/* =========================================================
   祥丰久欣 · 久欣智价
   纯静态单页站点：单色 + 细线 + 大留白 + 排版驱动
   ========================================================= */
:root {
  --paper: #ffffff;
  --paper-2: #f8f7f5;
  --ink: #111111;
  --ink-2: #333333;
  --muted: #666666;
  --faint: #8c8c8c;
  --line: #e6e3de;
  --line-2: #cfcac3;
  --dark: #0f0f0f;
  --accent: #7a1b2b;
  --font: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", "Hiragino Sans GB", Arial, sans-serif;
  --serif: "Songti SC", "STSong", "Noto Serif SC", "SimSun", Georgia, serif;
  --ease: cubic-bezier(.2, .6, .2, 1);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 88px; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.7;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
::selection { background: var(--ink); color: #fff; }
:focus-visible { outline: 1px solid var(--ink); outline-offset: 3px; }

.skip-link {
  position: absolute;
  left: 16px;
  top: -60px;
  z-index: 300;
  padding: 10px 16px;
  background: var(--ink);
  color: #fff;
  font-size: 12px;
  transition: top .2s var(--ease);
}
.skip-link:focus { top: 12px; }

.wrap { width: min(1120px, calc(100% - 56px)); margin: 0 auto; }
.section { padding: 112px 0; border-top: 1px solid var(--line); position: relative; }
.muted { color: var(--muted); }

/* ---------- type ---------- */
h1, h2, h3, h4 { margin: 0; }
h2 {
  font-family: var(--serif);
  font-size: clamp(30px, 3.2vw, 42px);
  font-weight: 600;
  line-height: 1.24;
  letter-spacing: -.01em;
}
.eyebrow {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .24em;
  text-transform: uppercase;
  color: var(--faint);
  margin-bottom: 20px;
}
.eyebrow.light { color: rgba(255, 255, 255, .46); }
.section-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 56px;
  margin-bottom: 58px;
}
.section-head > p {
  max-width: 360px;
  margin: 0;
  color: var(--muted);
  font-size: 14.5px;
  line-height: 1.9;
}
.section-head h2 { max-width: 640px; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 1px solid transparent;
  border-radius: 0;
  background: transparent;
  color: var(--ink);
  padding: 12px 22px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: .02em;
  line-height: 1;
  white-space: nowrap;
  transition: background .25s var(--ease), color .25s var(--ease), border-color .25s var(--ease);
}
.btn-primary { background: var(--ink); border-color: var(--ink); color: #fff; }
.btn-primary:hover { background: #2c2c2c; border-color: #2c2c2c; }
.btn-outline { border-color: var(--line-2); color: var(--ink); }
.btn-outline:hover { background: var(--ink); border-color: var(--ink); color: #fff; }
.btn-lg { padding: 15px 28px; font-size: 13.5px; }
.btn-block { width: 100%; }

/* ---------- header ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, .9);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}
.site-header.scrolled { background: #fff; }
.header-inner { height: 68px; display: flex; align-items: center; justify-content: space-between; gap: 32px; }
.brand { display: flex; align-items: center; gap: 10px; flex: 0 0 auto; }
.brand-logo { width: 38px; height: 38px; object-fit: contain; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-text strong { font-family: var(--serif); font-size: 17px; font-weight: 600; letter-spacing: .08em; }
.brand-text small { font-size: 9px; color: var(--faint); letter-spacing: .2em; margin-top: 3px; }
.nav { display: flex; align-items: center; gap: 30px; }
.nav a { position: relative; padding: 4px 0; font-size: 12.5px; color: var(--ink-2); transition: color .2s; }
.nav a::after { content: ""; position: absolute; left: 0; right: 100%; bottom: 0; height: 1px; background: var(--ink); transition: right .28s var(--ease); }
.nav a:hover { color: var(--ink); }
.nav a:hover::after { right: 0; }
.header-actions { display: flex; align-items: center; gap: 8px; }
.menu-btn { display: none; width: 36px; height: 36px; border: 1px solid var(--line); background: transparent; padding: 9px; border-radius: 0; }
.menu-btn span { display: block; height: 1px; background: var(--ink); margin: 4px 0; transition: .2s; }

/* ---------- hero ---------- */
.hero { padding: 146px 0 0; overflow: hidden; }
.hero-inner { display: grid; grid-template-columns: 1.06fr .94fr; gap: 64px; align-items: center; }
.hero h1 {
  font-family: var(--serif);
  font-size: clamp(40px, 4.8vw, 64px);
  font-weight: 600;
  line-height: 1.18;
  letter-spacing: -.015em;
}
.hero h1 em { font-style: normal; color: inherit; }
.hero-lead { max-width: 520px; margin: 26px 0 0; color: var(--muted); font-size: 15.5px; line-height: 1.95; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 38px; }
.hero-note { display: flex; align-items: center; gap: 14px; margin-top: 34px; color: var(--faint); font-size: 11.5px; letter-spacing: .06em; }
.hero-note i { width: 1px; height: 11px; background: var(--line-2); display: inline-block; }
.hero-visual { position: relative; }
.product-window { margin: 0; border: 1px solid var(--line); background: var(--paper-2); overflow: hidden; }
.window-bar { height: 34px; display: flex; align-items: center; gap: 14px; padding: 0 12px; background: #fff; border-bottom: 1px solid var(--line); }
.window-title { font-size: 10px; color: var(--faint); letter-spacing: .04em; }
.window-badge { margin-left: auto; font-size: 9px; color: var(--faint); border: 1px solid var(--line); padding: 2px 6px; }
.product-window img { width: 100%; height: auto; aspect-ratio: 16 / 10; object-fit: cover; object-position: top left; }
.stats {
  margin-top: 84px;
  border-top: 1px solid var(--line);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  padding: 26px 0 40px;
}
.stats > div { display: flex; align-items: baseline; gap: 10px; padding: 0 26px; border-right: 1px solid var(--line); }
.stats > div:first-child { padding-left: 0; }
.stats > div:last-child { border-right: 0; }
.stats b { font-family: var(--serif); font-size: 24px; font-weight: 600; letter-spacing: -.01em; }
.stats span { color: var(--faint); font-size: 11px; letter-spacing: .04em; }

/* ---------- features ---------- */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  border-top: 1px solid var(--line);
  border-left: 1px solid var(--line);
}
.feature-card {
  display: flex;
  flex-direction: column;
  min-height: 300px;
  padding: 32px 26px 28px;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  transition: background .3s var(--ease);
}
.feature-card:hover { background: var(--paper-2); }
.icon-box { margin-bottom: 26px; color: var(--ink); }
.icon-box svg { width: 22px; height: 22px; fill: none; stroke: currentColor; stroke-width: 1.25; stroke-linecap: round; stroke-linejoin: round; }
.card-kicker { font-size: 10px; font-weight: 600; letter-spacing: .18em; color: var(--faint); text-transform: uppercase; }
.feature-card h3 { font-family: var(--serif); font-size: 20px; font-weight: 600; margin: 8px 0 12px; letter-spacing: .01em; }
.feature-card p { flex: 1; margin: 0; color: var(--muted); font-size: 12.5px; line-height: 1.85; }

/* ---------- tour ---------- */
.tour-grid { display: grid; grid-template-columns: .8fr 1.2fr; gap: 72px; align-items: center; }
.tour-copy h2 { margin-bottom: 18px; }
.tour-copy > p { max-width: 400px; margin: 0 0 34px; color: var(--muted); font-size: 14.5px; line-height: 1.9; }
.tour-tabs { border-top: 1px solid var(--line); }
.tour-tab {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 16px;
  border: 0;
  border-bottom: 1px solid var(--line);
  background: transparent;
  padding: 16px 0;
  color: var(--muted);
  font-size: 13.5px;
  text-align: left;
  transition: color .2s;
}
.tour-tab span { width: 20px; font-size: 10px; letter-spacing: .1em; color: var(--faint); }
.tour-tab::after { content: "→"; margin-left: auto; opacity: 0; transition: .2s; }
.tour-tab:hover, .tour-tab.active { color: var(--ink); }
.tour-tab.active::after { opacity: 1; }
.tour-caption { margin: 18px 0 0; min-height: 40px; font-size: 12px; color: var(--faint); line-height: 1.7; }
.tour-frame { position: relative; margin: 0; border: 1px solid var(--line); }
.tour-frame img { width: 100%; height: auto; aspect-ratio: 16 / 10; object-fit: cover; object-position: top left; }
.tour-tag {
  position: absolute;
  left: 16px;
  bottom: 16px;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 5px 10px;
  background: rgba(255, 255, 255, .94);
  border: 1px solid var(--line);
  font-size: 10px;
  color: var(--muted);
}
.live-dot { width: 5px; height: 5px; border-radius: 50%; background: var(--ink); }

/* ---------- scenarios ---------- */
.scenario-grid { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid var(--line-2); }
.scenario-card { padding: 26px 24px 0 0; }
.scenario-card + .scenario-card { padding-left: 24px; border-left: 1px solid var(--line); }
.scenario-no { font-family: var(--serif); font-size: 12px; color: var(--faint); letter-spacing: .08em; }
.scenario-card h3 { font-family: var(--serif); font-size: 21px; font-weight: 600; margin: 26px 0 12px; }
.scenario-card p { margin: 0; min-height: 74px; color: var(--muted); font-size: 12.5px; line-height: 1.9; }
.scenario-card ul { display: flex; flex-wrap: wrap; gap: 6px 10px; list-style: none; padding: 0; margin: 20px 0 0; }
.scenario-card li { font-size: 10.5px; color: var(--muted); letter-spacing: .04em; }
.scenario-card li:not(:first-child)::before { content: "·"; margin-right: 8px; color: var(--line-2); }

/* ---------- value ---------- */
.dark { background: var(--dark); color: #f2f0ec; border-top: 0; }
.value-top { display: flex; justify-content: space-between; align-items: flex-end; gap: 56px; margin-bottom: 64px; }
.value-top h2 { font-family: var(--serif); font-size: clamp(32px, 3.6vw, 48px); font-weight: 600; line-height: 1.2; color: #fff; }
.value-top p { max-width: 380px; margin: 0; color: rgba(255, 255, 255, .56); font-size: 14px; line-height: 1.9; }
.value-grid { display: grid; grid-template-columns: repeat(4, 1fr); border-top: 1px solid rgba(255, 255, 255, .14); }
.value-item { padding: 30px 24px 0 0; border-right: 1px solid rgba(255, 255, 255, .14); }
.value-item:not(:first-child) { padding-left: 24px; }
.value-item:last-child { border-right: 0; }
.value-item > span { font-size: 10px; letter-spacing: .14em; color: rgba(255, 255, 255, .4); }
.value-item h3 { font-family: var(--serif); font-size: 19px; font-weight: 600; margin: 18px 0 10px; color: #fff; }
.value-item p { margin: 0; color: rgba(255, 255, 255, .54); font-size: 12px; line-height: 1.9; }

/* ---------- about ---------- */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 80px; align-items: center; }
.about-copy h2 { margin-bottom: 24px; }
.about-copy p { max-width: 460px; margin: 0 0 12px; color: var(--muted); font-size: 14px; line-height: 1.95; }
.about-stats { display: flex; gap: 44px; margin-top: 36px; padding-top: 26px; border-top: 1px solid var(--line); }
.about-stats b { display: block; font-family: var(--serif); font-size: 26px; font-weight: 600; }
.about-stats span { font-size: 10.5px; color: var(--faint); letter-spacing: .06em; }
.about-panel { border: 1px solid var(--line); padding: 56px 40px; text-align: center; }
.about-logo { width: 72px; margin: 0 auto 30px; }
.about-quote { font-family: var(--serif); font-size: clamp(24px, 2.4vw, 32px); font-weight: 600; line-height: 1.5; }
.about-sign { margin-top: 24px; color: var(--faint); font-size: 10.5px; letter-spacing: .08em; }
.about-tags { display: flex; justify-content: center; gap: 12px; margin-top: 18px; color: var(--muted); font-size: 10.5px; }
.about-tags span + span::before { content: "·"; margin-right: 12px; color: var(--line-2); }

/* ---------- faq ---------- */
.faq-grid { display: grid; grid-template-columns: .62fr 1.38fr; gap: 80px; }
.faq-head p { margin-top: 18px; font-size: 13px; color: var(--muted); }
.text-link-inline { color: var(--ink); border-bottom: 1px solid var(--ink); padding-bottom: 1px; font-weight: 600; }
.text-link-inline:hover { color: var(--accent); border-color: var(--accent); }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list details:first-child { border-top: 1px solid var(--line); }
.faq-list summary { position: relative; padding: 20px 40px 20px 0; cursor: pointer; list-style: none; font-size: 13.5px; font-weight: 600; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; position: absolute; right: 0; top: 17px; font-size: 16px; font-weight: 300; color: var(--faint); transition: .2s; }
.faq-list details[open] summary::after { transform: rotate(45deg); }
.faq-list p { max-width: 640px; margin: 0 0 22px; color: var(--muted); font-size: 12.5px; line-height: 1.95; }

/* ---------- contact ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr .86fr; gap: 80px; align-items: start; }
.contact-copy h2 { margin-bottom: 22px; }
.contact-copy > p { max-width: 420px; margin: 0; color: var(--muted); font-size: 14px; line-height: 1.95; }
.contact-points { margin-top: 38px; }
.contact-points > div { display: flex; gap: 18px; padding: 16px 0; border-top: 1px solid var(--line); }
.contact-points > div > span { padding-top: 3px; font-size: 10px; color: var(--faint); letter-spacing: .08em; }
.contact-points p { margin: 0; }
.contact-points b { display: block; font-size: 13px; font-weight: 600; }
.contact-points small { display: block; margin-top: 5px; color: var(--faint); font-size: 11px; }
.contact-meta { margin-top: 26px; color: var(--faint); font-size: 10.5px; letter-spacing: .04em; }
.contact-card { border: 1px solid var(--line); padding: 32px; background: var(--paper); }
.form-head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 24px; }
.form-head h3 { font-family: var(--serif); font-size: 20px; font-weight: 600; }
.form-head span { font-size: 10px; color: var(--faint); }
.contact-lead { margin: 0 0 18px; color: var(--muted); font-size: 12.5px; line-height: 1.85; }
.contact-mail {
  display: inline-block;
  margin-bottom: 22px;
  font-family: var(--serif);
  font-size: 20px;
  font-weight: 600;
  border-bottom: 1px solid var(--line-2);
  padding-bottom: 3px;
}
.contact-mail:hover { border-color: var(--ink); }
.form-fine { margin: 14px 0 0; text-align: center; color: var(--faint); font-size: 9.5px; line-height: 1.7; }

/* ---------- footer ---------- */
.site-footer { background: var(--dark); color: rgba(255, 255, 255, .55); padding: 56px 0 28px; }
.footer-top { display: flex; justify-content: space-between; align-items: center; gap: 30px; padding-bottom: 30px; border-bottom: 1px solid rgba(255, 255, 255, .12); }
.footer-brand { display: flex; align-items: center; gap: 12px; }
.footer-brand img { width: 28px; height: 28px; object-fit: contain; }
.footer-brand strong { display: block; font-family: var(--serif); color: #fff; font-size: 15px; font-weight: 600; letter-spacing: .08em; }
.footer-brand span { display: block; margin-top: 4px; font-size: 9px; color: rgba(255, 255, 255, .38); letter-spacing: .18em; }
.footer-links { display: flex; flex-wrap: wrap; gap: 26px; }
.footer-links a { font-size: 11px; color: rgba(255, 255, 255, .55); }
.footer-links a:hover { color: #fff; }
.footer-bottom { display: flex; justify-content: space-between; gap: 20px; padding-top: 24px; font-size: 10px; color: rgba(255, 255, 255, .3); }

/* ---------- reveal ---------- */
/* 仅当 JS 可用（html.js）时才隐藏内容做入场动画；禁用 JS 时内容直接可见 */
.js .reveal { opacity: 0; transition: opacity .6s var(--ease); }
.js .reveal.in { opacity: 1; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .js .reveal { opacity: 1; transition: none; }
}

/* ---------- responsive ---------- */
@media (max-width: 1080px) {
  .wrap { width: calc(100% - 40px); }
  .nav { gap: 20px; }
  .brand-text small { display: none; }
  .hero-inner { gap: 40px; }
  .feature-grid { grid-template-columns: repeat(2, 1fr); }
  .scenario-grid { grid-template-columns: repeat(2, 1fr); gap: 34px 24px; border-top: 0; }
  .scenario-card, .scenario-card + .scenario-card { padding: 26px 0 0; border-left: 0; border-top: 1px solid var(--line-2); }
  .scenario-card p { min-height: 0; }
  .value-grid { grid-template-columns: repeat(2, 1fr); }
  .value-item:nth-child(2n) { border-right: 0; padding-right: 0; }
  .value-item:nth-child(2n+1) { padding-left: 0; }
  .value-item:nth-child(n+3) { border-top: 1px solid rgba(255, 255, 255, .14); margin-top: 26px; }
  .about-grid, .contact-grid { gap: 48px; }
  .faq-grid { gap: 48px; }
}

@media (max-width: 900px) {
  .wrap { width: calc(100% - 36px); }
  .nav {
    position: fixed;
    top: 68px; left: 0; right: 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 18px 16px;
    background: #fff;
    border-bottom: 1px solid var(--line);
  }
  .nav.open { display: flex; }
  .nav a { padding: 14px 0; border-bottom: 1px solid var(--line); font-size: 14px; }
  .nav a::after { display: none; }
  .menu-btn { display: block; }
  .hero { padding-top: 118px; }
  .hero-inner { grid-template-columns: 1fr; gap: 38px; }
  .hero h1 { font-size: clamp(36px, 8vw, 54px); }
  .hero-visual { max-width: 640px; width: 100%; margin: 0 auto; }
  .stats { grid-template-columns: repeat(2, 1fr); row-gap: 22px; margin-top: 48px; }
  .stats > div { padding: 0; border-right: 0; }
  .section { padding: 84px 0; }
  .section-head { display: block; margin-bottom: 36px; }
  .section-head > p { margin-top: 16px; max-width: 100%; }
  .tour-grid { grid-template-columns: 1fr; gap: 40px; }
  .tour-copy > p { max-width: 100%; }
  .value-top { display: block; }
  .value-top p { margin-top: 20px; }
  .about-grid, .contact-grid, .faq-grid { grid-template-columns: 1fr; }
  .contact-copy > p { max-width: 100%; }
  .footer-top { display: block; }
  .footer-links { margin-top: 22px; }
  .footer-bottom { display: block; line-height: 1.9; }
  .footer-bottom span { display: block; }
}

@media (max-width: 560px) {
  .brand-logo { width: 32px; height: 32px; }
  .brand-text strong { font-size: 16px; }
  .header-actions .btn-primary { padding: 10px 14px; font-size: 12px; }
  .hero { padding-top: 104px; }
  .hero h1 { font-size: 34px; }
  .hero-lead { font-size: 14px; }
  .hero-actions .btn { flex: 1; padding-left: 14px; padding-right: 14px; }
  .hero-note { flex-wrap: wrap; gap: 8px; }
  .stats b { font-size: 22px; }
  .stats span { font-size: 10px; }
  .feature-grid, .scenario-grid, .value-grid { grid-template-columns: 1fr; }
  .feature-card { min-height: 0; }
  .scenario-card, .scenario-card + .scenario-card { padding: 24px 0 0; }
  .value-item, .value-item:nth-child(2n), .value-item:nth-child(2n+1) { border-right: 0; padding: 26px 0 0; }
  .value-item:nth-child(n+3) { margin-top: 0; }
  .value-item + .value-item { border-top: 1px solid rgba(255, 255, 255, .14); }
  .contact-card { padding: 24px 18px; }
  .form-head { display: block; }
  .form-head span { display: block; margin-top: 6px; }
  .about-panel { padding: 38px 24px; }
  .about-stats { flex-wrap: wrap; gap: 24px; }
  .about-stats b { font-size: 22px; }
  .contact-mail { font-size: 17px; }
}