/* ==========================================================================
   Seekr · 北京红线科技有限公司 — 全站设计系统
   配色：墨色 + 象牙白 + 一线朱红（红线的红）
   ========================================================================== */

/* ---------- 1. Design Tokens ---------- */
:root {
  /* 墨 */
  --ink: #14110f;
  --ink-2: #211c19;
  --ink-3: #332c27;
  /* 纸 */
  --ivory: #f8f5f0;
  --ivory-2: #f1ece4;
  --paper: #ffffff;
  /* 朱红 —— 品牌主色 */
  --crimson: #9c2b22;
  --crimson-deep: #7d1f18;
  --crimson-soft: rgba(156, 43, 34, 0.08);
  /* 金 —— 辅助点缀 */
  --gold: #b08d57;
  --gold-soft: rgba(176, 141, 87, 0.14);
  /* 文字 */
  --text: #1c1917;
  --text-2: #4a423b;
  --text-3: #7a7168;
  --text-inverse: #f5f1ea;
  --text-inverse-2: rgba(245, 241, 234, 0.66);
  /* 线 */
  --line: rgba(20, 17, 15, 0.1);
  --line-2: rgba(20, 17, 15, 0.16);
  --line-inverse: rgba(245, 241, 234, 0.14);

  /* 字体 */
  --font-display: "Songti SC", "STSong", "Noto Serif SC", "Source Han Serif SC",
    "SimSun", "Times New Roman", serif;
  --font-sans: "PingFang SC", "HarmonyOS Sans SC", "Hiragino Sans GB",
    "Microsoft YaHei", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "SF Mono", "JetBrains Mono", "Menlo", "Consolas", monospace;

  /* 尺度 */
  --max: 1200px;
  --max-narrow: 780px;
  --gutter: clamp(20px, 5vw, 56px);
  --section-y: clamp(72px, 9vw, 132px);
  --radius: 2px;
  --radius-lg: 4px;

  --shadow-1: 0 1px 2px rgba(20, 17, 15, 0.04), 0 8px 24px rgba(20, 17, 15, 0.05);
  --shadow-2: 0 2px 6px rgba(20, 17, 15, 0.06), 0 20px 48px rgba(20, 17, 15, 0.09);

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur: 0.6s;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 92px;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.85;
  color: var(--text);
  background: var(--ivory);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

body.no-scroll {
  overflow: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.25s var(--ease), opacity 0.25s var(--ease);
}

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

h1,
h2,
h3,
h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.28;
  letter-spacing: 0.01em;
  margin: 0;
  text-wrap: balance;
}

p {
  margin: 0;
}

ul,
ol {
  margin: 0;
  padding: 0;
}

::selection {
  background: var(--crimson);
  color: #fff;
}

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

/* ---------- 3. Layout ---------- */
.wrap {
  width: 100%;
  max-width: var(--max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.wrap--narrow {
  max-width: var(--max-narrow);
}

.section {
  padding-block: var(--section-y);
  position: relative;
}

.section--tight {
  padding-block: clamp(56px, 6vw, 84px);
}

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

.section--ink {
  background: var(--ink);
  color: var(--text-inverse);
}

.section--ivory {
  background: var(--ivory-2);
}

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

/* ---------- 4. Typography helpers ---------- */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--crimson);
  margin-bottom: 20px;
}

.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: var(--crimson);
  flex: none;
}

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

.section--ink .eyebrow::before {
  background: var(--gold);
}

.display-1 {
  font-size: clamp(2.55rem, 6.2vw, 4.6rem);
  line-height: 1.16;
  letter-spacing: 0.005em;
}

.display-2 {
  font-size: clamp(1.9rem, 3.7vw, 2.75rem);
  line-height: 1.26;
}

.display-3 {
  font-size: clamp(1.35rem, 2.3vw, 1.7rem);
  line-height: 1.44;
}

.lede {
  font-size: clamp(1rem, 1.28vw, 1.125rem);
  line-height: 1.95;
  color: var(--text-2);
  max-width: 62ch;
}

.section--ink .lede {
  color: var(--text-inverse-2);
}

.muted {
  color: var(--text-3);
}

.accent {
  color: var(--crimson);
}

.rule-short {
  width: 44px;
  height: 2px;
  background: var(--crimson);
  border: 0;
  margin: 28px 0;
}

.section--ink .rule-short {
  background: var(--gold);
}

/* ---------- 5. Header / Nav ---------- */
.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 90;
  background: transparent;
  transition: background 0.45s var(--ease), box-shadow 0.45s var(--ease),
    border-color 0.45s var(--ease);
  border-bottom: 1px solid transparent;
}

.site-header.is-scrolled,
.site-header.is-solid {
  background: rgba(248, 245, 240, 0.92);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom-color: var(--line);
  box-shadow: 0 1px 0 rgba(20, 17, 15, 0.02);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  height: 78px;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 10px;
  flex: none;
}

.brand__mark {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--text-inverse);
  transition: color 0.45s var(--ease);
}

.brand__cn {
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  color: var(--text-inverse-2);
  transition: color 0.45s var(--ease);
}

.site-header.is-scrolled .brand__mark,
.site-header.is-solid .brand__mark {
  color: var(--ink);
}

.site-header.is-scrolled .brand__cn,
.site-header.is-solid .brand__cn {
  color: var(--text-3);
}

.brand__dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--crimson);
  display: inline-block;
  margin-bottom: 1px;
}

.nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav a {
  position: relative;
  padding: 10px 16px;
  font-size: 0.94rem;
  letter-spacing: 0.06em;
  color: var(--text-inverse-2);
  transition: color 0.3s var(--ease);
}

.nav a::after {
  content: "";
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 4px;
  height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.4s var(--ease);
}

.nav a:hover::after,
.nav a[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav a:hover,
.nav a[aria-current="page"] {
  color: var(--text-inverse);
}

.site-header.is-scrolled .nav a,
.site-header.is-solid .nav a {
  color: var(--text-2);
}

.site-header.is-scrolled .nav a:hover,
.site-header.is-scrolled .nav a[aria-current="page"],
.site-header.is-solid .nav a:hover,
.site-header.is-solid .nav a[aria-current="page"] {
  color: var(--ink);
}

.header-cta {
  flex: none;
}

.nav-toggle {
  display: none;
  width: 42px;
  height: 42px;
  background: none;
  border: 1px solid var(--line-inverse);
  border-radius: var(--radius);
  cursor: pointer;
  position: relative;
}

.site-header.is-scrolled .nav-toggle,
.site-header.is-solid .nav-toggle {
  border-color: var(--line-2);
}

.nav-toggle span,
.nav-toggle span::before,
.nav-toggle span::after {
  position: absolute;
  left: 50%;
  width: 18px;
  height: 1px;
  background: var(--text-inverse);
  transform: translateX(-50%);
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease),
    background 0.3s var(--ease);
}

.nav-toggle span {
  top: 50%;
  margin-top: -0.5px;
}

.nav-toggle span::before,
.nav-toggle span::after {
  content: "";
  left: 0;
  transform: none;
}

.nav-toggle span::before {
  top: -6px;
}

.nav-toggle span::after {
  top: 6px;
}

.site-header.is-scrolled .nav-toggle span,
.site-header.is-scrolled .nav-toggle span::before,
.site-header.is-scrolled .nav-toggle span::after,
.site-header.is-solid .nav-toggle span,
.site-header.is-solid .nav-toggle span::before,
.site-header.is-solid .nav-toggle span::after {
  background: var(--ink);
}

.nav-toggle[aria-expanded="true"] span {
  background: transparent !important;
}

.nav-toggle[aria-expanded="true"] span::before {
  transform: translateY(6px) rotate(45deg);
  background: var(--ink);
}

.nav-toggle[aria-expanded="true"] span::after {
  transform: translateY(-6px) rotate(-45deg);
  background: var(--ink);
}

/* ---------- 6. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 30px;
  font-size: 0.92rem;
  letter-spacing: 0.1em;
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.35s var(--ease), color 0.35s var(--ease),
    border-color 0.35s var(--ease), transform 0.35s var(--ease);
}

.btn:active {
  transform: translateY(1px);
}

.btn--primary {
  background: var(--crimson);
  color: #fff;
}

.btn--primary:hover {
  background: var(--crimson-deep);
  color: #fff;
}

.btn--ghost {
  border-color: var(--line-inverse);
  color: var(--text-inverse);
}

.btn--ghost:hover {
  border-color: var(--text-inverse);
  background: rgba(245, 241, 234, 0.07);
}

.btn--outline {
  border-color: var(--line-2);
  color: var(--ink);
}

.btn--outline:hover {
  background: var(--ink);
  color: var(--ivory);
  border-color: var(--ink);
}

.btn--sm {
  padding: 10px 20px;
  font-size: 0.84rem;
}

.link-arrow {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 0.9rem;
  letter-spacing: 0.08em;
  color: var(--crimson);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
}

.link-arrow svg {
  transition: transform 0.35s var(--ease);
}

.link-arrow:hover {
  border-bottom-color: var(--crimson);
}

.link-arrow:hover svg {
  transform: translateX(4px);
}

/* ---------- 7. Hero ---------- */
.hero {
  position: relative;
  min-height: 92vh;
  display: flex;
  align-items: center;
  background: var(--ink);
  color: var(--text-inverse);
  overflow: hidden;
  padding-block: 140px 96px;
}

.hero__media {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero__media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.5;
  transform: scale(1.04);
  animation: heroDrift 22s var(--ease) forwards;
}

@keyframes heroDrift {
  to {
    transform: scale(1);
  }
}

.hero__media::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(
      105deg,
      rgba(20, 17, 15, 0.94) 0%,
      rgba(20, 17, 15, 0.82) 42%,
      rgba(20, 17, 15, 0.42) 100%
    ),
    radial-gradient(120% 80% at 80% 100%, rgba(156, 43, 34, 0.22), transparent 62%);
}

.hero__inner {
  position: relative;
  z-index: 1;
  width: 100%;
}

.hero__title {
  max-width: 17ch;
}

.hero__title em {
  font-style: normal;
  color: var(--gold);
}

.hero__sub {
  margin-top: 30px;
  max-width: 50ch;
  font-size: clamp(1rem, 1.35vw, 1.14rem);
  line-height: 2;
  color: var(--text-inverse-2);
}

.hero__actions {
  margin-top: 44px;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.hero__meta {
  margin-top: 76px;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border-top: 1px solid var(--line-inverse);
  border-bottom: 1px solid var(--line-inverse);
  max-width: 860px;
}

.hero__meta > div {
  padding: 26px 24px;
  border-left: 1px solid var(--line-inverse);
}

.hero__meta > div:first-child {
  border-left: 0;
  padding-left: 0;
}

.hero__meta dt {
  font-family: var(--font-display);
  font-size: 1.7rem;
  color: var(--text-inverse);
  line-height: 1.2;
  letter-spacing: 0.02em;
}

.hero__meta dd {
  margin: 10px 0 0;
  font-size: 0.84rem;
  letter-spacing: 0.08em;
  color: rgba(245, 241, 234, 0.5);
}

.scroll-hint {
  position: absolute;
  left: 50%;
  bottom: 30px;
  transform: translateX(-50%);
  z-index: 2;
  width: 1px;
  height: 52px;
  background: linear-gradient(to bottom, transparent, var(--line-inverse));
  overflow: hidden;
}

.scroll-hint::after {
  content: "";
  position: absolute;
  top: -52px;
  left: 0;
  width: 1px;
  height: 52px;
  background: linear-gradient(to bottom, transparent, var(--gold));
  animation: scrollLine 2.6s ease-in-out infinite;
}

@keyframes scrollLine {
  0% {
    top: -52px;
  }
  60%,
  100% {
    top: 52px;
  }
}

/* ---------- 8. Page hero (内页) ---------- */
.page-hero {
  background: var(--ink);
  color: var(--text-inverse);
  padding: 168px 0 88px;
  position: relative;
  overflow: hidden;
}

.page-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(
    58% 88% at 96% -12%,
    rgba(156, 43, 34, 0.2),
    transparent 55%
  );
  pointer-events: none;
}

.page-hero__inner {
  position: relative;
  z-index: 1;
}

.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  color: rgba(245, 241, 234, 0.42);
  margin-bottom: 26px;
}

.crumbs a:hover {
  color: var(--text-inverse);
}

.crumbs span[aria-hidden] {
  opacity: 0.5;
}

/* ---------- 9. Grids & cards ---------- */
.grid {
  display: grid;
  gap: 28px;
}

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

.grid--3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

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

.grid--sidebar {
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 64px;
  align-items: start;
}

.grid--article {
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 64px;
  align-items: start;
}

.split {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: clamp(36px, 6vw, 88px);
  align-items: center;
}

.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--ivory-2);
}

.media-frame img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  transition: transform 1.2s var(--ease);
}

.media-frame:hover img {
  transform: scale(1.035);
}

.media-frame--tall img {
  aspect-ratio: 3 / 4;
}

.figure-caption {
  margin-top: 14px;
  font-size: 0.8rem;
  color: var(--text-3);
  letter-spacing: 0.04em;
}

/* 圈层卡 */
.tier {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 38px 32px 34px;
  position: relative;
  overflow: hidden;
  transition: transform 0.5s var(--ease), box-shadow 0.5s var(--ease),
    border-color 0.5s var(--ease);
}

.tier::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: linear-gradient(90deg, var(--crimson), var(--gold));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.6s var(--ease);
}

.tier:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-2);
  border-color: var(--line-2);
}

.tier:hover::before {
  transform: scaleX(1);
}

.tier__no {
  font-family: var(--font-display);
  font-size: 0.86rem;
  letter-spacing: 0.18em;
  color: var(--gold);
  margin-bottom: 22px;
  display: block;
}

.tier__title {
  font-size: 1.28rem;
  margin-bottom: 14px;
}

.tier__desc {
  font-size: 0.93rem;
  line-height: 1.9;
  color: var(--text-2);
}

/* 流程步骤 */
.steps {
  counter-reset: step;
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.step {
  counter-increment: step;
  background: var(--ivory);
  padding: 34px 24px 38px;
  position: relative;
}

.section--paper .step {
  background: var(--paper);
}

.step::before {
  content: "0" counter(step);
  font-family: var(--font-display);
  font-size: 0.82rem;
  letter-spacing: 0.16em;
  color: var(--crimson);
  display: block;
  margin-bottom: 18px;
}

.step h3 {
  font-size: 1.02rem;
  margin-bottom: 10px;
}

.step p {
  font-size: 0.86rem;
  line-height: 1.85;
  color: var(--text-3);
}

/* 价值观/特性列表 */
.feature-list {
  list-style: none;
  display: grid;
  gap: 22px;
}

.feature-list li {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 18px;
  align-items: start;
}

.feature-list .ico {
  width: 38px;
  height: 38px;
  border: 1px solid var(--line-2);
  border-radius: 50%;
  display: grid;
  place-items: center;
  color: var(--crimson);
  flex: none;
}

.section--ink .feature-list .ico {
  border-color: var(--line-inverse);
  color: var(--gold);
}

.feature-list h3 {
  font-size: 1.05rem;
  margin-bottom: 6px;
}

.feature-list p {
  font-size: 0.9rem;
  line-height: 1.88;
  color: var(--text-2);
}

.section--ink .feature-list p {
  color: var(--text-inverse-2);
}

/* ---------- 10. Article cards ---------- */
.post-card {
  display: flex;
  flex-direction: column;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  height: 100%;
  transition: transform 0.5s var(--ease), box-shadow 0.5s var(--ease),
    border-color 0.5s var(--ease);
}

.post-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-2);
  border-color: var(--line-2);
}

.post-card__media {
  overflow: hidden;
  background: var(--ivory-2);
}

.post-card__media img {
  width: 100%;
  aspect-ratio: 16 / 10;
  object-fit: cover;
  transition: transform 1.2s var(--ease);
}

.post-card:hover .post-card__media img {
  transform: scale(1.05);
}

.post-card__body {
  padding: 26px 26px 28px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

.post-card__meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-size: 0.76rem;
  letter-spacing: 0.1em;
  color: var(--text-3);
  margin-bottom: 14px;
}

.tag {
  display: inline-block;
  padding: 3px 10px;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--crimson);
  background: var(--crimson-soft);
  border-radius: 999px;
}

.post-card__title {
  font-size: 1.16rem;
  line-height: 1.5;
  margin-bottom: 12px;
}

.post-card:hover .post-card__title {
  color: var(--crimson);
}

.post-card__excerpt {
  font-size: 0.9rem;
  line-height: 1.88;
  color: var(--text-2);
  flex: 1;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.post-card__foot {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  color: var(--text-3);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* 列表型（侧栏热门） */
.post-mini {
  display: grid;
  grid-template-columns: 74px 1fr;
  gap: 16px;
  align-items: start;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.post-mini:last-child {
  border-bottom: 0;
}

.post-mini img {
  width: 74px;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: var(--radius);
}

.post-mini h4 {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1.6;
  margin-bottom: 6px;
}

.post-mini:hover h4 {
  color: var(--crimson);
}

.post-mini time {
  font-size: 0.75rem;
  color: var(--text-3);
  letter-spacing: 0.06em;
}

/* 精选首篇 */
.post-feature {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 0;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.post-feature__media img {
  width: 100%;
  height: 100%;
  min-height: 340px;
  object-fit: cover;
}

.post-feature__body {
  padding: clamp(32px, 4vw, 56px);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

/* ---------- 11. Filter bar ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
  margin-bottom: 44px;
}

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.chip {
  padding: 8px 18px;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  color: var(--text-2);
  border: 1px solid transparent;
  border-radius: 999px;
  background: none;
  cursor: pointer;
  transition: all 0.3s var(--ease);
}

.chip:hover {
  color: var(--ink);
  border-color: var(--line-2);
}

.chip[aria-pressed="true"] {
  background: var(--ink);
  color: var(--ivory);
  border-color: var(--ink);
}

.search-box {
  display: flex;
  align-items: center;
  gap: 10px;
  border-bottom: 1px solid var(--line-2);
  padding-bottom: 8px;
  min-width: 220px;
}

.search-box input {
  border: 0;
  background: none;
  outline: none;
  width: 100%;
  font-size: 0.9rem;
}

.search-box input::placeholder {
  color: var(--text-3);
}

/* ---------- 12. Article body ---------- */
.article-head {
  max-width: 780px;
}

.article-title {
  font-size: clamp(1.9rem, 3.6vw, 2.7rem);
  line-height: 1.32;
  margin-bottom: 24px;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  font-size: 0.82rem;
  letter-spacing: 0.08em;
  color: rgba(245, 241, 234, 0.55);
}

.article-body {
  max-width: 748px;
  font-size: 1.02rem;
  line-height: 2.05;
  color: var(--text-2);
}

.article-body > * + * {
  margin-top: 1.5em;
}

.article-body h2 {
  font-size: 1.5rem;
  color: var(--ink);
  margin-top: 2.6em;
  padding-top: 1.1em;
  border-top: 1px solid var(--line);
  scroll-margin-top: 100px;
}

.article-body h3 {
  font-size: 1.16rem;
  color: var(--ink);
  margin-top: 2em;
  scroll-margin-top: 100px;
}

.article-body h2 + *,
.article-body h3 + * {
  margin-top: 0.85em;
}

.article-body strong {
  color: var(--ink);
  font-weight: 600;
}

.article-body a {
  color: var(--crimson);
  border-bottom: 1px solid rgba(156, 43, 34, 0.3);
}

.article-body a:hover {
  border-bottom-color: var(--crimson);
}

.article-body ul,
.article-body ol {
  padding-left: 1.35em;
}

.article-body li + li {
  margin-top: 0.6em;
}

.article-body li::marker {
  color: var(--crimson);
}

.article-body blockquote {
  margin-inline: 0;
  padding: 4px 0 4px 26px;
  border-left: 2px solid var(--crimson);
  font-family: var(--font-display);
  font-size: 1.12rem;
  line-height: 1.9;
  color: var(--ink);
}

.article-body blockquote p {
  margin: 0;
}

.article-body img {
  border-radius: var(--radius-lg);
  margin-inline: auto;
}

.article-body figure {
  margin: 2.2em 0;
}

.article-body figcaption {
  margin-top: 12px;
  text-align: center;
  font-size: 0.82rem;
  color: var(--text-3);
}

.article-body code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--ivory-2);
  padding: 2px 6px;
  border-radius: 3px;
}

.article-body pre {
  background: var(--ink);
  color: var(--text-inverse);
  padding: 22px 24px;
  border-radius: var(--radius-lg);
  overflow-x: auto;
  font-size: 0.86rem;
  line-height: 1.75;
}

.article-body pre code {
  background: none;
  padding: 0;
  color: inherit;
}

.article-body table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

.article-body th,
.article-body td {
  border-bottom: 1px solid var(--line);
  padding: 13px 14px;
  text-align: left;
}

.article-body th {
  background: var(--ivory-2);
  font-weight: 600;
  color: var(--ink);
}

.article-body hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin-block: 2.6em;
}

/* 目录 */
.toc {
  position: sticky;
  top: 104px;
  font-size: 0.86rem;
}

.toc h4 {
  font-family: var(--font-sans);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 16px;
}

.toc ol {
  list-style: none;
  border-left: 1px solid var(--line);
}

.toc li a {
  display: block;
  padding: 7px 0 7px 16px;
  margin-left: -1px;
  border-left: 1px solid transparent;
  color: var(--text-3);
  line-height: 1.6;
}

.toc li a:hover,
.toc li a.is-active {
  color: var(--crimson);
  border-left-color: var(--crimson);
}

/* 分享 */
.share-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px;
  margin-top: 56px;
  padding-top: 28px;
  border-top: 1px solid var(--line);
}

.share-row button {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-2);
  background: none;
  border-radius: 50%;
  cursor: pointer;
  color: var(--text-2);
  transition: all 0.3s var(--ease);
}

.share-row button:hover {
  background: var(--ink);
  color: var(--ivory);
  border-color: var(--ink);
}

/* 上下篇 */
.post-nav {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  margin-top: 48px;
}

.post-nav a {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  padding: 22px 24px;
  background: var(--paper);
  transition: border-color 0.4s var(--ease), transform 0.4s var(--ease);
}

.post-nav a:hover {
  border-color: var(--line-2);
  transform: translateY(-2px);
}

.post-nav span {
  display: block;
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  color: var(--text-3);
  margin-bottom: 8px;
}

.post-nav strong {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1rem;
  line-height: 1.55;
}

.post-nav .is-next {
  text-align: right;
}

/* ---------- 13. Forms ---------- */
.form-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.field--full {
  grid-column: 1 / -1;
}

.field label {
  font-size: 0.82rem;
  letter-spacing: 0.1em;
  color: var(--text-2);
}

.field label .req {
  color: var(--crimson);
  margin-left: 4px;
}

.field input,
.field select,
.field textarea {
  width: 100%;
  padding: 13px 15px;
  border: 1px solid var(--line-2);
  border-radius: var(--radius);
  background: var(--paper);
  font-size: 0.94rem;
  line-height: 1.6;
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
  outline: none;
}

.field textarea {
  min-height: 132px;
  resize: vertical;
}

.field input:focus,
.field select:focus,
.field textarea:focus {
  border-color: var(--crimson);
  box-shadow: 0 0 0 3px var(--crimson-soft);
}

.field .hint {
  font-size: 0.78rem;
  color: var(--text-3);
}

.form-note {
  font-size: 0.8rem;
  line-height: 1.8;
  color: var(--text-3);
}

.form-status {
  margin-top: 18px;
  font-size: 0.88rem;
  display: none;
  padding: 14px 18px;
  border-radius: var(--radius);
}

.form-status.is-ok {
  display: block;
  background: rgba(31, 122, 72, 0.08);
  color: #1c6b41;
  border: 1px solid rgba(31, 122, 72, 0.2);
}

.form-status.is-err {
  display: block;
  background: var(--crimson-soft);
  color: var(--crimson-deep);
  border: 1px solid rgba(156, 43, 34, 0.22);
}

/* ---------- 14. Contact info ---------- */
.info-list {
  list-style: none;
  display: grid;
  gap: 0;
}

.info-list li {
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
  display: grid;
  grid-template-columns: 108px 1fr;
  gap: 18px;
  align-items: baseline;
}

.info-list dt,
.info-list .k {
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--text-3);
}

.info-list .v {
  font-size: 0.98rem;
  color: var(--text);
  line-height: 1.8;
}

.info-list .v a:hover {
  color: var(--crimson);
}

/* FAQ */
.faq {
  border-top: 1px solid var(--line);
}

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

.faq summary {
  cursor: pointer;
  padding: 24px 44px 24px 0;
  font-family: var(--font-display);
  font-size: 1.08rem;
  font-weight: 600;
  position: relative;
  list-style: none;
  color: var(--ink);
}

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

.faq summary::after {
  content: "";
  position: absolute;
  right: 8px;
  top: 50%;
  width: 11px;
  height: 11px;
  border-right: 1px solid var(--crimson);
  border-bottom: 1px solid var(--crimson);
  transform: translateY(-70%) rotate(45deg);
  transition: transform 0.35s var(--ease);
}

.faq details[open] summary::after {
  transform: translateY(-30%) rotate(-135deg);
}

.faq .faq__body {
  padding: 0 44px 26px 0;
  font-size: 0.94rem;
  line-height: 1.95;
  color: var(--text-2);
}

/* ---------- 15. CTA band ---------- */
.cta-band {
  background: var(--ink);
  color: var(--text-inverse);
  position: relative;
  overflow: hidden;
}

.cta-band::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(
    70% 130% at 82% 50%,
    rgba(156, 43, 34, 0.28),
    transparent 60%
  );
}

.cta-band .wrap {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1.4fr auto;
  gap: 40px;
  align-items: center;
}

/* ---------- 16. Footer ---------- */
.site-footer {
  background: var(--ink-2);
  color: var(--text-inverse-2);
  padding: 72px 0 34px;
  font-size: 0.88rem;
}

.footer-top {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1fr 1.2fr;
  gap: 40px;
  padding-bottom: 52px;
  border-bottom: 1px solid var(--line-inverse);
}

.footer-brand .brand__mark {
  color: var(--text-inverse);
  font-size: 1.4rem;
}

.footer-brand .brand__cn {
  color: rgba(245, 241, 234, 0.5);
}

.footer-about {
  margin-top: 20px;
  max-width: 40ch;
  line-height: 1.95;
  font-size: 0.86rem;
  color: rgba(245, 241, 234, 0.5);
}

.footer-col h4 {
  font-family: var(--font-sans);
  font-size: 0.76rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: rgba(245, 241, 234, 0.42);
  margin-bottom: 20px;
}

.footer-col ul {
  list-style: none;
  display: grid;
  gap: 12px;
}

.footer-col a {
  font-size: 0.9rem;
}

.footer-col a:hover {
  color: var(--text-inverse);
}

.footer-col address {
  font-style: normal;
  line-height: 2;
  font-size: 0.88rem;
  color: rgba(245, 241, 234, 0.55);
}

.footer-bottom {
  padding-top: 28px;
  display: flex;
  flex-wrap: wrap;
  gap: 14px 28px;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: rgba(245, 241, 234, 0.4);
}

.footer-bottom nav {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
}

.footer-bottom a:hover {
  color: var(--text-inverse);
}

.footer-filing {
  margin-top: 20px;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: rgba(245, 241, 234, 0.42);
}

.footer-filing a {
  color: rgba(245, 241, 234, 0.56);
  border-bottom: 1px solid rgba(245, 241, 234, 0.18);
  padding-bottom: 1px;
}

.footer-filing a:hover {
  color: var(--text-inverse);
  border-bottom-color: rgba(245, 241, 234, 0.5);
}

.footer-disclaimer {
  margin-top: 22px;
  font-size: 0.76rem;
  line-height: 1.9;
  color: rgba(245, 241, 234, 0.32);
  max-width: 96ch;
}

/* ---------- 16.5 Sidebar blocks ---------- */
.sidebar {
  display: grid;
  gap: 40px;
  position: sticky;
  top: 104px;
}

.sidebar-block {
  padding-bottom: 32px;
  border-bottom: 1px solid var(--line);
}

.sidebar-block:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.sidebar-block__title {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 20px;
}

.sidebar-block--cta {
  padding: 28px 24px;
  background: var(--ivory-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
}

.sidebar-block--cta .sidebar-block__title {
  color: var(--crimson);
}

@media (max-width: 1080px) {
  .sidebar {
    position: static;
  }
}

/* ---------- 17. Reveal animation ---------- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
  will-change: opacity, transform;
}

.reveal.is-in {
  opacity: 1;
  transform: none;
}

.reveal[data-delay="1"] {
  transition-delay: 0.09s;
}
.reveal[data-delay="2"] {
  transition-delay: 0.18s;
}
.reveal[data-delay="3"] {
  transition-delay: 0.27s;
}
.reveal[data-delay="4"] {
  transition-delay: 0.36s;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
  .hero__media img {
    animation: none;
    transform: none;
  }
  .scroll-hint {
    display: none;
  }
}

/* ---------- 18. Skeleton / empty ---------- */
.skeleton {
  background: linear-gradient(
    100deg,
    var(--ivory-2) 30%,
    rgba(255, 255, 255, 0.75) 50%,
    var(--ivory-2) 70%
  );
  background-size: 220% 100%;
  animation: shimmer 1.5s linear infinite;
  border-radius: var(--radius-lg);
}

@keyframes shimmer {
  to {
    background-position: -220% 0;
  }
}

.empty-state {
  padding: 72px 24px;
  text-align: center;
  color: var(--text-3);
  border: 1px dashed var(--line-2);
  border-radius: var(--radius-lg);
  font-size: 0.94rem;
}

/* ---------- 19. Breadcrumb / pagination ---------- */
.pager {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin-top: 56px;
}

.pager button,
.pager span {
  min-width: 40px;
  height: 40px;
  padding: 0 12px;
  display: inline-grid;
  place-items: center;
  border: 1px solid var(--line-2);
  border-radius: var(--radius);
  background: none;
  font-size: 0.88rem;
  cursor: pointer;
  transition: all 0.3s var(--ease);
}

.pager button:hover:not(:disabled) {
  border-color: var(--ink);
  background: var(--ink);
  color: var(--ivory);
}

.pager button:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

.pager .is-current {
  background: var(--ink);
  color: var(--ivory);
  border-color: var(--ink);
}

/* ---------- 20. Back to top ---------- */
.to-top {
  position: fixed;
  right: 22px;
  bottom: 24px;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid var(--line-2);
  background: rgba(248, 245, 240, 0.9);
  backdrop-filter: blur(8px);
  color: var(--ink);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all 0.4s var(--ease);
  z-index: 80;
  box-shadow: var(--shadow-1);
}

.to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.to-top:hover {
  background: var(--ink);
  color: var(--ivory);
  border-color: var(--ink);
}

/* ---------- 21. Responsive ---------- */
@media (max-width: 1080px) {
  .grid--sidebar,
  .grid--article {
    grid-template-columns: minmax(0, 1fr);
    gap: 48px;
  }
  .toc {
    position: static;
  }
  .steps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .footer-top {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 36px;
  }
}

@media (max-width: 900px) {
  .nav {
    position: fixed;
    inset: 78px 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--ivory);
    border-bottom: 1px solid var(--line);
    padding: 12px var(--gutter) 28px;
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: all 0.35s var(--ease);
    box-shadow: var(--shadow-2);
    max-height: calc(100vh - 78px);
    overflow-y: auto;
  }
  .nav.is-open {
    transform: none;
    opacity: 1;
    visibility: visible;
  }
  .nav a {
    padding: 17px 4px;
    color: var(--text);
    border-bottom: 1px solid var(--line);
    font-size: 1rem;
  }
  .nav a::after {
    display: none;
  }
  .nav-toggle {
    display: block;
  }
  .header-cta {
    display: none;
  }
  .nav .nav-cta-mobile {
    margin-top: 20px;
    display: flex;
  }
}

@media (min-width: 901px) {
  .nav .nav-cta-mobile {
    display: none;
  }
}

@media (max-width: 860px) {
  .grid--2,
  .grid--3,
  .grid--4,
  .split,
  .form-grid,
  .post-feature,
  .post-nav,
  .cta-band .wrap {
    grid-template-columns: minmax(0, 1fr);
  }
  .post-feature__media img {
    min-height: 240px;
  }
  .hero__meta {
    grid-template-columns: minmax(0, 1fr);
  }
  .hero__meta > div {
    padding: 20px 0;
    border-left: 0;
    border-bottom: 1px solid var(--line-inverse);
  }
  .hero__meta > div:last-child {
    border-bottom: 0;
  }
  .post-nav .is-next {
    text-align: left;
  }
  .hero {
    min-height: auto;
    padding-block: 128px 72px;
  }
  .page-hero {
    padding: 132px 0 64px;
  }
  .info-list li {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }
}

@media (max-width: 560px) {
  .steps {
    grid-template-columns: minmax(0, 1fr);
  }
  .footer-top {
    grid-template-columns: minmax(0, 1fr);
  }
  .hero__actions .btn {
    flex: 1;
  }
  .section {
    padding-block: 64px;
  }
}

/* ---------- 22. Print ---------- */
@media print {
  .site-header,
  .to-top,
  .share-row,
  .cta-band,
  .hero__media {
    display: none !important;
  }
  body {
    background: #fff;
    font-size: 12pt;
  }
  .article-body {
    max-width: none;
  }
}