/* ============================================================
   K1体育（CN）· Site Kit 共享样式  /assets/site.css
   夜场通道：左侧轨道导航 + 切角 Bento + 珠宝色分区
   ============================================================ */

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

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

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

ul[class],
ol[class] {
  list-style: none;
  padding: 0;
}
ul[class] > li,
ol[class] > li { margin: 0; }

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

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

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

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

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

/* ---------- 2. 设计令牌 ---------- */
:root {
  /* 珠宝色分区 */
  --ink: #0B0F0E;
  --ink-2: #0F1715;
  --deep: #072A2B;
  --wine: #4A1220;
  --indigo: #19123A;
  --paper: #F3EFE4;
  /* 刺激色 */
  --volt: #B7FF3C;
  --sky: #2D7DFF;
  --amber: #FF9E1B;
  --fog: #9AA39B;

  --line: rgba(154, 163, 155, 0.24);
  --line-strong: rgba(243, 239, 228, 0.18);

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

  --rail-w: 0px;
  --bar-h: 58px;
  --pad-inline: 16px;
  --gap: 16px;
  --notch: 14px;
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
}

@media (min-width: 768px) {
  :root {
    --pad-inline: 28px;
    --gap: 20px;
  }
}

@media (min-width: 1024px) {
  :root {
    --rail-w: 112px;
    --bar-h: 0px;
    --pad-inline: 40px;
    --gap: 24px;
  }
}

/* ---------- 3. 基础排版与页面骨架 ---------- */
body {
  min-height: 100vh;
  padding-block-start: var(--bar-h);
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* 低透明度战术网格底纹 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(183, 255, 60, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(183, 255, 60, 0.035) 1px, transparent 1px);
  background-size: 64px 64px;
}

@media (min-width: 1024px) {
  body {
    padding-block-start: 0;
    padding-inline-start: var(--rail-w);
  }
}

#main-content {
  scroll-margin-block-start: calc(var(--bar-h) + 16px);
}

@media (min-width: 1024px) {
  #main-content { scroll-margin-block-start: 24px; }
}

p { line-height: 1.8; }

::selection {
  background: var(--volt);
  color: var(--ink);
}

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

/* ---------- 4. 无障碍工具 ---------- */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  inset-block-start: 10px;
  inset-inline-start: 10px;
  z-index: 200;
  padding: 10px 18px;
  background: var(--volt);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  transform: translateY(-240%);
  transition: transform 0.2s var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: translateY(0);
  outline: 2px solid var(--paper);
  outline-offset: 2px;
}

/* ---------- 5. 头部：左侧轨道 / 移动顶栏抽屉 ---------- */
.site-header {
  position: fixed;
  inset-block-start: 0;
  inset-inline: 0;
  z-index: 90;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  height: var(--bar-h);
  padding-inline: 14px;
  background: rgba(11, 15, 14, 0.97);
  border-block-end: 1px solid var(--line);
}

/* 品牌 */
.hdr-brand {
  display: flex;
  align-items: center;
  min-width: 0;
}

.hdr-brand__link {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
}

.hdr-brand__mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 40px;
  height: 30px;
  padding-inline: 7px;
  background: var(--volt);
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1;
  clip-path: polygon(0 0, 100% 0, 100% 68%, 86% 100%, 0 100%);
  transition: background-color 0.16s var(--ease), color 0.16s var(--ease);
}

.hdr-brand__link:hover .hdr-brand__mark,
.hdr-brand__link:focus-visible .hdr-brand__mark {
  background: var(--amber);
}

.hdr-brand__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
}

.hdr-brand__name {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 800;
  letter-spacing: 0.03em;
  line-height: 1.1;
  white-space: nowrap;
}

.hdr-brand__tag {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.08em;
  color: var(--fog);
  line-height: 1.2;
  white-space: nowrap;
}

@media (max-width: 519px) {
  .hdr-brand__tag { display: none; }
}

/* 移动端汉堡按钮 */
.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  min-width: 58px;
  height: 40px;
  padding-inline: 9px;
  border: 1px solid var(--line);
  background: var(--ink-2);
  color: var(--paper);
  clip-path: polygon(0 0, calc(100% - 9px) 0, 100% 9px, 100% 100%, 0 100%);
  transition: background-color 0.16s var(--ease), border-color 0.16s var(--ease), color 0.16s var(--ease);
}

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

.nav-toggle__bars {
  display: grid;
  gap: 4px;
  width: 18px;
}

.nav-toggle__bar {
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: transform 0.18s var(--ease), opacity 0.18s var(--ease), background-color 0.16s var(--ease);
}

.nav-toggle__text {
  font-family: var(--font-mono);
  font-size: 0.5625rem;
  letter-spacing: 0.16em;
  line-height: 1;
  color: var(--fog);
}

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

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(3px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(2) {
  transform: translateY(-3px) rotate(-45deg);
}

/* 移动端抽屉导航 */
.site-nav {
  position: fixed;
  inset-block-start: var(--bar-h);
  inset-inline: 0;
  z-index: 95;
  max-height: calc(100dvh - var(--bar-h));
  overflow-y: auto;
  padding: 14px 16px 22px;
  background: var(--indigo);
  border-block-end: 2px solid var(--volt);
  opacity: 0;
  visibility: hidden;
  transform: translateY(-12px);
  transition: opacity 0.2s var(--ease), transform 0.2s var(--ease), visibility 0.2s linear;
}

.site-header[data-open="true"] .site-nav {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.site-nav__list {
  display: grid;
  gap: 3px;
  margin-block-end: 16px;
}

.site-nav__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 12px;
  border-inline-start: 3px solid transparent;
  background: rgba(243, 239, 228, 0.035);
  color: var(--paper);
  transition: border-color 0.16s var(--ease), background-color 0.16s var(--ease), color 0.16s var(--ease);
}

.site-nav__link:hover,
.site-nav__link:focus-visible {
  border-inline-start-color: var(--volt);
  background: rgba(183, 255, 60, 0.08);
}

.site-nav__num {
  min-width: 2.2ch;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  color: var(--volt);
}

.site-nav__name {
  font-size: 0.9375rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  line-height: 1.5;
}

.site-nav__link[aria-current="page"] {
  border-inline-start-color: var(--amber);
  background: rgba(255, 158, 27, 0.14);
}

.site-nav__link[aria-current="page"] .site-nav__num,
.site-nav__link[aria-current="page"] .site-nav__name {
  color: var(--amber);
}

.site-nav__foot {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.site-nav__hint {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--fog);
  line-height: 1.5;
}

/* 滚动进度条（移动端横向） */
.rail-progress {
  position: absolute;
  inset-block-end: 0;
  inset-inline: 0;
  height: 2px;
  background: var(--volt);
  transform: scaleX(var(--progress, 0));
  transform-origin: left center;
  transition: transform 0.12s linear;
  pointer-events: none;
}

/* 桌面端：竖向赛道轨道 */
@media (min-width: 1024px) {
  .site-header {
    inset-block-start: 0;
    inset-block-end: 0;
    inset-inline-start: 0;
    inset-inline-end: auto;
    width: var(--rail-w);
    height: auto;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
    gap: 16px;
    padding: 18px 10px 16px;
    background: var(--indigo);
    border-block-end: 0;
    border-inline-end: 1px solid var(--line);
    overflow-y: auto;
    overflow-x: hidden;
    scrollbar-width: thin;
  }

  .hdr-brand__link {
    flex-direction: column;
    align-items: stretch;
    gap: 8px;
  }

  .hdr-brand__mark {
    width: 100%;
    min-width: 0;
    height: 34px;
    font-size: 1.15rem;
  }

  .hdr-brand__name {
    font-size: 0.8125rem;
    letter-spacing: 0.08em;
  }

  .hdr-brand__tag { display: none; }

  .nav-toggle { display: none; }

  .site-nav {
    position: static;
    display: flex;
    flex: 1 1 auto;
    flex-direction: column;
    justify-content: space-between;
    gap: 16px;
    max-height: none;
    overflow: visible;
    padding: 0;
    background: transparent;
    border: 0;
    opacity: 1;
    visibility: visible;
    transform: none;
    transition: none;
  }

  .site-nav__list {
    gap: 5px;
    margin-block-end: 0;
  }

  .site-nav__link {
    flex-direction: column;
    align-items: flex-start;
    gap: 2px;
    padding: 8px 8px 8px 2px;
    border-inline-start: 0;
    border-inline-end: 3px solid transparent;
    background: transparent;
  }

  .site-nav__link:hover,
  .site-nav__link:focus-visible {
    border-inline-start-color: transparent;
    border-inline-end-color: var(--volt);
    background: rgba(183, 255, 60, 0.08);
  }

  .site-nav__link[aria-current="page"] {
    border-inline-start-color: transparent;
    border-inline-end-color: var(--amber);
    background: rgba(255, 158, 27, 0.14);
  }

  .site-nav__num {
    min-width: 0;
    font-size: 0.625rem;
    letter-spacing: 0.1em;
  }

  .site-nav__name {
    font-size: 0.8125rem;
    line-height: 1.4;
    letter-spacing: 0.02em;
  }

  .site-nav__foot { gap: 8px; }

  .site-nav__hint {
    font-size: 0.5625rem;
    letter-spacing: 0.04em;
  }

  .rail-progress {
    inset-block: 0;
    inset-inline: auto 0;
    width: 2px;
    height: auto;
    transform: scaleY(var(--progress, 0));
    transform-origin: center top;
  }
}

/* ---------- 6. 页脚 ---------- */
.site-footer {
  position: relative;
  z-index: 1;
  margin-block-start: clamp(40px, 7vw, 88px);
  padding: clamp(32px, 5vw, 52px) var(--pad-inline) 24px;
  background: var(--deep);
  border-block-start: 1px solid var(--line);
  color: var(--paper);
}

.site-footer::before {
  content: "";
  position: absolute;
  inset-block-start: 0;
  inset-inline-start: 0;
  width: min(260px, 56%);
  height: 3px;
  background: var(--volt);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
  width: 100%;
  max-width: 1180px;
  margin-inline: auto;
}

.site-footer__brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 12px;
}

.footer-mark {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 800;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--paper);
  transition: color 0.16s var(--ease);
}

.footer-mark span { color: var(--volt); }

.footer-mark:hover,
.footer-mark:focus-visible { color: var(--amber); }

.footer-mark:hover span,
.footer-mark:focus-visible span { color: var(--amber); }

.footer-tagline {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  line-height: 1.7;
  color: var(--fog);
  max-width: 30ch;
}

.footer-col {
  display: block;
  min-width: 0;
}

.footer-col__title {
  margin-block-end: 12px;
  padding-block-end: 8px;
  border-block-end: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--volt);
  line-height: 1.4;
}

.footer-list {
  display: grid;
  gap: 7px;
}

.footer-list a {
  display: inline-block;
  font-size: 0.875rem;
  line-height: 1.6;
  color: rgba(243, 239, 228, 0.82);
  border-block-end: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.footer-list a:hover,
.footer-list a:focus-visible {
  color: var(--volt);
  border-block-end-color: var(--volt);
}

.footer-contact {
  display: grid;
  gap: 9px;
}

.footer-contact li {
  display: grid;
  gap: 1px;
}

.footer-contact__key {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.16em;
  color: var(--fog);
  line-height: 1.5;
}

.footer-contact__val {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.01em;
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}

.footer-note {
  margin-block-start: 14px;
  padding-inline-start: 10px;
  border-inline-start: 2px solid var(--amber);
  font-size: 0.75rem;
  line-height: 1.7;
  color: var(--fog);
}

.site-footer__legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 20px;
  width: 100%;
  max-width: 1180px;
  margin-inline: auto;
  margin-block-start: clamp(24px, 4vw, 36px);
  padding-block-start: 16px;
  border-block-start: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  color: var(--fog);
  line-height: 1.6;
}

.footer-legal__links {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
}

.footer-legal__links a {
  color: var(--fog);
  border-block-end: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.footer-legal__links a:hover,
.footer-legal__links a:focus-visible {
  color: var(--volt);
  border-block-end-color: var(--volt);
}

.footer-icp {
  color: rgba(154, 163, 155, 0.9);
}

.to-top {
  margin-inline-start: auto;
  padding: 6px 12px;
  border: 1px solid var(--line);
  background: transparent;
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.14em;
  color: var(--fog);
  clip-path: polygon(0 0, calc(100% - 8px) 0, 100% 8px, 100% 100%, 0 100%);
  transition: border-color 0.16s var(--ease), color 0.16s var(--ease), background-color 0.16s var(--ease);
}

.to-top:hover,
.to-top:focus-visible {
  border-color: var(--volt);
  color: var(--ink);
  background: var(--volt);
}

@media (min-width: 768px) {
  .site-footer__inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 28px 32px;
  }

  .site-footer__brand { grid-column: 1 / -1; }
}

@media (min-width: 1024px) {
  .site-footer__inner {
    grid-template-columns: 1.15fr 0.8fr 0.9fr 1.15fr;
    align-items: start;
  }

  .site-footer__brand { grid-column: auto; }
}

/* ---------- 7. 通用容器与版式 ---------- */
.container {
  width: 100%;
  max-width: 1180px;
  margin-inline: auto;
  padding-inline: var(--pad-inline);
}

.section {
  padding-block: clamp(32px, 6vw, 72px);
}

.prose {
  max-width: 68ch;
  font-size: 1rem;
  line-height: 1.85;
  color: rgba(243, 239, 228, 0.88);
}

.prose > * + * { margin-block-start: 1em; }

.prose h2,
.prose h3,
.prose h4 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.01em;
  line-height: 1.25;
  color: var(--paper);
}

.prose h2 {
  margin-block-start: 1.9em;
  font-size: clamp(1.35rem, 2.4vw, 1.75rem);
}

.prose h3 {
  margin-block-start: 1.6em;
  font-size: 1.125rem;
}

.prose ul,
.prose ol {
  display: grid;
  gap: 0.5em;
  padding-inline-start: 0;
  list-style: none;
}

.prose ul > li {
  position: relative;
  padding-inline-start: 1.4em;
}

.prose ul > li::before {
  content: "";
  position: absolute;
  inset-inline-start: 0;
  inset-block-start: 0.78em;
  width: 0.55em;
  height: 2px;
  background: var(--volt);
}

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

.prose ol > li {
  position: relative;
  padding-inline-start: 1.9em;
  counter-increment: prose-ol;
}

.prose ol > li::before {
  content: counter(prose-ol, decimal-leading-zero);
  position: absolute;
  inset-inline-start: 0;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--volt);
}

.prose a {
  color: var(--sky);
  text-decoration: underline;
  text-underline-offset: 3px;
  font-weight: 500;
}

.prose a:hover { color: var(--volt); }

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

.lede {
  max-width: 62ch;
  font-size: clamp(1rem, 1.6vw, 1.125rem);
  line-height: 1.8;
  color: rgba(243, 239, 228, 0.82);
}

.display {
  font-family: var(--font-display);
  font-size: clamp(2.8rem, 7vw, 6.5rem);
  font-weight: 800;
  line-height: 0.94;
  letter-spacing: -0.02em;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 4vw, 3.4rem);
  font-weight: 800;
  line-height: 1.02;
  letter-spacing: -0.015em;
  color: var(--paper);
}

.panel-title {
  font-family: var(--font-display);
  font-size: clamp(1.125rem, 2vw, 1.5rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: 0.005em;
  color: var(--paper);
}

.mono-label {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.16em;
  line-height: 1.5;
  color: var(--volt);
}

.chapter-num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1;
  color: var(--volt);
}

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

.score-num {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 800;
  line-height: 0.9;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  color: var(--paper);
}

.link {
  color: var(--sky);
  font-weight: 500;
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color 0.16s var(--ease);
}

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

/* ---------- 8. 面包屑 ---------- */
.breadcrumb {
  margin-block: 18px 22px;
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--fog);
  line-height: 1.6;
}

.breadcrumb__sep {
  color: rgba(154, 163, 155, 0.55);
}

.breadcrumb__link {
  color: var(--fog);
  transition: color 0.16s var(--ease);
}

.breadcrumb__link:hover,
.breadcrumb__link:focus-visible { color: var(--volt); }

.breadcrumb__current {
  color: var(--paper);
}

/* ---------- 9. 网格与 Bento 面板 ---------- */
.grid {
  display: grid;
  gap: var(--gap);
}

.bento {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: var(--gap);
}

@media (min-width: 768px) {
  .bento { grid-template-columns: repeat(8, minmax(0, 1fr)); }
}

@media (min-width: 1024px) {
  .bento { grid-template-columns: repeat(12, minmax(0, 1fr)); }
}

.panel {
  position: relative;
  padding: clamp(16px, 2.2vw, 22px);
  background: var(--deep);
  border: 1px solid var(--line);
  color: var(--paper);
  clip-path: polygon(
    0 0,
    calc(100% - var(--notch)) 0,
    100% var(--notch),
    100% 100%,
    var(--notch) 100%,
    0 calc(100% - var(--notch))
  );
}

.panel--wine { background: var(--wine); }
.panel--indigo { background: var(--indigo); }
.panel--ink { background: var(--ink-2); }

.panel__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-block-end: 10px;
}

.panel__num {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--volt);
  line-height: 1.5;
}

.panel__body {
  font-size: 0.9375rem;
  line-height: 1.75;
  color: rgba(243, 239, 228, 0.82);
}

/* ---------- 10. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 20px;
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.2;
  text-align: center;
  clip-path: polygon(
    0 0,
    calc(100% - 12px) 0,
    100% 12px,
    100% 100%,
    12px 100%,
    0 calc(100% - 12px)
  );
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.btn--primary {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  background: var(--volt);
  border-color: var(--volt);
  color: var(--ink);
}

.btn--volt {
  background: var(--volt);
  border-color: var(--volt);
  color: var(--ink);
}

.btn--volt:hover,
.btn--volt:focus-visible {
  background: var(--amber);
  border-color: var(--amber);
  color: var(--ink);
}

.btn--ghost {
  background: rgba(243, 239, 228, 0.04);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: var(--volt);
  background: rgba(183, 255, 60, 0.1);
  color: var(--volt);
}

.btn--sm {
  padding: 8px 14px;
  font-size: 0.8125rem;
}

.btn--block {
  display: flex;
  width: 100%;
}

@media (min-width: 1024px) {
  .site-nav__foot .btn--block {
    padding-inline: 6px;
    font-size: 0.75rem;
    letter-spacing: 0.02em;
  }
}

/* ---------- 11. 标签 / 筛选 / 提示 ---------- */
.tag {
  display: inline-block;
  padding: 2px 8px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.12em;
  line-height: 1.6;
  color: var(--fog);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border: 1px solid var(--line);
  background: rgba(243, 239, 228, 0.04);
  color: rgba(243, 239, 228, 0.85);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  line-height: 1.5;
  transition: border-color 0.16s var(--ease), background-color 0.16s var(--ease), color 0.16s var(--ease);
}

.chip:hover,
.chip:focus-visible {
  border-color: var(--volt);
  color: var(--volt);
}

.chip[aria-pressed="true"] {
  background: var(--volt);
  border-color: var(--volt);
  color: var(--ink);
}

.callout {
  padding: 16px 18px;
  border-inline-start: 3px solid var(--amber);
  background: rgba(255, 158, 27, 0.08);
  font-size: 0.9375rem;
  line-height: 1.75;
  color: rgba(243, 239, 228, 0.9);
}

/* ---------- 12. 图片容器基础规则 ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  background-color: var(--indigo);
  background-image: repeating-linear-gradient(
    135deg,
    rgba(183, 255, 60, 0.07) 0 12px,
    rgba(183, 255, 60, 0) 12px 24px
  );
  clip-path: polygon(
    0 0,
    calc(100% - 18px) 0,
    100% 18px,
    100% 100%,
    18px 100%,
    0 calc(100% - 18px)
  );
}

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

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

.media-caption {
  margin-block-start: 8px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.06em;
  line-height: 1.6;
  color: var(--fog);
}

@media (max-width: 767px) {
  .media-frame--wide { aspect-ratio: 16 / 10; }
}

/* ---------- 13. 减少动效 ---------- */
@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;
  }

  .rail-progress { transition: none; }

  .site-nav {
    transform: none;
  }
}