/* ==========================================================================
   IM钱包中心 — 共享站点样式 /assets/site.css
   母题：深空黑底色 · 非对称信息岛 · 纵向时间轴 · 侧向悬浮轨道
   ========================================================================== */

/* ---------- 1. 设计变量 ---------- */
:root {
  color-scheme: dark;

  --ink-void: #05070B;
  --ink-panel: #0C1017;
  --ink-line: #1B2129;
  --text-title: #E9EEF6;
  --text-body: #C3CBD6;
  --text-muted: #8A94A6;
  --teal: #00E0B8;
  --violet: #7C4DFF;
  --amber: #FFB020;
  --mint: #7BF2DA;

  --teal-soft: rgba(0, 224, 184, 0.14);
  --teal-line: rgba(0, 224, 184, 0.38);
  --violet-soft: rgba(124, 77, 255, 0.16);
  --amber-soft: rgba(255, 176, 32, 0.14);
  --amber-line: rgba(255, 176, 32, 0.42);
  --plate-soft: rgba(233, 238, 246, 0.04);

  --font-sans: "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans CJK SC", system-ui, sans-serif;
  --font-narrow: "Helvetica Neue", "Arial Narrow", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;

  --fs-12: 0.75rem;
  --fs-14: 0.875rem;
  --fs-16: 1rem;
  --fs-20: 1.25rem;
  --fs-28: 1.75rem;
  --fs-40: 2.5rem;
  --fs-64: 4rem;
  --fs-96: 6rem;

  --fs-display: clamp(3.25rem, 10vw, 6rem);
  --fs-h1: clamp(2.25rem, 5.6vw, 4rem);
  --fs-h2: clamp(1.6rem, 3.4vw, 2.5rem);
  --fs-h3: clamp(1.25rem, 2.2vw, 1.75rem);

  --gutter: clamp(1.25rem, 4vw, 2.5rem);
  --gap: clamp(1rem, 2.4vw, 2rem);
  --radius-lg: 28px;
  --radius-md: 18px;
  --radius-sm: 10px;
  --pill: 999px;

  --dur: 260ms;
  --dur-slow: 360ms;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 2. 重置与基础 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  background: var(--ink-void);
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  font-size: var(--fs-16);
  font-weight: 400;
  line-height: 1.75;
  color: var(--text-body);
  background-color: var(--ink-void);
  background-image:
    radial-gradient(circle at 84% -12%, var(--violet-soft), transparent 52%),
    radial-gradient(circle at 2% 4%, var(--teal-soft), transparent 38%);
  background-repeat: no-repeat;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

main { display: block; }

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

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

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

a { color: inherit; }

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

hr { border: 0; border-top: 1px solid var(--ink-line); margin: 0; }

:focus-visible { outline: 2px solid var(--mint); outline-offset: 3px; border-radius: 4px; }

::selection { background: rgba(0, 224, 184, 0.26); color: var(--text-title); }

[hidden] { display: none !important; }

/* ---------- 3. 中文排版 ---------- */
h1, .h1 {
  font-family: var(--font-narrow);
  font-weight: 300;
  font-size: var(--fs-h1);
  line-height: 1.05;
  letter-spacing: 0.01em;
  color: var(--text-title);
}

h2, .h2 {
  font-family: var(--font-narrow);
  font-weight: 300;
  font-size: var(--fs-h2);
  line-height: 1.12;
  letter-spacing: 0.01em;
  color: var(--text-title);
}

h3, .h3 {
  font-size: var(--fs-h3);
  font-weight: 500;
  line-height: 1.35;
  color: var(--text-title);
}

h4, .h4 {
  font-size: var(--fs-20);
  font-weight: 500;
  line-height: 1.4;
  color: var(--text-title);
}

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

.lead {
  max-width: 30em;
  font-size: var(--fs-20);
  line-height: 1.65;
  color: var(--text-body);
}

.prose { max-width: 38em; }
.prose > * + * { margin-top: 1.05em; }
.prose h2 { margin-top: 2.2em; }
.prose h3 { margin-top: 1.7em; }
.prose strong { color: var(--text-title); font-weight: 500; }
.prose a { color: var(--mint); border-bottom: 1px solid var(--teal-line); }
.prose a:hover { border-bottom-color: var(--mint); }
.prose li { position: relative; padding-left: 1.25rem; }
.prose li + li { margin-top: 0.5rem; }
.prose li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.78em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--teal);
  opacity: 0.75;
}

/* ---------- 4. 布局工具 ---------- */
.shell {
  width: min(1180px, 100% - var(--gutter) * 2);
  margin-inline: auto;
}

.shell--narrow { width: min(760px, 100% - var(--gutter) * 2); }

.section { padding-block: clamp(3rem, 7vw, 6rem); }
.section--tight { padding-block: clamp(1.75rem, 4vw, 3rem); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 0.85rem 2rem;
  margin-bottom: clamp(1.5rem, 3vw, 2.5rem);
}

.section__title {
  font-family: var(--font-narrow);
  font-weight: 300;
  font-size: var(--fs-h2);
  line-height: 1.12;
  color: var(--text-title);
}

.section__note {
  max-width: 32em;
  font-size: var(--fs-14);
  color: var(--text-muted);
}

.section__index {
  display: block;
  margin-bottom: 0.6rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.2em;
  color: var(--teal);
}

.grid { display: grid; gap: var(--gap); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--asym { grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); }
.grid--asym-flip { grid-template-columns: minmax(0, 1fr) minmax(0, 1.6fr); }

/* ---------- 5. 通用组件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 1.6rem;
  border: 1px solid var(--ink-line);
  border-radius: var(--pill);
  background: var(--ink-panel);
  color: var(--text-title);
  font-size: var(--fs-14);
  letter-spacing: 0.06em;
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              background-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.btn:hover {
  transform: translateY(-1px);
  border-color: var(--teal-line);
  color: var(--mint);
}

.btn--small { padding: 0.55rem 1.1rem; font-size: var(--fs-12); }

.btn--primary {
  background: var(--teal);
  border-color: var(--teal);
  color: #04120E;
  font-weight: 500;
}

.btn--primary:hover {
  background: var(--mint);
  border-color: var(--mint);
  color: #04120E;
}

.btn--ghost { background: transparent; }

.btn--amber { border-color: var(--amber-line); color: var(--amber); }

.btn--amber:hover {
  background: var(--amber-soft);
  border-color: var(--amber);
  color: var(--amber);
}

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem;
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--text-muted);
}

.crumbs a { text-decoration: none; color: var(--text-muted); }
.crumbs a:hover { color: var(--mint); }
.crumbs__sep { color: var(--ink-line); }

.island {
  position: relative;
  padding: clamp(1.25rem, 3vw, 2rem);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-lg);
  background: var(--ink-panel);
  overflow: hidden;
}

.island::before {
  content: "";
  position: absolute;
  top: 0;
  left: clamp(1.25rem, 3vw, 2rem);
  width: 3.5rem;
  height: 2px;
  background: var(--teal);
}

.island--offset { margin-top: clamp(1rem, 4vw, 3rem); }
.island--violet::before { background: var(--violet); }
.island--amber::before { background: var(--amber); }

.panel {
  padding: clamp(1rem, 2.4vw, 1.5rem);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-md);
  background: var(--ink-panel);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.2rem 0.7rem;
  border: 1px solid var(--ink-line);
  border-radius: var(--pill);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--text-muted);
  white-space: nowrap;
}

.tag--teal { color: var(--teal); border-color: var(--teal-line); }
.tag--amber { color: var(--amber); border-color: var(--amber-line); }

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.filter-btn {
  padding: 0.5rem 1.1rem;
  border: 1px solid var(--ink-line);
  border-radius: var(--pill);
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--text-muted);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.filter-btn:hover { color: var(--text-title); border-color: var(--text-muted); }

.filter-btn[aria-pressed="true"] {
  background: var(--teal);
  border-color: var(--teal);
  color: #04120E;
  font-weight: 500;
}

.timeline {
  position: relative;
  display: grid;
  gap: clamp(1.25rem, 3vw, 2rem);
}

.timeline__item { position: relative; padding-left: 2rem; }

.timeline__item::before {
  content: "";
  position: absolute;
  left: 4px;
  top: 0.6rem;
  bottom: -0.5rem;
  width: 1px;
  background: var(--ink-line);
}

.timeline__item:last-child::before { bottom: auto; height: 1.2rem; }

.timeline__item::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink-void);
  border: 1px solid var(--ink-line);
  transition: background-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease);
}

.timeline__item[data-state="current"]::after {
  background: var(--teal);
  border-color: var(--teal);
  box-shadow: 0 0 0 4px var(--teal-soft);
}

.timeline__meta {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.14em;
  color: var(--text-muted);
}

.timeline__title {
  margin-top: 0.25rem;
  font-size: var(--fs-20);
  font-weight: 500;
  color: var(--text-title);
}

.timeline__body {
  margin-top: 0.4rem;
  max-width: 40em;
  font-size: var(--fs-14);
  color: var(--text-body);
}

.steps {
  display: grid;
  gap: clamp(0.85rem, 2vw, 1.25rem);
}

.step {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: clamp(0.9rem, 2.4vw, 1.5rem);
  align-items: start;
  padding: clamp(1rem, 2.4vw, 1.5rem);
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-lg);
  background: var(--ink-panel);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.step__num {
  min-width: 2.4rem;
  font-family: var(--font-mono);
  font-size: var(--fs-20);
  line-height: 1.2;
  color: var(--teal);
}

.step__title {
  font-size: var(--fs-16);
  font-weight: 500;
  color: var(--text-title);
}

.step__text {
  margin-top: 0.35rem;
  max-width: 42em;
  font-size: var(--fs-14);
  color: var(--text-muted);
}

.step[data-done] {
  border-color: var(--teal-line);
  background-image: linear-gradient(180deg, var(--teal-soft), transparent 62%);
}

.step[data-done] .step__num { color: var(--mint); }

.disclosure {
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-md);
  background: var(--ink-panel);
  overflow: hidden;
}

.disclosure + .disclosure { margin-top: 0.75rem; }

.disclosure summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: clamp(1rem, 2.4vw, 1.25rem) clamp(1rem, 2.6vw, 1.5rem);
  color: var(--text-title);
  font-size: var(--fs-16);
  cursor: pointer;
  list-style: none;
}

.disclosure summary::-webkit-details-marker { display: none; }

.disclosure summary::after {
  content: "";
  flex: none;
  width: 0.6rem;
  height: 0.6rem;
  border-right: 1.5px solid var(--teal);
  border-bottom: 1.5px solid var(--teal);
  transform: rotate(45deg);
  transition: transform var(--dur) var(--ease);
}

.disclosure[open] summary::after { transform: rotate(-135deg); }

.disclosure summary:hover { color: var(--mint); }

.disclosure__body {
  padding: 0 clamp(1rem, 2.6vw, 1.5rem) clamp(1rem, 2.6vw, 1.5rem);
  font-size: var(--fs-14);
  color: var(--text-body);
}

.disclosure__body > * + * { margin-top: 0.75rem; }

.code {
  display: inline-block;
  padding: 0.15em 0.5em;
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-sm);
  background: var(--plate-soft);
  font-family: var(--font-mono);
  font-size: 0.9em;
  color: var(--text-title);
  word-break: break-all;
}

.code--copy {
  cursor: pointer;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.code--copy:hover { color: var(--mint); border-color: var(--teal-line); }

.code--copy[data-copied]::after {
  content: " 已复制";
  font-family: var(--font-sans);
  font-size: 0.85em;
  color: var(--mint);
}

.callout {
  padding: 0.75rem 0 0.75rem clamp(0.85rem, 2vw, 1.1rem);
  border-left: 2px solid var(--ink-line);
}

.callout--amber { border-left-color: var(--amber); }

.callout__title {
  font-size: var(--fs-14);
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--text-title);
}

.callout__text {
  margin-top: 0.25rem;
  max-width: 42em;
  font-size: var(--fs-14);
  color: var(--text-muted);
}

.callout--amber .callout__title { color: var(--amber); }

.media { margin: 0; }

.media__frame {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--ink-line);
  border-radius: var(--radius-lg);
  background: var(--ink-panel);
  aspect-ratio: 4 / 3;
}

.media__frame > img,
.media__frame > svg,
.media__frame > video {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

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

.media__frame--grid::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--ink-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--ink-line) 1px, transparent 1px);
  background-size: 32px 32px;
  opacity: 0.4;
  pointer-events: none;
}

.media__caption {
  margin-top: 0.7rem;
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.rail {
  position: fixed;
  top: 50%;
  right: clamp(0.75rem, 2vw, 1.5rem);
  z-index: 50;
  display: grid;
  gap: 0.55rem;
  transform: translateY(-50%);
}

.rail__link {
  writing-mode: vertical-rl;
  padding: 0.9rem 0.45rem;
  border: 1px solid var(--ink-line);
  border-radius: var(--pill);
  background: rgba(12, 16, 23, 0.92);
  color: var(--text-muted);
  font-size: var(--fs-12);
  letter-spacing: 0.16em;
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.rail__link:hover { color: var(--mint); border-color: var(--teal-line); }

.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;
}

.is-hidden { display: none !important; }

.js [data-reveal] {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity var(--dur-slow) var(--ease), transform var(--dur-slow) var(--ease);
}

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

/* ---------- 6. 头部 ---------- */
.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 200;
  padding: 0.7rem 1.2rem;
  border-radius: var(--pill);
  background: var(--teal);
  color: #04120E;
  font-size: var(--fs-14);
  font-weight: 500;
  text-decoration: none;
  transform: translateY(-220%);
  transition: transform var(--dur) var(--ease);
}

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

.site-header { position: relative; z-index: 70; }

.header-status {
  border-bottom: 1px solid var(--ink-line);
  background: var(--ink-void);
}

.header-status__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem 1.5rem;
  min-height: 2.75rem;
  padding-block: 0.45rem;
  font-size: var(--fs-12);
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.status-meta {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
}

.status-dot {
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 50%;
  background: var(--teal);
  animation: status-pulse 3.6s var(--ease) infinite;
}

@keyframes status-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(0, 224, 184, 0.42); }
  50% { box-shadow: 0 0 0 6px rgba(0, 224, 184, 0); }
}

.status-links {
  display: flex;
  align-items: center;
  gap: clamp(0.9rem, 2vw, 1.6rem);
}

.status-link {
  padding-bottom: 1px;
  border-bottom: 1px solid transparent;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.status-link:hover {
  color: var(--mint);
  border-bottom-color: var(--teal-line);
}

.masthead {
  padding-block: clamp(2.25rem, 5vw, 3.75rem) clamp(1rem, 2vw, 1.5rem);
  text-align: center;
}

.masthead__kicker {
  margin-bottom: clamp(0.75rem, 1.6vw, 1.1rem);
  font-size: var(--fs-12);
  letter-spacing: 0.32em;
  text-indent: 0.32em;
  color: var(--text-muted);
}

.masthead__brand {
  display: inline-block;
  font-family: var(--font-narrow);
  font-weight: 300;
  font-size: var(--fs-display);
  line-height: 0.95;
  letter-spacing: 0.04em;
  color: var(--text-title);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.masthead__brand::after {
  content: "";
  display: block;
  width: 3.5rem;
  height: 1px;
  margin: clamp(0.85rem, 2vw, 1.25rem) auto 0;
  background: var(--teal);
  opacity: 0.85;
}

.masthead__brand:hover { color: var(--mint); }

.nav-bar {
  position: sticky;
  top: 0;
  z-index: 60;
  border-top: 1px solid var(--ink-line);
  border-bottom: 1px solid var(--ink-line);
  background: rgba(5, 7, 11, 0.92);
  backdrop-filter: blur(12px);
}

.nav-bar__inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1rem;
  min-height: 3.5rem;
}

.site-nav__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: clamp(0.75rem, 2.2vw, 2.25rem);
}

.site-nav__link {
  position: relative;
  display: inline-block;
  padding: 0.6rem 0.15rem;
  font-size: var(--fs-14);
  letter-spacing: 0.08em;
  color: var(--text-body);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.site-nav__link::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0.15rem;
  height: 1px;
  background: var(--teal);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--dur) var(--ease);
}

.site-nav__link:hover { color: var(--text-title); }
.site-nav__link:hover::after { transform: scaleX(1); }

.site-nav__link[aria-current="page"] {
  color: var(--text-title);
  font-weight: 500;
}

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

.nav-toggle {
  display: none;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border: 1px solid var(--ink-line);
  border-radius: var(--pill);
  color: var(--text-body);
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
              background-color var(--dur) var(--ease);
}

.nav-toggle:hover { color: var(--mint); border-color: var(--teal-line); }

.nav-toggle[aria-expanded="true"] {
  color: var(--mint);
  border-color: var(--teal-line);
  background: var(--teal-soft);
}

.nav-toggle__label { line-height: 1; }

.nav-toggle__bars {
  position: relative;
  width: 14px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 14px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform var(--dur) var(--ease);
}

.nav-toggle__bars::before { top: -5px; }
.nav-toggle__bars::after { top: 5px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: transparent; }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-5px) rotate(-45deg); }

.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 120;
  height: 2px;
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--teal), var(--mint) 55%, var(--violet));
  transform: scaleX(0);
  transform-origin: left center;
}

/* ---------- 7. 页脚 ---------- */
.site-footer {
  margin-top: clamp(4rem, 9vw, 8rem);
  padding-block: clamp(2.5rem, 5vw, 4rem) 2rem;
  border-top: 1px solid var(--ink-line);
  background: var(--ink-void);
}

.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem 2rem;
  padding-bottom: clamp(1.5rem, 3vw, 2.25rem);
}

.footer-brand__brand {
  font-family: var(--font-narrow);
  font-weight: 300;
  font-size: var(--fs-28);
  line-height: 1.1;
  letter-spacing: 0.05em;
  color: var(--text-title);
  text-decoration: none;
  transition: color var(--dur) var(--ease);
}

.footer-brand__brand:hover { color: var(--mint); }

.footer-brand__note {
  font-size: var(--fs-14);
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(1.5rem, 4vw, 3rem);
  padding-top: clamp(1.5rem, 3vw, 2.25rem);
  border-top: 1px solid var(--ink-line);
}

.footer-col__title {
  font-size: var(--fs-12);
  font-weight: 400;
  letter-spacing: 0.24em;
  color: var(--text-muted);
}

.footer-col__list {
  display: grid;
  gap: 0.6rem;
  margin-top: 1rem;
}

.footer-col__list a {
  display: inline-block;
  font-size: var(--fs-14);
  color: var(--text-body);
  text-decoration: none;
  transition: color var(--dur) var(--ease), transform var(--dur) var(--ease);
}

.footer-col__list a:hover {
  color: var(--mint);
  transform: translateX(3px);
}

.footer-col__list--plain li {
  position: relative;
  padding-left: 1.1rem;
  font-size: var(--fs-14);
  color: var(--text-muted);
}

.footer-col__list--plain li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.8em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--teal);
  opacity: 0.75;
}

.footer-contact {
  display: grid;
  grid-template-columns: minmax(0, 0.75fr) minmax(0, 1.75fr);
  gap: clamp(1.25rem, 4vw, 3rem);
  margin-top: clamp(2.25rem, 5vw, 3.25rem);
  padding-top: clamp(1.5rem, 3vw, 2.25rem);
  border-top: 1px solid var(--ink-line);
}

.footer-contact__title {
  font-size: var(--fs-12);
  font-weight: 400;
  letter-spacing: 0.24em;
  color: var(--text-muted);
}

.footer-contact__list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1rem 2rem;
}

.footer-contact__list dt {
  font-size: var(--fs-12);
  letter-spacing: 0.12em;
  color: var(--text-muted);
}

.footer-contact__list dd {
  margin-top: 0.3rem;
  font-size: var(--fs-14);
  color: var(--text-body);
}

.footer-contact__note {
  grid-column: 1 / -1;
  margin-top: 0.25rem;
  font-size: var(--fs-12);
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem 1.75rem;
  margin-top: clamp(2rem, 4vw, 2.75rem);
  padding-top: 1.25rem;
  border-top: 1px solid var(--ink-line);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

/* ---------- 8. 响应式 ---------- */
@media (min-width: 901px) {
  .footer-col:nth-child(2) { margin-top: clamp(0.75rem, 1.6vw, 1.25rem); }
}

@media (max-width: 1023px) {
  .footer-cols { grid-template-columns: repeat(3, minmax(0, 1fr)); }
}

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

  .nav-bar__inner {
    flex-wrap: wrap;
    justify-content: space-between;
    padding-block: 0.5rem;
  }

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

  .site-nav {
    flex: 1 0 100%;
    max-height: 0;
    overflow: hidden;
    visibility: hidden;
    transition: max-height var(--dur-slow) var(--ease), visibility 0s linear var(--dur-slow);
  }

  .site-nav[data-open] {
    max-height: 32rem;
    visibility: visible;
    transition: max-height var(--dur-slow) var(--ease), visibility 0s;
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0.4rem;
    padding-bottom: 1rem;
  }

  .site-nav__link {
    display: block;
    padding: 0.75rem 1.1rem;
    border: 1px solid var(--ink-line);
    border-radius: var(--pill);
    font-size: var(--fs-16);
  }

  .site-nav__link::after { display: none; }

  .site-nav__link[aria-current="page"] {
    border-color: var(--teal-line);
    background: var(--teal-soft);
    color: var(--mint);
  }

  .footer-cols { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .footer-contact { grid-template-columns: minmax(0, 1fr); }
  .footer-contact__list { grid-template-columns: minmax(0, 1fr); }

  .rail {
    top: auto;
    bottom: 0;
    left: 0;
    right: 0;
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.6rem var(--gutter) calc(0.6rem + env(safe-area-inset-bottom, 0px));
    transform: none;
    border-top: 1px solid var(--ink-line);
    background: rgba(5, 7, 11, 0.94);
    backdrop-filter: blur(10px);
  }

  .rail__link {
    writing-mode: horizontal-tb;
    padding: 0.5rem 1.1rem;
  }
}

@media (max-width: 600px) {
  .header-status__inner {
    flex-wrap: wrap;
    row-gap: 0.25rem;
  }

  .masthead__kicker { letter-spacing: 0.24em; text-indent: 0.24em; }

  .footer-brand { flex-direction: column; align-items: flex-start; }
  .footer-cols { grid-template-columns: minmax(0, 1fr); gap: 1.75rem; }
  .footer-base { flex-direction: column; align-items: flex-start; gap: 0.35rem; }
}

/* ---------- 9. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  .status-dot { animation: none; }

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