/* ==========================================================================
   买球网官网 - 全站样式表
   Modern Sports Technology Magazine + Smart Stadium Lab + Sports Engineering Review
   ========================================================================== */

:root {
  --c-bg: #f7f5f0;              /* 暖白 */
  --c-bg-alt: #efece3;
  --c-surface: #ffffff;
  --c-ink: #1c2430;             /* 石墨灰-深 */
  --c-ink-soft: #4a5568;
  --c-line: #e2ddd0;
  --c-line-strong: #d3ccba;

  --c-blue: #0b3d75;            /* 深体育蓝 */
  --c-blue-soft: #eaf1fa;
  --c-cyan: #0f8fa3;            /* 工程青 */
  --c-cyan-soft: #e6f5f7;
  --c-green: #2f7d4f;           /* 草坪绿 */
  --c-green-soft: #e9f5ee;
  --c-orange: #c9611f;          /* 装备橙 */
  --c-orange-soft: #fbeee1;
  --c-graphite: #3a3f47;        /* 石墨灰 */

  --radius-s: 6px;
  --radius-m: 12px;
  --radius-l: 20px;
  --shadow-card: 0 2px 14px rgba(20, 30, 45, 0.08);
  --shadow-pop: 0 10px 30px rgba(20, 30, 45, 0.14);

  --font-base: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Segoe UI", system-ui, sans-serif;
  --font-mono: "Consolas", "SFMono-Regular", Menlo, monospace;

  --maxw: 1180px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-ink);
  font-family: var(--font-base);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--c-blue); text-decoration: none; }
a:hover { text-decoration: underline; }
ul, ol { padding-left: 1.3em; }
h1, h2, h3, h4 { line-height: 1.35; font-weight: 700; color: var(--c-ink); margin: 0 0 .6em; }
p { margin: 0 0 1em; }
.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }
.visually-hidden { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 200;
  background: rgba(247,245,240,0.96);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--c-line);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 66px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 20px; color: var(--c-blue); }
.logo .logo-mark { width: 34px; height: 34px; flex-shrink: 0; }
.logo .logo-sub { font-size: 12px; font-weight: 500; color: var(--c-ink-soft); display: block; }
.main-nav { display: flex; align-items: center; gap: 2px; }
.main-nav a {
  color: var(--c-ink);
  font-size: 14.5px;
  font-weight: 600;
  padding: 9px 12px;
  border-radius: var(--radius-s);
  white-space: nowrap;
}
.main-nav a:hover, .main-nav a.active { background: var(--c-blue-soft); color: var(--c-blue); text-decoration: none; }
.nav-toggle {
  display: none; background: none; border: 1px solid var(--c-line-strong); border-radius: var(--radius-s);
  width: 42px; height: 38px; cursor: pointer; position: relative;
}
.nav-toggle span, .nav-toggle::before, .nav-toggle::after {
  content: ""; position: absolute; left: 9px; right: 9px; height: 2px; background: var(--c-ink); transition: .2s;
}
.nav-toggle::before { top: 12px; }
.nav-toggle span { top: 18px; }
.nav-toggle::after { top: 24px; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(160deg, var(--c-blue) 0%, #103a63 45%, var(--c-cyan) 100%);
  color: #fff;
  padding: 56px 0 46px;
}
.hero .container { display: grid; grid-template-columns: 1.15fr .85fr; gap: 40px; align-items: center; }
.hero-eyebrow { font-size: 13px; letter-spacing: .06em; text-transform: uppercase; color: #bcd6ee; font-weight: 700; margin-bottom: 14px; }
.hero h1 { color: #fff; font-size: clamp(26px, 3.4vw, 38px); margin-bottom: 16px; }
.hero p.lead { color: #eaf1fa; font-size: 16px; line-height: 1.85; }
.hero-links { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 22px; }
.hero-links a {
  background: rgba(255,255,255,0.12); border: 1px solid rgba(255,255,255,0.35); color: #fff;
  padding: 9px 16px; border-radius: 999px; font-size: 13.5px; font-weight: 600;
}
.hero-links a:hover { background: rgba(255,255,255,0.24); text-decoration: none; }
.hero-visual { background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.25); border-radius: var(--radius-l); padding: 14px; }
.hero-visual svg { width: 100%; height: auto; }

/* sub-page hero (smaller, page-tinted) */
.page-hero { padding: 44px 0 36px; color: #fff; }
.page-hero .container { display: grid; grid-template-columns: 1.2fr .8fr; gap: 34px; align-items: center; }
.page-hero h1 { color: #fff; font-size: clamp(24px, 3vw, 32px); }
.page-hero p.lead { color: rgba(255,255,255,0.92); font-size: 15.5px; }
.page-hero .tag-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.page-hero .tag-row span { background: rgba(255,255,255,0.16); border: 1px solid rgba(255,255,255,0.3); padding: 5px 12px; border-radius: 999px; font-size: 12.5px; }
.theme-venue .page-hero, .theme-venue .section-band { background: linear-gradient(150deg, var(--c-blue), var(--c-cyan)); }
.theme-sports .page-hero { background: linear-gradient(150deg, #0b3d75, #1c5f8e); }
.theme-ai .page-hero { background: linear-gradient(150deg, #0f8fa3, #0b3d75); }
.theme-equipment .page-hero { background: linear-gradient(150deg, var(--c-graphite), var(--c-orange)); }
.theme-entertainment .page-hero { background: linear-gradient(150deg, #0b3d75, #2f7d4f); }
.theme-virtual .page-hero { background: linear-gradient(150deg, #123a63, #0f8fa3); }
.theme-app .page-hero { background: linear-gradient(150deg, #0b3d75, #16466e); }

/* ---------- Sections ---------- */
section { padding: 54px 0; }
section.alt { background: var(--c-bg-alt); }
section.surface { background: var(--c-surface); border-top: 1px solid var(--c-line); border-bottom: 1px solid var(--c-line); }
.section-head { max-width: 780px; margin-bottom: 30px; }
.section-head .kicker { display: inline-block; font-size: 12.5px; font-weight: 800; letter-spacing: .05em; color: var(--c-cyan); text-transform: uppercase; margin-bottom: 8px; }
.section-head h2 { font-size: clamp(22px, 2.6vw, 28px); }
.section-head p { color: var(--c-ink-soft); font-size: 15px; }

/* ---------- Cards / Grids ---------- */
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.card {
  background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius-m);
  padding: 22px; box-shadow: var(--shadow-card);
}
.card h3 { font-size: 17px; margin-bottom: 8px; }
.card p { color: var(--c-ink-soft); font-size: 14.5px; margin-bottom: 0; }
.card .card-icon { width: 40px; height: 40px; margin-bottom: 14px; }

.nav-card-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.nav-card {
  display: block; background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius-m);
  padding: 18px; transition: transform .15s, box-shadow .15s;
}
.nav-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-pop); text-decoration: none; }
.nav-card .nc-word { font-size: 15.5px; font-weight: 800; color: var(--c-blue); margin-bottom: 4px; }
.nav-card .nc-desc { font-size: 13px; color: var(--c-ink-soft); }

/* ---------- Articles (long-form) ---------- */
.article-block {
  background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius-l);
  padding: 34px clamp(20px, 4vw, 40px); margin-bottom: 26px; box-shadow: var(--shadow-card);
}
.article-block .a-meta { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; margin-bottom: 12px; }
.article-block .a-cat { background: var(--c-blue-soft); color: var(--c-blue); font-size: 12px; font-weight: 800; padding: 4px 10px; border-radius: 999px; }
.article-block .a-cat.cat-equip { background: var(--c-orange-soft); color: var(--c-orange); }
.article-block .a-cat.cat-pitch { background: var(--c-green-soft); color: var(--c-green); }
.article-block .a-cat.cat-ai { background: var(--c-cyan-soft); color: var(--c-cyan); }
.article-block h2 { font-size: clamp(19px, 2.4vw, 24px); }
.article-block .a-fig { margin: 20px 0; border: 1px solid var(--c-line); border-radius: var(--radius-m); background: var(--c-bg-alt); padding: 14px; }
.article-block .a-fig figcaption { font-size: 12.5px; color: var(--c-ink-soft); margin-top: 8px; text-align: center; }
.article-block .a-body p { font-size: 15.3px; color: #2a323d; }
.article-block .a-body strong { color: var(--c-blue); }

article.long h3.sub { font-size: 16.5px; margin-top: 22px; color: var(--c-cyan); }

/* summary rollup cards (index page, 21 items) */
.summary-list { display: grid; gap: 16px; }
.summary-item {
  background: var(--c-surface); border: 1px solid var(--c-line); border-left: 4px solid var(--c-cyan);
  border-radius: var(--radius-m); padding: 18px 20px;
}
.summary-item .s-col { font-size: 12px; font-weight: 800; color: var(--c-cyan); text-transform: uppercase; letter-spacing: .03em; margin-bottom: 6px; }
.summary-item h4 { font-size: 15.5px; margin-bottom: 8px; }
.summary-item h4 a { color: var(--c-ink); }
.summary-item h4 a:hover { color: var(--c-blue); }
.summary-item p { font-size: 13.8px; color: var(--c-ink-soft); margin-bottom: 6px; }
.summary-item .s-link { font-size: 13px; font-weight: 700; }

.page-tabs { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 24px; }
.page-tabs button {
  background: var(--c-surface); border: 1px solid var(--c-line-strong); color: var(--c-ink);
  padding: 8px 16px; border-radius: 999px; font-size: 13.5px; font-weight: 700; cursor: pointer;
}
.page-tabs button.active { background: var(--c-blue); color: #fff; border-color: var(--c-blue); }
.tab-panel { display: none; }
.tab-panel.active { display: block; }

/* ---------- Compare table (horizontal-scroll allowed) ---------- */
.scroll-table { overflow-x: auto; border: 1px solid var(--c-line); border-radius: var(--radius-m); background: var(--c-surface); }
.scroll-table table { border-collapse: collapse; width: 100%; min-width: 640px; font-size: 13.8px; }
.scroll-table th, .scroll-table td { padding: 12px 14px; border-bottom: 1px solid var(--c-line); text-align: left; vertical-align: top; }
.scroll-table th { background: var(--c-bg-alt); font-weight: 800; color: var(--c-blue); }

/* ---------- FAQ ---------- */
.faq-list { border-top: 1px solid var(--c-line); }
.faq-item { border-bottom: 1px solid var(--c-line); }
.faq-q {
  width: 100%; text-align: left; background: none; border: none; cursor: pointer;
  padding: 17px 4px; font-size: 15.3px; font-weight: 700; color: var(--c-ink);
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
}
.faq-q .qm { color: var(--c-cyan); font-size: 18px; flex-shrink: 0; transition: transform .2s; }
.faq-item.open .qm { transform: rotate(45deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .25s ease; }
.faq-item.open .faq-a { max-height: 400px; }
.faq-a p { padding: 0 4px 18px; color: var(--c-ink-soft); font-size: 14.3px; margin: 0; }

/* ---------- Chain / process diagram wrapper ---------- */
.chain-wrap { background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius-l); padding: 24px; margin: 20px 0; }
.chain-wrap svg { width: 100%; height: auto; }
.chain-wrap .chain-cap { font-size: 13px; color: var(--c-ink-soft); text-align: center; margin-top: 10px; }

/* ---------- About ---------- */
.about-box { background: var(--c-surface); border: 1px solid var(--c-line); border-radius: var(--radius-l); padding: 30px clamp(20px,4vw,40px); }

/* ---------- Footer ---------- */
.site-footer { background: #12202f; color: #cdd8e3; padding: 46px 0 22px; margin-top: 30px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 30px; }
.site-footer h5 { color: #fff; font-size: 14px; margin-bottom: 12px; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: 8px; }
.site-footer a { color: #aebdcc; font-size: 13.5px; }
.site-footer a:hover { color: #fff; }
.footer-brand { font-weight: 800; color: #fff; font-size: 19px; margin-bottom: 10px; }
.footer-desc { font-size: 13.3px; color: #9fb0c2; line-height: 1.8; }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.12); margin-top: 30px; padding-top: 18px; font-size: 12.8px; color: #8ea0b3; display: flex; flex-wrap: wrap; gap: 8px 18px; justify-content: space-between; }

/* ---------- Back to top ---------- */
.back-top {
  position: fixed; right: 22px; bottom: 22px; width: 44px; height: 44px; border-radius: 50%;
  background: var(--c-blue); color: #fff; border: none; cursor: pointer; box-shadow: var(--shadow-pop);
  display: none; align-items: center; justify-content: center; font-size: 18px; z-index: 150;
}
.back-top.show { display: flex; }

/* ---------- Breadcrumb / connectors ---------- */
.link-chain { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; font-size: 13px; color: var(--c-ink-soft); margin: 14px 0 0; }
.link-chain a { font-weight: 700; }
.link-chain .sep { color: var(--c-line-strong); }

.tag-strip { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0; }
.tag-strip span { background: var(--c-bg-alt); border: 1px solid var(--c-line); padding: 4px 10px; border-radius: 999px; font-size: 12px; color: var(--c-ink-soft); }

.callout {
  border-left: 4px solid var(--c-orange); background: var(--c-orange-soft); border-radius: var(--radius-s);
  padding: 14px 18px; font-size: 14.3px; color: #6b3c14; margin: 18px 0;
}
.callout.blue { border-left-color: var(--c-blue); background: var(--c-blue-soft); color: #1c3a5c; }
.callout.green { border-left-color: var(--c-green); background: var(--c-green-soft); color: #245a3a; }

/* ---------- Feature list (App) ---------- */
.feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
.feature-grid .f-num { font-size: 12px; font-weight: 800; color: var(--c-cyan); }

/* =========================== Responsive =========================== */
@media (max-width: 980px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .nav-card-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .hero .container, .page-hero .container { grid-template-columns: 1fr; }
  .hero-visual { order: -1; }
}
@media (max-width: 760px) {
  .main-nav { display: none; position: absolute; top: 66px; left: 0; right: 0; background: var(--c-bg); border-bottom: 1px solid var(--c-line); flex-direction: column; padding: 8px 14px 16px; box-shadow: var(--shadow-pop); }
  .main-nav.open { display: flex; }
  .main-nav a { width: 100%; padding: 12px 10px; }
  .nav-toggle { display: block; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .nav-card-grid { grid-template-columns: 1fr 1fr; }
  .feature-grid { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  section { padding: 40px 0; }
}
@media (max-width: 420px) {
  .nav-card-grid, .footer-grid, .feature-grid { grid-template-columns: 1fr; }
  .article-block { padding: 24px 16px; }
  .hero, .page-hero { padding: 34px 0 28px; }
}