/* ============================================================
   B体育登录 — 共享站点样式 /assets/site.css
   ============================================================ */

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

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

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd, ul, ol { margin: 0; }

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

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

button { font: inherit; color: inherit; }

/* ---------- variables ---------- */
:root {
  --ink: #08150F;
  --ink-2: #0F2A20;
  --ink-3: #16382A;
  --lime: #C8F751;
  --lime-2: #8FBF3A;
  --orange: #FF7A33;
  --paper: #F3EFE4;
  --paper-ink: #12241C;
  --fog: #A9B6AE;
  --bone: #EAF0E9;
  --rule: #2A463A;

  --sans: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Source Han Sans SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --mono: ui-monospace, "SFMono-Regular", "JetBrains Mono", "IBM Plex Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --wrap: 1440px;
  --gut: clamp(16px, 3vw, 40px);
  --ease: cubic-bezier(.2, .7, .2, 1);
  --head-h: 70px;
}

/* ---------- base ---------- */
html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--head-h) + 24px);
}

body {
  background: var(--ink);
  color: var(--bone);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.75;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

body.is-nav-open { overflow: hidden; }

a { color: inherit; }

p { max-width: 34em; }

h1, h2, h3, h4 {
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.12;
}

h1 { font-size: clamp(38px, 6vw, 82px); line-height: 1.06; }
h2 { font-size: clamp(26px, 3.4vw, 44px); }
h3 { font-size: clamp(20px, 2.1vw, 28px); }
h4 { font-size: clamp(17px, 1.4vw, 20px); letter-spacing: -0.01em; }

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

/* ---------- utilities ---------- */
.sr-only {
  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;
}

.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gut);
}

.num {
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

.label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--fog);
}

.label::before {
  content: "";
  display: block;
  width: 16px;
  height: 1px;
  background: var(--lime);
  flex: none;
}

/* ---------- layout blocks ---------- */
.page { padding-top: clamp(24px, 3.5vw, 52px); }

.section { padding-block: clamp(40px, 5vw, 82px); }

.section--paper {
  background: var(--paper);
  color: var(--paper-ink);
}

.section--paper h2,
.section--paper h3,
.section--paper h4 { color: var(--paper-ink); }

.section--paper .label { color: #4C5A50; }
.section--paper .label::before { background: var(--orange); }

.section--paper .card {
  background: #FBF8F0;
  border-color: #D6D0BF;
}

.section--paper .card:hover { border-color: var(--orange); }

.grid { display: grid; gap: clamp(14px, 1.6vw, 22px); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

@media (max-width: 900px) {
  .grid--3, .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 760px) {
  .grid--2, .grid--3, .grid--4 { grid-template-columns: minmax(0, 1fr); }
}

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 22px;
  border: 1px solid transparent;
  background: transparent;
  color: var(--bone);
  font-family: var(--sans);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color .2s var(--ease), color .2s var(--ease),
              border-color .2s var(--ease), transform .2s var(--ease);
}

.btn:hover { transform: translateY(-1px); }
.btn:active { transform: none; }

.btn--lime {
  background: var(--lime);
  border-color: var(--lime);
  color: var(--ink);
}
.btn--lime:hover {
  background: var(--lime-2);
  border-color: var(--lime-2);
  color: var(--ink);
}

.btn--ghost {
  border-color: var(--rule);
  color: var(--bone);
}
.btn--ghost:hover {
  border-color: var(--lime);
  color: var(--lime);
}

.btn--orange {
  background: var(--orange);
  border-color: var(--orange);
  color: #1B0C04;
}
.btn--orange:hover {
  background: #E8671F;
  border-color: #E8671F;
}

/* ---------- breadcrumb ---------- */
.crumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--fog);
}

.crumb li { display: flex; align-items: center; }

.crumb li + li::before {
  content: "/";
  margin-inline: 10px;
  color: var(--rule);
}

.crumb a {
  color: var(--fog);
  text-decoration: none;
  transition: color .18s var(--ease);
}
.crumb a:hover { color: var(--lime); }

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

/* ---------- section head ---------- */
.section-head {
  display: grid;
  gap: 8px;
  border-top: 1px solid var(--rule);
  padding-top: 16px;
  margin-bottom: clamp(20px, 3vw, 38px);
}

.section-head__index {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--lime);
}

.section-head__title { font-size: clamp(24px, 3vw, 36px); }

.section--paper .section-head { border-top-color: #CFC8B6; }
.section--paper .section-head__index { color: #B0521F; }

/* ---------- cards ---------- */
.card {
  background: var(--ink-2);
  border: 1px solid var(--rule);
  padding: clamp(18px, 2vw, 28px);
  transition: transform .2s var(--ease), border-color .2s var(--ease),
              background-color .2s var(--ease);
}

.card:hover {
  transform: translateY(-2px);
  border-color: var(--lime-2);
}

/* ---------- media containers ---------- */
.media {
  position: relative;
  display: block;
  overflow: hidden;
  background: var(--ink-2);
  border: 1px solid var(--rule);
  aspect-ratio: 16 / 10;
}

.media > img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.92) contrast(1.06);
}

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

.section--paper .media {
  background: #E4DECE;
  border-color: #CFC8B6;
}

/* ============================================================
   HEADER
   ============================================================ */
.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 300;
  transform: translateY(-220%);
  background: var(--lime);
  color: var(--ink);
  padding: 12px 20px;
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.04em;
  text-decoration: none;
  transition: transform .18s var(--ease);
}

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

.masthead {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(8, 21, 15, .93);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--rule);
  transition: background-color .25s var(--ease), border-color .25s var(--ease);
}

.masthead[data-scrolled] {
  background: var(--ink);
  border-bottom-color: var(--ink-3);
}

.masthead__inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 10px var(--gut);
  min-height: var(--head-h);
}

/* brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  flex: none;
  text-decoration: none;
  color: var(--bone);
}

.brand__mark {
  display: block;
  width: 12px;
  height: 12px;
  flex: none;
  background: var(--lime);
  transition: transform .2s var(--ease);
}

.brand:hover .brand__mark { transform: translateY(-2px); }

.brand__name {
  font-size: 19px;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1;
  white-space: nowrap;
}

/* motion track */
.masthead__track {
  position: relative;
  flex: 1 1 60px;
  min-width: 0;
  height: 26px;
  display: none;
}

.masthead__track::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 8px;
  background-image: repeating-linear-gradient(90deg, var(--rule) 0 1px, transparent 1px 9px);
  -webkit-mask-image: linear-gradient(90deg, #000 0, #000 58%, transparent 96%);
  mask-image: linear-gradient(90deg, #000 0, #000 58%, transparent 96%);
  opacity: .9;
}

.masthead__trace {
  position: absolute;
  left: 0;
  top: 0;
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 10px;
  line-height: 1;
  letter-spacing: 0.14em;
  color: var(--lime);
  white-space: nowrap;
  opacity: 0;
  transform: translateY(-4px);
  transition: opacity .28s var(--ease), transform .28s var(--ease);
  pointer-events: none;
}

.masthead[data-scrolled] .masthead__trace {
  opacity: 1;
  transform: none;
}

.masthead__trace-sep {
  display: block;
  width: 18px;
  height: 1px;
  background: var(--lime-2);
  flex: none;
}

.masthead__trace-index { color: var(--fog); }

/* desktop nav */
.masthead__nav { display: none; flex: none; }

.nav-list {
  display: flex;
  align-items: stretch;
}

.nav-list > li + li { border-left: 1px solid var(--rule); }

.nav-list a {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 6px;
  padding: 10px clamp(8px, 1.1vw, 14px);
  color: var(--fog);
  font-size: 14px;
  text-decoration: none;
  transition: color .18s var(--ease), background-color .18s var(--ease);
}

.nav-list a:hover {
  color: var(--bone);
  background: var(--ink-2);
}

.nav-list a[aria-current="page"] { color: var(--lime); }

.nav-list a[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--lime);
}

.nav-idx {
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: 0.06em;
  color: var(--fog);
  opacity: .55;
  transition: color .18s var(--ease), opacity .18s var(--ease);
}

.nav-list a:hover .nav-idx,
.nav-list a[aria-current="page"] .nav-idx {
  color: var(--lime-2);
  opacity: 1;
}

/* progress */
.masthead__progress {
  height: 2px;
  overflow: hidden;
  background: transparent;
}

.masthead__progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: var(--lime);
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform .12s linear;
  will-change: transform;
}

/* mobile toggle */
.nav-toggle {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 140;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 0 18px;
  border: 0;
  background: var(--lime);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: background-color .2s var(--ease), color .2s var(--ease);
}

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 14px;
  height: 9px;
  flex: none;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1.5px;
  background: currentColor;
  transition: transform .2s var(--ease), top .2s var(--ease), bottom .2s var(--ease);
}

.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }

.nav-toggle[aria-expanded="true"] {
  background: var(--ink-3);
  color: var(--lime);
  box-shadow: inset 0 0 0 1px var(--lime);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before {
  top: 3.5px;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after {
  bottom: 4px;
  transform: rotate(-45deg);
}

/* scrim */
.nav-scrim {
  position: fixed;
  inset: 0;
  z-index: 125;
  background: rgba(4, 12, 8, .72);
  opacity: 0;
  visibility: hidden;
  transition: opacity .28s var(--ease), visibility .28s var(--ease);
}

.nav-scrim[data-open] {
  opacity: 1;
  visibility: visible;
}

/* drawer */
.nav-drawer {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  z-index: 130;
  width: min(380px, 88vw);
  display: flex;
  flex-direction: column;
  gap: 18px;
  padding: 84px 24px 128px;
  overflow-y: auto;
  background: var(--ink-2);
  border-left: 1px solid var(--rule);
  transform: translateX(102%);
  visibility: hidden;
  transition: transform .3s var(--ease), visibility .3s var(--ease);
}

.nav-drawer[data-open] {
  transform: none;
  visibility: visible;
}

.nav-drawer__eyebrow {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--lime);
  margin: 0;
}

.nav-drawer__list {
  display: grid;
  border-top: 1px solid var(--rule);
}

.nav-drawer__list > li { border-bottom: 1px solid var(--rule); }

.nav-drawer__list a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px 4px;
  color: var(--bone);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
  text-decoration: none;
  transition: color .18s var(--ease), padding-left .18s var(--ease);
}

.nav-drawer__list a:hover,
.nav-drawer__list a:focus-visible {
  color: var(--lime);
  padding-left: 10px;
}

.nav-drawer__list a[aria-current="page"] { color: var(--lime); }

.nav-drawer__list a[aria-current="page"] .nav-idx {
  color: var(--lime);
  opacity: 1;
}

.nav-drawer__foot {
  margin-top: auto;
  padding-top: 20px;
  border-top: 1px solid var(--rule);
}

.nav-drawer__k {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--fog);
  opacity: .7;
  margin: 14px 0 2px;
}

.nav-drawer__v {
  font-size: 14px;
  color: var(--bone);
  margin: 0;
  word-break: break-all;
}

.nav-drawer__icp {
  margin: 22px 0 0;
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--fog);
  opacity: .7;
}

@media (min-width: 1000px) {
  .masthead__track { display: block; }
  .masthead__nav { display: block; }
  .nav-toggle { display: none; }
  .nav-drawer { display: none; }
  .nav-scrim { display: none; }
}

/* ============================================================
   FOOTER
   ============================================================ */
.site-foot {
  border-top: 2px solid var(--lime);
  background: var(--ink);
  color: var(--fog);
  margin-top: clamp(40px, 5vw, 88px);
}

.foot-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 3vw, 40px);
  padding-block: clamp(36px, 4.5vw, 64px);
  border-bottom: 1px solid var(--rule);
}

.foot-col { min-width: 0; }

.foot-label {
  font-family: var(--mono);
  font-size: 11px;
  line-height: 1;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--lime);
  margin: 0 0 20px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--rule);
}

.foot-mail-line {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 4px;
  max-width: none;
}

.foot-mail {
  font-family: var(--mono);
  font-size: 14.5px;
  letter-spacing: -0.01em;
  color: var(--bone);
  word-break: break-all;
}

.copy-btn {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0 10px;
  background: transparent;
  border: 1px solid var(--rule);
  color: var(--fog);
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 0.08em;
  cursor: pointer;
  transition: border-color .2s var(--ease), color .2s var(--ease),
              background-color .2s var(--ease);
}

.copy-btn:hover {
  border-color: var(--lime);
  color: var(--lime);
}

.copy-btn[data-copied] {
  border-color: var(--lime);
  background: rgba(200, 247, 81, .1);
  color: var(--lime);
}

.foot-line {
  display: grid;
  grid-template-columns: 3.4em minmax(0, 1fr);
  gap: 8px 12px;
  margin: 18px 0 0;
}

.foot-k {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--fog);
  opacity: .6;
  padding-top: 3px;
}

.foot-v {
  font-size: 14px;
  line-height: 1.6;
  color: var(--bone);
  margin: 0;
}

.foot-note {
  margin: 16px 0 0;
  font-size: 12.5px;
  line-height: 1.75;
  color: var(--fog);
  opacity: .85;
  max-width: 32em;
}

.foot-links {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 18px;
}

.foot-links a {
  display: block;
  padding: 10px 0;
  border-bottom: 1px solid rgba(42, 70, 58, .55);
  color: var(--fog);
  font-size: 14px;
  text-decoration: none;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}

.foot-links a:hover {
  color: var(--lime);
  border-bottom-color: var(--lime-2);
}

.feed-map {
  display: grid;
  gap: 12px;
  margin-bottom: 4px;
}

.feed-map > li {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 13.5px;
  color: var(--bone);
}

.glyph {
  display: block;
  width: 24px;
  height: 24px;
  flex: none;
  border: 1px solid var(--rule);
}

.glyph--block {
  background: var(--orange);
  border-color: var(--orange);
}

.glyph--line {
  background-image: repeating-linear-gradient(0deg, var(--lime) 0 2px, transparent 2px 6px);
  background-size: 12px 8px;
  background-position: center;
  background-repeat: no-repeat;
}

.glyph--dots {
  background-image: radial-gradient(circle at center, var(--fog) 1.3px, transparent 1.4px);
  background-size: 6px 6px;
  background-position: center;
}

.foot-cta { margin-top: 18px; }

.foot-base {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 26px;
  padding-block: 22px 30px;
}

.foot-brand {
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--bone);
  margin: 0;
  max-width: none;
}

.foot-icp {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--fog);
  opacity: .8;
  margin: 0;
  max-width: none;
}

.foot-year {
  margin: 0 0 0 auto;
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.06em;
  color: var(--fog);
  opacity: .8;
  max-width: none;
}

.foot-desc {
  flex: 1 1 100%;
  margin: 0;
  font-size: 12px;
  line-height: 1.7;
  color: var(--fog);
  opacity: .7;
  max-width: 52em;
}

@media (min-width: 760px) {
  .foot-grid { grid-template-columns: 1.15fr 0.95fr 1fr; }

  .foot-col + .foot-col {
    border-left: 1px solid var(--rule);
    padding-left: clamp(20px, 3vw, 38px);
  }
}

@media (min-width: 1120px) {
  .foot-grid { grid-template-columns: 1.2fr 0.9fr 1.05fr; }
}

/* ============================================================
   FOCUS / MOTION
   ============================================================ */
:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 3px;
}

.section--paper :focus-visible,
.section--paper a:focus-visible,
.section--paper button:focus-visible {
  outline-color: #B0521F;
}

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

  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  .masthead__progress span { transition: none; }
  .btn:hover,
  .card:hover,
  .brand:hover .brand__mark { transform: none; }
}