/* ===========================================================
   波胆网官网 - 全站样式表
   Football Analytics Lab + Sports Intelligence Desk 视觉体系
   =========================================================== */

:root {
  --color-bg: #f6f4ee;
  --color-bg-alt: #efece2;
  --color-panel: #ffffff;
  --color-navy: #0b2a4a;
  --color-navy-deep: #071c33;
  --color-cyan: #0e93a6;
  --color-cyan-light: #e4f4f6;
  --color-green: #3c7d54;
  --color-green-light: #e7f2ea;
  --color-orange: #d97a1f;
  --color-orange-light: #faeee0;
  --color-graphite: #33363b;
  --color-muted: #6b7280;
  --color-line: #e1ddd0;
  --color-line-strong: #cfc9b8;
  --radius-s: 6px;
  --radius-m: 10px;
  --radius-l: 16px;
  --shadow-card: 0 2px 10px rgba(11, 42, 74, 0.06);
  --shadow-card-hover: 0 8px 24px rgba(11, 42, 74, 0.10);
  --font-sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
    "Helvetica Neue", Arial, sans-serif;
  --max-width: 1120px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

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

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

a {
  color: var(--color-cyan);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

p {
  margin: 0 0 1em;
}

ul, ol {
  padding-left: 1.3em;
}

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

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* ---------------- Header / Nav ---------------- */

.site-header {
  background: var(--color-navy);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-weight: 700;
  font-size: 20px;
  letter-spacing: 0.5px;
}

.brand:hover {
  text-decoration: none;
  opacity: 0.9;
}

.brand-mark {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
}

.brand-sub {
  font-size: 11px;
  font-weight: 400;
  color: #9fb3c8;
  display: block;
  letter-spacing: 1px;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 4px;
}

.main-nav a {
  color: #d7e2ec;
  font-size: 14.5px;
  padding: 10px 12px;
  border-radius: var(--radius-s);
  transition: background 0.15s, color 0.15s;
}

.main-nav a:hover,
.main-nav a:focus {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  text-decoration: none;
}

.main-nav a.is-active {
  background: var(--color-cyan);
  color: #fff;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid rgba(255, 255, 255, 0.35);
  border-radius: var(--radius-s);
  color: #fff;
  font-size: 22px;
  line-height: 1;
  padding: 6px 10px;
  cursor: pointer;
}

/* ---------------- Hero ---------------- */

.hero {
  background: linear-gradient(150deg, var(--color-navy-deep) 0%, var(--color-navy) 55%, #113a5c 100%);
  color: #eef3f7;
  padding: 52px 0 44px;
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: "";
  position: absolute;
  right: -80px;
  top: -80px;
  width: 340px;
  height: 340px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(14, 147, 166, 0.25), transparent 70%);
}

.hero-kicker {
  display: inline-block;
  background: rgba(14, 147, 166, 0.18);
  border: 1px solid rgba(14, 147, 166, 0.5);
  color: #8fe0ea;
  font-size: 13px;
  padding: 4px 12px;
  border-radius: 999px;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
}

.hero h1 {
  color: #fff;
  font-size: clamp(24px, 4vw, 34px);
  max-width: 820px;
}

.hero-lead {
  max-width: 760px;
  color: #c9d6e2;
  font-size: 16px;
}

.hero-disclaimer {
  margin-top: 18px;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.06);
  border-left: 3px solid var(--color-orange);
  border-radius: var(--radius-s);
  font-size: 14px;
  color: #e8dfce;
  max-width: 760px;
}

.hero-cta-row {
  margin-top: 22px;
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  border-radius: 999px;
  font-size: 14.5px;
  font-weight: 600;
  border: 1px solid transparent;
  cursor: pointer;
}

.btn-primary {
  background: var(--color-cyan);
  color: #fff;
}

.btn-primary:hover {
  background: #0c7f90;
  text-decoration: none;
}

.btn-ghost {
  background: transparent;
  color: #eef3f7;
  border-color: rgba(255, 255, 255, 0.4);
}

.btn-ghost:hover {
  background: rgba(255, 255, 255, 0.08);
  text-decoration: none;
}

/* ---------------- Section scaffolding ---------------- */

.section {
  padding: 46px 0;
  border-bottom: 1px solid var(--color-line);
}

.section-alt {
  background: var(--color-bg-alt);
}

.section-head {
  max-width: 760px;
  margin-bottom: 26px;
}

.section-label {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  color: var(--color-cyan);
  text-transform: uppercase;
  letter-spacing: 1.2px;
  margin-bottom: 8px;
}

.section-head h2 {
  font-size: clamp(21px, 3vw, 27px);
  margin-bottom: 8px;
}

.section-desc {
  color: var(--color-muted);
  font-size: 15px;
}

/* ---------------- Trend / observation grid ---------------- */

.trend-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

.trend-card {
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 18px 20px;
  box-shadow: var(--shadow-card);
}

.trend-card h3 {
  font-size: 16px;
  margin-bottom: 8px;
  color: var(--color-navy);
}

.trend-card p {
  font-size: 14px;
  color: var(--color-graphite);
  margin-bottom: 0;
}

.tag {
  display: inline-block;
  font-size: 11.5px;
  font-weight: 700;
  padding: 2px 9px;
  border-radius: 999px;
  background: var(--color-cyan-light);
  color: var(--color-cyan);
  margin-bottom: 8px;
  letter-spacing: 0.3px;
}

.tag-green { background: var(--color-green-light); color: var(--color-green); }
.tag-orange { background: var(--color-orange-light); color: var(--color-orange); }

/* ---------------- Long-form article blocks ---------------- */

.article-block {
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-l);
  padding: 32px clamp(18px, 4vw, 40px);
  margin-bottom: 28px;
  box-shadow: var(--shadow-card);
}

.article-index {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-cyan);
  letter-spacing: 1px;
  margin-bottom: 10px;
}

.article-block h3 {
  font-size: clamp(19px, 2.6vw, 23px);
  max-width: 900px;
}

.article-body {
  font-size: 15.5px;
  color: #3a3d42;
}

.article-body h4 {
  font-size: 16px;
  color: var(--color-navy);
  margin-top: 1.3em;
}

.article-figure {
  margin: 20px 0;
  padding: 16px;
  background: var(--color-bg);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  text-align: center;
}

.article-figure img {
  margin: 0 auto;
  max-height: 420px;
}

.article-figure figcaption {
  font-size: 13px;
  color: var(--color-muted);
  margin-top: 10px;
  text-align: left;
}

.pullquote {
  border-left: 3px solid var(--color-orange);
  padding: 4px 18px;
  color: var(--color-navy);
  font-size: 15.5px;
  font-style: normal;
  margin: 18px 0;
  background: var(--color-orange-light);
  border-radius: 0 var(--radius-s) var(--radius-s) 0;
}

.boundary-box {
  margin-top: 18px;
  padding: 14px 18px;
  border: 1px dashed var(--color-line-strong);
  border-radius: var(--radius-m);
  background: var(--color-bg-alt);
  font-size: 14px;
  color: var(--color-muted);
}

.boundary-box strong {
  color: var(--color-navy);
}

/* ---------------- Observation (short) articles ---------------- */

.observe-grid {
  display: grid;
  gap: 20px;
}

.observe-card {
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-left: 4px solid var(--color-green);
  border-radius: var(--radius-m);
  padding: 22px 26px;
  box-shadow: var(--shadow-card);
}

.observe-card h3 {
  font-size: 17.5px;
}

.observe-card p {
  font-size: 14.5px;
  color: #3a3d42;
}

/* ---------------- Cluster / summary cards (21-article回流) ---------------- */

.cluster-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 22px;
}

.cluster-tab {
  border: 1px solid var(--color-line-strong);
  background: var(--color-panel);
  color: var(--color-navy);
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 13.5px;
  cursor: pointer;
}

.cluster-tab.is-active {
  background: var(--color-navy);
  border-color: var(--color-navy);
  color: #fff;
}

.cluster-panel {
  display: none;
}

.cluster-panel.is-active {
  display: block;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 18px;
}

.summary-card {
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 18px 20px;
  box-shadow: var(--shadow-card);
  display: flex;
  flex-direction: column;
}

.summary-card:hover {
  box-shadow: var(--shadow-card-hover);
}

.summary-card h4 {
  font-size: 15.5px;
  margin-bottom: 8px;
}

.summary-card h4 a {
  color: var(--color-navy);
}

.summary-card p {
  font-size: 13.5px;
  color: var(--color-muted);
  flex: 1;
  margin-bottom: 10px;
}

.summary-card .read-link {
  font-size: 13px;
  font-weight: 700;
  color: var(--color-cyan);
}

/* ---------------- Causal chain visual list ---------------- */

.chain-list {
  list-style: none;
  padding: 0;
  margin: 18px 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.chain-list li {
  background: var(--color-cyan-light);
  color: var(--color-navy);
  font-size: 13.5px;
  font-weight: 600;
  padding: 7px 13px;
  border-radius: var(--radius-s);
}

.chain-list .arrow {
  background: none;
  color: var(--color-muted);
  padding: 0;
  font-size: 16px;
}

/* ---------------- Evidence level badges ---------------- */

.evidence-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 14px 0;
}

.badge {
  font-size: 12.5px;
  font-weight: 700;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid transparent;
}

.badge-confirmed { background: #e7f2ea; color: #2e6b41; border-color: #bfe0c9; }
.badge-supported { background: #fdf1de; color: #a4620f; border-color: #f2d6a8; }
.badge-plausible { background: #f1eee2; color: #6b6350; border-color: #ded6bd; }
.badge-fact { background: #e4f4f6; color: #0c6b79; border-color: #b9e2e7; }

/* ---------------- FAQ ---------------- */

.faq-list {
  border-top: 1px solid var(--color-line);
}

.faq-item {
  border-bottom: 1px solid var(--color-line);
}

.faq-question {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 16px 4px;
  font-size: 15.5px;
  font-weight: 600;
  color: var(--color-navy);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.faq-question::after {
  content: "+";
  font-size: 20px;
  color: var(--color-cyan);
  flex-shrink: 0;
}

.faq-item.is-open .faq-question::after {
  content: "\2212";
}

.faq-answer {
  display: none;
  padding: 0 4px 18px;
  font-size: 14.5px;
  color: #3a3d42;
}

.faq-item.is-open .faq-answer {
  display: block;
}

/* ---------------- About ---------------- */

.about-box {
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-l);
  padding: 28px clamp(18px, 4vw, 36px);
  box-shadow: var(--shadow-card);
}

.about-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  margin-top: 16px;
  font-size: 13.5px;
  color: var(--color-muted);
}

/* ---------------- App feature grid ---------------- */

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
}

.feature-card {
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  padding: 20px;
  box-shadow: var(--shadow-card);
}

.feature-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--color-navy);
  color: #fff;
  font-size: 13px;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card h3 {
  font-size: 15.5px;
  margin-bottom: 6px;
}

.feature-card p {
  font-size: 13.5px;
  color: var(--color-muted);
  margin-bottom: 0;
}

/* ---------------- Data table (horizontal scroll wrapper) ---------------- */

.table-scroll {
  overflow-x: auto;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-m);
  margin: 18px 0;
}

table.data-table {
  border-collapse: collapse;
  width: 100%;
  min-width: 520px;
  font-size: 14px;
}

table.data-table th,
table.data-table td {
  padding: 10px 14px;
  border-bottom: 1px solid var(--color-line);
  text-align: left;
  white-space: nowrap;
}

table.data-table th {
  background: var(--color-bg-alt);
  color: var(--color-navy);
}

/* ---------------- Internal link panel ---------------- */

.link-panel {
  background: var(--color-cyan-light);
  border-radius: var(--radius-m);
  padding: 16px 20px;
  font-size: 14px;
  margin: 18px 0;
}

.link-panel strong {
  color: var(--color-navy);
}

.link-panel a {
  margin-right: 14px;
}

/* ---------------- Back to top ---------------- */

.back-top {
  position: fixed;
  right: 20px;
  bottom: 20px;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  background: var(--color-navy);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.2);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s;
  z-index: 90;
  cursor: pointer;
  border: none;
}

.back-top.is-visible {
  opacity: 1;
  pointer-events: auto;
}

/* ---------------- Footer ---------------- */

.site-footer {
  background: var(--color-navy-deep);
  color: #b9c6d4;
  padding: 40px 0 24px;
  font-size: 13.5px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 30px;
  padding-bottom: 24px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-brand {
  color: #fff;
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 10px;
}

.footer-col h4 {
  color: #fff;
  font-size: 14px;
  margin-bottom: 12px;
}

.footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-col li {
  margin-bottom: 8px;
}

.footer-col a {
  color: #b9c6d4;
}

.footer-disclaimer {
  margin-top: 18px;
  padding: 12px 16px;
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-s);
  color: #d9cfa9;
  font-size: 13px;
}

.footer-bottom {
  margin-top: 18px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  color: #8ea0b3;
}

/* ---------------- Responsive ---------------- */

@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 760px) {
  .main-nav {
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--color-navy);
    flex-direction: column;
    align-items: stretch;
    padding: 8px 14px 16px;
    display: none;
    gap: 2px;
  }

  .main-nav.is-open {
    display: flex;
  }

  .main-nav a {
    padding: 12px 10px;
  }

  .nav-toggle {
    display: inline-block;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .chain-list {
    flex-direction: column;
    align-items: flex-start;
  }

  .chain-list .arrow {
    align-self: center;
  }
}

@media (max-width: 400px) {
  .container {
    padding: 0 14px;
  }

  .article-block {
    padding: 22px 16px;
  }

  .hero {
    padding: 40px 0 32px;
  }
}