/* ==========================================================
   哲龟官网 · index.css
   风格：新中式水墨 —— 宣纸米色 / 墨色 / 朱砂红
   ========================================================== */

:root {
  --paper: #f7f3ea;          /* 宣纸底色 */
  --paper-deep: #efe9db;     /* 深一度的纸色 */
  --ink: #22211f;            /* 墨色 */
  --ink-soft: #55524b;       /* 淡墨 */
  --ink-faint: #8b877c;      /* 灰墨 */
  --cinnabar: #a63a2b;       /* 朱砂红 */
  --cinnabar-deep: #8c2f22;
  --gold: #b08d4f;           /* 赭金 */
  --line: #ddd5c4;           /* 分隔线 */
  --header-h: 72px;
  --serif: "Noto Serif SC", "Source Han Serif SC", "STSong", "SimSun", serif;
  --kai: "Kaiti SC", "STKaiti", "KaiTi", "Noto Serif SC", serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--serif);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.8;
  overflow-x: hidden;
  /* 宣纸质感：细微横向纹路 */
  background-image: repeating-linear-gradient(
    0deg, transparent 0 3px, rgba(0,0,0,.008) 3px 4px);
}

a { text-decoration: none; color: inherit; }
img { display: block; max-width: 100%; }

/* ==================== 顶部导航 ==================== */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  height: var(--header-h);
  background: rgba(247, 243, 234, .92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid transparent;
  transition: box-shadow .3s, border-color .3s, height .3s;
}
.site-header.scrolled {
  height: 60px;
  border-bottom-color: var(--line);
  box-shadow: 0 4px 24px rgba(34, 33, 31, .07);
}
.header-inner {
  max-width: 1200px; height: 100%; margin: 0 auto;
  padding: 0 24px;
  display: flex; align-items: center; justify-content: space-between;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-logo { width: 42px; height: 42px; object-fit: contain; transition: width .3s, height .3s; }
.site-header.scrolled .brand-logo { width: 34px; height: 34px; }
.brand-name {
  font-family: var(--kai);
  font-size: 26px; font-weight: 700; letter-spacing: 6px;
}
.site-nav { display: flex; gap: 36px; }
.nav-link {
  position: relative;
  font-size: 16px; letter-spacing: 3px; color: var(--ink-soft);
  padding: 6px 0;
  transition: color .25s;
}
.nav-link::after {
  content: ""; position: absolute; left: 50%; bottom: 0;
  width: 0; height: 2px; background: var(--cinnabar);
  transform: translateX(-50%);
  transition: width .3s;
}
.nav-link:hover, .nav-link.active { color: var(--ink); }
.nav-link:hover::after, .nav-link.active::after { width: 100%; }

/* 移动端汉堡 */
.nav-toggle {
  display: none;
  flex-direction: column; justify-content: center; gap: 5px;
  width: 40px; height: 40px;
  background: none; border: none; cursor: pointer;
}
.nav-toggle span {
  display: block; width: 22px; height: 2px;
  background: var(--ink); transition: transform .3s, opacity .3s;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ==================== 首屏 ==================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
  background:
    radial-gradient(ellipse 80% 60% at 50% 110%, rgba(166, 58, 43, .16), transparent 60%),
    radial-gradient(ellipse 60% 50% at 20% 0%, rgba(176, 141, 79, .10), transparent 60%),
    linear-gradient(180deg, #1d1c1a 0%, #26241f 55%, #2e2a23 100%);
  color: #f2ede1;
  overflow: hidden;
}
.hero-glow {
  position: absolute; border-radius: 50%;
  filter: blur(90px); opacity: .35; pointer-events: none;
  animation: float 9s ease-in-out infinite alternate;
}
.hero-glow-1 { width: 480px; height: 480px; left: -140px; top: 12%; background: rgba(166,58,43,.5); }
.hero-glow-2 { width: 420px; height: 420px; right: -120px; bottom: 8%; background: rgba(176,141,79,.4); animation-delay: -4s; }
@keyframes float {
  from { transform: translate(0, 0) scale(1); }
  to   { transform: translate(30px, -26px) scale(1.08); }
}
.hero-inner { position: relative; z-index: 2; padding: 100px 24px 80px; max-width: 860px; }

.hero-seal {
  display: inline-block;
  font-family: var(--kai);
  font-size: 15px; letter-spacing: 3px;
  color: #f5efe2;
  background: var(--cinnabar);
  padding: 8px 14px;
  writing-mode: vertical-rl;
  border-radius: 4px;
  box-shadow: 0 0 0 2px rgba(245, 239, 226, .35) inset, 0 6px 18px rgba(0,0,0,.4);
  margin-bottom: 28px;
  animation: sealIn 1s .2s both;
}
@keyframes sealIn {
  from { opacity: 0; transform: scale(1.4) rotate(-6deg); }
  to   { opacity: 1; transform: scale(1) rotate(0); }
}
.hero-eyebrow {
  font-size: 17px; letter-spacing: 10px;
  color: var(--gold);
  margin-bottom: 22px;
  animation: fadeUp .9s .4s both;
}
.hero-title {
  font-family: var(--kai);
  font-size: clamp(34px, 6vw, 64px);
  font-weight: 700; letter-spacing: 8px;
  margin-bottom: 26px;
  animation: fadeUp .9s .55s both;
}
.hero-sub {
  font-size: 16px; color: rgba(242, 237, 225, .72);
  margin-bottom: 46px;
  animation: fadeUp .9s .7s both;
}
.hero-cta {
  display: inline-flex; align-items: center; gap: 10px;
  font-size: 16px; letter-spacing: 4px;
  color: #f5efe2;
  border: 1px solid rgba(245, 239, 226, .5);
  padding: 14px 38px;
  border-radius: 999px;
  transition: background .3s, border-color .3s, transform .3s;
  animation: fadeUp .9s .85s both;
}
.hero-cta:hover {
  background: var(--cinnabar);
  border-color: var(--cinnabar);
  transform: translateY(-2px);
}
.cta-arrow { display: inline-block; animation: bob 1.6s ease-in-out infinite; }
@keyframes bob { 0%,100% { transform: translateY(0); } 50% { transform: translateY(5px); } }
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(26px); }
  to   { opacity: 1; transform: translateY(0); }
}

.scroll-hint {
  position: absolute; bottom: 30px; left: 50%; transform: translateX(-50%);
  width: 24px; height: 40px;
  border: 2px solid rgba(245, 239, 226, .4); border-radius: 14px;
}
.scroll-hint span {
  position: absolute; left: 50%; top: 7px;
  width: 4px; height: 8px; margin-left: -2px;
  border-radius: 2px; background: rgba(245, 239, 226, .7);
  animation: scrollHint 1.8s ease-in-out infinite;
}
@keyframes scrollHint {
  0% { opacity: 1; transform: translateY(0); }
  70% { opacity: 0; transform: translateY(14px); }
  100% { opacity: 0; transform: translateY(0); }
}

/* ==================== 通用 Section ==================== */
.section { padding: 110px 24px; }
.section-head { text-align: center; margin-bottom: 70px; }
.section-eyebrow {
  font-size: 14px; letter-spacing: 8px;
  color: var(--cinnabar);
  margin-bottom: 14px;
}
.section-title {
  font-family: var(--kai);
  font-size: clamp(30px, 4.5vw, 44px);
  font-weight: 700; letter-spacing: 10px;
  margin-bottom: 20px;
}
.section-desc { font-size: 16px; color: var(--ink-soft); }

/* ==================== 文明长河 · 时间轴 ==================== */
.timeline-section {
  background:
    radial-gradient(ellipse 70% 40% at 50% 0%, rgba(176,141,79,.07), transparent 60%),
    var(--paper);
}
.timeline {
  position: relative;
  max-width: 980px; margin: 0 auto;
}
/* 中轴线 */
.timeline::before {
  content: "";
  position: absolute; left: 50%; top: 0; bottom: 0;
  width: 2px; margin-left: -1px;
  background: linear-gradient(180deg, transparent, var(--line) 6%, var(--line) 94%, transparent);
}
.tl-item {
  position: relative;
  width: 50%;
  padding: 0 48px 56px 0;
}
.tl-item:nth-child(even) {
  left: 50%;
  padding: 0 0 56px 48px;
}
/* 轴上圆点 */
.tl-item::before {
  content: "";
  position: absolute; top: 26px; right: -7px; z-index: 2;
  width: 14px; height: 14px; border-radius: 50%;
  background: var(--paper);
  border: 3px solid var(--cinnabar);
  box-shadow: 0 0 0 5px rgba(166, 58, 43, .12);
}
.tl-item:nth-child(even)::before { right: auto; left: -7px; }

.tl-card {
  background: #fffdf7;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 28px 30px 26px;
  position: relative;
  transition: transform .35s, box-shadow .35s, border-color .35s;
}
.tl-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 40px rgba(34, 33, 31, .10);
  border-color: rgba(166, 58, 43, .35);
}
/* 卡片指向中轴的小三角 */
.tl-card::after {
  content: "";
  position: absolute; top: 24px; right: -7px;
  width: 12px; height: 12px;
  background: #fffdf7;
  border-top: 1px solid var(--line);
  border-right: 1px solid var(--line);
  transform: rotate(45deg);
}
.tl-item:nth-child(even) .tl-card::after {
  right: auto; left: -7px;
  transform: rotate(225deg);
}
.tl-era {
  display: inline-block;
  font-family: var(--kai);
  font-size: 15px; font-weight: 700; letter-spacing: 2px;
  color: var(--cinnabar);
  background: rgba(166, 58, 43, .08);
  border: 1px solid rgba(166, 58, 43, .22);
  padding: 3px 14px;
  border-radius: 999px;
  margin-bottom: 14px;
}
.tl-title {
  font-family: var(--kai);
  font-size: 21px; font-weight: 700; letter-spacing: 3px;
  margin-bottom: 10px;
}
.tl-text { font-size: 15px; color: var(--ink-soft); }

.timeline-end {
  text-align: center;
  margin-top: 30px;
  font-family: var(--kai);
  font-size: clamp(18px, 2.6vw, 24px);
  letter-spacing: 4px;
  color: var(--ink);
}
.timeline-end p { line-height: 2.2; }

/* ==================== 关于哲龟 ==================== */
.about-section { background: var(--paper-deep); }
.about-grid {
  max-width: 1080px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px;
}
.about-card {
  background: #fffdf7;
  border: 1px solid var(--line);
  border-top: 3px solid var(--cinnabar);
  border-radius: 10px;
  padding: 44px 32px;
  text-align: center;
  transition: transform .35s, box-shadow .35s;
}
.about-card:hover {
  transform: translateY(-8px);
  box-shadow: 0 18px 44px rgba(34, 33, 31, .10);
}
.about-icon {
  width: 68px; height: 68px;
  margin: 0 auto 22px;
  display: flex; align-items: center; justify-content: center;
  font-family: var(--kai);
  font-size: 30px; font-weight: 700;
  color: #f5efe2;
  background: var(--ink);
  border-radius: 50%;
  box-shadow: 0 8px 20px rgba(34, 33, 31, .25);
}
.about-card h3 {
  font-family: var(--kai);
  font-size: 22px; letter-spacing: 5px;
  margin-bottom: 14px;
}
.about-card p { font-size: 15px; color: var(--ink-soft); }

/* ==================== 品牌理念 ==================== */
.philosophy-section {
  background:
    radial-gradient(ellipse 60% 70% at 50% 50%, rgba(166,58,43,.08), transparent 65%),
    var(--paper);
}
.philosophy-inner {
  max-width: 760px; margin: 0 auto;
  text-align: center;
  position: relative;
  padding: 30px 20px;
}
.quote-mark {
  font-family: var(--kai);
  font-size: 90px; line-height: .6;
  color: rgba(166, 58, 43, .25);
  user-select: none;
}
.quote-mark.close { margin-top: 26px; }
.philosophy-line {
  font-family: var(--kai);
  font-size: clamp(19px, 3vw, 27px);
  letter-spacing: 6px;
  color: var(--ink-soft);
  margin: 10px 0;
}
.philosophy-line.strong {
  color: var(--cinnabar);
  font-weight: 700;
  font-size: clamp(23px, 3.6vw, 32px);
  margin-top: 22px;
}

/* ==================== 页脚 ==================== */
.site-footer {
  background: #1d1c1a;
  color: rgba(242, 237, 225, .75);
  padding: 64px 24px 30px;
}
.footer-main {
  max-width: 1080px; margin: 0 auto;
  display: flex; justify-content: space-between; gap: 40px;
  text-align: center;
  padding-bottom: 42px;
}
.footer-brand-col { flex: 1; }
.footer-col { flex: 1; }

.footer-logo {
  width: 84px; height: 84px; object-fit: contain;
  margin: 0 auto 14px;
  /* 黑字 logo 在深色页脚反白 */
  filter: invert(1) brightness(1.6);
}
.footer-name {
  font-family: var(--kai);
  font-size: 24px; letter-spacing: 8px; color: #f2ede1;
}
.footer-slogan {
  font-size: 14px; letter-spacing: 5px;
  margin-top: 10px;
  color: var(--gold);
}

.footer-title {
  font-family: var(--kai);
  font-size: 17px; font-weight: 700; letter-spacing: 4px;
  color: #f2ede1;
  margin-bottom: 20px;
}
.footer-title::after {
  content: "";
  display: block;
  width: 32px; height: 2px;
  margin: 10px auto 0;
  background: var(--cinnabar);
}
.footer-list { list-style: none; }
.footer-list li {
  font-size: 14px; letter-spacing: 1px;
  display: inline-flex; align-items: center; gap: 10px;
}
.f-label {
  color: rgba(242, 237, 225, .45);
  background: rgba(242, 237, 225, .08);
  padding: 2px 10px; border-radius: 4px;
  font-size: 12px; letter-spacing: 2px;
}
.f-mail {
  color: rgba(242, 237, 225, .85);
  transition: color .25s;
}
.f-mail:hover { color: var(--gold); }

.footer-qr {
  width: 128px; height: 128px;
  margin: 0 auto 10px;
  object-fit: contain;
  border: 1px solid rgba(242, 237, 225, .15);
  border-radius: 8px;
  background: #fff;
  padding: 6px;
}
.qr-tip { font-size: 12px; letter-spacing: 2px; color: rgba(242, 237, 225, .5); }

.footer-bottom {
  max-width: 1080px; margin: 0 auto;
  border-top: 1px solid rgba(242, 237, 225, .12);
  padding-top: 22px;
  display: flex; flex-wrap: wrap; gap: 10px 26px;
  align-items: center; justify-content: center;
}
.footer-copy { font-size: 13px; color: rgba(242, 237, 225, .4); letter-spacing: 2px; }
.icp-link {
  font-size: 13px; letter-spacing: 1px;
  color: rgba(242, 237, 225, .45);
  transition: color .25s;
}
.icp-link:hover { color: var(--gold); }

@media (max-width: 720px) {
  .footer-main { flex-direction: column; gap: 36px; }
}

/* ==================== 回到顶部 ==================== */
.back-top {
  position: fixed; right: 28px; bottom: 32px; z-index: 90;
  width: 46px; height: 46px;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: rgba(255, 253, 247, .92);
  color: var(--ink-soft);
  font-size: 18px;
  cursor: pointer;
  opacity: 0; visibility: hidden; transform: translateY(14px);
  transition: opacity .3s, transform .3s, background .3s, color .3s;
  box-shadow: 0 6px 18px rgba(34, 33, 31, .12);
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { background: var(--cinnabar); color: #fff; border-color: var(--cinnabar); }

/* ==================== 滚动渐入 ==================== */
.reveal { opacity: 0; transform: translateY(36px); transition: opacity .8s ease, transform .8s ease; }
.reveal.in { opacity: 1; transform: translateY(0); }

/* ==================== 响应式 ==================== */
@media (max-width: 860px) {
  .site-nav {
    position: fixed; top: 60px; left: 0; right: 0;
    flex-direction: column; gap: 0;
    background: rgba(247, 243, 234, .98);
    border-bottom: 1px solid var(--line);
    max-height: 0; overflow: hidden;
    transition: max-height .35s ease;
  }
  .site-nav.open { max-height: 320px; }
  .site-nav .nav-link {
    padding: 16px 28px;
    border-top: 1px solid var(--line);
  }
  .nav-toggle { display: flex; }

  /* 时间轴改为单列 */
  .timeline::before { left: 12px; }
  .tl-item,
  .tl-item:nth-child(even) {
    width: 100%; left: 0;
    padding: 0 0 44px 42px;
  }
  .tl-item::before,
  .tl-item:nth-child(even)::before { left: 5px; right: auto; }
  .tl-card::after,
  .tl-item:nth-child(even) .tl-card::after {
    left: -7px; right: auto;
    transform: rotate(225deg);
  }

  .about-grid { grid-template-columns: 1fr; max-width: 460px; }
  .section { padding: 80px 20px; }
  .back-top { right: 18px; bottom: 20px; }
}