/* ==========================================================================
   龙虎斗游戏官网 — 全站样式表
   Tactical AI Command Center / Game Director Control Room /
   Sandbox Simulation Observatory / Civilization Strategy Terminal
   ========================================================================== */

:root {
  --bg-deep: #0a0d12;
  --bg-panel: #10151d;
  --bg-panel-2: #151c27;
  --bg-panel-3: #1a2230;
  --line: #232c3b;
  --line-soft: #1a2130;

  --text-primary: #e9edf4;
  --text-secondary: #a8b3c4;
  --text-dim: #6d7889;

  --blue: #3b74e0;
  --blue-soft: #274a8c;
  --cyan: #2fd0c6;
  --purple: #8f74f0;
  --orange: #e79a3f;
  --red: #e0564d;
  --white: #f5f7fb;

  --radius: 10px;
  --radius-lg: 16px;
  --maxw: 1180px;

  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", -apple-system, sans-serif;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg-deep);
  color: var(--text-primary);
  font-family: var(--font);
  line-height: 1.75;
  font-size: 16px;
  overflow-x: hidden;
  background-image:
    radial-gradient(ellipse 900px 500px at 15% -10%, rgba(59, 116, 224, 0.12), transparent 60%),
    radial-gradient(ellipse 900px 600px at 100% 0%, rgba(143, 116, 240, 0.10), transparent 60%);
  background-repeat: no-repeat;
}

img { max-width: 100%; display: block; }
a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3, h4 { color: var(--white); line-height: 1.4; font-weight: 700; margin: 0 0 .6em; }
p { margin: 0 0 1em; color: var(--text-secondary); }
ul, ol { color: var(--text-secondary); }

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Skip link ---------- */
.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--blue);
  color: #fff;
  padding: 10px 16px;
  z-index: 999;
}
.skip-link:focus { left: 10px; top: 10px; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(10, 13, 18, 0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 20px;
  max-width: var(--maxw);
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--white);
  font-weight: 800;
  font-size: 18px;
  white-space: nowrap;
}
.brand img { width: 32px; height: 32px; }

.nav-toggle {
  display: none;
  background: var(--bg-panel-2);
  border: 1px solid var(--line);
  color: var(--text-primary);
  border-radius: 8px;
  padding: 8px 12px;
  cursor: pointer;
  font-size: 14px;
}

.main-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 6px;
  justify-content: flex-end;
}

.main-nav a {
  color: var(--text-secondary);
  font-size: 13.5px;
  padding: 8px 10px;
  border-radius: 8px;
  white-space: nowrap;
}
.main-nav a:hover,
.main-nav a[aria-current="page"] {
  color: var(--white);
  background: var(--bg-panel-2);
  text-decoration: none;
}

/* ---------- Hero ---------- */
.hero {
  padding: 56px 0 40px;
  border-bottom: 1px solid var(--line-soft);
}
.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 40px;
  align-items: center;
}
.eyebrow {
  display: inline-block;
  font-size: 12.5px;
  letter-spacing: .06em;
  color: var(--cyan);
  background: rgba(47, 208, 198, 0.08);
  border: 1px solid rgba(47, 208, 198, 0.25);
  padding: 4px 10px;
  border-radius: 999px;
  margin-bottom: 14px;
}
.hero h1 {
  font-size: 32px;
  margin-bottom: 16px;
}
.hero .lead {
  font-size: 16px;
  color: var(--text-secondary);
}
.hero-art {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--bg-panel);
  padding: 12px;
}

/* ---------- Section ---------- */
section { padding: 48px 0; }
.section-head {
  margin-bottom: 28px;
}
.section-head h2 {
  font-size: 24px;
}
.section-head .sub {
  color: var(--text-dim);
  font-size: 14.5px;
}
.divider {
  height: 1px;
  background: var(--line-soft);
  border: none;
  margin: 0;
}

/* ---------- System overview cards ---------- */
.system-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 14px;
}
.system-card {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 16px;
}
.system-card .tag {
  font-size: 11.5px;
  color: var(--cyan);
  letter-spacing: .04em;
}
.system-card h3 {
  font-size: 15.5px;
  margin: 8px 0 6px;
}
.system-card p {
  font-size: 13.5px;
  margin: 0;
}

/* ---------- Article ---------- */
.article {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 30px 30px 24px;
  margin-bottom: 26px;
  scroll-margin-top: 90px;
}
.article .kicker {
  font-size: 12.5px;
  color: var(--purple);
  letter-spacing: .04em;
  margin-bottom: 8px;
}
.article h2, .article h3.article-title {
  font-size: 21px;
  color: var(--white);
}
.article .meta {
  font-size: 12.5px;
  color: var(--text-dim);
  margin-bottom: 16px;
}
.article figure {
  margin: 20px 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-panel-2);
  padding: 14px;
}
.article figure figcaption {
  font-size: 12.5px;
  color: var(--text-dim);
  margin-top: 8px;
  text-align: center;
}
.article h4 {
  font-size: 15.5px;
  color: var(--white);
  margin-top: 22px;
}

.related-reading {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px dashed var(--line);
}
.related-reading h3 {
  font-size: 13.5px;
  color: var(--text-dim);
  font-weight: 600;
  margin-bottom: 10px;
  letter-spacing: .03em;
}
.related-reading ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}
.related-reading a {
  font-size: 14px;
  color: var(--cyan);
}
.related-reading a::before {
  content: "→ ";
  color: var(--text-dim);
}

/* ---------- Summary grid (回流卡片) ---------- */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.summary-grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.summary-card {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
  display: flex;
  flex-direction: column;
}
.summary-card .badge {
  font-size: 11px;
  color: var(--orange);
  margin-bottom: 8px;
}
.summary-card h4 {
  font-size: 15px;
  margin-bottom: 8px;
}
.summary-card p {
  font-size: 13.5px;
  flex: 1;
}
.summary-card a.more {
  font-size: 13px;
  margin-top: 10px;
  color: var(--cyan);
}

/* ---------- Category section title bar ---------- */
.cat-bar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 16px;
  flex-wrap: wrap;
  gap: 8px;
}
.cat-bar h2 { font-size: 20px; margin: 0; }
.cat-bar a.view-all { font-size: 13.5px; color: var(--text-dim); }

/* ---------- FAQ ---------- */
.faq-grid {
  display: grid;
  gap: 10px;
}
.faq-item {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 4px 18px;
}
.faq-item summary {
  cursor: pointer;
  padding: 14px 0;
  color: var(--white);
  font-size: 14.5px;
  font-weight: 600;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 12px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  color: var(--text-dim);
  flex-shrink: 0;
}
.faq-item[open] summary::after { content: "–"; }
.faq-item p {
  padding-bottom: 14px;
  margin: 0;
  font-size: 13.8px;
}
.faq-cols {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px 16px;
}

/* ---------- Company / disclaimer ---------- */
.panel {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 28px 30px;
}
.disclaimer {
  font-size: 12.5px;
  color: var(--text-dim);
  border-top: 1px solid var(--line-soft);
  padding-top: 16px;
  margin-top: 16px;
}

/* ---------- Breadcrumb ---------- */
.breadcrumb {
  font-size: 13px;
  color: var(--text-dim);
  padding: 14px 0 0;
}
.breadcrumb a { color: var(--text-dim); }
.breadcrumb a:hover { color: var(--cyan); }

/* ---------- Page hero (secondary pages) ---------- */
.page-hero {
  padding: 40px 0 30px;
  border-bottom: 1px solid var(--line-soft);
}
.page-hero h1 { font-size: 27px; }
.page-hero .lead { max-width: 760px; }
.stat-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-top: 16px;
}
.stat-chip {
  font-size: 12.5px;
  color: var(--text-secondary);
  border: 1px solid var(--line);
  background: var(--bg-panel);
  padding: 6px 12px;
  border-radius: 999px;
}

/* ---------- Timeline / pipeline strip ---------- */
.pipeline {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  font-size: 13px;
  color: var(--text-secondary);
  background: var(--bg-panel-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin: 18px 0;
}
.pipeline .step {
  background: var(--bg-panel-3);
  border: 1px solid var(--line);
  padding: 6px 10px;
  border-radius: 8px;
  color: var(--white);
  font-size: 12.5px;
}
.pipeline .arrow { color: var(--text-dim); }

/* ---------- App feature grid ---------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 14px;
}
.feature-card {
  background: var(--bg-panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
  text-align: center;
}
.feature-card .num {
  font-size: 12px;
  color: var(--purple);
}
.feature-card h4 { font-size: 14px; margin: 6px 0 0; }

.download-note {
  background: var(--bg-panel-2);
  border: 1px solid var(--line);
  border-left: 3px solid var(--orange);
  border-radius: var(--radius);
  padding: 16px 18px;
  font-size: 13.8px;
  color: var(--text-secondary);
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-panel);
  padding: 40px 0 24px;
  margin-top: 40px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.3fr repeat(2, 1fr);
  gap: 30px;
}
.footer-col h4 {
  font-size: 13.5px;
  color: var(--text-dim);
  letter-spacing: .04em;
  margin-bottom: 12px;
}
.footer-col ul { list-style: none; margin: 0; padding: 0; }
.footer-col li { margin-bottom: 8px; }
.footer-col a { color: var(--text-secondary); font-size: 13.8px; }
.footer-brand {
  color: var(--white);
  font-weight: 800;
  font-size: 17px;
  margin-bottom: 10px;
}
.footer-legal {
  font-size: 12.5px;
  color: var(--text-dim);
  line-height: 1.9;
}
.footer-bottom {
  margin-top: 30px;
  padding-top: 18px;
  border-top: 1px solid var(--line-soft);
  font-size: 12.2px;
  color: var(--text-dim);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- 轻量状态演示组件 ---------- */
.sim-widget {
  background: var(--bg-panel-2);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px 18px;
  margin: 18px 0;
}
.sim-widget .sim-buttons {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 12px;
}
.sim-widget button {
  font-size: 12.8px;
  color: var(--text-secondary);
  background: var(--bg-panel-3);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 6px 13px;
  cursor: pointer;
}
.sim-widget button.active {
  color: var(--white);
  border-color: var(--cyan);
  background: rgba(47, 208, 198, 0.12);
}
.sim-bar-track {
  height: 8px;
  background: var(--bg-panel-3);
  border-radius: 999px;
  overflow: hidden;
  border: 1px solid var(--line);
}
.sim-bar-fill {
  height: 100%;
  width: 30%;
  background: linear-gradient(90deg, var(--blue), var(--cyan));
  transition: width .35s ease;
}
.sim-label {
  display: block;
  margin-top: 10px;
  font-size: 12.8px;
  color: var(--text-dim);
}

/* ---------- Back to top ---------- */
.back-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--blue);
  color: #fff;
  border: none;
  cursor: pointer;
  font-size: 16px;
  opacity: 0;
  visibility: hidden;
  transition: opacity .2s;
  z-index: 90;
}
.back-top.show { opacity: 1; visibility: visible; }

/* ---------- Responsive ---------- */
@media (max-width: 980px) {
  .hero-grid { grid-template-columns: 1fr; }
  .system-grid { grid-template-columns: repeat(2, 1fr); }
  .summary-grid, .summary-grid.cols-4 { grid-template-columns: 1fr 1fr; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .faq-cols { grid-template-columns: 1fr; }
}

@media (max-width: 680px) {
  .nav-toggle { display: inline-block; }
  .main-nav {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: stretch;
    background: var(--bg-panel);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 8px;
    margin-top: 10px;
  }
  .main-nav.open { display: flex; }
  .header-inner { flex-wrap: wrap; }
  .system-grid { grid-template-columns: 1fr; }
  .summary-grid, .summary-grid.cols-4 { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .article { padding: 22px 18px; }
  .hero h1 { font-size: 25px; }
  .page-hero h1 { font-size: 22px; }
}