/* ==========================================================================
   四季指南 / 四季CN — /assets/site.css
   共享外壳：reset、变量、中文排版、页头、页脚、通用组件
   ========================================================================== */

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

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

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

ul, ol { list-style: none; }

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

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

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

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

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

[hidden] { display: none !important; }

/* ---------- 2. Tokens ---------- */
:root {
  /* 色彩 */
  --paper: #F5F1E8;
  --ink: #1B1E22;
  --winter: #3A4A5A;
  --night: #16212B;
  --spring: #7EC8A3;
  --summer: #E4572E;
  --summer-deep: #B8391B;
  --autumn: #D9A441;
  --mist: #DCEBE2;
  --cinnabar: #F6DCD2;
  --gray: #5C6670;

  /* 线条 */
  --line: rgba(58, 74, 90, 0.2);
  --line-strong: rgba(58, 74, 90, 0.48);
  --line-light: rgba(245, 241, 232, 0.22);
  --line-gold: rgba(217, 164, 65, 0.55);

  /* 度量 */
  --maxw: 1280px;
  --gut: clamp(18px, 4.2vw, 64px);
  --header-h: 84px;
  --ease: cubic-bezier(0.32, 0.72, 0.28, 1);

  /* 字体族 */
  --font-display: "Noto Serif SC", "Songti SC", "Noto Serif", "SimSun", serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", ui-monospace, "Courier New", monospace;
}

/* ---------- 3. 中文排版基线 ---------- */
body {
  background-color: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.75;
  letter-spacing: 0.005em;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.16;
  text-wrap: balance;
}

h1 { font-size: clamp(2.4rem, 5vw, 4.2rem); }
h2 { font-size: clamp(1.6rem, 2.6vw, 2.4rem); }
h3 { font-size: clamp(1.15rem, 1.6vw, 1.4rem); font-weight: 700; letter-spacing: -0.01em; }
h4 { font-size: 1rem; font-weight: 700; font-family: var(--font-body); letter-spacing: 0; }

p { max-width: 38em; }
p + p { margin-top: 1em; }

strong, b { font-weight: 700; }

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

/* ---------- 4. 焦点 ---------- */
:focus-visible {
  outline: 2px solid var(--summer-deep);
  outline-offset: 3px;
}

.site-footer :focus-visible {
  outline-color: var(--autumn);
}

.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;
}

/* ---------- 5. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 300;
  padding: 10px 18px;
  background: var(--night);
  color: var(--paper);
  font-size: 14px;
  font-weight: 500;
  border-left: 3px solid var(--autumn);
  transform: translateY(-220%);
  transition: transform 0.18s var(--ease);
}

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

/* ---------- 6. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background-image: linear-gradient(180deg, rgba(245, 241, 232, 0.94) 0%, rgba(245, 241, 232, 0.72) 55%, rgba(245, 241, 232, 0) 100%);
  border-bottom: 1px solid transparent;
  transition: background-color 0.2s var(--ease), border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.site-header[data-scrolled] {
  background-color: var(--paper);
  background-image: none;
  border-bottom-color: var(--winter);
  box-shadow: 0 1px 0 rgba(217, 164, 65, 0.35);
}

.header-inner {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gut);
  min-height: var(--header-h);
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: clamp(12px, 2vw, 36px);
}

/* 字标 */
.brand {
  display: flex;
  align-items: baseline;
  gap: 9px;
  flex: 0 0 auto;
}

.brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 23px;
  letter-spacing: -0.01em;
  line-height: 1;
  color: var(--ink);
}

.brand__sub {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--summer-deep);
  transform: translateY(-1px);
}

/* 四时标尺导航 */
.nav {
  justify-self: center;
  min-width: 0;
}

.nav__list {
  display: flex;
  align-items: stretch;
}

.nav__item {
  display: flex;
  border-left: 1px solid var(--line);
}

.nav__item:last-child {
  border-right: 1px solid var(--line);
}

.nav__link {
  position: relative;
  display: grid;
  justify-items: center;
  gap: 2px;
  padding: 12px clamp(8px, 1.15vw, 18px) 22px;
  color: var(--ink);
  transition: color 0.18s var(--ease);
}

.nav__idx {
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 500;
  letter-spacing: 0.14em;
  color: var(--gray);
  transition: color 0.18s var(--ease);
}

.nav__label {
  font-size: 15px;
  font-weight: 500;
  line-height: 1.2;
  white-space: nowrap;
}

/* 悬停细线 */
.nav__link::before {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: var(--autumn);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform 0.2s var(--ease);
}

/* 去向说明 */
.nav__link::after {
  content: attr(data-note);
  position: absolute;
  top: calc(100% + 2px);
  left: 50%;
  z-index: 5;
  transform: translate(-50%, 4px);
  padding: 6px 10px;
  background: var(--night);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 400;
  line-height: 1.4;
  letter-spacing: 0;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.18s var(--ease), transform 0.18s var(--ease);
}

.nav__link:hover::after,
.nav__link:focus-visible::after {
  opacity: 1;
  transform: translate(-50%, 0);
}

.nav__link:hover::before,
.nav__link:focus-visible::before {
  transform: scaleX(1);
}

.nav__link:hover .nav__idx,
.nav__link:focus-visible .nav__idx {
  color: var(--summer-deep);
}

/* 当前页刻度 */
.nav__mark {
  display: none;
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 18px;
  height: 2px;
  background: var(--autumn);
  transform: translateX(-50%);
}

.nav__link[aria-current="page"] .nav__mark {
  display: block;
}

.nav__link[aria-current="page"] .nav__label {
  font-weight: 700;
}

.nav__link[aria-current="page"] .nav__idx {
  color: var(--summer-deep);
}

/* 右侧行动 */
.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
  flex: 0 0 auto;
}

/* 移动菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 10px;
  border: 1px solid var(--line-strong);
  color: var(--ink);
  font-size: 13px;
  font-weight: 500;
  line-height: 1;
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}

.nav-toggle__bars {
  width: 18px;
  height: 11px;
  background-image:
    linear-gradient(var(--ink), var(--ink)),
    linear-gradient(var(--ink), var(--ink)),
    linear-gradient(var(--ink), var(--ink));
  background-repeat: no-repeat;
  background-size: 100% 1.5px, 100% 1.5px, 100% 1.5px;
  background-position: 0 0, 0 50%, 0 100%;
}

.nav-toggle[aria-expanded="true"] {
  border-color: var(--autumn);
  color: var(--summer-deep);
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bars {
  background-image:
    linear-gradient(var(--summer-deep), var(--summer-deep)),
    linear-gradient(transparent, transparent),
    linear-gradient(var(--summer-deep), var(--summer-deep));
}

/* 阅读进度 */
.read-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  overflow: hidden;
  pointer-events: none;
}

.read-progress__bar {
  display: block;
  width: 0;
  height: 100%;
  background: var(--autumn);
  transition: width 0.1s linear;
}

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border: 1px solid transparent;
  border-radius: 0;
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.2;
  letter-spacing: 0.02em;
  white-space: nowrap;
  text-align: center;
  transition: background-color 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.btn--primary {
  background: var(--summer);
  border-color: var(--summer);
  color: var(--ink);
  font-weight: 700;
}

.btn--primary:hover,
.btn--primary:focus-visible {
  background: var(--summer-deep);
  border-color: var(--summer-deep);
  color: var(--paper);
}

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

.btn--ghost:hover,
.btn--ghost:focus-visible {
  border-color: var(--autumn);
  color: var(--summer-deep);
}

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

.btn--line:hover,
.btn--line:focus-visible {
  background: var(--ink);
  color: var(--paper);
}

.btn--sm {
  padding: 7px 14px;
  font-size: 13px;
}

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

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  background: var(--winter);
  color: rgba(245, 241, 232, 0.86);
  font-size: 14px;
}

.site-footer::before {
  content: "";
  display: block;
  height: 6px;
  background-image: repeating-linear-gradient(
    90deg,
    var(--autumn) 0,
    var(--autumn) 1px,
    transparent 1px,
    transparent 48px
  );
  opacity: 0.65;
}

.footer-grid {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding: clamp(34px, 5vw, 68px) var(--gut) clamp(28px, 4vw, 54px);
  display: grid;
  grid-template-columns: 1.15fr 1.55fr 0.85fr 1.25fr;
  gap: clamp(24px, 3vw, 48px);
  align-items: start;
}

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

.footer-title {
  margin-bottom: 16px;
  padding-bottom: 9px;
  border-bottom: 1px solid var(--line-light);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--autumn);
}

.footer-brand {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-bottom: 14px;
}

.footer-brand__mark {
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 900;
  letter-spacing: -0.01em;
  line-height: 1.1;
  color: var(--paper);
}

.footer-brand__sub {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.16em;
  color: var(--autumn);
}

.footer-note {
  max-width: 26em;
  font-size: 13px;
  line-height: 1.75;
  color: rgba(245, 241, 232, 0.62);
}

.footer-note + .footer-link {
  margin-top: 14px;
}

.footer-icp {
  margin-top: 18px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: rgba(245, 241, 232, 0.5);
}

/* 折叠资料架 */
.footer-col--shelf {
  background: var(--night);
  border: 1px solid var(--line-gold);
  padding: 20px 20px 14px;
}

.shelf {
  display: grid;
}

.shelf__item + .shelf__item {
  border-top: 1px solid rgba(245, 241, 232, 0.12);
}

.shelf__toggle {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 13px 0;
  text-align: left;
  color: var(--paper);
  transition: color 0.18s var(--ease);
}

.shelf__toggle:hover,
.shelf__toggle:focus-visible {
  color: var(--autumn);
}

.shelf__range {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.1em;
  color: var(--autumn);
  flex: 0 0 auto;
}

.shelf__meta {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-size: 13.5px;
  font-weight: 500;
  line-height: 1.4;
}

.shelf__count {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 400;
  letter-spacing: 0.08em;
  color: rgba(245, 241, 232, 0.45);
}

.shelf__sign {
  position: relative;
  flex: 0 0 auto;
  width: 12px;
  height: 12px;
}

.shelf__sign::before,
.shelf__sign::after {
  content: "";
  position: absolute;
  background: var(--autumn);
  transition: transform 0.18s var(--ease);
}

.shelf__sign::before {
  left: 0;
  top: 5.5px;
  width: 12px;
  height: 1px;
}

.shelf__sign::after {
  left: 5.5px;
  top: 0;
  width: 1px;
  height: 12px;
}

.shelf__item.is-open .shelf__sign::after {
  transform: scaleY(0);
}

.shelf__panel {
  display: grid;
  grid-template-rows: 0fr;
  visibility: hidden;
  transition: grid-template-rows 0.18s var(--ease), visibility 0s linear 0.18s;
}

.shelf__item.is-open .shelf__panel {
  grid-template-rows: 1fr;
  visibility: visible;
  transition: grid-template-rows 0.18s var(--ease), visibility 0s linear 0s;
}

.shelf__panelInner {
  overflow: hidden;
  min-height: 0;
}

.shelf__list {
  display: grid;
  gap: 1px;
  padding: 2px 0 12px;
}

.shelf__link {
  position: relative;
  display: block;
  padding: 5px 0 5px 18px;
  font-size: 12.5px;
  line-height: 1.6;
  color: rgba(245, 241, 232, 0.66);
  transition: color 0.18s var(--ease);
}

.shelf__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 13px;
  width: 8px;
  height: 1px;
  background: var(--autumn);
  transition: width 0.18s var(--ease);
}

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

.shelf__link:hover::before,
.shelf__link:focus-visible::before {
  width: 13px;
}

/* 页脚链接列 */
.footer-links {
  display: grid;
  gap: 1px;
}

.footer-link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 0;
  font-size: 14px;
  line-height: 1.55;
  color: rgba(245, 241, 232, 0.82);
  transition: color 0.18s var(--ease);
}

.footer-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 3px;
  width: 0;
  height: 1px;
  background: var(--autumn);
  transition: width 0.2s var(--ease);
}

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

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

.footer-link--path {
  color: var(--autumn);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
}

/* 联系信息 */
.footer-contact {
  display: grid;
  gap: 10px;
  margin-bottom: 16px;
}

.contact-line {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 10px;
  align-items: baseline;
}

.contact-label {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  color: var(--autumn);
  text-transform: uppercase;
}

.contact-value {
  font-size: 13px;
  line-height: 1.6;
  color: rgba(245, 241, 232, 0.86);
  overflow-wrap: anywhere;
}

/* 底部通栏 */
.footer-bottom {
  background: var(--night);
  border-top: 1px solid rgba(245, 241, 232, 0.1);
}

.footer-bottom__inner {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding: 18px var(--gut);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 28px;
}

.footer-copy {
  max-width: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.05em;
  color: rgba(245, 241, 232, 0.5);
}

.footer-legal {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
}

.footer-legal a {
  font-size: 12px;
  color: rgba(245, 241, 232, 0.66);
  transition: color 0.18s var(--ease);
}

.footer-legal a:hover,
.footer-legal a:focus-visible {
  color: var(--autumn);
  text-decoration: underline;
  text-underline-offset: 4px;
}

/* ---------- 9. 通用布局容器 ---------- */
.container {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gut);
}

.section {
  padding-block: clamp(48px, 7vw, 104px);
}

.section--tight {
  padding-block: clamp(28px, 4vw, 56px);
}

.section--wide {
  padding-block: clamp(72px, 11vw, 156px);
}

.section--ink {
  background: var(--night);
  color: rgba(245, 241, 232, 0.9);
}

.section--mist {
  background: var(--mist);
}

.section--cinnabar {
  background: var(--cinnabar);
}

.prose {
  max-width: 38em;
}

.prose p {
  max-width: none;
}

.prose h2,
.prose h3 {
  margin-top: 1.8em;
  margin-bottom: 0.7em;
}

.prose ul,
.prose ol {
  margin-block: 1em;
  padding-left: 1.2em;
  list-style: disc;
}

.prose li + li {
  margin-top: 0.4em;
}

/* 栅格 */
.grid {
  display: grid;
  gap: clamp(16px, 2.4vw, 32px);
  grid-template-columns: minmax(0, 1fr);
}

.split {
  display: grid;
  gap: clamp(20px, 3vw, 48px);
  grid-template-columns: minmax(0, 1fr);
}

/* 小标签 */
.eyebrow {
  display: block;
  margin-bottom: 0.9em;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--summer-deep);
}

.section--ink .eyebrow {
  color: var(--autumn);
}

.mono {
  font-family: var(--font-mono);
  font-weight: 500;
  letter-spacing: 0.04em;
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--winter);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  line-height: 1.4;
  white-space: nowrap;
}

.tag--spring {
  background: rgba(126, 200, 163, 0.2);
  border-color: rgba(126, 200, 163, 0.9);
  color: #204a37;
}

.tag--summer {
  background: rgba(228, 87, 46, 0.14);
  border-color: rgba(184, 57, 27, 0.55);
  color: var(--summer-deep);
}

.tag--autumn {
  background: rgba(217, 164, 65, 0.2);
  border-color: rgba(217, 164, 65, 0.75);
  color: #63430b;
}

.tag--winter {
  background: rgba(58, 74, 90, 0.1);
  border-color: rgba(58, 74, 90, 0.42);
  color: var(--winter);
}

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

.rule--gold {
  width: 48px;
  height: 2px;
  background: var(--autumn);
}

/* 面包屑 */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.breadcrumb a {
  color: var(--winter);
  transition: color 0.18s var(--ease);
}

.breadcrumb a:hover,
.breadcrumb a:focus-visible {
  color: var(--summer-deep);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.breadcrumb__sep {
  color: var(--autumn);
}

/* 索引簇 */
.index-list {
  display: grid;
  border-top: 1px solid var(--line-strong);
}

.index-item {
  border-bottom: 1px solid var(--line);
}

.index-item > a {
  display: grid;
  grid-template-columns: auto 1fr auto;
  gap: 16px;
  align-items: baseline;
  padding: 15px 0;
  transition: color 0.18s var(--ease);
}

.index-item > a:hover,
.index-item > a:focus-visible {
  color: var(--summer-deep);
}

.index-item__num {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--autumn);
}

.index-item__title {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 700;
  line-height: 1.4;
}

.index-item__meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--gray);
}

.index-item__arrow {
  display: inline-block;
  margin-left: 8px;
  color: var(--autumn);
  transition: transform 0.18s var(--ease);
}

.index-item > a:hover .index-item__arrow,
.index-item > a:focus-visible .index-item__arrow {
  transform: translateX(4px);
}

/* 纵向时间轴 */
.timeline {
  position: relative;
  padding-left: 26px;
  border-left: 1px solid var(--line-strong);
}

.timeline__node {
  position: relative;
  padding-bottom: 26px;
}

.timeline__node:last-child {
  padding-bottom: 0;
}

.timeline__node::before {
  content: "";
  position: absolute;
  left: -31px;
  top: 9px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--winter);
  background: var(--paper);
}

.section--ink .timeline,
.section--ink .timeline__node {
  border-color: var(--line-light);
}

.section--ink .timeline__node::before {
  border-color: var(--autumn);
  background: var(--night);
}

/* 可展开组 */
.accordion {
  display: grid;
  border-top: 1px solid var(--line-strong);
}

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

.accordion__trigger {
  width: 100%;
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 18px 0;
  text-align: left;
  color: var(--ink);
  transition: color 0.18s var(--ease);
}

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

.accordion__idx {
  flex: 0 0 auto;
  min-width: 30px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--gray);
}

.accordion__title {
  flex: 1 1 auto;
  font-size: 16px;
  font-weight: 500;
  line-height: 1.5;
}

.accordion__item.is-open .accordion__title::before {
  content: "";
  display: inline-block;
  width: 18px;
  height: 2px;
  margin-right: 10px;
  vertical-align: middle;
  background: var(--autumn);
}

.accordion__sign {
  position: relative;
  flex: 0 0 auto;
  width: 12px;
  height: 12px;
  align-self: center;
}

.accordion__sign::before,
.accordion__sign::after {
  content: "";
  position: absolute;
  background: var(--summer-deep);
  transition: transform 0.18s var(--ease);
}

.accordion__sign::before {
  left: 0;
  top: 5.5px;
  width: 12px;
  height: 1px;
}

.accordion__sign::after {
  left: 5.5px;
  top: 0;
  width: 1px;
  height: 12px;
}

.accordion__item.is-open .accordion__sign::after {
  transform: scaleY(0);
}

.accordion__panel {
  display: grid;
  grid-template-rows: 0fr;
  visibility: hidden;
  transition: grid-template-rows 0.18s var(--ease), visibility 0s linear 0.18s;
}

.accordion__item.is-open .accordion__panel {
  grid-template-rows: 1fr;
  visibility: visible;
  transition: grid-template-rows 0.18s var(--ease), visibility 0s linear 0s;
}

.accordion__panelInner {
  overflow: hidden;
  min-height: 0;
}

.accordion__body {
  padding: 0 0 22px 44px;
  max-width: 44em;
  color: var(--ink);
  font-size: 15px;
}

/* 图片容器 */
.figure {
  position: relative;
  margin: 0;
  background: var(--mist);
  border: 1px solid var(--line);
  overflow: hidden;
}

.figure__img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  aspect-ratio: 4 / 3;
  border-radius: 0;
}

.figure--wide .figure__img { aspect-ratio: 16 / 9; }
.figure--tall .figure__img { aspect-ratio: 3 / 4; }

.figure--veil::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(58, 74, 90, 0) 55%, rgba(58, 74, 90, 0.12) 100%);
  pointer-events: none;
}

.figure__cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  line-height: 1.6;
  color: var(--gray);
}

/* ---------- 10. 动效协议 ---------- */
[data-stagger] > * {
  transition: opacity 0.45s var(--ease), transform 0.45s var(--ease);
}

[data-reveal].reveal-armed {
  opacity: 0;
  transform: translateY(12px);
}

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

/* ---------- 11. 响应式 ---------- */
@media (min-width: 861px) {
  .grid--12 {
    grid-template-columns: repeat(12, minmax(0, 1fr));
  }

  .col-3 { grid-column: span 3; }
  .col-4 { grid-column: span 4; }
  .col-5 { grid-column: span 5; }
  .col-6 { grid-column: span 6; }
  .col-7 { grid-column: span 7; }
  .col-8 { grid-column: span 8; }
  .col-12 { grid-column: span 12; }

  .split {
    grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
  }

  .split--even {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 1180px) and (min-width: 861px) {
  .nav__link {
    padding: 12px 8px 22px;
  }

  .nav__label {
    font-size: 13.5px;
  }

  .nav__idx {
    font-size: 8.5px;
  }

  .brand__sub {
    display: none;
  }

  .btn {
    padding: 9px 14px;
    font-size: 13px;
  }

  .header-inner {
    gap: 14px;
  }
}

@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 32px;
  }

  .footer-col--brand,
  .footer-col--shelf {
    grid-column: span 1;
  }
}

@media (max-width: 860px) {
  body {
    padding-bottom: 72px;
  }

  .header-inner {
    grid-template-columns: minmax(0, 1fr) auto auto;
    min-height: 62px;
    gap: 10px;
  }

  .brand__name {
    font-size: 20px;
  }

  .brand__sub {
    font-size: 9px;
    letter-spacing: 0.12em;
  }

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

  .header-actions .btn--ghost {
    display: none;
  }

  .header-actions .btn {
    padding: 8px 12px;
    font-size: 13px;
  }

  /* 底部固定刻度条 */
  .nav {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    top: auto;
    z-index: 90;
    justify-self: stretch;
    background: var(--night);
    color: var(--paper);
    border-top: 1px solid var(--autumn);
    padding-bottom: env(safe-area-inset-bottom, 0);
    transition: box-shadow 0.2s var(--ease);
  }

  .nav__list {
    display: flex;
    align-items: stretch;
    overflow-x: auto;
    overscroll-behavior-x: contain;
    scrollbar-width: thin;
    padding-inline: 4px;
    background: var(--night);
  }

  .nav__item {
    flex: 0 0 auto;
    border-left: 1px solid rgba(245, 241, 232, 0.14);
  }

  .nav__item:last-child {
    border-right: 1px solid rgba(245, 241, 232, 0.14);
  }

  .nav__link {
    padding: 9px 14px 11px;
    min-width: 86px;
    color: var(--paper);
  }

  .nav__idx {
    font-size: 8.5px;
    letter-spacing: 0.12em;
    color: var(--autumn);
  }

  .nav__label {
    font-size: 13px;
    white-space: nowrap;
  }

  .nav__link::before {
    background: var(--autumn);
  }

  .nav__link::after {
    display: none;
  }

  .nav__link:hover .nav__idx,
  .nav__link:focus-visible .nav__idx {
    color: var(--paper);
  }

  .nav__mark {
    bottom: 3px;
    height: 2px;
  }

  /* 展开态：两列索引面板 */
  .nav[data-open] {
    box-shadow: 0 -18px 42px rgba(22, 33, 43, 0.4);
  }

  .nav[data-open] .nav__list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 0;
    overflow: visible;
    max-height: 62vh;
    overflow-y: auto;
    padding: 4px 8px 10px;
  }

  .nav[data-open] .nav__item {
    border-left: 0;
    border-right: 0;
    border-top: 1px solid rgba(245, 241, 232, 0.13);
  }

  .nav[data-open] .nav__item:first-child,
  .nav[data-open] .nav__item:nth-child(2) {
    border-top: 0;
  }

  .nav[data-open] .nav__link {
    min-width: 0;
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-items: start;
    gap: 8px;
    padding: 13px 10px;
    text-align: left;
  }

  .nav[data-open] .nav__label {
    font-size: 14px;
    font-weight: 700;
  }

  .nav[data-open] .nav__link::after {
    display: block;
    position: static;
    flex: 1 0 100%;
    transform: none;
    opacity: 1;
    padding: 0;
    background: none;
    color: rgba(245, 241, 232, 0.58);
    font-size: 11.5px;
    line-height: 1.5;
    white-space: normal;
  }

  .nav[data-open] .nav__mark {
    display: none !important;
  }

  .nav[data-open] .nav__link[aria-current="page"] .nav__label {
    text-decoration: underline;
    text-decoration-color: var(--autumn);
    text-decoration-thickness: 2px;
    text-underline-offset: 5px;
  }

  body:has(.nav[data-open]) {
    overflow: hidden;
  }

  .footer-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 30px;
    padding-bottom: 40px;
  }

  .footer-col--shelf {
    padding: 16px 16px 10px;
  }

  .footer-bottom__inner {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
  }

  .accordion__trigger {
    gap: 10px;
    padding: 15px 0;
  }

  .accordion__body {
    padding-left: 0;
  }

  .index-item > a {
    grid-template-columns: auto 1fr;
    gap: 10px;
  }

  .index-item__meta {
    grid-column: 2;
  }
}

@media (max-width: 520px) {
  body {
    font-size: 16px;
  }

  .brand__sub {
    display: none;
  }

  .nav__link {
    min-width: 78px;
    padding: 8px 11px 10px;
  }

  .nav__label {
    font-size: 12.5px;
  }

  .nav[data-open] .nav__list {
    grid-template-columns: minmax(0, 1fr);
  }

  .footer-brand__mark {
    font-size: 23px;
  }

  .contact-line {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
  }
}

/* ---------- 12. 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }

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

  [data-stagger] > * {
    transition: none;
  }
}