/* ==========================================================================
   /assets/site.css — YABO 中文站共享外壳
   深墨绿底 + 荧光青柠强调 + 等宽数字 + 印刷边框
   ========================================================================== */

:root {
  --ink-900: #071A15;
  --ink-800: #0E2A22;
  --ink-700: #14382D;
  --line: #2A5546;
  --lime: #C8FF4D;
  --lime-soft: #DBFF8A;
  --blue: #4CC9FF;
  --orange: #FF8A3D;
  --paper: #F2F7EF;
  --fog: #A9C6B6;

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

  --header-h: 74px;
  --pad-x: 20px;
  --gap: 24px;
  --ease: cubic-bezier(.2, .7, .3, 1);
  --dur: 180ms;
}

@media (min-width: 768px) {
  :root { --pad-x: 32px; }
}

@media (min-width: 1024px) {
  :root { --pad-x: 48px; }
}

@media (min-width: 1400px) {
  :root { --pad-x: 80px; }
}

@media (max-width: 1024px) {
  :root { --header-h: 64px; }
}

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

* { margin: 0; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  background: #071A15;
  BACKGROUND: var(--ink-900);
}

body {
  background: var(--ink-900);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  font-weight: 400;
  line-height: 1.7;
  padding-top: var(--header-h);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

main { display: block; }

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

::selection {
  background: var(--lime);
  color: var(--ink-900);
}

/* ---------- 中文排版基线 ---------- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.12;
  letter-spacing: .01em;
  color: var(--paper);
}

h1 { font-size: clamp(40px, 6vw, 96px); font-weight: 700; letter-spacing: -.01em; }
h2 { font-size: clamp(28px, 3.6vw, 64px); }
h3 { font-size: clamp(20px, 2.2vw, 28px); }
h4 { font-size: 20px; }

p { margin: 0 0 1em; }

p:last-child { margin-bottom: 0; }

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

ul, ol { padding-left: 1.1em; }

strong, b { font-weight: 500; color: var(--lime); }

small { font-size: 12px; }

code, kbd, samp, pre {
  font-family: var(--font-mono);
  font-size: .92em;
}

/* ---------- 焦点与可访问性 ---------- */
:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 3px;
  border-radius: 1px;
}

:focus:not(:focus-visible) { outline: none; }

/* ---------- 工具层 ---------- */
.shell {
  width: 100%;
  max-width: 1520px;
  margin-inline: auto;
  padding-inline: var(--pad-x);
}

.section { padding-block: 96px; }

@media (min-width: 1024px) {
  .section { padding-block: 128px; }
}

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

.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -.01em;
}

.grid {
  display: grid;
  gap: var(--gap);
}

.grid-12 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

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

/* ---------- 章节头（画册编号体系） ---------- */
.section-head {
  display: flex;
  align-items: flex-end;
  gap: clamp(14px, 2vw, 28px);
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
  margin-bottom: clamp(28px, 4vw, 52px);
}

.section-index {
  font-family: var(--font-display);
  font-size: clamp(44px, 7vw, 96px);
  font-weight: 700;
  line-height: .78;
  letter-spacing: -.02em;
  color: transparent;
  -webkit-text-stroke: 1px var(--line);
  flex: 0 0 auto;
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(22px, 2.8vw, 40px);
  font-weight: 600;
  line-height: 1.05;
  letter-spacing: .01em;
}

/* ---------- 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 5px 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.4;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--fog);
  background: rgba(20, 56, 45, .62);
  border: 1px solid var(--line);
  white-space: nowrap;
}

.tag--lime {
  background: var(--lime);
  border-color: var(--lime);
  color: #06150F;
  font-weight: 700;
}

.tag--blue {
  border-color: rgba(76, 201, 255, .45);
  color: var(--blue);
  background: rgba(76, 201, 255, .08);
}

.tag--orange {
  border-color: rgba(255, 138, 61, .5);
  color: var(--orange);
  background: rgba(255, 138, 61, .08);
}

/* ---------- 纸张叠层卡片 ---------- */
.paper-card {
  position: relative;
  background: var(--ink-800);
  border: 1px solid var(--line);
  padding: 24px;
  transition: transform var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}

.paper-card:hover,
.paper-card:focus-within {
  transform: translateY(-2px);
  border-color: var(--lime);
  box-shadow: 0 0 0 1px rgba(200, 255, 77, .22),
              0 22px 44px -28px rgba(0, 0, 0, .95);
}

.paper-card--stacked::after {
  content: "";
  position: absolute;
  inset: 0;
  transform: translate(8px, 8px);
  border: 1px solid rgba(42, 85, 70, .9);
  pointer-events: none;
  transition: transform var(--dur) var(--ease);
}

.paper-card--stacked:hover::after,
.paper-card--stacked:focus-within::after {
  transform: translate(10px, 10px);
  border-color: rgba(200, 255, 77, .35);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 11px 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .1em;
  line-height: 1.4;
  color: var(--paper);
  background: transparent;
  border: 1px solid var(--line);
  cursor: pointer;
  text-align: center;
  transition: background var(--dur) var(--ease),
              color var(--dur) var(--ease),
              border-color var(--dur) var(--ease),
              transform var(--dur) var(--ease);
}

.btn--lime {
  background: var(--lime);
  border-color: var(--lime);
  color: #06150F;
  font-weight: 700;
}

.btn--lime:hover {
  background: var(--lime-soft);
  border-color: var(--lime-soft);
  color: #06150F;
  transform: translateY(-2px);
}

.btn--ghost { color: var(--fog); }

.btn--ghost:hover {
  background: var(--lime);
  border-color: var(--lime);
  color: #06150F;
  transform: translateY(-2px);
}

.btn--sm {
  padding: 8px 14px;
  font-size: 11px;
}

/* ---------- 面包屑 ---------- */
.breadcrumbs {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--fog);
}

.breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}

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

.breadcrumbs li + li::before {
  content: "/";
  color: var(--line);
  margin-right: 10px;
}

.breadcrumbs a { transition: color var(--dur) var(--ease); }

.breadcrumbs a:hover { color: var(--lime); }

/* ---------- 图片容器基础规则（页面阶段填充占位内容） ---------- */
.media-frame {
  position: relative;
  display: block;
  overflow: hidden;
  isolation: isolate;
  aspect-ratio: 16 / 9;
  background:
    radial-gradient(120% 90% at 20% 0%, rgba(76, 201, 255, .14), transparent 62%),
    radial-gradient(90% 80% at 90% 100%, rgba(200, 255, 77, .10), transparent 60%),
    var(--ink-700);
  border: 1px solid var(--line);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: .55;
  background-image:
    repeating-linear-gradient(90deg, rgba(42, 85, 70, .85) 0 1px, transparent 1px 56px),
    repeating-linear-gradient(0deg, rgba(42, 85, 70, .45) 0 1px, transparent 1px 56px);
}

.media-frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: saturate(.72) contrast(1.05) brightness(.92);
}

.media-frame figcaption {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  margin: 0;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--paper);
  background: rgba(7, 26, 21, .82);
  border-top: 1px solid var(--line);
  border-right: 1px solid var(--line);
}

.media-frame--wide { aspect-ratio: 21 / 9; }
.media-frame--16x9 { aspect-ratio: 16 / 9; }
.media-frame--4x3 { aspect-ratio: 4 / 3; }
.media-frame--1x1 { aspect-ratio: 1 / 1; }
.media-frame--tall { aspect-ratio: 3 / 4; }

/* ==========================================================================
   跳过链接
   ========================================================================== */
.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  transform: translateY(-180%);
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: #06150F;
  background: var(--lime);
  border: 1px solid var(--lime);
  transition: transform var(--dur) var(--ease);
}

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

/* ==========================================================================
   头部框架横梁
   ========================================================================== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 80;
  color: var(--paper);
  background: var(--ink-900);
  border-bottom: 1px solid var(--line);
  transition: background var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease);
}

.site-header[data-scrolled="true"] {
  background: var(--ink-800);
  box-shadow: 0 28px 52px -36px rgba(0, 0, 0, .95);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 28px);
  width: 100%;
  max-width: 1520px;
  margin-inline: auto;
  padding-inline: var(--pad-x);
  height: var(--header-h);
}

/* ---------- 品牌 ---------- */
.brand-mark {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding-right: clamp(12px, 2vw, 24px);
  border-right: 1px solid var(--line);
  min-height: 32px;
}

.brand-glyph {
  position: relative;
  padding-left: 14px;
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: .16em;
  color: var(--paper);
}

.brand-glyph::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 5px;
  height: 22px;
  transform: translateY(-50%);
  background: var(--lime);
}

.brand-meta {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-family: var(--font-mono);
  font-size: 10px;
  line-height: 1.4;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--fog);
  white-space: nowrap;
}

.brand-meta em {
  font-style: normal;
  letter-spacing: .1em;
  color: var(--lime);
  opacity: .9;
}

/* ---------- 移动开合按钮 ---------- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  margin-left: auto;
  padding: 8px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--paper);
  background: transparent;
  border: 1px solid var(--line);
  cursor: pointer;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

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

.nav-toggle-bars {
  display: inline-flex;
  flex-direction: column;
  gap: 4px;
  width: 16px;
}

.nav-toggle-bars i {
  display: block;
  height: 1.5px;
  width: 100%;
  background: var(--lime);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.site-header[data-open="true"] .nav-toggle-bars i:first-child {
  transform: translateY(2.75px) rotate(45deg);
}

.site-header[data-open="true"] .nav-toggle-bars i:last-child {
  transform: translateY(-2.75px) rotate(-45deg);
}

/* ---------- 主导航 ---------- */
.primary-nav {
  margin-left: auto;
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.4vw, 20px);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(8px, 1.5vw, 24px);
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: navidx;
}

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

.nav-link {
  position: relative;
  display: inline-block;
  padding: 6px 2px;
  font-size: 14px;
  font-weight: 500;
  line-height: 1.4;
  white-space: nowrap;
  color: var(--fog);
  transition: color var(--dur) var(--ease);
}

.nav-link::before {
  counter-increment: navidx;
  content: counter(navidx, decimal-leading-zero);
  margin-right: 6px;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: .08em;
  vertical-align: 1px;
  color: var(--line);
  transition: color var(--dur) var(--ease);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--lime);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--dur) var(--ease),
              background var(--dur) var(--ease);
}

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

.nav-link:hover::before,
.nav-link:focus-visible::before { color: var(--lime); }

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

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

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

.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
  background: var(--orange);
}

.nav-cta { display: none; }

.header-cta {
  flex: 0 0 auto;
  display: flex;
  margin-left: clamp(4px, 1vw, 12px);
}

/* ---------- 滚动进度轨 ---------- */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  pointer-events: none;
  background: transparent;
}

.scroll-progress span {
  display: block;
  width: 0;
  height: 100%;
  background: var(--lime);
  box-shadow: 0 0 12px rgba(200, 255, 77, .55);
  transition: width 80ms linear;
}

/* ==========================================================================
   页脚
   ========================================================================== */
.site-footer {
  position: relative;
  background: var(--ink-800);
  border-top: 1px solid var(--line);
  color: var(--paper);
}

.site-footer p { margin: 0; }

.footer-frame {
  width: 100%;
  max-width: 1520px;
  margin-inline: auto;
  padding: clamp(48px, 7vw, 92px) var(--pad-x) 0;
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr) minmax(0, 1.1fr);
  gap: clamp(28px, 4vw, 72px);
  padding-bottom: clamp(36px, 5vw, 68px);
  border-bottom: 1px solid var(--line);
}

/* ---------- 页脚品牌 ---------- */
.footer-brand { min-width: 0; }

.footer-glyph {
  display: block;
  font-family: var(--font-display);
  font-size: clamp(40px, 6vw, 72px);
  font-weight: 700;
  line-height: .86;
  letter-spacing: .06em;
  color: var(--paper);
  margin-bottom: 16px;
}

.footer-line {
  font-size: 14px;
  font-weight: 500;
  letter-spacing: .04em;
  color: var(--paper);
}

.footer-line small {
  display: block;
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--lime);
}

.footer-summary {
  margin-top: 16px;
  max-width: 34ch;
  font-size: 14px;
  line-height: 1.8;
  color: var(--fog);
}

/* ---------- 页脚栏目 ---------- */
.footer-col { min-width: 0; }

.footer-col-title {
  margin-bottom: 16px;
  padding-bottom: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--lime);
  border-bottom: 1px dashed var(--line);
}

.footer-links {
  display: grid;
  gap: 10px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-links a {
  display: inline-block;
  font-size: 14px;
  color: var(--fog);
  transition: color var(--dur) var(--ease),
              transform var(--dur) var(--ease);
}

.footer-links a::before {
  content: "—";
  margin-right: 8px;
  color: var(--line);
  transition: color var(--dur) var(--ease);
}

.footer-links a:hover,
.footer-links a:focus-visible {
  color: var(--paper);
  transform: translateX(2px);
}

.footer-links a:hover::before,
.footer-links a:focus-visible::before { color: var(--orange); }

/* ---------- 页脚联络 ---------- */
.footer-contact { min-width: 0; }

.contact-list {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
}

.contact-item {
  display: grid;
  gap: 2px;
}

.contact-item dt {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--line);
}

.contact-item dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--paper);
  word-break: break-word;
}

/* ---------- 页脚底条 ---------- */
.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 14px 32px;
  padding: 24px 0 32px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--fog);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.footer-legal a {
  color: var(--fog);
  transition: color var(--dur) var(--ease);
}

.footer-legal a:hover,
.footer-legal a:focus-visible { color: var(--lime); }

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

.footer-copy { color: var(--line); }

.footer-rail {
  height: 34px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background-image: repeating-linear-gradient(
    90deg,
    var(--line) 0 1px,
    transparent 1px 34px
  );
  opacity: .7;
}

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1280px) {
  .brand-meta { display: none; }
  .brand-mark { border-right: 0; padding-right: 0; }
}

@media (max-width: 1024px) {
  .nav-toggle { display: inline-flex; }

  .header-cta { display: none; }

  .primary-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-left: 0;
    display: block;
    padding: 8px var(--pad-x) 24px;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
    background: var(--ink-800);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 32px 56px -40px rgba(0, 0, 0, .95);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition: opacity var(--dur) var(--ease),
                transform var(--dur) var(--ease),
                visibility var(--dur) var(--ease);
  }

  .site-header[data-open="true"] .primary-nav {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
  }

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

  .nav-item { display: block; }

  .nav-link {
    display: block;
    padding: 16px 0;
    font-size: 16px;
    border-bottom: 1px dashed var(--line);
    color: var(--paper);
  }

  .nav-link::before {
    font-size: 10px;
    margin-right: 10px;
  }

  .nav-link::after { display: none; }

  .nav-cta {
    display: inline-flex;
    width: 100%;
    margin-top: 20px;
  }
}

@media (max-width: 860px) {
  .footer-top {
    grid-template-columns: minmax(0, 1fr);
    gap: 36px;
  }

  .footer-summary { max-width: 46ch; }
}

@media (max-width: 520px) {
  .brand-glyph { font-size: 22px; letter-spacing: .12em; }

  .nav-toggle-text { display: none; }

  .footer-bottom {
    justify-content: flex-start;
    gap: 12px 20px;
  }

  .footer-legal { gap: 8px 16px; }
}

/* ==========================================================================
   减少动效偏好
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

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

  .paper-card:hover,
  .paper-card:focus-within,
  .btn--lime:hover,
  .btn--ghost:hover,
  .footer-links a:hover,
  .footer-links a:focus-visible {
    transform: none;
  }

  .paper-card--stacked::after { transform: translate(8px, 8px) !important; }
}