:root {
  --bg-color: #0d1117;
  --card-bg: #161b22;
  --card-border: #30363d;
  --text-main: #e6edf3;
  --text-muted: #8b949e;
  --accent-blue: #58a6ff;
  --accent-cyan: #39c5cf;
  --accent-purple: #bc8cff;
  --accent-green: #3fb950;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { background-color: var(--bg-color); color: var(--text-main); font-family: var(--font-main); line-height: 1.7; -webkit-font-smoothing: antialiased; }
a { color: var(--accent-blue); text-decoration: none; transition: 0.2s; }
a:hover { opacity: 0.8; }

.container { max-width: 1100px; margin: 0 auto; padding: 2rem 1.5rem; }
.site-header { border-bottom: 1px solid var(--card-border); background: rgba(13, 17, 23, 0.9); backdrop-filter: blur(10px); position: sticky; top: 0; z-index: 100; }
.nav-container { max-width: 1100px; margin: 0 auto; padding: 1rem 1.5rem; display: flex; justify-content: space-between; align-items: center; }
.brand-logo { font-size: 1.3rem; font-weight: 700; color: #fff; }
.brand-accent { color: var(--accent-cyan); }
.nav-links { display: flex; align-items: center; gap: 1.5rem; }
.nav-links a { color: var(--text-muted); font-size: 0.95rem; }
.nav-links a:hover { color: #fff; }

.btn { display: inline-block; padding: 0.75rem 1.5rem; border-radius: 8px; font-weight: 600; font-size: 0.95rem; cursor: pointer; transition: 0.2s; }
.btn-primary { background: var(--accent-cyan); color: #0d1117; }
.btn-secondary { background: var(--card-bg); border: 1px solid var(--card-border); color: var(--text-main); }
.btn:hover { transform: translateY(-2px); opacity: 0.95; }
.btn-nav { padding: 0.4rem 0.8rem; border-radius: 6px; background: var(--card-bg); border: 1px solid var(--card-border); color: var(--accent-cyan) !important; }

.badge { display: inline-block; padding: 0.3rem 0.8rem; border-radius: 20px; font-size: 0.8rem; font-weight: 600; background: rgba(57, 197, 207, 0.15); color: var(--accent-cyan); margin-bottom: 1rem; border: 1px solid rgba(57, 197, 207, 0.3); }
.hero-section, .article-hero { padding: 5rem 0 3rem; text-align: center; }
.hero-title { font-size: 2.5rem; font-weight: 800; line-height: 1.3; margin-bottom: 1.5rem; letter-spacing: -0.5px; }
.text-gradient { background: linear-gradient(135deg, var(--accent-cyan), var(--accent-blue)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.hero-desc { font-size: 1.15rem; color: var(--text-muted); max-width: 800px; margin: 0 auto 2rem; }
.hero-cta { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

.section-title { font-size: 1.8rem; font-weight: 700; text-align: center; margin-bottom: 2.5rem; }
.section-subtitle { text-align: center; color: var(--text-muted); margin-top: -1.8rem; margin-bottom: 2.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1.5rem; }
.card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; padding: 2rem; display: flex; flex-direction: column; gap: 1rem; }
.card-icon { font-size: 2rem; }
.card-link { margin-top: auto; font-weight: 600; color: var(--accent-cyan); }

.timeline-table-wrapper { overflow-x: auto; border: 1px solid var(--card-border); border-radius: 12px; background: var(--card-bg); }
.timeline-table { width: 100%; border-collapse: collapse; text-align: left; font-size: 0.95rem; }
.timeline-table th, .timeline-table td { padding: 1.2rem; border-bottom: 1px solid var(--card-border); }
.timeline-table th { background: rgba(255, 255, 255, 0.03); color: var(--text-muted); font-weight: 600; }
.grade-cell { white-space: nowrap; }
.age-label { font-size: 0.8rem; color: var(--text-muted); font-weight: normal; }
.highlight-row { background: rgba(57, 197, 207, 0.04); }

.article-container { max-width: 850px; }
.article-card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; padding: 2.5rem; margin-bottom: 2rem; }
.article-card h2 { font-size: 1.4rem; margin-bottom: 1.2rem; color: var(--accent-blue); }
.step-box { display: flex; gap: 1.5rem; padding: 1.2rem 0; border-bottom: 1px solid var(--card-border); }
.step-box:last-child { border-bottom: none; }
.step-num { font-weight: 700; color: var(--accent-cyan); white-space: nowrap; }
.highlight-card { border-color: rgba(57, 197, 207, 0.4); background: rgba(57, 197, 207, 0.03); }
.styled-list { padding-left: 1.5rem; margin-top: 1rem; display: flex; flex-direction: column; gap: 0.8rem; }

.roadmap-cards-wrapper { display: flex; flex-direction: column; gap: 1.5rem; }
.roadmap-card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 12px; padding: 1.8rem; }
.roadmap-card-highlight { border-color: var(--accent-cyan); box-shadow: 0 0 20px rgba(57, 197, 207, 0.1); }
.roadmap-card-header { display: flex; justify-content: space-between; align-items: center; border-bottom: 1px solid var(--card-border); padding-bottom: 0.8rem; margin-bottom: 1.2rem; }
.roadmap-grade { font-size: 1.3rem; font-weight: 700; color: var(--accent-cyan); }
.roadmap-card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1.5rem; }
.roadmap-track h4 { font-size: 0.95rem; margin-bottom: 0.5rem; color: var(--text-muted); }

.text-center { text-align: center; }
.mt-4 { margin-top: 2rem; }
.mt-5 { margin-top: 3rem; }

.site-footer { border-top: 1px solid var(--card-border); margin-top: 5rem; padding: 3rem 0; color: var(--text-muted); font-size: 0.875rem; text-align: center; }
.footer-container { display: flex; flex-direction: column; gap: 1.2rem; align-items: center; }
.footer-links { display: flex; gap: 1.5rem; }

/* Simulator Section */
.simulator-section {
  padding: 60px 20px;
  min-height: 80vh;
}
.simulator-card {
  max-width: 1000px;
  margin: 30px auto 0;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 36px;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}
.simulator-grid {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 36px;
}
@media (max-width: 860px) {
  .simulator-grid {
    grid-template-columns: 1fr;
  }
}
.sim-controls {
  display: flex;
  flex-direction: column;
  gap: 20px;
}
.sim-field label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent-cyan);
  margin-bottom: 8px;
}
.sim-select {
  width: 100%;
  padding: 12px 14px;
  background: var(--bg-color);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  color: var(--text-main);
  font-size: 0.95rem;
}
.sim-select:focus {
  outline: none;
  border-color: var(--accent-cyan);
}
.roi-summary {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}
.roi-item {
  background: var(--bg-color);
  padding: 16px;
  border-radius: 10px;
  border: 1px solid var(--card-border);
}
.roi-item.highlight {
  grid-column: span 2;
  border-color: var(--accent-blue);
  background: linear-gradient(135deg, var(--bg-color), rgba(56, 189, 248, 0.1));
}
.roi-label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 6px;
}
.roi-val {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent-cyan);
}
.roi-val-large {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--accent-green);
}
.sim-timeline-wrapper h4 {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 16px;
  border-bottom: 1px solid var(--card-border);
  padding-bottom: 8px;
}
.sim-timeline {
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.sim-step {
  display: flex;
  gap: 14px;
  padding: 12px;
  background: var(--bg-color);
  border-left: 3px solid var(--accent-cyan);
  border-radius: 0 8px 8px 0;
}
.step-phase {
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--accent-cyan);
  min-width: 85px;
}
.step-content strong {
  display: block;
  font-size: 0.95rem;
  color: var(--text-main);
  margin-bottom: 2px;
}
.step-content p {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin: 0;
}

/* Guide Detail & GEO Structured Elements */
.guide-content h2 {
  font-size: 1.45rem;
  color: var(--accent-blue);
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--card-border);
  line-height: 1.4;
}
.guide-content h3 {
  font-size: 1.18rem;
  color: var(--accent-cyan);
  margin: 1.8rem 0 0.8rem;
  line-height: 1.4;
}
.guide-content p {
  margin-bottom: 1.2rem;
  color: var(--text-main);
  line-height: 1.85;
}
.guide-content ul, .guide-content ol {
  margin: 0 0 1.4rem 1.5rem;
  color: var(--text-main);
}
.guide-content li {
  margin-bottom: 0.6rem;
  line-height: 1.75;
}
.guide-content strong {
  color: #fff;
  font-weight: 700;
}
.guide-content blockquote {
  background: rgba(56, 189, 248, 0.06);
  border-left: 4px solid var(--accent-cyan);
  padding: 1.2rem 1.4rem;
  margin: 1.5rem 0;
  border-radius: 0 8px 8px 0;
  color: var(--text-main);
}
.guide-content blockquote p:last-child {
  margin-bottom: 0;
}
.guide-content pre {
  background: #090d16;
  border: 1px solid var(--card-border);
  border-radius: 8px;
  padding: 1.2rem;
  overflow-x: auto;
  margin: 1.4rem 0;
  font-family: var(--font-mono);
  font-size: 0.88rem;
  line-height: 1.6;
  color: #d2a8ff;
}
.guide-content code {
  font-family: var(--font-mono);
  background: rgba(255, 255, 255, 0.08);
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9em;
  color: var(--accent-cyan);
}
.guide-content pre code {
  background: transparent;
  padding: 0;
  color: inherit;
}
.guide-content hr {
  border: 0;
  border-top: 1px solid var(--card-border);
  margin: 2.5rem 0;
}
.guide-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.8rem 0;
  background: #0d1117;
  border: 1px solid var(--card-border);
  border-radius: 8px;
  overflow: hidden;
  font-size: 0.92rem;
}
.guide-content th, .guide-content td {
  padding: 0.9rem 1rem;
  border: 1px solid var(--card-border);
  text-align: left;
  vertical-align: top;
  line-height: 1.6;
}
.guide-content th {
  background: rgba(57, 197, 207, 0.12);
  color: var(--accent-cyan);
  font-weight: 700;
}
.guide-content tr:nth-child(even) td {
  background: rgba(255, 255, 255, 0.02);
}

.geo-prompt-box {
  background: rgba(188, 140, 255, 0.07);
  border: 1px solid rgba(188, 140, 255, 0.35);
  border-radius: 10px;
  padding: 1.2rem 1.4rem;
  margin-bottom: 1.5rem;
}
.geo-prompt-label {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--accent-purple);
  background: rgba(188, 140, 255, 0.15);
  padding: 2px 10px;
  border-radius: 12px;
  margin-bottom: 0.5rem;
}
.geo-direct-answer {
  background: linear-gradient(135deg, rgba(57, 197, 207, 0.1), rgba(88, 166, 255, 0.05));
  border: 1px solid rgba(57, 197, 207, 0.4);
  border-radius: 10px;
  padding: 1.4rem 1.6rem;
  margin-bottom: 2rem;
}
.geo-direct-answer h2 {
  font-size: 1.1rem !important;
  color: var(--accent-cyan) !important;
  margin: 0 0 0.8rem 0 !important;
  border: none !important;
  padding: 0 !important;
}
.geo-direct-answer ul {
  margin: 0;
  padding-left: 1.3rem;
}
.geo-direct-answer li {
  margin-bottom: 0.5rem;
  font-size: 0.95rem;
  line-height: 1.65;
  color: #fff;
}
.geo-faq-section {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--card-border);
}
.geo-faq-item {
  background: #0d1117;
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 1.3rem 1.5rem;
  margin-bottom: 1rem;
}
.geo-faq-q {
  font-weight: 700;
  color: var(--accent-cyan);
  font-size: 1rem;
  margin-bottom: 0.6rem;
  line-height: 1.5;
}
.geo-faq-a {
  color: var(--text-main);
  font-size: 0.93rem;
  line-height: 1.75;
  margin: 0;
}