/* ==========================================================================
   LEYU 巧寻导航厅 — 共享站点工具包
   文件：/assets/site.css
   1 重置  2 令牌  3 基础排版  4 跳转链与焦点  5 头部
   6 页脚  7 版式骨架  8 通用组件  9 图片容器  10 动效  11 响应式
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h, 76px) + 14px);
}

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

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

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

button { font: inherit; color: inherit; }

a { color: inherit; }

/* 2 令牌 ------------------------------------------------------------------ */
:root {
  --deep-space: #071A2F;
  --midnight-panel: #0D2B45;
  --signal-cyan: #31E6D6;
  --compass-amber: #FF9A3D;
  --jewel-teal: #0F5C5B;
  --jewel-wine: #6B1F3A;
  --jewel-indigo: #2B2A6E;
  --paper: #F4F1E8;
  --graphite: #1C2430;
  --mist: #C9D6E3;
  --ink-soft: #333C46;
  --link-teal: #0B4847;

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

  --header-h: 76px;
  --content-max: 1320px;
  --gutter: clamp(1rem, 4vw, 3rem);

  --radius-s: 2px;
  --radius-m: 4px;

  --line-soft: rgba(201, 214, 227, 0.18);
  --line-cyan: rgba(49, 230, 214, 0.34);
  --line-dark: rgba(28, 36, 48, 0.16);

  --shadow-panel: 0 18px 48px rgba(3, 11, 20, 0.45);
  --ease: cubic-bezier(0.32, 0.72, 0, 1);
}

/* 3 基础排版 -------------------------------------------------------------- */
body {
  background-color: var(--deep-space);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.75;
  letter-spacing: 0.01em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  font-stretch: 90%;
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--paper);
}

strong, b { font-weight: 700; }

::selection {
  background: var(--signal-cyan);
  color: #04262B;
}

/* 4 跳转链与焦点 ---------------------------------------------------------- */
.skip-link {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 999;
  padding: 0.7rem 1.1rem;
  background: var(--compass-amber);
  color: var(--graphite);
  font-size: 0.875rem;
  font-weight: 700;
  text-decoration: none;
  border-radius: var(--radius-s);
  box-shadow: 0 10px 26px rgba(3, 11, 20, 0.5);
  transform: translateY(-180%);
  transition: transform 0.18s var(--ease);
}

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

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

/* 5 头部 ------------------------------------------------------------------ */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  background-color: transparent;
  border-bottom: 1px solid transparent;
  transition: background-color 0.26s var(--ease), border-color 0.26s var(--ease), box-shadow 0.26s var(--ease);
}

.site-header::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 5px;
  background-image: repeating-linear-gradient(90deg, rgba(49, 230, 214, 0.5) 0 1px, transparent 1px 14px);
  opacity: 0.5;
  pointer-events: none;
}

.site-header.is-scrolled {
  background-color: rgba(7, 26, 47, 0.97);
  border-bottom-color: var(--line-cyan);
  box-shadow: 0 14px 40px rgba(3, 11, 20, 0.55);
  -webkit-backdrop-filter: saturate(140%) blur(6px);
  backdrop-filter: saturate(140%) blur(6px);
}

.header-frame {
  position: relative;
  width: min(100%, var(--content-max));
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: clamp(0.75rem, 2.5vw, 2rem);
}

/* 品牌 */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  padding-block: 0.5rem;
  min-width: 0;
  color: inherit;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  flex: 0 0 auto;
  width: 38px;
  height: 38px;
  color: var(--signal-cyan);
  background-color: rgba(13, 43, 69, 0.55);
  border: 1px solid var(--line-cyan);
  border-radius: 50%;
}

.brand-mark svg {
  width: 22px;
  height: 22px;
  transition: transform 0.6s var(--ease);
}

.brand:hover .brand-mark svg,
.brand:focus-visible .brand-mark svg { transform: rotate(28deg); }

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
  line-height: 1.15;
}

.brand-line {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.0625rem;
  letter-spacing: 0.01em;
  color: var(--paper);
  white-space: nowrap;
}

.brand-support {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.1em;
  color: var(--mist);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* 移动按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.55rem;
  flex: 0 0 auto;
  padding: 0.5rem 0.75rem;
  color: var(--paper);
  background-color: rgba(13, 43, 69, 0.72);
  border: 1px solid var(--line-cyan);
  border-radius: var(--radius-s);
  cursor: pointer;
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.nav-toggle:hover { border-color: var(--signal-cyan); }

.nav-toggle-icon {
  position: relative;
  display: block;
  width: 16px;
  height: 10px;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--signal-cyan);
  transition: transform 0.22s var(--ease), top 0.22s var(--ease);
}

.nav-toggle-icon::before { top: 0; }
.nav-toggle-icon::after { top: 8px; }

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  top: 4px;
  transform: rotate(45deg);
}

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

.nav-toggle-label {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.16em;
  line-height: 1;
}

/* 主导航 */
.site-nav {
  display: flex;
  align-items: center;
  gap: clamp(0.5rem, 1.6vw, 1.5rem);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: clamp(0.1rem, 0.7vw, 0.75rem);
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 0.4rem;
  padding: 0.6rem 0.55rem;
  font-size: 0.875rem;
  color: var(--mist);
  text-decoration: none;
  border-radius: var(--radius-s);
  transition: color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.nav-link:hover,
.nav-link:focus-visible {
  color: var(--paper);
  background-color: rgba(49, 230, 214, 0.08);
}

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

.nav-link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 0.55rem;
  right: 0.55rem;
  bottom: 0.18rem;
  height: 2px;
  background-color: var(--compass-amber);
  border-radius: 1px;
}

.nav-num {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.06em;
  color: rgba(49, 230, 214, 0.72);
}

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

.nav-label { white-space: nowrap; }

.nav-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  flex: 0 0 auto;
  padding: 0.6rem 1rem;
  font-size: 0.8125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  white-space: nowrap;
  color: var(--graphite);
  background-color: var(--compass-amber);
  text-decoration: none;
  border-radius: var(--radius-s);
  transition: transform 0.18s var(--ease), background-color 0.18s var(--ease);
}

.nav-cta:hover,
.nav-cta:focus-visible {
  background-color: #FFAD61;
  transform: translateY(-1px);
}

/* 阅读进度 */
.header-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background-color: rgba(201, 214, 227, 0.12);
  overflow: hidden;
  pointer-events: none;
}

.header-progress-bar {
  display: block;
  height: 100%;
  width: 0;
  background-color: var(--compass-amber);
  transition: width 0.1s linear;
}

/* 6 页脚 ------------------------------------------------------------------ */
.site-footer {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(2.5rem, 6vw, 4.5rem) 0 clamp(1.25rem, 3vw, 2rem);
  color: var(--mist);
  background-color: var(--deep-space);
  border-top: 1px solid var(--line-cyan);
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background-image: repeating-linear-gradient(118deg, rgba(49, 230, 214, 0.06) 0 1px, transparent 1px 64px);
  pointer-events: none;
}

.footer-ruler {
  position: absolute;
  inset: 0 0 auto 0;
  height: 8px;
  background-image: repeating-linear-gradient(90deg, rgba(201, 214, 227, 0.28) 0 1px, transparent 1px 18px);
  opacity: 0.6;
  pointer-events: none;
}

.footer-frame {
  width: min(100%, var(--content-max));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer-top {
  display: grid;
  grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  gap: clamp(2rem, 5vw, 4.5rem);
  padding-bottom: clamp(1.75rem, 4vw, 3rem);
  border-bottom: 1px solid var(--line-soft);
}

.footer-brand { min-width: 0; }

.footer-brand-line {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.25rem, 2.6vw, 1.75rem);
  letter-spacing: -0.01em;
  color: var(--paper);
}

.footer-brand-text {
  margin-top: 0.75rem;
  max-width: 34ch;
  font-size: 0.875rem;
  line-height: 1.8;
  color: var(--mist);
}

.footer-stamp {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-top: 1.25rem;
  padding: 0.35rem 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.625rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--signal-cyan);
  border: 1px dashed var(--line-cyan);
  border-radius: var(--radius-s);
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(1.5rem, 3vw, 2.5rem);
}

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

.footer-col-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 1rem;
  padding-bottom: 0.6rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 700;
  letter-spacing: 0.2em;
  color: var(--signal-cyan);
  border-bottom: 1px solid var(--line-soft);
}

.footer-col-title::before {
  content: "";
  width: 6px;
  height: 6px;
  flex: 0 0 auto;
  background-color: var(--compass-amber);
  transform: rotate(45deg);
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  padding: 0.45rem 0;
  font-size: 0.9375rem;
  color: var(--mist);
  text-decoration: none;
  transition: color 0.18s var(--ease);
}

.footer-link::before {
  content: "";
  width: 10px;
  height: 1px;
  flex: 0 0 auto;
  background-color: currentColor;
  opacity: 0.45;
  transition: width 0.18s var(--ease), background-color 0.18s var(--ease), opacity 0.18s var(--ease);
}

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

.footer-link:hover::before,
.footer-link:focus-visible::before {
  width: 20px;
  opacity: 1;
  background-color: var(--compass-amber);
}

.footer-contact {
  display: grid;
  gap: 0.4rem;
  padding: clamp(1.25rem, 3vw, 2rem) 0;
  border-bottom: 1px solid var(--line-soft);
}

.footer-contact-line {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.02em;
  color: var(--paper);
  word-break: break-word;
}

.footer-note {
  font-size: 0.8125rem;
  color: rgba(201, 214, 227, 0.72);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding-top: clamp(1rem, 2.5vw, 1.5rem);
}

.footer-copy {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  color: rgba(201, 214, 227, 0.66);
}

.footer-legal-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem;
}

.footer-legal-link {
  font-size: 0.75rem;
  color: rgba(201, 214, 227, 0.78);
  text-decoration: none;
}

.footer-legal-link:hover,
.footer-legal-link:focus-visible {
  color: var(--signal-cyan);
  text-decoration: underline;
  text-underline-offset: 0.2em;
}

/* 7 版式骨架 -------------------------------------------------------------- */
main {
  display: block;
  padding-top: var(--header-h);
}

.shell {
  width: min(100%, var(--content-max));
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.hero {
  position: relative;
  margin-top: calc(var(--header-h) * -1);
  padding-top: calc(var(--header-h) + clamp(2.5rem, 7vw, 5rem));
  padding-bottom: clamp(2.5rem, 7vw, 5rem);
  overflow: hidden;
}

.section {
  position: relative;
  padding-block: clamp(3rem, 7vw, 6rem);
}

.section--tight { padding-block: clamp(2rem, 4vw, 3rem); }
.section--flush-top { padding-top: 0; }

.section--panel { background-color: var(--midnight-panel); }
.section--teal { background-color: var(--jewel-teal); }
.section--wine { background-color: var(--jewel-wine); }
.section--indigo { background-color: var(--jewel-indigo); }

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

.section--paper :where(h1, h2, h3, h4, h5, h6) { color: var(--graphite); }
.section--paper :where(p, li, dd, dt, figcaption, td, th) { color: var(--ink-soft); }
.section--paper :where(a) { color: var(--link-teal); }

/* 框景 */
.frame {
  position: relative;
  padding: clamp(1.25rem, 3vw, 2.5rem);
  border: 1px solid var(--line-cyan);
}

.frame::before,
.frame::after {
  content: "";
  position: absolute;
  width: 14px;
  height: 14px;
  border: 1px solid var(--compass-amber);
  pointer-events: none;
}

.frame::before {
  top: -1px;
  left: -1px;
  border-right: 0;
  border-bottom: 0;
}

.frame::after {
  right: -1px;
  bottom: -1px;
  border-top: 0;
  border-left: 0;
}

/* 8 通用组件 -------------------------------------------------------------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--signal-cyan);
}

.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  flex: 0 0 auto;
  background-color: currentColor;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.22rem 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  white-space: nowrap;
  color: var(--signal-cyan);
  background-color: rgba(49, 230, 214, 0.07);
  border: 1px solid var(--line-cyan);
  border-radius: var(--radius-s);
}

.tag--amber {
  color: var(--compass-amber);
  background-color: rgba(255, 154, 61, 0.08);
  border-color: rgba(255, 154, 61, 0.42);
}

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

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
  border: 0;
}

.rule {
  height: 6px;
  border: 0;
  margin-block: clamp(1.5rem, 3vw, 2.5rem);
  background-image: repeating-linear-gradient(90deg, var(--line-cyan) 0 1px, transparent 1px 10px);
}

.prose {
  max-width: 68ch;
  font-size: 1rem;
  line-height: 1.85;
  color: var(--mist);
}

.prose > * + * { margin-top: 1.1em; }

.prose h2 {
  margin-top: 2.2em;
  font-size: clamp(1.35rem, 2.4vw, 1.75rem);
  color: var(--paper);
}

.prose h3 {
  margin-top: 1.8em;
  font-size: 1.125rem;
  color: var(--paper);
}

.prose :where(ul, ol) {
  padding-left: 1.3rem;
  list-style: disc;
}

.prose ol { list-style: decimal; }
.prose li + li { margin-top: 0.45em; }
.prose a { color: var(--signal-cyan); text-decoration: underline; }
.prose strong { color: var(--paper); }

.section--paper .prose { color: var(--ink-soft); }
.section--paper .prose a { color: var(--link-teal); }
.section--paper .prose strong { color: var(--graphite); }
.section--paper .prose :where(h2, h3) { color: var(--graphite); }

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.45rem;
  padding-block: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: rgba(201, 214, 227, 0.7);
}

.crumbs a {
  color: var(--mist);
  text-decoration: none;
}

.crumbs a:hover,
.crumbs a:focus-visible {
  color: var(--signal-cyan);
  text-decoration: underline;
}

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

.crumb-sep { color: rgba(49, 230, 214, 0.5); }

.section--paper .crumbs { color: rgba(28, 36, 48, 0.62); }
.section--paper .crumbs a { color: var(--graphite); }
.section--paper .crumbs [aria-current="page"] { color: var(--link-teal); }
.section--paper .crumb-sep { color: rgba(11, 72, 71, 0.45); }

.grid-12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(1rem, 2.4vw, 2rem);
}

.span-4 { grid-column: span 4; }
.span-5 { grid-column: span 5; }
.span-6 { grid-column: span 6; }
.span-7 { grid-column: span 7; }
.span-8 { grid-column: span 8; }
.span-12 { grid-column: span 12; }

/* 按钮 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.35rem;
  font-size: 0.9375rem;
  font-weight: 700;
  letter-spacing: 0.01em;
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--radius-s);
  cursor: pointer;
  transition: transform 0.18s var(--ease), background-color 0.18s var(--ease),
              border-color 0.18s var(--ease), color 0.18s var(--ease);
}

.btn:hover,
.btn:focus-visible { transform: translateY(-1px); }

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

.btn--primary:hover,
.btn--primary:focus-visible { background-color: #FFAD61; }

.btn--cyan {
  color: #04262B;
  background-color: var(--signal-cyan);
  border-color: var(--signal-cyan);
}

.btn--cyan:hover,
.btn--cyan:focus-visible { background-color: #63F0E4; }

.btn--ghost {
  color: var(--paper);
  background-color: transparent;
  border-color: var(--line-cyan);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  background-color: rgba(49, 230, 214, 0.1);
  border-color: var(--signal-cyan);
}

.btn--quiet {
  color: var(--paper);
  background-color: rgba(201, 214, 227, 0.08);
  border-color: var(--line-soft);
}

.btn--quiet:hover,
.btn--quiet:focus-visible { background-color: rgba(201, 214, 227, 0.16); }

/* 章节索引 */
.chapter-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.3rem 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  color: rgba(201, 214, 227, 0.68);
  text-decoration: none;
  transition: color 0.18s var(--ease);
}

.chapter-link::before {
  content: "";
  width: 14px;
  height: 1px;
  flex: 0 0 auto;
  background-color: currentColor;
  opacity: 0.6;
  transition: background-color 0.18s var(--ease), width 0.18s var(--ease);
}

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

.chapter-link[data-active="true"] { color: var(--signal-cyan); }

.chapter-link[data-active="true"]::before {
  width: 22px;
  opacity: 1;
  background-color: var(--compass-amber);
}

/* 回到顶部（由 site.js 注入） */
.to-top {
  position: fixed;
  right: clamp(0.75rem, 2vw, 1.5rem);
  bottom: clamp(0.75rem, 2vw, 1.5rem);
  z-index: 90;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  color: var(--signal-cyan);
  background-color: rgba(13, 43, 69, 0.92);
  border: 1px solid var(--line-cyan);
  border-radius: 50%;
  cursor: pointer;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition: opacity 0.22s var(--ease), transform 0.22s var(--ease), background-color 0.22s var(--ease);
}

.to-top[data-visible="true"] {
  opacity: 1;
  transform: none;
  pointer-events: auto;
}

.to-top:hover,
.to-top:focus-visible { background-color: var(--jewel-teal); }

/* 9 图片容器 -------------------------------------------------------------- */
.media-frame {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  background-color: var(--midnight-panel);
  border: 1px solid var(--line-soft);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background-image: repeating-linear-gradient(115deg, rgba(49, 230, 214, 0.09) 0 1px, transparent 1px 40px);
  pointer-events: none;
}

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

.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--photo { aspect-ratio: 4 / 3; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame--angle {
  clip-path: polygon(0 0, 100% 0, 100% 88%, 92% 100%, 0 100%);
}

.section--paper .media-frame {
  background-color: #E4DFD2;
  border-color: rgba(28, 36, 48, 0.18);
}

.section--paper .media-frame::after {
  background-image: repeating-linear-gradient(115deg, rgba(11, 72, 71, 0.1) 0 1px, transparent 1px 40px);
}

/* 10 动效 ----------------------------------------------------------------- */
[data-reveal] {
  transition: opacity 0.55s var(--ease), transform 0.55s var(--ease);
}

.has-js [data-reveal]:not([data-revealed="true"]) {
  opacity: 0;
  transform: translate3d(0, 18px, 0);
}

/* 11 响应式 -------------------------------------------------------------- */
@media (max-width: 1180px) {
  .nav-num { display: none; }
  .nav-link {
    padding: 0.55rem 0.45rem;
    font-size: 0.8125rem;
  }
}

@media (max-width: 960px) {
  :root { --header-h: 66px; }

  .brand-mark { width: 34px; height: 34px; }
  .brand-mark svg { width: 20px; height: 20px; }

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

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    max-height: calc(100vh - var(--header-h));
    overflow-y: auto;
    padding: 1rem var(--gutter) 1.5rem;
    background-color: var(--deep-space);
    border-bottom: 1px solid var(--line-cyan);
    box-shadow: var(--shadow-panel);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition: opacity 0.2s var(--ease), transform 0.2s var(--ease), visibility 0.2s;
  }

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

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

  .nav-link {
    width: 100%;
    justify-content: flex-start;
    padding: 0.9rem 0.25rem;
    font-size: 1rem;
    border-bottom: 1px solid var(--line-soft);
    border-radius: 0;
  }

  .nav-num { display: inline; }

  .nav-link[aria-current="page"] {
    color: var(--signal-cyan);
    background-color: rgba(49, 230, 214, 0.06);
  }

  .nav-link[aria-current="page"]::after { display: none; }
  .nav-link[aria-current="page"] .nav-num { color: var(--signal-cyan); }

  .nav-cta {
    margin-top: 1.1rem;
    justify-content: center;
    padding: 0.9rem 1rem;
    font-size: 0.9375rem;
  }

  .footer-top { grid-template-columns: 1fr; }
}

@media (max-width: 900px) {
  .grid-12 > [class*="span-"] { grid-column: 1 / -1; }
}

@media (max-width: 560px) {
  .brand-support { display: none; }
  .brand-line { font-size: 1rem; }
  .footer-legal {
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 520px) {
  .footer-nav { grid-template-columns: 1fr; }
  .footer-legal-links { gap: 0.9rem; }
}

@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;
  }

  [data-reveal],
  .has-js [data-reveal]:not([data-revealed="true"]) {
    opacity: 1 !important;
    transform: none !important;
  }

  .brand:hover .brand-mark svg { transform: none; }
}