/* ==========================================================
   KAIYUN 小组赛竞猜中国区官网 · 全站共享样式
   /assets/site.css
   深空蓝 × 荧光绿 · 赛博体育海报杂志
   ========================================================== */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 0.875rem;
  line-height: 1.6;
  color: var(--color-cloud);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-title);
  font-weight: 900;
  line-height: 1.15;
  color: var(--color-cloud);
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

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

button {
  font: inherit;
  border: none;
  background: none;
  color: inherit;
  cursor: pointer;
}

fieldset {
  border: none;
}

/* ---------- 2. CSS Variables ---------- */
:root {
  --color-bg: #0A1128;
  --color-bg-deep: #060D1F;
  --color-bg-panel: #101B3C;
  --color-steel: #1B2A4A;
  --color-neon: #00FF6A;
  --color-neon-weak: rgba(0, 255, 106, 0.25);
  --color-orange: #FF6D00;
  --color-gold: #FFD700;
  --color-cloud: #F5F7FA;
  --color-muted: #8A94A6;

  --font-title: Georgia, 'Songti SC', 'SimSun', 'Noto Serif CJK SC', 'Source Han Serif SC', serif;
  --font-body: 'SF Mono', 'Cascadia Code', 'Roboto Mono', Menlo, Consolas, 'Liberation Mono', monospace;

  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --space-9: 6rem;

  --container: 80rem;
  --radius: 2px;
  --header-z: 1000;
  --progress-z: 1200;
  --skip-z: 1400;
}

/* ---------- 3. Base ---------- */
p {
  margin: 0;
}

::selection {
  background: var(--color-neon);
  color: var(--color-bg);
}

[hidden] {
  display: none !important;
}

/* ---------- 4. Skip Link ---------- */
.skip-link {
  position: fixed;
  top: -12rem;
  left: var(--space-4);
  z-index: var(--skip-z);
  background: var(--color-neon);
  color: var(--color-bg);
  font-family: var(--font-body);
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: var(--space-3) var(--space-5);
  border-radius: 0 0 var(--radius) var(--radius);
  transition: top 0.2s ease;
}

.skip-link:focus-visible {
  top: 0;
}

/* ---------- 5. Reading Progress ---------- */
.reading-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: var(--progress-z);
  pointer-events: none;
  background: transparent;
}

.reading-progress-bar {
  display: block;
  height: 100%;
  width: 0%;
  background: var(--color-neon);
  box-shadow: 0 0 8px rgba(0, 255, 106, 0.5);
}

/* ---------- 6. Header & Masthead ---------- */
.site-header {
  position: relative;
  z-index: var(--header-z);
  background: var(--color-bg);
  border-bottom: 2px solid var(--color-steel);
}

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

.masthead-kicker {
  background: var(--color-steel);
  color: var(--color-cloud);
  font-family: var(--font-body);
  font-size: 0.625rem;
  font-weight: 500;
  letter-spacing: 0.35em;
  text-align: center;
  text-transform: uppercase;
  padding: var(--space-2) var(--space-4);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.masthead-inner {
  position: relative;
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-6) var(--space-5) var(--space-4);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
}

.masthead-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-4);
}

.masthead-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 3.5rem;
  height: 3.5rem;
  background: var(--color-neon);
  color: var(--color-bg);
  font-family: var(--font-title);
  font-size: 1.375rem;
  font-weight: 900;
  line-height: 1;
  transform: rotate(-6deg);
  box-shadow: 0 0 12px rgba(0, 255, 106, 0.25);
  flex-shrink: 0;
}

.masthead-copy {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: var(--space-1);
}

.masthead-name {
  font-size: clamp(1.375rem, 3.2vw, 2.25rem);
  font-weight: 900;
  letter-spacing: 0.03em;
  line-height: 1.1;
  white-space: nowrap;
  color: var(--color-cloud);
}

.masthead-name-hl {
  color: var(--color-neon);
}

.masthead-locale {
  font-family: var(--font-body);
  font-size: 0.6875rem;
  font-weight: 500;
  letter-spacing: 0.4em;
  text-transform: uppercase;
  color: var(--color-muted);
}

.masthead-tagline {
  font-family: var(--font-body);
  font-size: 0.75rem;
  color: var(--color-muted);
  letter-spacing: 0.12em;
  position: relative;
  padding-inline: var(--space-5);
}

.masthead-tagline::before,
.masthead-tagline::after {
  content: "";
  position: absolute;
  top: 50%;
  width: var(--space-4);
  height: 1px;
  background: var(--color-neon);
}

.masthead-tagline::before {
  left: 0;
}

.masthead-tagline::after {
  right: 0;
}

/* ---------- 7. Navigation ---------- */
.site-nav {
  background: var(--color-bg);
  border-top: 1px solid var(--color-steel);
}

.site-nav-inner {
  max-width: var(--container);
  margin-inline: auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-1);
  padding: 0 var(--space-4);
}

.nav-link {
  position: relative;
  display: block;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-body);
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--color-muted);
  transition: color 0.2s ease;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: var(--space-4);
  right: var(--space-4);
  bottom: 8px;
  height: 2px;
  background: var(--color-neon);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform 0.25s ease;
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--color-neon);
}

.nav-link:hover::after,
.nav-link:focus-visible::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--color-cloud);
}

/* Toggle */
.nav-toggle {
  position: absolute;
  top: var(--space-4);
  right: var(--space-4);
  display: none;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-steel);
  color: var(--color-muted);
  font-family: var(--font-body);
  font-size: 0.75rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.nav-toggle:hover,
.nav-toggle:focus-visible {
  color: var(--color-neon);
  border-color: var(--color-neon);
}

.nav-toggle[aria-expanded="true"] {
  color: var(--color-neon);
  border-color: var(--color-neon);
}

.nav-toggle-box {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  width: 1.25rem;
  gap: 4px;
}

.nav-toggle-box span {
  display: block;
  width: 100%;
  height: 2px;
  background: currentColor;
  border-radius: 1px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-box span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-box span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-box span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

/* ---------- 8. Footer ---------- */
.site-footer {
  background: var(--color-bg-deep);
  border-top: 3px solid var(--color-steel);
}

.footer-top {
  max-width: var(--container);
  margin-inline: auto;
  padding: var(--space-8) var(--space-5) var(--space-7);
  display: grid;
  grid-template-columns: 2fr 1fr 1.5fr 1fr;
  gap: var(--space-6);
}

.footer-brand-name {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-family: var(--font-title);
  font-size: 1.375rem;
  font-weight: 900;
  color: var(--color-cloud);
}

.footer-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.75rem;
  height: 2.75rem;
  background: var(--color-neon);
  color: var(--color-bg);
  font-family: var(--font-title);
  font-weight: 900;
  font-size: 1rem;
  transform: rotate(-6deg);
  flex-shrink: 0;
}

.footer-tagline {
  margin-top: var(--space-4);
  font-family: var(--font-body);
  font-size: 0.75rem;
  color: var(--color-muted);
  letter-spacing: 0.12em;
}

.footer-trust {
  margin-top: var(--space-5);
  font-family: var(--font-body);
  font-size: 0.6875rem;
  line-height: 1.5;
  color: var(--color-neon);
  border: 1px dashed var(--color-steel);
  padding: var(--space-3) var(--space-4);
  max-width: 24rem;
}

.footer-heading {
  font-family: var(--font-body);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--color-muted);
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-steel);
  position: relative;
}

.footer-heading::after {
  content: "";
  position: absolute;
  bottom: -1px;
  left: 0;
  width: 2rem;
  height: 2px;
  background: var(--color-neon);
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-links a {
  color: var(--color-muted);
  font-family: var(--font-body);
  font-size: 0.8125rem;
  transition: color 0.2s ease;
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--color-neon);
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-contact li {
  color: var(--color-muted);
  font-size: 0.75rem;
  line-height: 1.5;
}

.footer-bottom {
  border-top: 1px solid var(--color-steel);
  padding: var(--space-4) var(--space-5);
}

.footer-bottom-inner {
  max-width: var(--container);
  margin-inline: auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-size: 0.6875rem;
  color: var(--color-muted);
}

/* ---------- 9. Container & Grid ---------- */
.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--space-5);
}

.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--space-5);
}

.col-span-3 { grid-column: span 3; }
.col-span-4 { grid-column: span 4; }
.col-span-6 { grid-column: span 6; }
.col-span-8 { grid-column: span 8; }
.col-span-9 { grid-column: span 9; }
.col-span-12 { grid-column: span 12; }

/* ---------- 10. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border: 1px solid var(--color-steel);
  background: transparent;
  color: var(--color-cloud);
  font-family: var(--font-body);
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  line-height: 1;
  border-radius: var(--radius);
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
  cursor: pointer;
}

.btn:hover,
.btn:focus-visible {
  border-color: var(--color-neon);
  color: var(--color-neon);
}

.btn-primary {
  background: var(--color-neon);
  border-color: var(--color-neon);
  color: var(--color-bg);
  font-weight: 700;
}

.btn-primary:hover,
.btn-primary:focus-visible {
  background: transparent;
  color: var(--color-neon);
}

/* ---------- 11. Cards ---------- */
.card {
  background: var(--color-bg-panel);
  border: 1px solid var(--color-steel);
  border-radius: var(--radius);
  box-shadow: 4px 4px 0 rgba(27, 42, 74, 0.4);
  padding: var(--space-5);
}

.panel {
  background: var(--color-bg-panel);
  border: 1px solid var(--color-steel);
  border-left: 3px solid var(--color-neon);
  padding: var(--space-5);
}

/* ---------- 12. Breadcrumbs ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-2);
  font-family: var(--font-body);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--color-muted);
  padding: var(--space-3) 0;
}

.breadcrumb a {
  color: var(--color-muted);
  transition: color 0.2s ease;
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--color-neon);
}

.breadcrumb-sep {
  color: var(--color-steel);
}

/* ---------- 13. Chapter / Section ---------- */
.chapter {
  margin-top: var(--space-8);
}

.chapter-number {
  display: block;
  font-family: var(--font-title);
  font-size: clamp(3.5rem, 8vw, 6rem);
  font-weight: 900;
  line-height: 0.85;
  color: rgba(0, 255, 106, 0.2);
  -webkit-text-stroke: 1.5px rgba(0, 255, 106, 0.6);
  letter-spacing: -0.02em;
}

.chapter-title {
  margin-top: var(--space-2);
  font-size: clamp(1.375rem, 3vw, 2rem);
  font-weight: 900;
  color: var(--color-cloud);
}

/* ---------- 14. Figures / Images ---------- */
.figure-frame {
  position: relative;
  display: block;
  background: var(--color-bg-panel);
  border: 1px solid var(--color-steel);
  border-radius: var(--radius);
  aspect-ratio: 16 / 9;
  overflow: hidden;
}

.figure-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    -45deg,
    transparent,
    transparent 10px,
    rgba(27, 42, 74, 0.5) 10px,
    rgba(27, 42, 74, 0.5) 12px
  );
  z-index: 0;
}

.figure-frame > * {
  position: relative;
  z-index: 1;
}

.img-responsive {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  position: relative;
  z-index: 1;
}

.figure-caption {
  padding-top: var(--space-2);
  font-family: var(--font-body);
  font-size: 0.6875rem;
  color: var(--color-muted);
  letter-spacing: 0.05em;
}

/* ---------- 15. Filter Bar ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-bottom: var(--space-5);
}

.filter-btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-4);
  border: 1px solid var(--color-steel);
  background: transparent;
  color: var(--color-muted);
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border-radius: 999px;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
  cursor: pointer;
}

.filter-btn:hover,
.filter-btn:focus-visible {
  border-color: var(--color-neon);
  color: var(--color-neon);
}

.filter-btn.is-active {
  background: var(--color-neon);
  border-color: var(--color-neon);
  color: var(--color-bg);
  font-weight: 700;
}

/* ---------- 16. Tags & Labels ---------- */
.tag {
  display: inline-block;
  padding: 0.125rem 0.5rem;
  font-family: var(--font-body);
  font-size: 0.625rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  border: 1px solid var(--color-steel);
  color: var(--color-muted);
  line-height: 1.4;
}

.tag-neon {
  color: var(--color-neon);
  border-color: var(--color-neon);
}

.tag-orange {
  color: var(--color-orange);
  border-color: var(--color-orange);
}

.tag-gold {
  color: var(--color-gold);
  border-color: var(--color-gold);
}

.badge-live {
  display: inline-block;
  background: var(--color-orange);
  color: var(--color-bg);
  font-family: var(--font-body);
  font-size: 0.5625rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  padding: 0.15rem 0.5rem;
  line-height: 1.4;
}

/* ---------- 17. Data Numbers ---------- */
.stat-number {
  font-family: var(--font-body);
  font-size: clamp(2rem, 5vw, 3.5rem);
  font-weight: 700;
  color: var(--color-neon);
  line-height: 1;
}

.stat-label {
  display: block;
  font-family: var(--font-body);
  font-size: 0.6875rem;
  color: var(--color-muted);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin-top: var(--space-2);
}

/* ---------- 18. Misc Utilities ---------- */
.lead {
  font-size: 1.125rem;
  line-height: 1.6;
  color: var(--color-cloud);
}

.meta {
  font-family: var(--font-body);
  font-size: 0.75rem;
  color: var(--color-muted);
  letter-spacing: 0.05em;
}

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); }
.mt-6 { margin-top: var(--space-6); }
.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-5 { margin-bottom: var(--space-5); }
.mb-6 { margin-bottom: var(--space-6); }

/* ---------- 19. Focus Visible ---------- */
a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--color-neon);
  outline-offset: 2px;
}

#main-content:focus-visible {
  outline: 2px solid var(--color-neon);
  outline-offset: -2px;
}

/* ---------- 20. Responsive ---------- */
@media (max-width: 1023px) {
  .footer-top {
    grid-template-columns: 1fr 1fr;
  }

  .footer-brand {
    grid-column: span 2;
  }

  .col-span-3,
  .col-span-4,
  .col-span-6,
  .col-span-8,
  .col-span-9,
  .col-span-12 {
    grid-column: span 6;
  }
}

@media (max-width: 767px) {
  .nav-toggle {
    display: inline-flex;
  }

  .masthead-inner {
    padding-top: var(--space-5);
  }

  .masthead-mark {
    width: 3rem;
    height: 3rem;
    font-size: 1.125rem;
  }

  .site-nav {
    display: none;
  }

  .site-nav[data-open] {
    display: block;
  }

  .site-nav-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: var(--space-2) var(--space-4) var(--space-4);
  }

  .nav-link {
    text-align: center;
    padding: var(--space-3) var(--space-4);
  }

  .nav-link + .nav-link {
    border-top: 1px solid rgba(27, 42, 74, 0.5);
  }

  .nav-link::after {
    display: none;
  }

  .footer-top {
    grid-template-columns: 1fr;
    gap: var(--space-6);
    padding: var(--space-7) var(--space-5);
  }

  .footer-brand {
    grid-column: span 1;
  }

  .footer-bottom-inner {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .col-span-3,
  .col-span-4,
  .col-span-6,
  .col-span-8,
  .col-span-9,
  .col-span-12 {
    grid-column: span 12;
  }
}

/* ---------- 21. Reduced Motion ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}