/* ===========================================================
   LM SPORTS 体育平台赛场 · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 页头 / 页脚 / 基础组件
   =========================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 150px;
}

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

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

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

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

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

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

/* ---------- 变量 ---------- */
:root {
  --bg-deep: #071512;
  --bg-panel: #0D231E;
  --bg-panel-2: #0A1B17;
  --ink: #E8FFF8;
  --ink-muted: #9DB8B0;
  --cyan: #26F7D0;
  --teal: #0E8F7A;
  --amber: #FFC24B;
  --indigo: #1B2A5B;
  --wine: #5C1F33;
  --scan: rgba(38, 247, 208, 0.18);
  --line: rgba(38, 247, 208, 0.24);
  --line-soft: rgba(157, 184, 176, 0.18);

  --font-display: 'Barlow Condensed', 'Oswald', 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Noto Sans SC', 'Inter', system-ui, -apple-system, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-num: 'IBM Plex Mono', 'Roboto Mono', 'SFMono-Regular', ui-monospace, Menlo, Consolas, monospace;

  --shell: 1200px;
  --gutter: clamp(16px, 4vw, 40px);
  --r-lg: 22px;
  --r-md: 14px;
  --r-sm: 8px;
  --t: 150ms;
  --t-slow: 180ms;
}

/* ---------- 基础排版 ---------- */
body {
  background-color: var(--bg-deep);
  background-image:
    radial-gradient(900px 620px at 88% -10%, rgba(27, 42, 91, 0.55), transparent 70%),
    radial-gradient(720px 520px at -12% 18%, rgba(14, 143, 122, 0.22), transparent 72%),
    radial-gradient(640px 460px at 52% 118%, rgba(92, 31, 51, 0.34), transparent 72%);
  background-attachment: fixed;
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 400;
  line-height: 1.08;
  letter-spacing: 0.02em;
}

h1 { font-size: clamp(38px, 7vw, 84px); font-weight: 300; }
h2 { font-size: clamp(26px, 3.6vw, 40px); }
h3 { font-size: clamp(20px, 2.2vw, 26px); }

p { text-wrap: pretty; }

strong { color: var(--amber); font-weight: 600; }

.arena-num,
.num {
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.02em;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 8px;
  left: 8px;
  z-index: 999;
  padding: 10px 18px;
  background: var(--cyan);
  color: #04140F;
  font-family: var(--font-num);
  font-size: 13px;
  letter-spacing: 0.08em;
  border-radius: var(--r-sm);
  transform: translateY(-160%);
  transition: transform var(--t) ease;
}

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

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

.arena-prose {
  max-width: 68ch;
  color: var(--ink-muted);
  font-size: 15.5px;
}

.arena-prose > * + * {
  margin-top: 1.05em;
}

.arena-prose h2,
.arena-prose h3 {
  color: var(--ink);
  margin-top: 1.6em;
}

.arena-main {
  display: block;
  padding-block: clamp(24px, 4vw, 52px) clamp(40px, 6vw, 80px);
}

/* ---------- 章节与标签 ---------- */
.arena-section {
  margin-block: clamp(36px, 6vw, 72px);
}

.arena-section__label,
.arena-kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}

.arena-section__label::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--cyan);
}

.arena-divider {
  border: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--line), rgba(38, 247, 208, 0) 82%);
  margin-block: clamp(24px, 4vw, 40px);
}

/* ---------- 链接与按钮 ---------- */
.arena-link {
  color: var(--cyan);
  padding-bottom: 1px;
  background-image: linear-gradient(90deg, currentColor, currentColor);
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0% 1px;
  transition: background-size var(--t) ease, color var(--t) ease;
}

.arena-link:hover,
.arena-link:focus-visible {
  color: var(--amber);
  background-size: 100% 1px;
}

.arena-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.6em;
  padding: 12px 22px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-family: var(--font-num);
  font-size: 13.5px;
  letter-spacing: 0.08em;
  color: var(--ink);
  background: rgba(13, 35, 30, 0.7);
  transition: background var(--t) ease, border-color var(--t) ease,
              color var(--t) ease, transform var(--t) ease;
}

.arena-btn:hover,
.arena-btn:focus-visible {
  border-color: var(--cyan);
  color: var(--cyan);
  background: rgba(38, 247, 208, 0.09);
  transform: translateY(-1px);
}

.arena-btn--solid {
  background: var(--cyan);
  border-color: var(--cyan);
  color: #04140F;
  font-weight: 700;
}

.arena-btn--solid:hover,
.arena-btn--solid:focus-visible {
  background: var(--amber);
  border-color: var(--amber);
  color: #1A1204;
}

/* ---------- 面包屑 ---------- */
.arena-breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--ink-muted);
  margin-bottom: clamp(16px, 2.4vw, 28px);
}

.arena-breadcrumb a {
  color: var(--ink-muted);
  transition: color var(--t) ease;
}

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

.arena-breadcrumb__sep {
  color: var(--teal);
}

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

/* ===========================================================
   页头：双层信息带 + 刻度线 + 进度条
   =========================================================== */
.arena-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: linear-gradient(180deg, #071512 0%, #0A1F1A 100%);
  border-bottom: 1px solid var(--line);
}

.arena-header__top {
  position: relative;
}

.arena-header__top-inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  padding-block: 10px 9px;
}

.arena-brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.arena-brand__mark {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  flex: 0 0 auto;
  border: 1px solid var(--cyan);
  border-radius: 10px;
  background: rgba(38, 247, 208, 0.08);
  color: var(--cyan);
  font-family: var(--font-num);
  font-size: 15px;
  letter-spacing: 0.04em;
  transition: background var(--t) ease, color var(--t) ease, border-color var(--t) ease;
}

.arena-brand:hover .arena-brand__mark,
.arena-brand:focus-visible .arena-brand__mark {
  background: var(--cyan);
  color: #04140F;
  border-color: var(--amber);
}

.arena-brand__text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  min-width: 0;
}

.arena-brand__name {
  font-family: var(--font-display);
  font-size: 19px;
  letter-spacing: 0.1em;
  color: var(--ink);
  line-height: 1.2;
}

.arena-brand__line {
  font-family: var(--font-num);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--ink-muted);
  line-height: 1.4;
}

.arena-utility {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-left: auto;
}

.arena-utility__list {
  display: flex;
  align-items: center;
  gap: 18px;
}

.arena-utility__link {
  position: relative;
  font-size: 13px;
  color: var(--ink-muted);
  padding-bottom: 3px;
  background-image: linear-gradient(90deg, var(--cyan), var(--cyan));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 0% 1px;
  transition: color var(--t) ease, background-size var(--t) ease;
}

.arena-utility__link:hover,
.arena-utility__link:focus-visible {
  color: var(--cyan);
  background-size: 100% 1px;
}

.arena-cta {
  display: inline-flex;
  align-items: center;
  padding: 9px 18px;
  border: 1px solid var(--cyan);
  border-radius: 999px;
  background: var(--cyan);
  color: #04140F;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  white-space: nowrap;
  transition: background var(--t) ease, border-color var(--t) ease,
              color var(--t) ease, transform var(--t) ease;
}

.arena-cta:hover,
.arena-cta:focus-visible {
  background: var(--amber);
  border-color: var(--amber);
  transform: translateY(-1px);
}

.arena-ticks {
  height: 7px;
  border-top: 1px solid rgba(38, 247, 208, 0.14);
  background-image:
    repeating-linear-gradient(90deg, rgba(38, 247, 208, 0.34) 0 1px, transparent 1px 12px),
    repeating-linear-gradient(90deg, rgba(38, 247, 208, 0.55) 0 1px, transparent 1px 72px);
  background-repeat: repeat-x;
}

.arena-nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--cyan);
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.16em;
  transition: border-color var(--t) ease, background var(--t) ease;
}

.arena-nav-toggle:hover,
.arena-nav-toggle:focus-visible {
  border-color: var(--cyan);
  background: rgba(38, 247, 208, 0.08);
}

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

.arena-nav-toggle__bars span {
  display: block;
  height: 1.5px;
  background: currentColor;
  transition: transform var(--t) ease;
}

.arena-header[data-open] .arena-nav-toggle__bars span:nth-child(1) {
  transform: translateY(2.75px) rotate(45deg);
}

.arena-header[data-open] .arena-nav-toggle__bars span:nth-child(2) {
  transform: translateY(-2.75px) rotate(-45deg);
}

.arena-header__bar {
  background: #091C18;
  border-top: 1px solid rgba(38, 247, 208, 0.12);
}

.arena-nav__list {
  display: flex;
  align-items: stretch;
  gap: clamp(2px, 1.2vw, 18px);
  overflow-x: auto;
  scrollbar-width: thin;
}

.arena-nav__item {
  flex: 0 0 auto;
}

.arena-nav__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 13px 9px 11px;
  font-size: 15px;
  color: var(--ink);
  border-bottom: 2px solid transparent;
  transition: color var(--t) ease, border-color var(--t) ease, background var(--t) ease;
}

.arena-nav__link:hover,
.arena-nav__link:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--teal);
  background: rgba(38, 247, 208, 0.06);
}

.arena-nav__index {
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--teal);
  transition: color var(--t) ease;
}

.arena-nav__link[aria-current="page"] {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.arena-nav__link[aria-current="page"] .arena-nav__index {
  color: var(--amber);
}

.arena-progress {
  display: block;
  height: 2px;
  background: rgba(38, 247, 208, 0.12);
}

.arena-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--teal), var(--cyan) 58%, var(--amber));
  transition: width 120ms linear;
}

/* ===========================================================
   页脚
   =========================================================== */
.arena-footer {
  position: relative;
  margin-top: clamp(48px, 8vw, 96px);
  background: linear-gradient(180deg, rgba(7, 21, 18, 0.35) 0%, #05110F 42%);
  border-top: 1px solid var(--line);
}

.arena-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 8px;
  background-image: repeating-linear-gradient(90deg, var(--scan) 0 1px, transparent 1px 14px);
  pointer-events: none;
}

.arena-footer__inner {
  padding-block: clamp(38px, 6vw, 68px) 22px;
}

.arena-footer__eyebrow {
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.24em;
  color: var(--cyan);
}

.arena-footer__brand {
  margin-top: 12px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(38px, 7vw, 78px);
  line-height: 0.96;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.arena-footer__note {
  max-width: 52ch;
  margin-top: 14px;
  color: var(--ink-muted);
  font-size: 14.5px;
}

.arena-footer__refresh {
  margin-top: 10px;
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--teal);
}

.arena-footer__grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1.35fr;
  gap: clamp(24px, 4vw, 48px);
  margin-top: clamp(32px, 5vw, 56px);
  padding-top: clamp(24px, 4vw, 38px);
  border-top: 1px solid var(--line-soft);
}

.arena-footer__col-title {
  font-family: var(--font-num);
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--cyan);
  margin-bottom: 14px;
}

.arena-footer__list {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.arena-footer__link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 14px;
  color: var(--ink-muted);
  transition: color var(--t) ease, transform var(--t) ease;
}

.arena-footer__link::before {
  content: "";
  width: 6px;
  height: 1px;
  background: var(--teal);
  transition: width var(--t) ease, background var(--t) ease;
}

.arena-footer__link:hover,
.arena-footer__link:focus-visible {
  color: var(--cyan);
  transform: translateX(2px);
}

.arena-footer__link:hover::before,
.arena-footer__link:focus-visible::before {
  width: 15px;
  background: var(--cyan);
}

.arena-footer__contact {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.arena-contact__row {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.arena-contact__label {
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--teal);
}

.arena-contact__value {
  font-size: 14px;
  color: var(--ink);
  word-break: break-word;
}

.arena-contact__note {
  margin-top: 4px;
  padding-left: 11px;
  border-left: 2px solid var(--wine);
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--ink-muted);
}

.arena-footer__legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 22px;
  margin-top: clamp(28px, 4vw, 42px);
  padding-top: 18px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--font-num);
  font-size: 12px;
  color: var(--ink-muted);
}

.arena-footer__legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-left: auto;
}

.arena-footer__legal-link {
  color: var(--ink-muted);
  transition: color var(--t) ease;
}

.arena-footer__legal-link:hover,
.arena-footer__legal-link:focus-visible {
  color: var(--cyan);
}

/* ===========================================================
   通用内容组件
   =========================================================== */
.arena-grid {
  display: grid;
  gap: clamp(14px, 1.8vw, 22px);
}

.arena-grid--bento {
  grid-template-columns: repeat(12, minmax(0, 1fr));
}

.arena-grid--halves {
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.arena-grid--thirds {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

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

.arena-card {
  position: relative;
  overflow: hidden;
  padding: clamp(16px, 2.2vw, 26px);
  border: 1px solid var(--line-soft);
  border-radius: var(--r-md);
  background: linear-gradient(180deg, rgba(13, 35, 30, 0.96), rgba(10, 27, 23, 0.96));
  transition: border-color var(--t) ease, box-shadow var(--t) ease, transform var(--t) ease;
}

.arena-card:hover,
.arena-card:focus-within {
  border-color: var(--line);
  box-shadow: 0 0 0 1px rgba(38, 247, 208, 0.08), 0 20px 42px -32px rgba(38, 247, 208, 0.55);
  transform: translateY(-1px);
}

.arena-card__index {
  display: block;
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--amber);
  margin-bottom: 10px;
}

.arena-card__title {
  font-family: var(--font-display);
  font-weight: 400;
  font-size: clamp(20px, 2.2vw, 27px);
  line-height: 1.15;
  letter-spacing: 0.03em;
  color: var(--ink);
}

.arena-card__body {
  margin-top: 10px;
  font-size: 14.5px;
  color: var(--ink-muted);
}

.arena-card--accent {
  border-color: rgba(38, 247, 208, 0.4);
}

.arena-card--indigo {
  background: linear-gradient(180deg, rgba(27, 42, 91, 0.6), rgba(10, 27, 23, 0.96));
}

.arena-card--wine {
  background: linear-gradient(180deg, rgba(92, 31, 51, 0.5), rgba(10, 27, 23, 0.96));
}

.arena-scan {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: repeating-linear-gradient(0deg, var(--scan) 0 1px, transparent 1px 7px);
  opacity: 0.35;
  mix-blend-mode: screen;
}

.arena-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.arena-stat__value {
  font-family: var(--font-num);
  font-variant-numeric: tabular-nums;
  font-size: clamp(26px, 4vw, 40px);
  line-height: 1;
  letter-spacing: 0.01em;
  color: var(--amber);
}

.arena-stat__label {
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--ink-muted);
}

.arena-tag {
  display: inline-flex;
  align-items: center;
  padding: 4px 11px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(38, 247, 208, 0.07);
  color: var(--cyan);
  font-family: var(--font-num);
  font-size: 11px;
  letter-spacing: 0.1em;
}

.arena-tag--amber {
  border-color: rgba(255, 194, 75, 0.4);
  background: rgba(255, 194, 75, 0.12);
  color: var(--amber);
}

.arena-tag--indigo {
  border-color: rgba(27, 42, 91, 0.9);
  background: rgba(27, 42, 91, 0.66);
  color: #CFD9FF;
}

.arena-figure {
  position: relative;
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line-soft);
  border-radius: var(--r-md);
  background: linear-gradient(140deg, #0D231E 0%, #071512 58%, #1B2A5B 100%);
}

.arena-figure__frame {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
}

.arena-figure__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform var(--t-slow) ease, opacity var(--t-slow) ease;
}

.arena-figure:hover .arena-figure__img {
  transform: scale(1.015);
}

.arena-figure__grid {
  position: absolute;
  inset: 0;
  background-image:
    repeating-linear-gradient(90deg, rgba(38, 247, 208, 0.13) 0 1px, transparent 1px 46px),
    repeating-linear-gradient(0deg, rgba(38, 247, 208, 0.13) 0 1px, transparent 1px 46px);
  pointer-events: none;
}

.arena-figure__caption {
  padding: 10px 14px;
  border-top: 1px solid var(--line-soft);
  font-family: var(--font-num);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--ink-muted);
}

.arena-figure--wide .arena-figure__frame { aspect-ratio: 21 / 9; }
.arena-figure--square .arena-figure__frame { aspect-ratio: 1 / 1; }
.arena-figure--tall .arena-figure__frame { aspect-ratio: 4 / 5; }

.arena-index {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: 14px;
  border-left: 2px solid var(--line);
}

.arena-index__title {
  font-family: var(--font-num);
  font-size: 11.5px;
  letter-spacing: 0.2em;
  color: var(--cyan);
  margin-bottom: 10px;
}

.arena-index__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 8px 0;
  font-size: 13.5px;
  color: var(--ink-muted);
  border-bottom: 1px dashed rgba(157, 184, 176, 0.14);
  transition: color var(--t) ease, border-color var(--t) ease;
}

.arena-index__link:hover,
.arena-index__link:focus-visible,
.arena-index__link[data-active] {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

.arena-index__num {
  font-family: var(--font-num);
  font-size: 11px;
  color: var(--teal);
}

.arena-details {
  border: 1px solid var(--line-soft);
  border-radius: var(--r-md);
  background: rgba(13, 35, 30, 0.72);
  overflow: hidden;
  transition: border-color var(--t) ease;
}

.arena-details + .arena-details {
  margin-top: 10px;
}

.arena-details:hover {
  border-color: var(--line);
}

.arena-details summary {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 15px 18px;
  font-size: 15px;
  color: var(--ink);
  cursor: pointer;
  list-style: none;
  transition: color var(--t) ease, background var(--t) ease;
}

.arena-details summary::-webkit-details-marker {
  display: none;
}

.arena-details summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-num);
  color: var(--cyan);
}

.arena-details[open] summary {
  color: var(--cyan);
  border-bottom: 1px solid var(--line-soft);
  background: rgba(38, 247, 208, 0.05);
}

.arena-details[open] summary::after {
  content: "–";
  color: var(--amber);
}

.arena-details__body {
  padding: 14px 18px 16px;
  font-size: 14.5px;
  color: var(--ink-muted);
}

.arena-note {
  padding: 2px 0 2px 14px;
  border-left: 3px solid var(--amber);
  font-size: 14px;
  color: var(--ink-muted);
}

/* ---------- 轻量入场（JS 加 html.js-reveal 后生效） ---------- */
[data-reveal] {
  transition: opacity var(--t-slow) ease, transform var(--t-slow) ease;
}

html.js-reveal [data-reveal] {
  opacity: 0;
  transform: translateY(10px);
}

html.js-reveal [data-reveal][data-visible] {
  opacity: 1;
  transform: none;
}

/* ===========================================================
   响应式
   =========================================================== */
@media (max-width: 1080px) {
  .arena-footer__grid {
    grid-template-columns: 1fr 1fr;
  }
  .arena-col-4 { grid-column: span 6; }
  .arena-col-8 { grid-column: span 12; }
}

@media (max-width: 900px) {
  html { scroll-padding-top: 190px; }

  .arena-header__top-inner {
    flex-wrap: wrap;
    gap: 10px;
    padding-block: 9px 6px;
  }

  .arena-brand { order: 1; }

  .arena-nav-toggle {
    order: 2;
    display: inline-flex;
    margin-left: auto;
  }

  .arena-utility {
    order: 3;
    width: 100%;
    margin-left: 0;
    gap: 10px;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .arena-utility__list {
    gap: 10px;
  }

  .arena-utility__link {
    padding: 5px 11px;
    border: 1px solid var(--line);
    border-radius: 999px;
    color: var(--ink);
    white-space: nowrap;
    background: none;
  }

  .arena-utility__link:hover,
  .arena-utility__link:focus-visible {
    background: rgba(38, 247, 208, 0.1);
  }

  .arena-cta {
    padding: 6px 13px;
    font-size: 12px;
  }

  .arena-nav {
    display: none;
  }

  .arena-header[data-open] .arena-nav {
    display: block;
    padding-block: 6px 14px;
  }

  .arena-nav__list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
  }

  .arena-nav__item { width: 100%; }

  .arena-nav__link {
    width: 100%;
    padding: 13px 6px;
    border-bottom: 1px solid var(--line-soft);
    border-left: 2px solid transparent;
  }

  .arena-nav__link:hover,
  .arena-nav__link:focus-visible {
    border-bottom-color: var(--line-soft);
    border-left-color: var(--teal);
    background: rgba(38, 247, 208, 0.05);
  }

  .arena-nav__link[aria-current="page"] {
    border-bottom-color: var(--line-soft);
    border-left-color: var(--cyan);
  }

  .arena-footer__legal-links {
    margin-left: 0;
  }

  .arena-index {
    border-left: 0;
    padding-left: 0;
  }
}

@media (max-width: 640px) {
  h1 { font-size: clamp(32px, 10vw, 48px); }

  .arena-brand__mark {
    width: 36px;
    height: 36px;
    font-size: 13px;
  }

  .arena-brand__name { font-size: 17px; }

  .arena-brand__line { font-size: 10.5px; letter-spacing: 0.1em; }

  .arena-footer__grid {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .arena-grid--bento {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

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

/* ---------- 无障碍：减少动态 ---------- */
@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;
  }

  html.js-reveal [data-reveal] {
    opacity: 1;
    transform: none;
  }
}