/* ==========================================================================
   环亚赛场 /assets/site.css
   共享外壳：reset、变量、中文排版、双层页头、页脚、按钮、网格与基础组件
   ========================================================================== */

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

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

body,
h1, h2, h3, h4, h5, p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; }

ul, ol { padding: 0; list-style: none; }

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

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

button { font: inherit; color: inherit; background: none; border: 0; }

/* ---------- tokens ---------- */
:root {
  --bg: #070B14;
  --bg-mid: #0E1626;
  --panel: #111E33;
  --grid: #22324A;
  --ink: #E8F1F8;
  --ink-soft: #9BB0C3;
  --cyan: #28F0FF;
  --orange: #FF6A2A;
  --gold: #FFC857;
  --red: #FF3D5A;
  --cream: #F4E9D8;

  --shell: 1440px;
  --gutter: 64px;

  --font-display: "Barlow Condensed", "Oswald", "PingFang SC", "Noto Sans SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --line: 1px solid var(--grid);
  --speed: 0.16s;
}

@media (max-width: 1079px) {
  :root { --gutter: 32px; }
}

@media (max-width: 639px) {
  :root { --gutter: 20px; }
}

/* ---------- base ---------- */
body {
  min-height: 100vh;
  background-color: var(--bg);
  background-image: linear-gradient(180deg, rgba(40, 240, 255, 0.055), rgba(7, 11, 20, 0) 420px);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main { display: block; }

#main-content:focus { outline: none; }

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: 0.01em;
}

:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

::selection {
  background: var(--cyan);
  color: #04121A;
}

/* ---------- layout shell ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

/* ---------- skip link ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  transform: translateY(-160%);
  padding: 10px 18px;
  background: var(--cyan);
  color: #04121A;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  transition: transform var(--speed) ease;
}

.skip-link:focus {
  transform: translateY(0);
}

/* ---------- header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: var(--bg);
  border-bottom: 1px solid var(--grid);
}

.header-utility {
  background: var(--bg-mid);
  border-bottom: 1px solid var(--grid);
}

.header-utility__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  min-height: 42px;
  padding-block: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.4;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}

.header-utility__brand {
  color: var(--cream);
  letter-spacing: 0.16em;
}

.header-utility__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 16px;
}

.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 3px 10px;
  border: 1px solid var(--grid);
  color: var(--ink-soft);
  white-space: nowrap;
}

.status-pill__dot {
  width: 6px;
  height: 6px;
  flex: none;
  background: var(--cyan);
  box-shadow: 0 0 0 3px rgba(40, 240, 255, 0.16);
  animation: statusPulse 2.6s ease-in-out infinite;
}

@keyframes statusPulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.35; }
}

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--ink);
}

.header-subscribe {
  display: inline-flex;
  align-items: center;
  padding: 6px 18px;
  background: var(--gold);
  color: #120C02;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.1em;
  clip-path: polygon(10px 0, 100% 0, calc(100% - 10px) 100%, 0 100%);
  transition: background-color var(--speed) ease, color var(--speed) ease;
}

.header-subscribe:hover,
.header-subscribe:focus-visible {
  background: var(--cream);
  color: #120C02;
}

.header-utility__link {
  color: var(--ink-soft);
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
  transition: color var(--speed) ease, border-color var(--speed) ease;
}

.header-utility__link:hover,
.header-utility__link:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.header-main {
  position: relative;
  background-color: var(--bg);
  background-image: repeating-linear-gradient(90deg, rgba(34, 50, 74, 0.55) 0 1px, transparent 1px 96px);
}

.header-main__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  min-height: 76px;
}

/* brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: none;
}

.brand__mark {
  position: relative;
  display: block;
  width: 34px;
  height: 34px;
  flex: none;
  background: linear-gradient(158deg, var(--cyan) 0 56%, var(--orange) 56% 100%);
  clip-path: polygon(0 0, 100% 0, 100% 68%, 68% 100%, 0 100%);
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand__name {
  display: block;
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--ink);
}

.brand__sub {
  display: block;
  margin-top: 5px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.34em;
  color: var(--ink-soft);
}

/* primary nav */
.primary-nav__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.primary-nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  min-height: 76px;
  padding: 0 16px;
  font-size: 14px;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
  transition: color var(--speed) ease, background-color var(--speed) ease;
}

.primary-nav__link::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 0;
  height: 2px;
  background: var(--cyan);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.18s ease;
}

.primary-nav__link:hover,
.primary-nav__link:focus-visible {
  color: var(--ink);
  background-color: rgba(17, 30, 51, 0.75);
}

.primary-nav__link:hover::after,
.primary-nav__link:focus-visible::after {
  transform: scaleX(1);
}

.primary-nav__link[aria-current="page"] {
  color: var(--ink);
}

.primary-nav__link[aria-current="page"]::after {
  transform: scaleX(1);
}

/* nav toggle */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 9px 14px;
  border: 1px solid var(--grid);
  background: var(--panel);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  cursor: pointer;
  transition: border-color var(--speed) ease, color var(--speed) ease;
}

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

.nav-toggle__bars {
  display: grid;
  gap: 4px;
  width: 16px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  background: currentColor;
  transition: transform var(--speed) ease;
}

.nav-toggle__label {
  line-height: 1;
}

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

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

/* ---------- footer ---------- */
.site-footer {
  position: relative;
  margin-top: 0;
  background: var(--bg-mid);
  border-top: 1px solid var(--grid);
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 3px;
  background: linear-gradient(90deg, var(--cyan) 0 26%, var(--orange) 26% 34%, rgba(34, 50, 74, 0.4) 34% 100%);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.6fr 0.8fr 0.8fr 1.2fr;
  gap: 48px 32px;
  padding-block: 64px 48px;
}

.footer-brand .brand__mark {
  margin-bottom: 16px;
}

.footer-brand__name {
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--ink);
}

.footer-brand__desc {
  margin-top: 10px;
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--ink-soft);
}

.footer-col__title {
  padding-bottom: 12px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--grid);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.22em;
  color: var(--cream);
  text-transform: uppercase;
}

.footer-list {
  display: grid;
  gap: 10px;
}

.footer-list a {
  display: inline-block;
  font-size: 14px;
  color: var(--ink-soft);
  transition: color var(--speed) ease, transform var(--speed) ease;
}

.footer-list a:hover,
.footer-list a:focus-visible {
  color: var(--cyan);
  transform: translateX(4px);
}

.footer-contact {
  display: grid;
  gap: 14px;
  align-content: start;
}

.footer-contact__row {
  display: grid;
  gap: 3px;
}

.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  color: var(--orange);
  text-transform: uppercase;
}

.footer-contact__value {
  font-size: 13.5px;
  line-height: 1.65;
  color: var(--ink);
  word-break: break-word;
}

.footer-contact__note {
  padding-left: 10px;
  border-left: 2px solid var(--grid);
  font-size: 12px;
  line-height: 1.8;
  color: var(--ink-soft);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding-block: 20px 30px;
  border-top: 1px solid var(--grid);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink-soft);
}

.footer-bottom__legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
}

.footer-bottom__meta {
  color: var(--ink-soft);
}

.footer-icp {
  color: var(--cream);
}

/* ---------- typography components ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  color: var(--cyan);
  text-transform: uppercase;
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  flex: none;
  background: var(--cyan);
}

.display-title {
  font-size: clamp(40px, 5.4vw, 72px);
  letter-spacing: -0.005em;
  color: var(--ink);
}

.display-title--xl {
  font-size: clamp(46px, 7.6vw, 96px);
  line-height: 0.95;
}

.lede {
  max-width: 62ch;
  font-size: 17px;
  line-height: 1.78;
  color: var(--ink-soft);
}

.rule {
  height: 1px;
  border: 0;
  background: var(--grid);
}

/* ---------- breadcrumb ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 18px;
  border-bottom: 1px solid var(--grid);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--ink-soft);
}

.breadcrumb a {
  color: var(--ink-soft);
  transition: color var(--speed) ease;
}

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

.breadcrumb__sep {
  color: #3B4E68;
}

.breadcrumb [aria-current="page"] {
  color: var(--cream);
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 44px;
  padding: 0 22px;
  border: 1px solid var(--grid);
  background: var(--panel);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: color var(--speed) ease, border-color var(--speed) ease, background-color var(--speed) ease;
}

.btn:hover,
.btn:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  background: #0C1A2E;
}

.btn--gold {
  border-color: transparent;
  background: var(--gold);
  color: #120C02;
  clip-path: polygon(12px 0, 100% 0, calc(100% - 12px) 100%, 0 100%);
}

.btn--gold:hover,
.btn--gold:focus-visible {
  background: var(--cream);
  color: #120C02;
  border-color: transparent;
}

.btn--line {
  background: transparent;
  border-color: var(--grid);
}

.btn.is-copied,
.btn.is-copied:hover {
  border-color: var(--cyan);
  color: var(--cyan);
  background: rgba(40, 240, 255, 0.1);
}

/* ---------- section ---------- */
.section {
  padding-block: 64px;
  border-top: 1px solid var(--grid);
}

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px 24px;
  margin-bottom: 32px;
}

/* ---------- grid ---------- */
.grid {
  display: grid;
  gap: 24px;
}

.grid--7-5 { grid-template-columns: 7fr 5fr; }
.grid--3-9 { grid-template-columns: 3fr 9fr; }
.grid--4-8 { grid-template-columns: 4fr 8fr; }
.grid--thirds { grid-template-columns: repeat(3, 1fr); }

/* ---------- panel / tag / stat ---------- */
.panel {
  position: relative;
  padding: 24px;
  border: 1px solid var(--grid);
  background: var(--panel);
}

.panel::before {
  content: "";
  position: absolute;
  left: -1px;
  top: -1px;
  width: 14px;
  height: 14px;
  border-left: 2px solid var(--cyan);
  border-top: 2px solid var(--cyan);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 9px;
  border: 1px solid var(--grid);
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.tag--cyan {
  color: var(--cyan);
  border-color: rgba(40, 240, 255, 0.45);
}

.tag--orange {
  color: var(--orange);
  border-color: rgba(255, 106, 42, 0.45);
}

.stat {
  display: grid;
  gap: 4px;
}

.stat__value {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(24px, 3vw, 36px);
  line-height: 1.1;
  color: var(--cyan);
}

.stat__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-soft);
  text-transform: uppercase;
}

/* ---------- media frame ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 9;
  border: 1px solid var(--grid);
  background: linear-gradient(140deg, #0B1524, #111E33 58%, #0A1220);
}

.media-frame__img,
.media-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media-frame__caption {
  position: absolute;
  left: 0;
  bottom: 0;
  max-width: calc(100% - 24px);
  padding: 6px 12px;
  background: var(--cream);
  color: #1A1206;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

/* ---------- read progress ---------- */
.read-progress {
  position: fixed;
  inset: 0 0 auto 0;
  height: 2px;
  z-index: 120;
  background: rgba(34, 50, 74, 0.55);
  pointer-events: none;
}

.read-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--cyan), var(--gold));
}

/* ---------- tabs ---------- */
.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--grid);
}

.tab {
  padding: 8px 16px;
  border: 1px solid var(--grid);
  background: var(--bg-mid);
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: color var(--speed) ease, border-color var(--speed) ease, background-color var(--speed) ease;
}

.tab:hover,
.tab:focus-visible {
  color: var(--ink);
  border-color: var(--cyan);
}

.tab[aria-selected="true"] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: #04121A;
  font-weight: 700;
}

.tabpanel {
  padding-top: 24px;
}

.tabpanel[hidden] {
  display: none;
}

/* ---------- accordion ---------- */
.accordion {
  border-top: 1px solid var(--grid);
}

.accordion__item {
  border-bottom: 1px solid var(--grid);
}

.accordion__btn {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 4px;
  text-align: left;
  font-size: 16px;
  color: var(--ink);
  cursor: pointer;
  transition: color var(--speed) ease;
}

.accordion__btn::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--cyan);
}

.accordion__btn:hover,
.accordion__btn:focus-visible {
  color: var(--cyan);
}

.accordion__btn[aria-expanded="true"]::after {
  content: "–";
}

.accordion__panel {
  padding: 0 4px 20px;
  font-size: 15px;
  color: var(--ink-soft);
}

.accordion__panel[hidden] {
  display: none;
}

/* ---------- responsive ---------- */
@media (max-width: 1079px) {
  .header-main__inner {
    min-height: 64px;
    gap: 16px;
  }

  .brand__mark {
    width: 30px;
    height: 30px;
  }

  .brand__name {
    font-size: 19px;
  }

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

  .primary-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    z-index: 70;
    display: none;
    background: var(--bg-mid);
    border-top: 1px solid var(--grid);
    border-bottom: 1px solid var(--grid);
    box-shadow: 0 26px 42px -26px rgba(0, 0, 0, 0.92);
  }

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

  .primary-nav__list {
    display: block;
    max-width: var(--shell);
    margin-inline: auto;
    padding: 8px var(--gutter) 16px;
  }

  .primary-nav__link {
    width: 100%;
    min-height: 52px;
    padding: 0 4px;
    border-bottom: 1px solid var(--grid);
    font-size: 15px;
    justify-content: flex-start;
  }

  .primary-nav__link::after {
    left: 0;
    right: auto;
    top: 12px;
    bottom: 12px;
    width: 2px;
    height: auto;
    transform: scaleY(0);
    transform-origin: top center;
  }

  .primary-nav__link:hover::after,
  .primary-nav__link:focus-visible::after,
  .primary-nav__link[aria-current="page"]::after {
    transform: scaleY(1);
  }

  .primary-nav__link[aria-current="page"] {
    padding-left: 16px;
    color: var(--cyan);
    background: rgba(40, 240, 255, 0.06);
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px 28px;
    padding-block: 48px 36px;
  }
}

@media (max-width: 959px) {
  .grid--7-5,
  .grid--3-9,
  .grid--4-8,
  .grid--thirds {
    grid-template-columns: 1fr;
  }

  .section {
    padding-block: 48px;
  }
}

@media (max-width: 860px) {
  .header-utility__brand {
    font-size: 11px;
    letter-spacing: 0.1em;
  }
}

@media (max-width: 639px) {
  .header-utility__inner {
    min-height: 40px;
    gap: 10px;
    font-size: 11px;
  }

  .header-utility__brand {
    display: none;
  }

  .header-utility__meta {
    width: 100%;
    justify-content: space-between;
    gap: 8px;
  }

  .status-pill {
    padding: 2px 8px;
  }

  .header-subscribe {
    padding: 6px 14px;
  }

  .header-utility__link {
    display: none;
  }

  .brand__sub {
    letter-spacing: 0.22em;
  }

  .footer-grid {
    grid-template-columns: 1fr;
    padding-block: 40px 28px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .lede {
    font-size: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  .status-pill__dot { animation: none; }
  .footer-list a:hover { transform: none; }
}