/* ============================================================
   知易丨环境科学研究中心 —— 东方手卷美学 × Apple 式流畅
   意象 · 深夜书房一盏暖灯 · 墨色留黑 · 细弱金丝 · 印章落款
   ============================================================ */

/* ---------- Design Tokens ---------- */
:root {
  /* 墨色系 */
  --ink: #0f0e0c;            /* 主底 */
  --ink-2: #14120f;          /* 次级暗面 */
  --ink-3: #191512;          /* 卡片 hover 微亮 */
  --line: rgba(232, 226, 214, 0.1);      /* 细分隔线 */
  --line-strong: rgba(232, 226, 214, 0.16);

  /* 缀色 */
  --gold: #c9ab7f;                    /* 暖金（偏暗，拒艳） */
  --gold-dim: rgba(201, 171, 127, 0.55);
  --gold-line: rgba(201, 171, 127, 0.26);
  --vermillion: #9c4632;              /* 印章朱砂（仅落款/印章） */

  /* 文字 */
  --paper: #e9e3d6;                    /* 米白正文 */
  --paper-dim: rgba(233, 227, 214, 0.6);
  --paper-faint: rgba(233, 227, 214, 0.34);

  /* 字体 */
  --serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", "STSong",
    "SimSun", serif;
  --sans: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", "Helvetica Neue", sans-serif;

  /* 间距 */
  --space: clamp(5.5rem, 11vw, 10rem);
  --container: 76rem;

  /* 动效 */
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --slow: 0.9s;
  --mid: 0.55s;
}

/* ---------- Base ---------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
}
body {
  background: var(--ink);
  color: var(--paper);
  font-family: var(--sans);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  text-rendering: optimizeLegibility;
}
::selection {
  background: var(--gold);
  color: var(--ink);
}

/* 全局：宣纸颗粒 */
.grain {
  position: fixed;
  inset: 0;
  z-index: 1;
  pointer-events: none;
  opacity: 0.55;
  background-image: radial-gradient(rgba(201, 171, 127, 0.028) 0.6px, transparent 0.6px);
  background-size: 4px 4px;
  mix-blend-mode: screen;
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(1.4rem, 5.5vw, 3.4rem);
  position: relative;
  z-index: 2;
}

/* ---------- 印章 ---------- */
.seal {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2.1rem;
  height: 2.1rem;
  border: 1px solid var(--gold);
  border-radius: 0.28rem;
  color: var(--gold);
  font-family: var(--serif);
  font-size: 1.05rem;
  line-height: 1;
}

/* 竖排小字 */
.v-text {
  writing-mode: vertical-rl;
  letter-spacing: 0.5em;
  font-family: var(--serif);
  color: var(--paper-faint);
  font-size: 0.78rem;
}

/* ---------- 滚动渐入 ---------- */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity var(--slow) var(--ease), transform var(--slow) var(--ease);
}
.reveal.is-visible {
  opacity: 1;
  transform: none;
}
.reveal[data-d] { transition-delay: 0.1s; }
.reveal[data-d="1"] { transition-delay: 0.15s; }
.reveal[data-d="2"] { transition-delay: 0.25s; }
.reveal[data-d="3"] { transition-delay: 0.35s; }

/* ---------- 导航 ---------- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 60;
  padding: 1.05rem 0;
  background: rgba(15, 14, 12, 0.66);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid transparent;
  transition: border-color 0.5s var(--ease), background 0.5s var(--ease);
}
.nav.is-scrolled {
  border-bottom-color: var(--line);
  background: rgba(15, 14, 12, 0.86);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  text-decoration: none;
  color: var(--paper);
}
.brand-name {
  font-family: var(--serif);
  letter-spacing: 0.34em;
  font-size: 1.02rem;
}
.nav-links {
  display: flex;
  gap: clamp(1rem, 3vw, 2.2rem);
}
.nav-links a {
  color: var(--paper-dim);
  text-decoration: none;
  font-size: 0.9rem;
  letter-spacing: 0.22em;
  position: relative;
  padding-bottom: 0.25rem;
  transition: color 0.35s var(--ease);
}
.nav-links a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: var(--gold);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.45s var(--ease);
}
.nav-links a:hover,
.nav-links a.is-active {
  color: var(--gold);
}
.nav-links a:hover::after {
  transform: scaleX(1);
}

/* 汉堡（移动端） */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.4rem;
  height: 2.4rem;
  background: transparent;
  border: none;
  cursor: pointer;
  z-index: 70;
}
.nav-toggle span {
  display: block;
  height: 1.5px;
  width: 100%;
  background: var(--gold);
  transition: transform 0.4s var(--ease), opacity 0.4s var(--ease);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6.5px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}
.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6.5px) rotate(-45deg);
}

/* ---------- Hero ---------- */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  position: relative;
  padding: 6rem 1.4rem 4rem;
}
/* 中央细金丝 */
.hero::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 0;
  bottom: 0;
  width: 1px;
  background: linear-gradient(180deg, transparent, var(--gold-line), transparent);
  opacity: 0.5;
}
/* 一轮淡金满月 · 纸上月华 */
.hero-moon {
  position: absolute;
  width: clamp(11rem, 24vw, 20rem);
  aspect-ratio: 1;
  right: clamp(-3rem, 6vw, 4rem);
  top: 8%;
  border-radius: 50%;
  border: 1px solid rgba(200, 169, 126, 0.5);
  box-shadow: 0 0 70px rgba(200, 169, 126, 0.22), inset 0 0 40px rgba(200, 169, 126, 0.12);
  background: radial-gradient(circle at 38% 34%, rgba(233,227,214,0.05), rgba(233,227,214,0.02) 46%, transparent 72%);
  opacity: 0.8;
  pointer-events: none;
  animation: moonDrift 14s ease-in-out infinite alternate;
}
.hero-moon::after {
  content: "";
  position: absolute;
  inset: 9%;
  border-radius: 50%;
  border: 1px solid rgba(200, 169, 126, 0.18);
}
@keyframes moonDrift {
  from { transform: translateY(0); }
  to { transform: translateY(-18px); }
}
@media (max-width: 700px) {
  .hero-moon { opacity: 0.38; right: -3rem; top: 6%; }
}

/* 极淡远山 · 一气连绵 */
.hero-horizon {
  position: absolute;
  left: 10%;
  right: 10%;
  bottom: clamp(2rem, 6vh, 4rem);
  height: 1px;
  pointer-events: none;
}
.hero-horizon::before,
.hero-horizon::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(200,169,126,0.35), transparent);
}
.hero-horizon::after {
  top: 12px;
  opacity: 0.4;
  transform: scaleX(0.7);
  background: linear-gradient(90deg, transparent, rgba(200,169,126,0.22) 30%, transparent 70%);
}
.hero-side {
  position: absolute;
  right: clamp(1rem, 4vw, 3rem);
  top: 50%;
  transform: translateY(-50%);
  opacity: 0;
}
@media (min-width: 900px) {
  .hero-side.is-visible { opacity: 1; }
}
.hero-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
}
.eyebrow {
  font-size: 0.72rem;
  letter-spacing: 0.6em;
  color: var(--paper-faint);
  margin-bottom: 2.6rem;
}
.hero-title {
  font-family: var(--serif);
  font-weight: 200;
  font-size: clamp(3.6rem, 14vw, 8.5rem);
  line-height: 1;
  letter-spacing: 0.24em;
  margin-left: 0.24em;
  color: var(--paper);
  position: relative;
}
.hero-sub {
  margin-top: 2.2rem;
  font-size: clamp(1rem, 2.4vw, 1.35rem);
  letter-spacing: 0.3em;
  color: var(--paper-dim);
  line-height: 2.2;
}
.hero-sub b {
  color: var(--gold);
  font-weight: 400;
  font-family: var(--serif);
}
.hero-motto {
  margin-top: 1.5rem;
  font-size: 0.88rem;
  letter-spacing: 0.24em;
  color: var(--paper-faint);
}
.hero-actions {
  margin-top: 3rem;
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
}
.hero-cta {
  display: inline-block;
  padding: 0.9rem 2.8rem;
  border: 1px solid var(--gold);
  color: var(--gold);
  text-decoration: none;
  letter-spacing: 0.3em;
  font-size: 0.9rem;
  transition: background 0.45s var(--ease), color 0.45s var(--ease),
    border-color 0.45s var(--ease);
}
.hero-cta:hover {
  background: var(--gold);
  color: var(--ink);
}
.hero-cta.ghost {
  background: transparent;
  color: var(--paper-dim);
  border-color: var(--line-strong);
}
.hero-cta.ghost:hover {
  color: var(--paper);
  border-color: var(--paper-dim);
  background: transparent;
}
/* 落款印章 */
.hero-seal {
  margin-top: 3.2rem;
  width: 3.4rem;
  height: 3.4rem;
  font-size: 0.98rem;
  border-radius: 0.34rem;
  letter-spacing: 0.16em;
  color: var(--vermillion);
  border-color: var(--vermillion);
  writing-mode: vertical-rl;
  padding: 0.4rem;
}
.hero-scroll {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  width: 1px;
  height: 3rem;
  background: var(--gold-line);
  animation: breathe 3s var(--ease) infinite;
}
@keyframes breathe {
  0%, 100% { transform: translateX(-50%) scaleY(0.5); opacity: 0.35; }
  50% { transform: translateX(-50%) scaleY(1); opacity: 0.9; }
}

/* ---------- Section 通用 ---------- */
.section {
  padding: var(--space) 0;
  position: relative;
}
.section + .section::before {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 68%;
  max-width: 60rem;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line-strong), transparent);
}
.section-head {
  margin-bottom: clamp(2.8rem, 6vw, 4.5rem);
  text-align: center;
}
.chapter {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  font-family: var(--serif);
  font-size: 0.72rem;
  letter-spacing: 0.6em;
  color: var(--gold-dim);
  margin-bottom: 1.6rem;
}
.chapter::before {
  content: "";
  width: 1.1rem;
  height: 1.1rem;
  border: 1px solid rgba(200, 169, 126, 0.5);
  transform: rotate(45deg);
  position: relative;
}
.chapter::before {
  box-shadow: inset 0 0 0 3px var(--ink-soft);
}
.section-title {
  font-family: var(--serif);
  font-weight: 300;
  font-size: clamp(1.9rem, 5vw, 3rem);
  line-height: 1.5;
  letter-spacing: 0.1em;
  color: var(--paper);
}
.section-title br { display: none; }
.section-title.two-line br { display: inline; }
.section-title.two-line { text-wrap: balance; }
@media (max-width: 440px) { .section-title.two-line { font-size: 1.5rem; } }
.section-lead {
  margin: 1.6rem auto 0;
  max-width: 40rem;
  color: var(--paper-dim);
  font-size: 0.98rem;
  letter-spacing: 0.06em;
}
.section-lead b { color: var(--paper); font-weight: 400; }

/* ---------- 卷壹 · 优势速览 ---------- */
.idea-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.2rem, 3vw, 2rem);
}
.idea {
  padding: clamp(1.8rem, 3.5vw, 2.4rem);
  border-top: 1px solid var(--gold-line);
  transition: transform 0.5s var(--ease), border-color 0.5s var(--ease);
}
.idea:hover {
  transform: translateY(-4px);
  border-top-color: var(--gold);
}
.idea-no {
  display: block;
  font-family: var(--serif);
  font-size: 0.9rem;
  letter-spacing: 0.3em;
  color: var(--gold);
  margin-bottom: 1.4rem;
}
.idea-title {
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--paper);
  margin-bottom: 1.1rem;
}
.idea-desc {
  color: var(--paper-dim);
  font-size: 0.94rem;
  line-height: 2;
}
.idea-backing {
  margin-top: clamp(3rem, 6vw, 4.5rem);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: clamp(2rem, 6vw, 4.5rem);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  padding: 2.2rem 0;
}
.digit {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}
.digit b {
  font-family: var(--serif);
  font-weight: 300;
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  color: var(--gold);
  letter-spacing: 0.04em;
}
.digit span {
  font-size: 0.78rem;
  letter-spacing: 0.3em;
  color: var(--paper-faint);
  white-space: nowrap;
}
.idea-mission {
  width: 100%;
  text-align: center;
  margin-top: 1rem;
  font-family: var(--serif);
  font-size: clamp(1.05rem, 2.4vw, 1.35rem);
  letter-spacing: 0.18em;
  color: var(--paper);
}
.idea-mission::before,
.idea-mission::after {
  content: "——";
  color: var(--gold-dim);
  margin: 0 0.7em;
  font-size: 0.8em;
  vertical-align: 0.2em;
}

/* ---------- 卷贰 · 核心团队 ---------- */
.team-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.2rem, 3vw, 2rem);
}
.card {
  background: linear-gradient(180deg, var(--ink-2), var(--ink));
  border: 1px solid var(--line);
  padding: clamp(1.7rem, 3vw, 2.2rem);
  display: flex;
  flex-direction: column;
  transition: transform 0.5s var(--ease), border-color 0.5s var(--ease),
    background 0.5s var(--ease);
}
.card:hover {
  transform: translateY(-5px);
  border-color: var(--gold-line);
  background: linear-gradient(180deg, var(--ink-3), var(--ink-2));
}
.card-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 1.6rem;
}
.role-tag {
  font-size: 0.74rem;
  letter-spacing: 0.4em;
  color: var(--gold);
  border: 1px solid var(--gold-line);
  border-radius: 2rem;
  padding: 0.3rem 0.95rem;
  white-space: nowrap;
}
.avatar {
  width: 6rem;
  height: 6rem;
  margin-left: 0.4rem;
  flex-shrink: 0;
  position: relative;
  border-radius: 50%;
  border: 1px solid var(--gold-line);
  overflow: hidden;
  background: var(--ink-soft);
  box-shadow: inset 0 0 0 1px rgba(232, 226, 214, 0.06), 0 1px 14px rgba(0, 0, 0, 0.5);
}
.avatar::after {
  content: "";
  position: absolute;
  inset: 5px;
  border-radius: 50%;
  border: 1px solid rgba(200, 169, 126, 0.35);
  pointer-events: none;
}
.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  display: block;
  border-radius: 50%;
}
.person-name {
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 400;
  letter-spacing: 0.18em;
  color: var(--gold);
}
.person-role {
  margin-top: 0.5rem;
  font-size: 0.82rem;
  letter-spacing: 0.14em;
  color: var(--paper-faint);
  padding-bottom: 1.2rem;
  border-bottom: 1px solid var(--line);
}
.person-bio {
  margin-top: 1.3rem;
  color: var(--paper-dim);
  font-size: 0.92rem;
  line-height: 2;
}
.cred-list {
  margin-top: auto;
  padding-top: 1.4rem;
  list-style: none;
  border-top: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}
.cred-list li {
  position: relative;
  padding-left: 1.1rem;
  color: var(--paper-faint);
  font-size: 0.86rem;
  line-height: 1.65;
}
.cred-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.66em;
  width: 0.32rem;
  height: 0.32rem;
  border-radius: 50%;
  background: var(--gold);
}

/* ---------- 卷叁 · 产品 / 闭环链路 ---------- */
.flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: clamp(1rem, 3vw, 2.2rem);
  margin-bottom: 3rem;
}
.flow span {
  font-family: var(--serif);
  font-size: clamp(1rem, 2.4vw, 1.4rem);
  letter-spacing: 0.2em;
  color: var(--paper);
}
.flow i {
  display: block;
  width: clamp(2rem, 6vw, 4rem);
  height: 1px;
  background: var(--gold-line);
  position: relative;
}
.flow i::after {
  content: "";
  position: absolute;
  right: 0;
  top: -2px;
  width: 5px;
  height: 5px;
  border-top: 1px solid var(--gold);
  border-right: 1px solid var(--gold);
  transform: rotate(45deg);
}
.service-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.2rem, 3vw, 2rem);
  align-items: stretch;
}
.service {
  background: linear-gradient(180deg, var(--ink-2), var(--ink));
  border: 1px solid var(--line);
  padding: clamp(1.7rem, 3vw, 2.3rem);
  display: flex;
  flex-direction: column;
  transition: transform 0.5s var(--ease), border-color 0.5s var(--ease);
}
.service:hover {
  transform: translateY(-5px);
  border-color: var(--gold-line);
}
.service-label {
  font-size: 0.72rem;
  letter-spacing: 0.5em;
  color: var(--gold-dim);
  margin-bottom: 1.2rem;
}
.service-title {
  font-family: var(--serif);
  font-size: 1.55rem;
  font-weight: 400;
  line-height: 1.55;
  letter-spacing: 0.1em;
  color: var(--paper);
}
.service-tagline {
  margin-top: 1rem;
  font-family: var(--serif);
  font-size: 0.98rem;
  letter-spacing: 0.16em;
  color: var(--gold);
}
.service-desc {
  margin-top: 1rem;
  color: var(--paper-dim);
  font-size: 0.92rem;
  line-height: 2;
  flex: 1;
}
.steps {
  margin-top: 1.6rem;
  list-style: none;
  border-top: 1px solid var(--line);
  padding-top: 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}
.steps li {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  color: var(--paper-dim);
  font-size: 0.9rem;
}
.steps li em { font-style: normal; letter-spacing: 0.1em; }
.steps li span {
  font-family: var(--serif);
  color: var(--gold);
  font-size: 0.8rem;
  letter-spacing: 0.2em;
}
.service-foot {
  margin-top: clamp(2.6rem, 5vw, 3.6rem);
  text-align: center;
  font-family: var(--serif);
  font-size: clamp(1.1rem, 2.4vw, 1.4rem);
  letter-spacing: 0.16em;
  color: var(--gold);
  position: relative;
  padding-top: 2rem;
}
.service-foot::before {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 1px;
  height: 2rem;
  background: var(--gold-line);
}

/* ---------- 卷肆 · 案例 ---------- */
.case-list {
  list-style: none;
  border-top: 1px solid var(--line);
  max-width: 60rem;
  margin: 0 auto;
  position: relative;
  padding-left: 1.6rem;
}
.case-list::before {
  content: "";
  position: absolute;
  left: 0;
  top: 1.2rem;
  bottom: 1.2rem;
  width: 1px;
  background: linear-gradient(180deg, rgba(200, 169, 126, 0.6), rgba(200, 169, 126, 0.08));
}
.case {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1.2fr 1.6fr;
  align-items: center;
  gap: clamp(1rem, 3vw, 2.4rem);
  padding: clamp(1.4rem, 2.5vw, 1.8rem) 0;
  border-bottom: 1px solid var(--line);
  transition: background 0.45s var(--ease);
}
.case::before {
  content: "";
  position: absolute;
  left: -1.62rem;
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
  width: 7px;
  height: 7px;
  background: var(--gold);
  box-shadow: 0 0 0 1px var(--ink-soft);
  border-radius: 1px;
}
.case:hover {
  background: linear-gradient(90deg, rgba(201, 171, 127, 0.05), transparent);
}
.case-tag {
  font-size: 0.74rem;
  letter-spacing: 0.3em;
  color: var(--paper-faint);
  white-space: nowrap;
}
.case-title {
  font-family: var(--serif);
  font-size: 1.3rem;
  font-weight: 400;
  letter-spacing: 0.14em;
  color: var(--paper);
  transition: color 0.3s var(--ease);
}
.case:hover .case-title { color: var(--gold); }
.case-desc {
  color: var(--paper-dim);
  font-size: 0.88rem;
  line-height: 1.9;
}

/* ---------- 卷伍 · 联系 ---------- */
.section-contact {
  background: linear-gradient(180deg, var(--ink-2), var(--ink));
}
.contact-grid {
  display: grid;
  grid-template-columns: 1.5fr 1fr;
  gap: clamp(2rem, 6vw, 4.5rem);
  align-items: start;
}
.contact-text > p {
  color: var(--paper-dim);
  font-size: 1rem;
  line-height: 2;
  max-width: 42rem;
}
.contact-links {
  margin-top: 1.8rem;
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.7rem;
}
.contact-links li {
  position: relative;
  padding-left: 1.2rem;
  font-family: var(--serif);
  letter-spacing: 0.12em;
  color: var(--paper);
}
.contact-links li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 0.4rem;
  height: 0.4rem;
  border-radius: 50%;
  background: var(--gold);
}
.faq {
  margin-top: 2.4rem;
  border-top: 1px solid var(--line);
  display: flex;
  flex-direction: column;
}
.faq-item {
  border-bottom: 1px solid var(--line);
}
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: 0.9rem 0;
  color: var(--paper);
  font-size: 0.95rem;
  letter-spacing: 0.06em;
  position: relative;
  transition: color 0.3s var(--ease);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 0.2rem;
  top: 0.75rem;
  color: var(--gold);
  font-size: 1.05rem;
  transition: transform 0.35s var(--ease);
}
.faq-item[open] summary { color: var(--gold); }
.faq-item[open] summary::after { transform: rotate(45deg); }
.faq-item summary:hover { color: var(--gold); }
.faq-item p {
  padding: 0 0 1rem;
  color: var(--paper-dim);
  font-size: 0.9rem;
  line-height: 1.9;
  max-width: 40rem;
}
.qr { text-align: center; }
.qr-box {
  position: relative;
  width: 100%;
  max-width: 14rem;
  aspect-ratio: 1;
  margin: 0 auto;
  padding: 0.55rem;
  border: 1px solid var(--gold);
  background: linear-gradient(160deg, #f5efe2, #e9e0cc);
  box-shadow: 0 18px 46px rgba(0, 0, 0, 0.45), 0 2px 10px rgba(0, 0, 0, 0.5);
}
/* 装裱回字框 */
.qr-box::before {
  content: "";
  position: absolute;
  inset: 0.4rem;
  border: 1px solid rgba(200, 169, 126, 0.6);
  pointer-events: none;
}
.qr-box img {
  position: relative;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  background: #fff;
  border-radius: 2px;
}
.qr-hint {
  margin-top: 0.9rem;
  font-size: 0.7rem;
  color: var(--paper-faint);
  letter-spacing: 0.3em;
}
.qr-caption {
  margin-top: 0.5rem;
  color: var(--gold);
  letter-spacing: 0.28em;
  font-size: 0.92rem;
  font-family: var(--serif);
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--line);
  padding: 3rem 0;
  background: var(--ink);
}
.footer-inner {
  text-align: center;
  color: var(--paper-faint);
  font-size: 0.85rem;
  letter-spacing: 0.1em;
}
.footer-inner p { margin-bottom: 0.7rem; }
.footer-brand {
  font-family: var(--serif);
  font-size: 1.05rem;
  letter-spacing: 0.24em;
  color: var(--paper);
}
.footer-brand .seal {
  width: 1.5rem;
  height: 1.5rem;
  font-size: 0.8rem;
  margin: 0 0.4rem;
  border-radius: 0.2rem;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.6rem;
  color: var(--paper-faint);
}
.footer-links a {
  color: var(--paper-faint);
  text-decoration: none;
  transition: color 0.3s var(--ease);
}
.footer-links a:hover { color: var(--gold); }
.footer-admin { margin-top: 2rem; text-align: center; opacity: 0.34; }
.footer-admin a { color: var(--paper-faint); font-size: 0.72rem; letter-spacing: 0.2em; text-decoration: none; }
.footer-admin a:hover { opacity: 0.75; }

/* 页脚合规信息：主体 / 核心服务 / 更新时间 */
.footer-meta {
  margin-top: 1.6rem;
  padding-top: 1.4rem;
  border-top: 1px solid rgba(233, 227, 214, 0.08);
}
.footer-meta p { margin-bottom: 0.45rem; font-size: 0.78rem; letter-spacing: 0.08em; }
.footer-entity strong { color: rgba(233, 227, 214, 0.78); font-weight: 500; }
.footer-services { color: var(--paper-faint); }
.footer-update { color: rgba(233, 227, 214, 0.34); font-size: 0.72rem; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .idea-grid,
  .team-grid,
  .service-grid {
    grid-template-columns: 1fr;
  }
  .idea {
    border: 1px solid var(--line);
    border-top: 1px solid var(--gold-line);
    background: linear-gradient(180deg, var(--ink-2), var(--ink));
  }
  .card,
  .service { background: linear-gradient(180deg, var(--ink-2), var(--ink)); }
  .case {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }
  .contact-grid { grid-template-columns: 1fr; }
}
@media (max-width: 700px) {
  .nav-toggle { display: flex; }
  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    height: 100vh;
    width: min(76vw, 19rem);
    flex-direction: column;
    justify-content: center;
    align-items: flex-start;
    gap: 1.8rem;
    padding-left: 2.6rem;
    background: rgba(20, 18, 15, 0.98);
    border-left: 1px solid var(--gold-line);
    transform: translateX(100%);
    transition: transform 0.5s var(--ease);
  }
  .nav-links.is-open { transform: translateX(0); }
  .nav-links a {
    font-size: 1.05rem;
    letter-spacing: 0.28em;
    color: var(--paper);
  }
  .section-title br { display: inline; }
}

/* ---------- 减少动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}

/* ---------- Hero 品牌广告语 ---------- */
.hero-title-sub {
  display: block;
  font-weight: 300;
  letter-spacing: 0.34em;
  font-size: clamp(1.7rem, 6vw, 3.8rem);
  color: var(--gold);
}
.accent { color: var(--gold); font-style: normal; }
.hero-ad {
  margin-top: 1.6rem;
  font-family: var(--serif);
  font-size: clamp(2.2rem, 7.5vw, 5rem);
  letter-spacing: 0.14em;
  color: var(--paper);
  line-height: 1.35;
}
.hero-ad em { color: var(--gold); font-style: normal; }
.hero-tag {
  margin-top: 0.9rem;
  font-size: clamp(0.92rem, 2.3vw, 1.2rem);
  letter-spacing: 0.22em;
  color: var(--paper-faint);
}
.hero-tag i { color: var(--gold); font-style: normal; margin: 0 0.35em; font-size: 0.7em; }
.hero-value {
  margin: 1.4rem auto 0;
  padding: 0.7rem 1.5rem;
  font-size: clamp(1rem, 2.7vw, 1.4rem);
  letter-spacing: 0.18em;
  color: var(--gold);
  border-top: 1px solid var(--gold-line);
  border-bottom: 1px solid var(--gold-line);
}
.hero-value b { color: var(--gold); font-weight: 600; }

/* ---------- 关于我们 ---------- */
.about-donts {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.7em 1.6em;
  padding: 0;
  margin: 0 0 3.2rem;
}
.about-donts li {
  font-family: var(--serif);
  font-size: 1.05rem;
  letter-spacing: 0.2em;
  color: var(--paper);
}
.about-donts li b { color: var(--gold); font-weight: 400; margin-right: 0.3em; }
.about-donts li.ab-wid {
  color: var(--gold);
  font-size: 0.98rem;
  letter-spacing: 0.16em;
}
.about-donts li.ab-wid em { font-style: normal; color: var(--paper); }
.about-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.about-card {
  position: relative;
  padding: 2.2rem 1.6rem 1.8rem;
  border: 1px solid var(--line);
  border-top: 1px solid var(--gold-line);
  background: linear-gradient(180deg, var(--ink-2), var(--ink));
}
.about-card:hover {
  transform: translateY(-4px);
  border-color: rgba(200, 169, 126, 0.4);
}
.about-card h3 {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 1.25rem;
  letter-spacing: 0.14em;
  color: var(--paper);
  margin: 0 0 0.9rem;
}
.about-card p {
  color: var(--paper-faint);
  font-size: 0.96rem;
  line-height: 1.9;
  letter-spacing: 0.03em;
  margin: 0;
}
.about-no {
  display: inline-block;
  font-family: var(--serif);
  color: var(--gold);
  font-size: 0.85rem;
  letter-spacing: 0.3em;
  margin-bottom: 1rem;
}
.about-vision {
  margin: 3rem auto 0;
  max-width: 44rem;
  text-align: center;
  color: var(--paper-faint);
  font-size: 1rem;
  line-height: 2;
  letter-spacing: 0.06em;
}
.about-vision b { color: var(--gold); font-weight: 400; }

/* ---------- 研究动态 ---------- */
.news-list {
  list-style: none;
  padding: 0;
  margin: 0;
  max-width: 52rem;
  margin-inline: auto;
}
.news-item {
  position: relative;
  padding: 1.6rem 0 1.6rem 1.5rem;
  border-left: 1px solid var(--gold-line);
  margin-bottom: 1.6rem;
  transition: transform 0.4s var(--ease);
}
.news-item::before {
  content: "";
  position: absolute;
  left: -0.28rem;
  top: 2.2rem;
  width: 0.5rem;
  height: 0.5rem;
  background: var(--ink);
  border: 1px solid var(--gold);
  transform: rotate(45deg);
}
.news-item:hover { transform: translateX(6px); }
.news-meta { display: flex; gap: 1rem; align-items: baseline; }
.news-tag {
  font-style: normal;
  font-size: 0.75rem;
  letter-spacing: 0.24em;
  color: var(--gold);
  border: 1px solid rgba(200, 169, 126, 0.4);
  padding: 0.12rem 0.6rem;
}
.news-date {
  font-style: normal;
  font-size: 0.78rem;
  color: var(--paper-faint);
  letter-spacing: 0.14em;
}
.news-title {
  font-family: var(--serif);
  font-weight: 400;
  font-size: 1.18rem;
  letter-spacing: 0.1em;
  color: var(--paper);
  margin: 0.7rem 0 0.4rem;
}
.news-desc {
  color: var(--paper-faint);
  font-size: 0.95rem;
  line-height: 1.9;
  letter-spacing: 0.02em;
  margin: 0;
  max-width: 46rem;
}
.news-img { display: block; width: 100%; max-width: 34rem; max-height: 20rem; object-fit: cover; border-radius: 6px; margin: 0 0 1.1rem; border: 1px solid var(--gold-line); }
.am-img { display: block; width: 100%; max-height: 26rem; object-fit: cover; border-radius: 6px; margin: 0 0 1.2rem; border: 1px solid var(--gold-line); }
.news-hint {
  text-align: center;
  color: var(--paper-faint);
  font-size: 0.85rem;
  letter-spacing: 0.3em;
  opacity: 0.7;
  margin-top: 2rem;
}
.news-hint .news-admin {
  color: var(--gold);
  letter-spacing: 0.06em;
  text-decoration: none;
  border-bottom: 1px solid rgba(200, 169, 126, 0.4);
  padding-bottom: 1px;
}
.news-hint .news-admin:hover { opacity: 0.8; }
.news-more {
  display: inline-block;
  margin-top: 0.8rem;
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  color: var(--gold);
  cursor: pointer;
}
.news-item.has-body:hover .news-more { opacity: 0.85; }

/* 文章全文弹层 */
.article-modal { position: fixed; inset: 0; z-index: 200; display: flex; align-items: center; justify-content: center; padding: 1.2rem; }
.article-modal .am-mask { position: absolute; inset: 0; background: rgba(6, 5, 3, 0.78); backdrop-filter: blur(3px); }
.article-modal .am-card {
  position: relative; z-index: 1; width: min(46rem, 100%); max-height: 82vh; overflow: auto;
  background: #15120f; border: 1px solid var(--gold-line); border-radius: 8px; padding: 2.2rem 2.4rem 2rem;
  box-shadow: 0 24px 60px rgba(0,0,0,0.5);
  opacity: 0; transform: translateY(14px); transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
}
.article-modal.show .am-card { opacity: 1; transform: none; }
.article-modal .am-tag { font-size: 0.72rem; letter-spacing: 0.24em; color: var(--gold); border: 1px solid rgba(200,169,126,.4); padding: .12rem .6rem; }
.article-modal h3 { font-family: var(--serif); font-weight: 400; font-size: 1.7rem; letter-spacing: .08em; color: var(--paper); margin: 1rem 0 .4rem; }
.article-modal .am-date { font-size: .8rem; color: var(--paper-faint); letter-spacing: .14em; }
.article-modal .am-body { margin-top: 1.4rem; }
.article-modal .am-body p { font-size: 1rem; line-height: 2; color: var(--paper-dim); letter-spacing: .03em; margin: 0 0 1.1rem; }
.article-modal .am-close { margin-top: 1.2rem; cursor: pointer; border: 1px solid var(--gold); color: var(--gold); background: transparent; padding: .5rem 1.6rem; border-radius: 4px; letter-spacing: .3em; font: inherit; font-size: .86rem; transition: all .3s var(--ease); }
.article-modal .am-close:hover { background: var(--gold); color: #15120f; }
.article-modal.out .am-card { opacity: 0; transform: translateY(10px); }

/* ---------- 响应式补充 ---------- */
@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; }
  .about-donts { justify-content: flex-start; }
}