      position: absolute;
      top: 0; left: 0; width: 100%; height: 4px;
      background: var(--color-primary);
    }

    .usecase-icon { font-size: 40px; margin-bottom: 20px; line-height: 1; }
    .usecase-card h3 { font-size: 20px !important; color: #fff !important; margin: 0 0 16px !important; }
    .usecase-card p { font-size: 14px !important; margin-bottom: 24px !important; line-height: 1.8; color: var(--text-muted); flex-grow: 1; }
    .usecase-pick { font-size: 14px; font-weight: bold; color: var(--color-primary); padding: 8px 16px; background: rgba(220, 151, 0, 0.1); border-radius: 6px; width: 100%; }
    .usecase-pick.vultr-pick { color: var(--color-vultr); background: rgba(59, 130, 246, 0.1); }

    /* 对比板块 (对称 2 列) */
    .pros-cons {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
      margin: 32px 0;
    }

    .pros, .cons {
      background: var(--bg-card);
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 40px 32px;
      transition: all 0.3s ease;
    }

    .pros:hover, .cons:hover { transform: translateY(-4px); }
    .pros { border-top: 4px solid var(--color-primary); }
    .cons { border-top: 4px solid var(--color-vultr); }
    
    .pros h4 { font-size: 22px; color: var(--color-primary); margin-bottom: 24px; text-align: center; }
    .cons h4 { font-size: 22px; color: var(--color-vultr); margin-bottom: 24px; text-align: center; }
    
    .pros ul, .cons ul { list-style: none; margin: 0; padding: 0; }
    .pros ul li, .cons ul li {
      position: relative;
      padding-left: 24px;
      margin-bottom: 16px;
      color: var(--text-main);
      font-size: 15px;
      line-height: 1.8;
      text-align: justify;
    }
    .pros ul li::before {
      content: "•";
      position: absolute;
      left: 0;
      color: var(--color-primary);
      font-size: 20px;
    }
    .cons ul li::before {
      content: "•";
      position: absolute;
      left: 0;
      color: var(--color-vultr);
      font-size: 20px;
    }

    /* 表格设计 */
    .table-wrapper { overflow-x: auto; margin: 32px 0; border-radius: 12px; border: 1px solid var(--border-color); }
    .table-wrapper table { width: 100%; border-collapse: collapse; font-size: 15px; background: var(--bg-card); text-align: center; min-width: 800px;}
    .table-wrapper th, .table-wrapper td { padding: 18px 24px; border-bottom: 1px solid var(--border-color); white-space: nowrap;}
    .table-wrapper th { background: var(--bg-hf-hover); color: #fff; font-weight: 600; font-size: 16px; }
    .table-wrapper tr:hover { background: var(--bg-card-hover); }
    .highlight-col { color: var(--color-primary); font-weight: bold; }
    .vultr-col { color: var(--color-vultr); font-weight: bold; }

    /* FAQ 列表 (对称 2 列) */
    .faq-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
      margin: 32px 0;
    }

    .faq-item { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 32px; transition: all 0.3s; }
    .faq-item:hover { border-color: rgba(220, 151, 0, 0.3); transform: translateY(-4px); }
    .faq-q { font-size: 18px; font-weight: 600; color: #fff; margin-bottom: 16px; }
    .faq-a { font-size: 15px; color: var(--text-muted); line-height: 1.8; margin: 0; text-align: justify; }

    /* 中部过渡 CTA 模块 */
    .mid-cta { background: var(--bg-card); border-top: 1px solid var(--border-color); border-bottom: 1px solid var(--border-color); padding: 60px 0; text-align: center; }
    .mid-cta h2 { color: #fff; font-size: 28px; margin-bottom: 16px; }
    .mid-cta p { color: var(--text-muted); margin-bottom: 32px; font-size: 16px; }

    /* 独立 CTA 模块 */
    .cta-box {
      background: linear-gradient(135deg, var(--bg-hf-hover) 0%, var(--bg-card) 100%);
      border: 1px solid var(--border-color);
      border-radius: 12px;
      padding: 48px;
      text-align: center;
      margin: 48px 0;
      box-shadow: 0 8px 24px rgba(0,0,0,0.3);
    }
    .cta-box h3 { color: var(--color-primary); margin: 0 0 16px; font-size: 26px; }
    .cta-box p { margin: 0 0 32px; color: var(--text-main); font-size: 16px; }
    .btn-group { display: flex; gap: 20px; justify-content: center; flex-wrap: wrap; }

    /* 替代原侧边栏的底部网格扩展区 (对称 3 列) */
    .appendix-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      padding: 60px 0;
    }
    .appendix-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: 12px; padding: 32px; transition: all 0.3s ease; position: relative; }
    .appendix-card:hover { border-color: var(--color-primary); transform: translateY(-4px); }
    .appendix-card h2 { font-size: 18px; color: #fff; margin-bottom: 16px; border-bottom: none; text-align: left; }
    .appendix-card p { font-size: 14px; color: var(--text-muted); line-height: 1.6; margin-bottom: 24px; text-align: justify; }
    .article-tag { font-size: 12px; padding: 4px 10px; border-radius: 4px; font-weight: bold; margin-bottom: 16px; display: inline-block; }
    .tag-guide { background: rgba(220, 151, 0, 0.2); color: var(--color-primary); }
    .tag-tips { background: rgba(34, 197, 94, 0.2); color: #22c55e; }
    .tag-compare { background: rgba(59, 130, 246, 0.2); color: #3b82f6; }
    .article-meta { font-size: 13px; color: var(--color-primary); font-weight: bold; }

    /* Footer */
    .footer { background: var(--bg-header-footer); padding: 60px 0 24px; border-top: 1px solid #5a3a1e; }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px; margin-bottom: 40px; }
    .footer-col h4 { color: var(--color-primary); font-size: 18px; margin-bottom: 24px; }
    .footer-col p { color: var(--text-muted); font-size: 14px; max-width: 400px; line-height: 1.8; text-align: justify; }
    .footer-col ul { list-style: none; }
    .footer-col ul li { margin-bottom: 12px; }
    .footer-col ul a { color: var(--text-muted); font-size: 14px; }
    .footer-col ul a:hover { color: var(--color-primary); padding-left: 4px; }
    .footer-bottom { text-align: center; padding-top: 24px; border-top: 1px solid rgba(255,255,255,0.05); color: rgba(255,255,255,0.3); font-size: 14px; }

    /* 响应式 */
    @media (max-width: 1024px) {
      .usecase-cards { grid-template-columns: repeat(2, 1fr); }
      .toc-card ol { grid-template-columns: repeat(2, 1fr); }
      .appendix-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
	.toc-list, 
    .toc-card ol, 
	.toc ol,
	.overview-grid,
	.tips-grid,
	.article-grid, 
	.faq-grid, 
	.appendix-grid, 
	.series-grid, 
    .mistakes-grid, 
    .step-list,
	.pros-cons { grid-template-columns: 1fr; }
      .hero h1 { font-size: 32px; }
      .stats-row { grid-template-columns: repeat(2, 1fr); gap: 30px 15px; }
      .plan-cards { grid-template-columns: 1fr; }
      .advantages-grid { grid-template-columns: 1fr; }
      .usecase-cards { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: repeat(2, 1fr); text-align: center; gap: 30px 20px; }
      .footer-col:nth-child(1) { grid-column: span 2; text-align: center; }
      .footer-col p { max-width: 100%; margin: 0 auto; }
      .hero-buttons { flex-direction: column; padding: 0 20px; }
      .nav-toggle { display: block; }
      .nav-links {
        display: none; position: absolute; top: 70px; left: 0; width: 100%;
        background: var(--bg-header-footer); flex-direction: column; padding: 20px;
        text-align: center; box-shadow: 0 10px 20px rgba(0,0,0,0.5);
      }
      .nav-links.active { display: flex; }
      .nav-cta { display: none; }
    }

    .animate { opacity: 0; transform: translateY(30px); transition: all 0.8s cubic-bezier(0.2, 0.8, 0.2, 1); }
    .animate.visible { opacity: 1; transform: translateY(0); }