:root {
  --bg: #ffffff;
  --surface: #f4f7f6;
  --surface-alt: #e9eff5;
  --text: #1a1e23;
  --text-light: #525a66;
  
  --primary: #0066cc;
  --primary-hover: #0052a3;
  --accent-blue: #3399ff;
  --accent-cyan: #00ccff;
  --accent-purple: #6666cc;
  
  --border: #dce3e8;
  --shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
  --radius: 8px;
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif; }
body { background: var(--bg); color: var(--text); line-height: 1.6; }
a { text-decoration: none; color: inherit; }
button { cursor: pointer; border: none; background: none; font: inherit; }

@keyframes spin { 100% { transform: rotate(360deg); } }

/* Navbar */
.nav { position: fixed; top: 0; left: 0; right: 0; background: rgba(255, 255, 255, 0.9); backdrop-filter: blur(10px); border-bottom: 1px solid var(--border); z-index: 100; height: 60px; display: flex; align-items: center; }
.nav-inner { max-width: 1200px; margin: 0 auto; width: 100%; padding: 0 24px; display: flex; justify-content: space-between; align-items: center; }
.brand { display: flex; align-items: center; gap: 12px; font-size: 20px; font-weight: 700; color: var(--primary); }
.nav-links { display: flex; gap: 32px; }
.nav-link { font-weight: 500; color: var(--text-light); transition: color 0.2s; padding: 4px 0; border-bottom: 2px solid transparent; }
.nav-link:hover { color: var(--primary); }
.nav-link.active { color: var(--primary); border-bottom-color: var(--primary); }

/* Buttons */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 24px; border-radius: var(--radius); font-weight: 600; font-size: 16px; transition: all 0.2s; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-hover); transform: translateY(-2px); box-shadow: 0 6px 16px rgba(0, 102, 204, 0.2); }
.btn-outline { border: 1px solid var(--border); color: var(--text); background: #fff; }
.btn-outline:hover { border-color: var(--primary); color: var(--primary); }
.btn-lg { padding: 16px 32px; font-size: 18px; }

/* Sections */
.sec { padding: 80px 24px; }
.sec-alt { background: var(--surface); }
.sec-alt2 { background: var(--surface-alt); }
.sec-inner { max-width: 1200px; margin: 0 auto; }
.sec-head { text-align: center; margin-bottom: 48px; }
.sec-title { font-size: 36px; font-weight: 800; margin-bottom: 16px; color: var(--text); }
.sec-desc { font-size: 18px; color: var(--text-light); max-width: 600px; margin: 0 auto; }

/* Hero */
.hero { padding: 140px 24px 80px; background: linear-gradient(135deg, #e6f0fa 0%, #ffffff 100%); text-align: center; }
.hero-title { font-size: 56px; font-weight: 800; margin-bottom: 24px; background: linear-gradient(90deg, var(--primary), var(--accent-purple)); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; }
.hero-desc { font-size: 20px; color: var(--text-light); margin-bottom: 40px; max-width: 700px; margin-inline: auto; }
.hero-actions { display: flex; justify-content: center; gap: 16px; margin-bottom: 60px; }

/* Grid Cards */
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 32px; }
.card { background: #fff; padding: 32px; border-radius: var(--radius); border: 1px solid var(--border); transition: all 0.3s; }
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow); border-color: var(--accent-blue); }
.card-icon { width: 48px; height: 48px; border-radius: 12px; background: var(--surface); display: flex; align-items: center; justify-content: center; margin-bottom: 20px; color: var(--primary); }
.card-title { font-size: 20px; font-weight: 700; margin-bottom: 12px; }
.card-desc { color: var(--text-light); }

/* Deep Dive Row */
.row { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; margin-bottom: 64px; }
.row:last-child { margin-bottom: 0; }
.row-rev { direction: rtl; }
.row-rev > * { direction: ltr; }
.row-content { display: flex; flex-direction: column; gap: 16px; }
.row-title { font-size: 32px; font-weight: 700; }
.row-desc { color: var(--text-light); font-size: 18px; }
.row-list { list-style: none; display: flex; flex-direction: column; gap: 12px; margin-top: 16px; }
.row-li { display: flex; align-items: flex-start; gap: 12px; }
.row-li svg { color: var(--primary); flex-shrink: 0; margin-top: 4px; }

/* Stats */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; background: var(--surface); padding: 48px; border-radius: var(--radius); text-align: center; }
.stat-val { font-size: 40px; font-weight: 800; color: var(--primary); margin-bottom: 8px; }
.stat-lbl { color: var(--text-light); font-weight: 500; }

/* Table */
.table-wrap { overflow-x: auto; background: #fff; border-radius: var(--radius); border: 1px solid var(--border); box-shadow: var(--shadow); }
table { width: 100%; border-collapse: collapse; min-width: 600px; text-align: center; }
th, td { padding: 16px; border-bottom: 1px solid var(--border); }
th { background: var(--surface); font-weight: 600; color: var(--text); }
td:first-child, th:first-child { text-align: left; padding-left: 24px; }
td svg { color: var(--primary); margin: 0 auto; display: block; }
.table-hl { background: rgba(0, 102, 204, 0.05); }

/* Reviews */
.rev-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 24px; }
.rev-card { background: #fff; padding: 32px; border-radius: var(--radius); border: 1px solid var(--border); display: flex; flex-direction: column; gap: 16px; }
.rev-top { display: flex; align-items: center; gap: 16px; }
.rev-av { width: 48px; height: 48px; border-radius: 50%; background: var(--surface-alt); display: flex; align-items: center; justify-content: center; font-weight: bold; color: var(--primary); font-size: 20px; }
.rev-info { display: flex; flex-direction: column; }
.rev-name { font-weight: 700; }
.rev-role { font-size: 14px; color: var(--text-light); }
.rev-stars { display: flex; gap: 4px; color: #f59e0b; }
.rev-stars svg { fill: currentColor; }
.rev-text { font-style: italic; color: var(--text-light); }

/* Steps */
.steps-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 32px; margin-top: 48px; }
.step-card { background: #fff; padding: 32px 24px 24px; border-radius: var(--radius); border: 1px solid var(--border); position: relative; text-align: center; }
.step-num { position: absolute; top: -16px; left: 50%; transform: translateX(-50%); width: 32px; height: 32px; background: var(--primary); color: #fff; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: bold; box-shadow: 0 4px 8px rgba(0,102,204,0.3); }

/* Timeline */
.timeline { display: flex; flex-direction: column; gap: 24px; padding-left: 16px; border-left: 2px solid var(--border); margin-left: 16px; }
.tl-item { position: relative; }
.tl-dot { position: absolute; left: -25px; top: 4px; width: 16px; height: 16px; border-radius: 50%; background: var(--primary); border: 3px solid #fff; }
.tl-date { font-weight: 700; color: var(--text); margin-bottom: 8px; }
.tl-content { color: var(--text-light); background: #fff; padding: 16px; border-radius: var(--radius); border: 1px solid var(--border); }

/* FAQ */
.faq-list { max-width: 800px; margin: 0 auto; display: flex; flex-direction: column; gap: 16px; }
.faq-item { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.faq-q { padding: 20px; font-weight: 600; display: flex; justify-content: space-between; align-items: center; cursor: pointer; user-select: none; }
.faq-icon { transition: transform 0.3s; color: var(--text-light); }
.faq-a { padding: 0 20px; height: 0; opacity: 0; overflow: hidden; transition: all 0.3s; color: var(--text-light); }
.faq-item.active { border-color: var(--primary); box-shadow: 0 4px 12px rgba(0, 102, 204, 0.05); }
.faq-item.active .faq-icon { transform: rotate(180deg); color: var(--primary); }
.faq-item.active .faq-a { padding: 0 20px 20px; height: auto; opacity: 1; }

/* Article */
.art-layout { display: grid; grid-template-columns: 1fr 320px; gap: 48px; }
.art-body { display: flex; flex-direction: column; gap: 32px; }
.art-sec { background: #fff; padding: 40px; border-radius: var(--radius); border: 1px solid var(--border); }
.art-sec h2 { font-size: 28px; margin-bottom: 20px; color: var(--primary); border-bottom: 2px solid var(--surface); padding-bottom: 12px; }
.art-sec h3 { font-size: 20px; margin: 24px 0 12px; color: var(--text); }
.art-sec p { margin-bottom: 16px; color: var(--text-light); }
.art-sec ul { margin-left: 24px; margin-bottom: 16px; color: var(--text-light); }
.art-sec li { margin-bottom: 8px; }

/* Sidebar */
.side { position: sticky; top: 80px; display: flex; flex-direction: column; gap: 24px; }
.side-box { background: #fff; padding: 24px; border-radius: var(--radius); border: 1px solid var(--border); }
.side-title { font-size: 18px; font-weight: 700; margin-bottom: 16px; padding-bottom: 12px; border-bottom: 1px solid var(--border); }
.side-links { display: flex; flex-direction: column; gap: 12px; }
.side-btn { display: flex; align-items: center; justify-content: space-between; padding: 12px 16px; border-radius: 6px; background: var(--surface); color: var(--text); font-weight: 500; transition: background 0.2s; }
.side-btn:hover { background: var(--surface-alt); }
.side-btn svg { color: var(--primary); }

/* Tips Grid */
.tips-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 16px; }
.tip-card { background: var(--surface); padding: 20px; border-radius: var(--radius); border-left: 4px solid var(--primary); }
.tip-title { font-weight: 700; margin-bottom: 8px; }
.tip-desc { font-size: 14px; color: var(--text-light); }

/* Footer */
.footer { background: #1a1e23; color: #8892a0; padding: 48px 24px; text-align: center; font-size: 14px; }
.footer p { margin-bottom: 8px; }
.footer-sec { display: inline-flex; align-items: center; gap: 8px; color: #a9b5c2; background: rgba(255,255,255,0.05); padding: 8px 16px; border-radius: 20px; margin-bottom: 16px; }

@media (max-width: 992px) {
  .art-layout { grid-template-columns: 1fr; }
  .row { grid-template-columns: 1fr; gap: 32px; }
}
@media (max-width: 768px) {
  .hero-title { font-size: 40px; }
  .stats { grid-template-columns: 1fr 1fr; }
  .hero-actions { flex-direction: column; }
}
@media (max-width: 480px) {
  .stats { grid-template-columns: 1fr; }
  .nav-links { display: none; }
}