/* ============================================================
   优乐电子 · 共享站点样式 /assets/site.css
   框架式导航 + 纵向路径长卷 + 控制台面板语言
   ============================================================ */

/* ---------- 1. 变量 ---------- */
:root {
  --deep: #061826;
  --panel: #0B2540;
  --steel: #173F63;
  --cyan: #35D6C4;
  --cyan-soft: #9BEFE6;
  --orange: #FF8B3D;
  --orange-soft: #FFC49A;
  --paper: #F5F2EA;
  --mist: #C7D6DE;
  --ink: #04101C;

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

  --bar-h: 64px;
  --rail-w: 190px;
  --gutter: clamp(20px, 4.4vw, 72px);
  --maxw: 1440px;
  --radius: 14px;
  --hard: 8px 8px 0 rgba(4, 16, 28, 0.9);
  --hair: rgba(53, 214, 196, 0.16);
  --hair-strong: rgba(53, 214, 196, 0.3);
  --mono-ls: 0.12em;
}

/* ---------- 2. Reset 与中文排版 ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--bar-h) + 18px);
}

body {
  margin: 0;
  padding-top: var(--bar-h);
  padding-left: var(--rail-w);
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 450;
  line-height: 1.9;
  color: var(--mist);
  background: var(--deep);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5, h6 {
  margin: 0;
  font-family: var(--font-sans);
  font-weight: 700;
  line-height: 1.28;
  letter-spacing: 0.02em;
  color: var(--paper);
}

p { margin: 0; }

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

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

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

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

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

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

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

/* ---------- 3. 通用工具 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: clamp(20px, 2.4vw, 32px);
}

.grid > * { grid-column: span 12; }
.grid--split > * { grid-column: span 6; }

.mono {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: var(--mono-ls);
  color: rgba(199, 214, 222, 0.62);
}

.lede {
  max-width: 60ch;
  font-size: clamp(17px, 1.6vw, 20px);
  line-height: 1.9;
  color: rgba(199, 214, 222, 0.9);
}

/* ---------- 4. 跳过导航 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 320;
  padding: 10px 18px;
  border-radius: 8px;
  background: var(--orange);
  color: var(--ink);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.04em;
  transform: translateY(-180%);
  transition: transform 0.18s ease;
}

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

/* ---------- 5. 头部框架式导航 ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--bar-h);
  z-index: 140;
}

.header-bar {
  position: relative;
  display: flex;
  align-items: center;
  gap: clamp(12px, 2vw, 26px);
  height: 100%;
  padding: 0 22px 0 calc(var(--rail-w) + 22px);
  background: linear-gradient(90deg, rgba(6, 24, 38, 0.97) 0%, rgba(11, 37, 64, 0.96) 62%, rgba(6, 24, 38, 0.97) 100%);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--hair-strong);
}

.header-bar::after {
  content: "";
  position: absolute;
  left: calc(var(--rail-w) + 22px);
  bottom: -1px;
  width: 72px;
  height: 2px;
  background: var(--cyan);
  box-shadow: 0 0 12px rgba(53, 214, 196, 0.7);
}

/* 品牌 */
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 0 0 auto;
  padding: 4px 2px;
  color: var(--paper);
}

.brand__mark {
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
  background: var(--cyan);
  clip-path: polygon(50% 0%, 100% 50%, 50% 100%, 0% 50%);
  filter: drop-shadow(0 0 8px rgba(53, 214, 196, 0.85));
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 1px;
  line-height: 1.25;
}

.brand__name {
  font-size: 17px;
  font-weight: 700;
  letter-spacing: 0.11em;
  color: var(--paper);
}

.brand__note {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: rgba(155, 239, 230, 0.78);
}

/* 右上角入口角标 */
.entry-badge {
  position: relative;
  overflow: hidden;
  margin-left: auto;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 8px 15px;
  border: 1px solid rgba(255, 139, 61, 0.5);
  border-radius: 999px;
  background: linear-gradient(96deg, rgba(255, 139, 61, 0.18), rgba(53, 214, 196, 0.1));
  color: var(--orange-soft);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.05em;
  white-space: nowrap;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease, color 0.2s ease;
}

.entry-badge::before {
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 38%;
  background: linear-gradient(90deg, transparent, rgba(255, 196, 154, 0.34), transparent);
  transform: translateX(-160%);
  animation: badgeSweep 6s ease-in-out infinite;
  pointer-events: none;
}

.entry-badge:hover,
.entry-badge:focus-visible {
  border-color: var(--orange);
  color: var(--paper);
  box-shadow: 0 0 0 4px rgba(255, 139, 61, 0.14);
  transform: translateY(-1px);
}

.entry-badge__dot {
  width: 7px;
  height: 7px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--orange);
  animation: dotPulse 6s ease-in-out infinite;
}

.entry-badge__ver {
  padding-left: 10px;
  border-left: 1px solid rgba(255, 139, 61, 0.38);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: rgba(245, 242, 234, 0.64);
}

@keyframes badgeSweep {
  0%, 70%, 100% { transform: translateX(-160%); }
  86% { transform: translateX(320%); }
}

@keyframes dotPulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(255, 139, 61, 0.55); }
  50% { box-shadow: 0 0 0 6px rgba(255, 139, 61, 0); }
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  flex: 0 0 auto;
  padding: 9px 12px;
  border: 1px solid var(--hair-strong);
  border-radius: 8px;
  background: rgba(53, 214, 196, 0.07);
  color: var(--paper);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  transition: border-color 0.2s ease, background 0.2s ease;
}

.nav-toggle:hover,
.nav-toggle[aria-expanded="true"] {
  border-color: var(--cyan);
  background: rgba(53, 214, 196, 0.16);
}

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

.nav-toggle__bar {
  display: block;
  height: 2px;
  border-radius: 2px;
  background: var(--cyan);
  transition: transform 0.22s ease;
}

.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); }

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

/* 左缘导航轨道 */
.frame-rail {
  position: fixed;
  top: var(--bar-h);
  left: 0;
  bottom: 0;
  width: var(--rail-w);
  z-index: 130;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 20px;
  padding: 26px 0 22px;
  overflow-y: auto;
  background: linear-gradient(180deg, #08202f 0%, #04121f 46%, #061826 100%);
  border-right: 1px solid var(--hair-strong);
}

.frame-rail::before {
  content: "";
  position: absolute;
  top: 0;
  right: -1px;
  width: 2px;
  height: 84px;
  background: linear-gradient(180deg, var(--cyan), transparent);
}

.rail-nav { width: 100%; }

.rail-nav__list {
  display: flex;
  flex-direction: column;
}

.rail-nav__item { position: relative; }

.rail-nav__link {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 12px 18px 12px 24px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: rgba(199, 214, 222, 0.82);
  border-left: 2px solid transparent;
  transition: color 0.2s ease, background 0.2s ease;
}

.rail-nav__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 2px;
  height: 0;
  background: var(--cyan);
  transform: translateY(-50%);
  transition: height 0.24s ease, background 0.24s ease;
}

.rail-nav__link:hover {
  color: var(--paper);
  background: rgba(53, 214, 196, 0.07);
}

.rail-nav__link:hover::before { height: 62%; }

.rail-nav__link[aria-current="page"] {
  color: var(--paper);
  background: rgba(53, 214, 196, 0.1);
  font-weight: 600;
}

.rail-nav__link[aria-current="page"]::before {
  height: 70%;
  background: var(--cyan);
  box-shadow: 0 0 10px rgba(53, 214, 196, 0.8);
}

.rail-nav__index {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  color: rgba(199, 214, 222, 0.48);
  transition: color 0.2s ease;
}

.rail-nav__link:hover .rail-nav__index,
.rail-nav__link[aria-current="page"] .rail-nav__index { color: var(--orange); }

.rail-nav__label { flex: 1 1 auto; }

.rail-foot {
  padding: 18px 24px 0;
  border-top: 1px solid var(--hair);
}

.rail-foot__line {
  font-family: var(--font-mono);
  font-size: 10px;
  line-height: 1.9;
  letter-spacing: 0.14em;
  color: rgba(199, 214, 222, 0.42);
}

.rail-foot__line:first-child {
  font-family: var(--font-sans);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: rgba(199, 214, 222, 0.55);
}

/* ---------- 6. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(64px, 8vw, 120px);
  padding: clamp(48px, 6vw, 88px) 0 0;
  background: linear-gradient(180deg, var(--panel) 0%, #071b2c 58%, var(--deep) 100%);
  border-top: 1px solid var(--hair-strong);
  color: var(--mist);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: var(--gutter);
  width: clamp(80px, 14vw, 200px);
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--orange));
}

.footer-inner {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer-brand {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px 28px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--hair);
}

.footer-brand__line {
  max-width: 34ch;
  font-size: clamp(19px, 2.3vw, 27px);
  font-weight: 300;
  line-height: 1.45;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.footer-brand__meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.footer-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: clamp(24px, 4vw, 56px);
  padding: clamp(30px, 4vw, 52px) 0;
  border-bottom: 1px solid var(--hair);
}

.footer-col__title {
  margin-bottom: 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.18em;
  color: var(--orange);
}

.footer-col__list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-link {
  position: relative;
  display: inline-block;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.03em;
  color: rgba(199, 214, 222, 0.86);
  transition: color 0.2s ease, transform 0.2s ease;
}

.footer-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 0;
  height: 1px;
  background: var(--cyan);
  transition: width 0.24s ease;
}

.footer-link:hover,
.footer-link:focus-visible {
  color: var(--cyan);
  transform: translateX(3px);
}

.footer-link:hover::after,
.footer-link:focus-visible::after { width: 100%; }

.footer-contact {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(215px, 1fr));
  gap: clamp(20px, 3vw, 40px);
  padding: clamp(28px, 4vw, 44px) 0;
  border-bottom: 1px solid var(--hair);
}

.footer-contact__item {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.footer-contact__label {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.16em;
  color: var(--orange);
}

.footer-contact__value {
  font-size: 15px;
  line-height: 1.7;
  color: var(--paper);
  word-break: break-word;
}

.footer-contact__note {
  grid-column: 1 / -1;
  max-width: 68ch;
  margin-top: 4px;
  font-size: 13px;
  line-height: 1.85;
  color: rgba(199, 214, 222, 0.64);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  padding: 24px 0 36px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
}

.footer-legal__icp { color: rgba(199, 214, 222, 0.62); }
.footer-legal__copy { color: rgba(199, 214, 222, 0.44); }

/* ---------- 7. 章节与色带 ---------- */
.chapter {
  position: relative;
  padding-block: clamp(48px, 6vw, 96px);
  border-top: 1px solid var(--hair);
}

.chapter__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px 20px;
  margin-bottom: clamp(20px, 3vw, 36px);
}

.chapter__index {
  padding: 3px 9px;
  border: 1px solid var(--hair-strong);
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.chapter__title {
  font-size: clamp(24px, 3.2vw, 36px);
  letter-spacing: 0.03em;
}

.chapter__lede {
  max-width: 62ch;
  font-size: 16px;
  line-height: 1.9;
  color: rgba(199, 214, 222, 0.8);
}

.band {
  position: relative;
  height: clamp(72px, 9vw, 140px);
  overflow: hidden;
  background: linear-gradient(104deg, var(--deep) 0%, var(--steel) 54%, var(--panel) 100%);
  border-top: 1px solid var(--hair);
  border-bottom: 1px solid var(--hair);
}

.band::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
}

/* ---------- 8. 面板卡片 ---------- */
.panel {
  position: relative;
  padding: clamp(20px, 3vw, 32px);
  border: 2px solid var(--steel);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--hard);
}

.panel::after {
  content: "";
  position: absolute;
  top: 12px;
  right: 12px;
  width: 14px;
  height: 14px;
  border-top: 2px solid var(--cyan);
  border-right: 2px solid var(--cyan);
  opacity: 0.6;
  pointer-events: none;
}

.panel--dark {
  background: linear-gradient(158deg, #0B2540 0%, #061826 100%);
}

.panel--paper {
  background: var(--paper);
  border-color: var(--ink);
  color: var(--ink);
  box-shadow: 8px 8px 0 var(--ink);
}

.panel--paper::after {
  border-top-color: #0f6f66;
  border-right-color: #0f6f66;
  opacity: 0.75;
}

.panel--paper h1,
.panel--paper h2,
.panel--paper h3,
.panel--paper h4 { color: var(--ink); }

.panel__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.panel__body { font-size: 16px; }

/* ---------- 9. 按钮与标签 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 13px 22px;
  border: 2px solid var(--cyan);
  border-radius: 8px;
  background: transparent;
  color: var(--cyan);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.06em;
  transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}

.btn:hover,
.btn:focus-visible {
  background: rgba(53, 214, 196, 0.14);
  transform: translateY(-2px);
}

.btn--primary {
  border-color: var(--orange);
  background: var(--orange);
  color: var(--ink);
  box-shadow: 4px 4px 0 rgba(4, 16, 28, 0.72);
}

.btn--primary:hover,
.btn--primary:focus-visible {
  border-color: var(--orange-soft);
  background: var(--orange-soft);
  box-shadow: 6px 6px 0 rgba(4, 16, 28, 0.82);
}

.btn--ghost {
  border-color: rgba(199, 214, 222, 0.34);
  color: var(--paper);
}

.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: var(--cyan);
  background: rgba(53, 214, 196, 0.1);
  color: var(--cyan);
}

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

.tag {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 10px;
  border: 1px solid transparent;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
}

.tag--cyan {
  color: var(--cyan);
  border-color: rgba(53, 214, 196, 0.42);
  background: rgba(53, 214, 196, 0.09);
}

.tag--orange {
  color: var(--orange);
  border-color: rgba(255, 139, 61, 0.44);
  background: rgba(255, 139, 61, 0.11);
}

.status-dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--cyan-soft);
}

.status-dot--cyan {
  background: var(--cyan);
  box-shadow: 0 0 10px rgba(53, 214, 196, 0.8);
}

.status-dot--orange {
  background: var(--orange);
  box-shadow: 0 0 10px rgba(255, 139, 61, 0.8);
}

/* ---------- 10. 正文排版 ---------- */
.prose {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.9;
}

.prose p { margin-bottom: 1.1em; }
.prose p:last-child { margin-bottom: 0; }

.prose h2,
.prose h3,
.prose h4 { margin: 1.6em 0 0.6em; }

.prose h2 { font-size: clamp(22px, 2.4vw, 28px); }
.prose h3 { font-size: clamp(19px, 2vw, 22px); }

.prose ul { margin: 0 0 1.1em; }

.prose ul li {
  position: relative;
  margin-bottom: 0.6em;
  padding-left: 20px;
}

.prose ul li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.82em;
  width: 6px;
  height: 6px;
  border-radius: 1px;
  background: var(--cyan);
}

.prose a {
  color: var(--cyan);
  border-bottom: 1px solid rgba(53, 214, 196, 0.42);
  transition: color 0.2s ease, border-color 0.2s ease;
}

.prose a:hover,
.prose a:focus-visible {
  color: var(--orange);
  border-color: var(--orange);
}

.panel--paper .prose { color: var(--ink); }
.panel--paper .prose a { color: #0f6f66; border-color: rgba(15, 111, 102, 0.45); }
.panel--paper .prose ul li::before { background: #0f6f66; }

/* ---------- 11. 图片容器基础规则 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  border: 2px solid var(--steel);
  border-radius: var(--radius);
  background:
    radial-gradient(120% 100% at 82% 0%, rgba(53, 214, 196, 0.22), transparent 62%),
    linear-gradient(155deg, var(--panel) 0%, #04121f 100%);
  box-shadow: var(--hard);
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image: linear-gradient(rgba(53, 214, 196, 0.07) 1px, transparent 1px);
  background-size: 100% 28px;
  opacity: 0.7;
}

.media-frame__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  position: relative;
  z-index: 1;
}

.media-frame__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 2;
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--cyan-soft);
  background: linear-gradient(0deg, rgba(6, 24, 38, 0.94), rgba(6, 24, 38, 0));
}

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

/* ---------- 12. 面包屑 ---------- */
.breadcrumb {
  padding: 18px 0;
  border-bottom: 1px solid var(--hair);
}

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
}

.breadcrumb__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: rgba(199, 214, 222, 0.56);
}

.breadcrumb__link {
  color: rgba(199, 214, 222, 0.72);
  transition: color 0.2s ease;
}

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

.breadcrumb__sep { color: rgba(53, 214, 196, 0.5); }

/* ---------- 13. 可展开问答组 ---------- */
.accordion {
  border-top: 1px solid var(--hair);
}

.accordion__item {
  border-bottom: 1px solid var(--hair);
}

.accordion__trigger {
  display: flex;
  align-items: center;
  gap: 14px;
  width: 100%;
  padding: 20px 4px;
  text-align: left;
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--paper);
  transition: color 0.2s ease;
}

.accordion__trigger:hover,
.accordion__trigger:focus-visible { color: var(--cyan); }

.accordion__trigger::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--cyan);
  transition: color 0.24s ease;
}

.accordion__trigger[aria-expanded="true"]::after { color: var(--orange); }

.accordion__state {
  width: 10px;
  height: 10px;
  flex: 0 0 auto;
  border-radius: 50%;
  background: var(--cyan-soft);
  box-shadow: 0 0 0 3px rgba(155, 239, 230, 0.14);
  transition: background 0.24s ease, box-shadow 0.24s ease;
}

.accordion__trigger[aria-expanded="true"] .accordion__state {
  background: var(--orange);
  box-shadow: 0 0 0 3px rgba(255, 139, 61, 0.2);
}

.accordion__label { flex: 1 1 auto; }

.accordion__panel {
  padding: 0 4px 22px 28px;
  font-size: 15.5px;
  line-height: 1.9;
  color: rgba(199, 214, 222, 0.86);
}

.accordion__item.is-open .accordion__panel {
  animation: panelIn 0.24s ease-out;
}

@keyframes panelIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: none; }
}

/* ---------- 14. 阅读进度条（JS 注入） ---------- */
.scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 200;
  transform: scaleX(0);
  transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--cyan) 0%, var(--cyan-soft) 46%, var(--orange) 100%);
  box-shadow: 0 0 10px rgba(53, 214, 196, 0.5);
  pointer-events: none;
}

/* ---------- 15. 响应式 ---------- */
@media (max-width: 1180px) {
  :root { --rail-w: 168px; }
  .rail-nav__link { padding-right: 14px; font-size: 14px; }
}

@media (max-width: 900px) {
  :root { --bar-h: 58px; --rail-w: 0px; }

  body {
    padding-left: 0;
    font-size: 16.5px;
  }

  .header-bar {
    padding: 0 16px;
    gap: 12px;
  }

  .header-bar::after { left: 16px; }

  .nav-toggle { display: flex; }

  .brand__note { display: none; }
  .brand__name { font-size: 16px; letter-spacing: 0.08em; }

  .entry-badge { padding: 7px 11px; gap: 7px; font-size: 12px; }
  .entry-badge__ver { display: none; }

  .frame-rail {
    top: var(--bar-h);
    width: min(80vw, 300px);
    visibility: hidden;
    transform: translateX(-104%);
    transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.28s;
    box-shadow: 18px 0 44px rgba(0, 0, 0, 0.55);
  }

  .frame-rail[data-open="true"] {
    visibility: visible;
    transform: translateX(0);
  }

  body.nav-locked { overflow: hidden; }

  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .grid--split > * { grid-column: span 12; }
}

@media (max-width: 600px) {
  .entry-badge__text { display: none; }
  .entry-badge { padding: 8px 10px; }

  .footer-grid { grid-template-columns: minmax(0, 1fr); gap: 26px; }

  .footer-brand { flex-direction: column; align-items: flex-start; }

  .footer-legal { flex-direction: column; align-items: flex-start; gap: 6px; }

  .rail-nav__link { padding: 13px 16px 13px 20px; }
}

@media (max-width: 380px) {
  .nav-toggle__label { display: none; }
}

/* ---------- 16. 降低动效 ---------- */
@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;
  }

  .entry-badge::before,
  .entry-badge__dot { animation: none !important; }

  .btn:hover,
  .footer-link:hover { transform: none; }
}