/* =========================================================
   KAIYUN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;
}

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

ul, ol { list-style: none; }

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

button, input, select, textarea { font: inherit; color: inherit; }

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

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

table { border-collapse: collapse; width: 100%; }

[hidden] { display: none !important; }

/* ---------- 变量 ---------- */
:root {
  --night: #061527;
  --panel: #0D2540;
  --slate: #1B2C3E;
  --white: #F2F5F8;
  --muted: #9FB3C8;
  --accent: #FF5A1F;
  --accent-soft: #FF8A4C;
  --jade: #2FBF9B;
  --cold: #DCE7F2;
  --amber: #F0B429;

  --font-sans: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-num: "Source Han Sans SC", "Noto Sans SC", ui-monospace, "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;

  --gutter: clamp(20px, 5vw, 72px);
  --measure: 1280px;
  --hairline: 1px solid var(--slate);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 中文排版基底 ---------- */
body {
  min-height: 100vh;
  background-color: var(--night);
  background-image:
    radial-gradient(900px 520px at 82% -8%, rgba(255, 90, 31, 0.10), transparent 68%),
    radial-gradient(720px 460px at 4% 10%, rgba(47, 191, 155, 0.06), transparent 70%);
  background-repeat: no-repeat;
  color: var(--white);
  font-family: var(--font-sans);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

p { text-wrap: pretty; }
h1, h2, h3 { text-wrap: balance; }

::selection { background: var(--accent); color: var(--night); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}
:focus:not(:focus-visible) { outline: none; }

html.nav-open { overflow: hidden; }

/* ---------- 通用容器与无障碍 ---------- */
.container {
  width: 100%;
  max-width: var(--measure);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

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

.skip-link {
  position: absolute;
  top: 0;
  left: 50%;
  z-index: 300;
  padding: 12px 22px;
  background: var(--accent);
  color: var(--night);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  transform: translate(-50%, -140%);
  transition: transform 0.22s var(--ease);
}
.skip-link:focus { transform: translate(-50%, 0); }

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

/* ---------- 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(6, 21, 39, 0.92);
  border-bottom: var(--hairline);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(16px, 3vw, 48px);
  width: 100%;
  max-width: var(--measure);
  margin-inline: auto;
  padding: 12px var(--gutter);
  min-height: 74px;
}

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

.brand__mark {
  width: 12px;
  height: 20px;
  flex: none;
  background-image:
    linear-gradient(var(--accent), var(--accent)),
    linear-gradient(var(--cold), var(--cold)),
    linear-gradient(var(--jade), var(--jade));
  background-repeat: no-repeat;
  background-size: 12px 4px;
  background-position: 0 0, 0 8px, 0 16px;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand__name {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--white);
}

.brand__tagline {
  margin-top: 4px;
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.2em;
  color: var(--muted);
}

/* 菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  position: relative;
  z-index: 80;
  padding: 8px 0;
}

.nav-toggle__bars {
  display: block;
  width: 22px;
}

.nav-toggle__bars span {
  display: block;
  height: 2px;
  background: var(--white);
  margin: 5px 0;
  transition: transform 0.24s var(--ease), background-color 0.24s var(--ease);
}

.nav-toggle__label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--muted);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:first-child { transform: translateY(3.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars span:last-child { transform: translateY(-3.5px) rotate(-45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__label { color: var(--accent); }

/* 主导航 */
.header__nav {
  display: flex;
  align-items: center;
  gap: clamp(18px, 3vw, 44px);
}

.nav__list {
  display: flex;
  align-items: center;
  gap: clamp(14px, 2vw, 30px);
}

.nav__link {
  position: relative;
  display: inline-block;
  padding: 6px 0;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--cold);
  transition: color 0.2s var(--ease);
}

.nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.24s var(--ease);
}

.nav__link:hover,
.nav__link:focus-visible { color: var(--white); }

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

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

/* 页头工具区 */
.header__utility {
  display: flex;
  align-items: center;
  gap: 16px;
  padding-left: clamp(16px, 2vw, 28px);
  border-left: var(--hairline);
}

.utility-link {
  padding: 6px 0;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--cold);
  border-bottom: 2px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.utility-link:hover,
.utility-link:focus-visible {
  color: var(--accent-soft);
  border-bottom-color: var(--accent);
}

.icon-link {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border: var(--hairline);
  color: var(--cold);
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.icon-link:hover,
.icon-link:focus-visible {
  color: var(--accent);
  border-color: var(--accent);
}

.icon-link svg { width: 16px; height: 16px; }

/* ---------- 页脚 ---------- */
.site-footer {
  margin-top: clamp(64px, 10vw, 140px);
  border-top: var(--hairline);
  color: var(--cold);
}

.footer__inner { padding-block: clamp(40px, 6vw, 72px) 28px; }

.footer__brand {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 28px;
  padding-bottom: clamp(26px, 4vw, 44px);
}

.footer__brand-name {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: var(--white);
}

.footer__brand-note {
  font-size: 14px;
  letter-spacing: 0.04em;
  color: var(--muted);
  max-width: 40ch;
}

.footer__grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: var(--hairline);
}

.footer__col {
  padding: clamp(24px, 3vw, 40px) clamp(20px, 2.6vw, 36px);
  border-left: var(--hairline);
}

.footer__col:first-child {
  border-left: 0;
  padding-left: 0;
}

.footer__col:last-child { padding-right: 0; }

.footer__title {
  margin-bottom: 16px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--white);
}

.footer__list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.footer__list--plain li {
  font-size: 14px;
  line-height: 1.6;
  color: var(--cold);
  overflow-wrap: anywhere;
}

.footer__link {
  display: inline-block;
  padding: 3px 0;
  font-size: 14px;
  color: var(--cold);
  transition: color 0.2s var(--ease), padding-left 0.2s var(--ease);
}

.footer__link:hover,
.footer__link:focus-visible {
  color: var(--accent-soft);
  padding-left: 8px;
}

.footer__meta {
  margin-top: 18px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.footer__baseline {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 24px;
  margin-top: clamp(24px, 3vw, 40px);
  padding-top: 20px;
  border-top: var(--hairline);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

/* ---------- 基础组件 ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 2px;
  flex: none;
  background: var(--accent);
}

.display-title {
  font-size: clamp(36px, 6vw, 72px);
  font-weight: 200;
  letter-spacing: -0.02em;
  line-height: 1.08;
  color: var(--white);
}

.section-title {
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 500;
  letter-spacing: -0.01em;
  line-height: 1.3;
  color: var(--white);
}

.lede {
  max-width: 60ch;
  font-size: clamp(16px, 1.5vw, 18px);
  line-height: 1.8;
  color: var(--cold);
}

.section { padding-block: clamp(40px, 7vw, 96px); }
.section--tight { padding-block: clamp(24px, 4vw, 48px); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px 32px;
  padding-bottom: 18px;
  border-bottom: var(--hairline);
  margin-bottom: clamp(24px, 3vw, 40px);
}

.prose {
  max-width: 70ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--cold);
}

.prose > * + * { margin-top: 1.25em; }

.prose h2 {
  margin-top: 2em;
  font-size: clamp(20px, 2.4vw, 26px);
  font-weight: 500;
  letter-spacing: -0.01em;
  color: var(--white);
}

.prose h3 {
  margin-top: 1.6em;
  font-size: 18px;
  font-weight: 500;
  color: var(--white);
}

.prose strong { color: var(--white); font-weight: 700; }

.prose a {
  color: var(--accent-soft);
  border-bottom: 1px solid rgba(255, 138, 76, 0.5);
}

.prose ul li {
  position: relative;
  padding-left: 20px;
}

.prose ul li + li { margin-top: 0.5em; }

.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 8px;
  height: 1px;
  background: var(--accent);
}

.prose ol { counter-reset: prose-ol; }

.prose ol li {
  position: relative;
  padding-left: 30px;
  counter-increment: prose-ol;
}

.prose ol li + li { margin-top: 0.5em; }

.prose ol li::before {
  content: counter(prose-ol, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0.42em;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--accent);
}

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

.stat__value {
  font-family: var(--font-num);
  font-size: clamp(48px, 8vw, 120px);
  font-weight: 900;
  letter-spacing: -0.04em;
  line-height: 0.88;
  font-variant-numeric: tabular-nums;
  color: var(--white);
}

.stat__label {
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.panel {
  background: var(--panel);
  padding: clamp(20px, 3vw, 36px);
}

.panel--lit { box-shadow: inset 2px 0 0 var(--accent); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 13px 26px;
  border: 1px solid var(--slate);
  background: transparent;
  color: var(--white);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.08em;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background-color 0.2s var(--ease);
}

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

.btn--accent {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--night);
  font-weight: 700;
}

.btn--accent:hover,
.btn--accent:focus-visible {
  background: var(--accent-soft);
  border-color: var(--accent-soft);
  color: var(--night);
}

.btn--quiet {
  padding-inline: 0;
  border-color: transparent;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid var(--slate);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--muted);
}

.tag--accent { color: var(--accent-soft); border-color: rgba(255, 90, 31, 0.42); }
.tag--jade { color: var(--jade); border-color: rgba(47, 191, 155, 0.42); }
.tag--amber { color: var(--amber); border-color: rgba(240, 180, 41, 0.42); }

.tabs { display: block; }

.tabs__list {
  display: flex;
  align-items: stretch;
  gap: 0;
  border-bottom: var(--hairline);
  overflow-x: auto;
}

.tabs__tab {
  position: relative;
  padding: 14px 22px;
  white-space: nowrap;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--muted);
  transition: color 0.2s var(--ease);
}

.tabs__tab::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.24s var(--ease);
}

.tabs__tab:hover { color: var(--cold); }
.tabs__tab[aria-selected="true"] { color: var(--white); }
.tabs__tab[aria-selected="true"]::after { transform: scaleX(1); }

.tabs__panels { padding-top: clamp(20px, 3vw, 32px); }

.tabs__panel[hidden] { display: none !important; }

.media {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: var(--panel);
}

.media--wide { aspect-ratio: 21 / 9; }
.media--panorama { aspect-ratio: 3 / 1; }
.media--tall { aspect-ratio: 4 / 5; }

.media::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  background-image:
    linear-gradient(90deg, rgba(220, 231, 242, 0.06) 1px, transparent 1px),
    linear-gradient(0deg, rgba(220, 231, 242, 0.06) 1px, transparent 1px);
  background-size: 64px 64px;
}

.media__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.media__caption {
  margin-top: 12px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.breadcrumb {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: var(--slate);
}

.breadcrumb__link {
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.breadcrumb__link:hover,
.breadcrumb__link:focus-visible {
  color: var(--accent-soft);
  border-bottom-color: var(--accent);
}

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

.grid {
  display: grid;
  gap: clamp(20px, 3vw, 40px);
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }

/* ---------- 动效 ---------- */
.js-reveal [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity 0.32s ease-out, transform 0.32s ease-out;
}

.js-reveal [data-reveal="in"] {
  opacity: 1;
  transform: none;
}

/* ---------- 响应式 ---------- */
@media (max-width: 960px) {
  .nav-toggle { display: inline-flex; }

  .header__nav {
    position: fixed;
    inset: 0;
    z-index: 70;
    flex-direction: column;
    align-items: stretch;
    justify-content: center;
    gap: 0;
    padding: 104px var(--gutter) 48px;
    background: var(--night);
    overflow-y: auto;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-12px);
    transition: opacity 0.28s var(--ease), transform 0.28s var(--ease), visibility 0.28s linear;
  }

  .header__nav[data-open] {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: none;
  }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav__list li { border-bottom: var(--hairline); }

  .nav__link {
    display: flex;
    align-items: center;
    padding: 18px 0;
    font-size: 20px;
    letter-spacing: 0.04em;
    color: var(--cold);
  }

  .nav__link::after {
    left: 0;
    right: auto;
    top: 50%;
    bottom: auto;
    width: 3px;
    height: 18px;
    transform: translateY(-50%) scaleY(0);
    transform-origin: center top;
  }

  .nav__link:hover::after,
  .nav__link:focus-visible::after,
  .nav__link[aria-current="page"]::after { transform: translateY(-50%) scaleY(1); }

  .header__utility {
    margin-top: 28px;
    padding: 24px 0 0;
    border-left: 0;
    border-top: var(--hairline);
    gap: 28px;
  }

  .utility-link { font-size: 15px; }

  .footer__grid { grid-template-columns: 1fr; }
  .footer__col {
    border-left: 0;
    padding-inline: 0;
  }
  .footer__col + .footer__col { border-top: var(--hairline); }

  .grid--2,
  .grid--3 { grid-template-columns: 1fr; }
}

@media (max-width: 600px) {
  body { font-size: 15px; }

  .header__inner { min-height: 64px; }

  .brand__tagline { display: none; }

  .footer__baseline {
    flex-direction: column;
    justify-content: flex-start;
  }

  .tabs__tab { padding: 12px 16px; font-size: 13px; }
}

@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;
  }

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