/* ===================================================================
   万利官网 / Wanli Generative Sports Game AI — Shared Stylesheet
   =================================================================== */

:root{
  --color-bg: #F7F5F0;
  --color-bg-alt: #EFEBE3;
  --color-surface: #FFFFFF;
  --color-ink: #23262B;
  --color-ink-soft: #4A5057;
  --color-line: #E2DED4;
  --color-blue: #0E2C4E;
  --color-blue-soft: #17406E;
  --color-cyan: #16B8B0;
  --color-cyan-soft: #E4F7F5;
  --color-orange: #FF7A33;
  --color-orange-soft: #FFE7D6;
  --color-graphite: #2B2F33;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", "Hiragino Sans GB", "Heiti SC", sans-serif;

  --radius-s: 6px;
  --radius-m: 12px;
  --radius-l: 20px;

  --shadow-card: 0 2px 14px rgba(14, 44, 78, 0.08);
  --shadow-card-hover: 0 10px 28px rgba(14, 44, 78, 0.14);

  --maxw: 1160px;
}

*, *::before, *::after{ box-sizing: border-box; }

html{ scroll-behavior: smooth; }

body{
  margin: 0;
  font-family: var(--font-sans);
  color: var(--color-ink);
  background: var(--color-bg);
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img, svg{ max-width: 100%; height: auto; display: block; }

a{ color: var(--color-blue-soft); text-decoration: none; }
a:hover{ color: var(--color-cyan); text-decoration: underline; }

h1, h2, h3, h4{
  font-weight: 700;
  color: var(--color-blue);
  line-height: 1.35;
  margin: 0 0 0.6em;
}

p{ margin: 0 0 1em; }

ul, ol{ margin: 0 0 1em; padding-left: 1.4em; }

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

/* ---------------- Skip link ---------------- */
.skip-link{
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--color-blue);
  color: #fff;
  padding: 10px 16px;
  z-index: 999;
  border-radius: 0 0 8px 0;
}
.skip-link:focus{ left: 0; }

/* ---------------- Header / Nav ---------------- */
.site-header{
  position: sticky;
  top: 0;
  z-index: 200;
  background: rgba(247, 245, 240, 0.94);
  backdrop-filter: saturate(160%) blur(6px);
  border-bottom: 1px solid var(--color-line);
}

.nav-bar{
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 20px;
  max-width: var(--maxw);
  margin: 0 auto;
  gap: 16px;
}

.brand{
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  font-size: 1.35rem;
  color: var(--color-blue);
  white-space: nowrap;
}
.brand:hover{ color: var(--color-blue); text-decoration: none; }
.brand .brand-mark{ width: 36px; height: 36px; flex-shrink: 0; }
.brand .brand-sub{
  font-size: 0.62rem;
  font-weight: 500;
  color: var(--color-ink-soft);
  display: block;
  letter-spacing: 0.02em;
}
.brand-text-wrap{ display: flex; flex-direction: column; line-height: 1.1; }

.nav-toggle{
  display: none;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  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(--color-blue);
  transition: transform .2s ease, opacity .2s ease;
}
.nav-toggle::before{ top: 12px; }
.nav-toggle span{ top: 18px; }
.nav-toggle::after{ top: 24px; }
.nav-toggle[aria-expanded="true"]::before{ transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"]::after{ transform: translateY(-6px) rotate(-45deg); }
.nav-toggle[aria-expanded="true"] span{ opacity: 0; }

.nav-links{
  display: flex;
  flex-wrap: wrap;
  gap: 4px 6px;
  list-style: none;
  margin: 0;
  padding: 0;
  justify-content: flex-end;
}
.nav-links a{
  display: inline-block;
  padding: 8px 12px;
  border-radius: var(--radius-s);
  color: var(--color-blue);
  font-size: 0.92rem;
  font-weight: 600;
}
.nav-links a:hover, .nav-links a[aria-current="page"]{
  background: var(--color-cyan-soft);
  color: var(--color-blue);
  text-decoration: none;
}
.nav-links a[aria-current="page"]{ box-shadow: inset 0 -3px 0 var(--color-cyan); }

@media (max-width: 880px){
  .nav-toggle{ display: block; }
  .nav-links{
    display: none;
    flex-direction: column;
    width: 100%;
    justify-content: flex-start;
    background: var(--color-surface);
    border: 1px solid var(--color-line);
    border-radius: var(--radius-m);
    padding: 10px;
    margin-top: 10px;
  }
  .nav-links.open{ display: flex; }
  .nav-links a{ width: 100%; }
  .nav-bar{ flex-wrap: wrap; }
}

/* ---------------- Hero ---------------- */
.hero{
  padding: 56px 0 44px;
  background:
    radial-gradient(1100px 460px at 82% -10%, rgba(22,184,176,0.14), transparent 60%),
    radial-gradient(900px 420px at -10% 10%, rgba(255,122,51,0.10), transparent 55%),
    var(--color-bg);
}
.hero-grid{
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 40px;
  align-items: center;
}
@media (max-width: 900px){
  .hero-grid{ grid-template-columns: 1fr; }
}
.eyebrow{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--color-blue-soft);
  background: var(--color-cyan-soft);
  border-radius: 999px;
  padding: 6px 14px;
  margin-bottom: 14px;
}
.hero h1{
  font-size: clamp(1.6rem, 3.4vw, 2.5rem);
  margin-bottom: 0.5em;
}
.hero-lead{
  font-size: 1.04rem;
  color: var(--color-ink-soft);
}
.hero-figure{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-l);
  padding: 18px;
  box-shadow: var(--shadow-card);
}
.hero-figure figcaption{
  font-size: 0.82rem;
  color: var(--color-ink-soft);
  margin-top: 10px;
  text-align: center;
}

.hero-actions{
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}
.btn{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.94rem;
  border: 1px solid transparent;
  cursor: pointer;
}
.btn-primary{ background: var(--color-blue); color: #fff; }
.btn-primary:hover{ background: var(--color-blue-soft); color: #fff; text-decoration: none; }
.btn-ghost{ background: var(--color-surface); border-color: var(--color-line); color: var(--color-blue); }
.btn-ghost:hover{ border-color: var(--color-cyan); text-decoration: none; }

/* ---------------- Section scaffolding ---------------- */
section{ padding: 52px 0; }
.section-alt{ background: var(--color-bg-alt); }
.section-head{ max-width: 760px; margin: 0 0 30px; }
.section-tag{
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-cyan);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
  display: block;
}
.section-head h2{ font-size: clamp(1.3rem, 2.4vw, 1.8rem); }
.section-desc{ color: var(--color-ink-soft); }

/* ---------------- TOC ---------------- */
.toc{
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.toc a{
  display: inline-block;
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: 999px;
  padding: 7px 14px;
  font-size: 0.86rem;
  font-weight: 600;
  color: var(--color-blue-soft);
}
.toc a:hover{ background: var(--color-cyan-soft); text-decoration: none; }

/* ---------------- Core long-form articles ---------------- */
.core-article{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-l);
  padding: 30px clamp(18px, 4vw, 38px);
  margin-bottom: 26px;
  box-shadow: var(--shadow-card);
  scroll-margin-top: 90px;
}
.core-article .tag-row{
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}
.tag{
  font-size: 0.74rem;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--color-cyan-soft);
  color: var(--color-blue-soft);
}
.tag-orange{ background: var(--color-orange-soft); color: #A6480F; }
.core-article h3{ font-size: clamp(1.12rem, 2.2vw, 1.42rem); }
.core-article .meta-line{
  font-size: 0.82rem;
  color: var(--color-ink-soft);
  margin-bottom: 16px;
}
.figure-inline{
  margin: 18px 0;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 14px;
  background: var(--color-bg-alt);
}
.figure-inline figcaption{
  font-size: 0.8rem;
  color: var(--color-ink-soft);
  margin-top: 8px;
}
.callout{
  border-left: 3px solid var(--color-cyan);
  background: var(--color-cyan-soft);
  padding: 12px 16px;
  border-radius: 0 var(--radius-s) var(--radius-s) 0;
  font-size: 0.95rem;
  margin: 16px 0;
}
.further-reading{
  margin-top: 18px;
  padding-top: 14px;
  border-top: 1px dashed var(--color-line);
  font-size: 0.9rem;
  color: var(--color-ink-soft);
}
.further-reading strong{ color: var(--color-blue); }

/* ---------------- Observation cards ---------------- */
.observation-grid{
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
@media (max-width: 900px){ .observation-grid{ grid-template-columns: 1fr; } }
.observation-card{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 22px;
  box-shadow: var(--shadow-card);
}
.observation-card h3{ font-size: 1.02rem; }
.observation-card p{ font-size: 0.94rem; color: var(--color-ink-soft); }

/* ---------------- Cluster / excerpt cards ---------------- */
.cluster-block{ margin-bottom: 34px; }
.cluster-head{
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}
.cluster-head h3{ font-size: 1.12rem; margin-bottom: 0; }
.cluster-head a.more{ font-size: 0.86rem; font-weight: 700; }

.excerpt-grid{
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
@media (max-width: 980px){ .excerpt-grid{ grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px){ .excerpt-grid{ grid-template-columns: 1fr; } }

.excerpt-card{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 18px;
  display: flex;
  flex-direction: column;
  transition: box-shadow .15s ease, transform .15s ease;
}
.excerpt-card:hover{ box-shadow: var(--shadow-card-hover); transform: translateY(-2px); }
.excerpt-card h4{
  font-size: 0.98rem;
  margin-bottom: 8px;
  color: var(--color-blue);
}
.excerpt-card h4 a{ color: inherit; }
.excerpt-card h4 a:hover{ color: var(--color-cyan); }
.excerpt-card p{
  font-size: 0.87rem;
  color: var(--color-ink-soft);
  flex: 1;
  margin-bottom: 10px;
}
.excerpt-card .read-more{ font-size: 0.82rem; font-weight: 700; }

/* ---------------- Feature grid (secondary pages) ---------------- */
.feature-grid{
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
@media (max-width: 980px){ .feature-grid{ grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px){ .feature-grid{ grid-template-columns: 1fr; } }
.feature-card{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 18px;
  text-align: left;
}
.feature-card .icon{ width: 34px; height: 34px; margin-bottom: 10px; }
.feature-card h4{ font-size: 0.98rem; }
.feature-card p{ font-size: 0.86rem; color: var(--color-ink-soft); margin-bottom: 0; }

/* ---------------- Pipeline diagram wrapper ---------------- */
.pipeline-figure{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-l);
  padding: 20px;
  box-shadow: var(--shadow-card);
}
.pipeline-figure figcaption{
  font-size: 0.84rem;
  color: var(--color-ink-soft);
  margin-top: 10px;
  text-align: center;
}

/* ---------------- FAQ ---------------- */
.faq-list{ display: flex; flex-direction: column; gap: 10px; }
.faq-item{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 4px 18px;
}
.faq-item summary{
  cursor: pointer;
  font-weight: 700;
  padding: 14px 0;
  color: var(--color-blue);
  list-style: none;
  position: relative;
  padding-right: 28px;
}
.faq-item summary::-webkit-details-marker{ display: none; }
.faq-item summary::after{
  content: "+";
  position: absolute;
  right: 0;
  top: 12px;
  font-size: 1.3rem;
  color: var(--color-cyan);
}
.faq-item[open] summary::after{ content: "\2212"; }
.faq-item p{ color: var(--color-ink-soft); padding-bottom: 16px; margin-bottom: 0; }

/* ---------------- About ---------------- */
.about-box{
  background: var(--color-surface);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-l);
  padding: clamp(20px, 4vw, 34px);
  box-shadow: var(--shadow-card);
}
.about-box p{ color: var(--color-ink-soft); }
.about-facts{
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 18px;
}
@media (max-width: 760px){ .about-facts{ grid-template-columns: 1fr; } }
.about-fact{
  background: var(--color-bg-alt);
  border-radius: var(--radius-s);
  padding: 14px;
  font-size: 0.86rem;
}
.about-fact strong{ display: block; color: var(--color-blue); margin-bottom: 4px; }

/* ---------------- Footer ---------------- */
.site-footer{
  background: var(--color-graphite);
  color: #D8DBDE;
  padding: 46px 0 24px;
  margin-top: 20px;
  font-size: 0.9rem;
}
.footer-grid{
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 28px;
  margin-bottom: 26px;
}
@media (max-width: 760px){ .footer-grid{ grid-template-columns: 1fr; } }
.footer-brand{ font-size: 1.2rem; font-weight: 800; color: #fff; margin-bottom: 10px; }
.footer-col h5{
  color: #fff;
  font-size: 0.86rem;
  letter-spacing: 0.03em;
  margin-bottom: 12px;
  text-transform: uppercase;
}
.footer-col ul{ list-style: none; padding: 0; margin: 0; }
.footer-col li{ margin-bottom: 8px; }
.footer-col a{ color: #B9BEC4; }
.footer-col a:hover{ color: #fff; }
.footer-bottom{
  border-top: 1px solid #40454B;
  padding-top: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  justify-content: space-between;
  color: #9CA1A7;
  font-size: 0.82rem;
}

/* ---------------- Back to top ---------------- */
.back-to-top{
  position: fixed;
  right: 18px;
  bottom: 18px;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-blue);
  color: #fff;
  border: none;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 6px 18px rgba(14,44,78,0.3);
  z-index: 150;
  font-size: 1.1rem;
}
.back-to-top.visible{ display: flex; }

/* ---------------- Utility ---------------- */
.visually-hidden{
  position: absolute;
  width: 1px; height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}
.mt-0{ margin-top: 0; }
.text-center{ text-align: center; }
.small-note{ font-size: 0.82rem; color: var(--color-ink-soft); }

.chain-note{
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.8rem;
  color: var(--color-blue-soft);
  background: var(--color-bg-alt);
  padding: 4px 10px;
  border-radius: 999px;
  margin: 2px 6px 2px 0;
}