/* ============================================================
   小虹桥AI 官网 — style.css
   品牌: Atelier Notebook (暖奶油 · 可可墨 · 深森林绿 · 焦糖)
   ============================================================ */

/* === TOKENS === */
:root {
  --paper:          #faf6f0;
  --paper-deep:     #f1e8d9;
  --paper-elevated: #ffffff;
  --ink:            #4a3a2a;
  --ink-dim:        #7a7066;
  --ink-soft:       #a89b8c;
  --line:           #e8dfd0;
  --line-soft:      #f1ebdf;
  --accent:         #4a6850;
  --accent-hover:   #3a5440;
  --accent-soft:    #dfeae2;
  --accent-deep:    #2f4536;
  --highlight:      #c9925e;
  --highlight-soft: #f4e6d3;
  --on-dark:        #f4ece0;
  --on-dark-dim:    #b3c2b3;
  --night:          #232e27;
  --night-elevated: #2c3a31;
  --night-ink:      #f1ece1;
  --night-dim:      #a6b1a5;
  --night-line:     #3a4940;
  --font-display:   "Fraunces", "Noto Serif SC", Georgia, serif;
  --font-sans:      "DM Sans", "Noto Sans SC", system-ui, sans-serif;
  --max-w:          1120px;
  --nav-h:          64px;
}

/* === RESET === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  background: var(--paper);
  color: var(--ink);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }

/* === LAYOUT === */
.container {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 40px;
}
@media (max-width: 768px) { .container { padding: 0 24px; } }

/* === TYPOGRAPHY UTILS === */
.eyebrow {
  font-family: var(--font-sans);
  font-size: 12px;
  font-weight: 500;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 20px;
}
.section-title {
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 600;
  line-height: 1.15;
  color: var(--ink);
  margin-bottom: 20px;
}
.section-intro {
  font-size: 18px;
  color: var(--ink-dim);
  max-width: 640px;
  margin-bottom: 56px;
}

/* === FADE-IN ANIMATION === */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ============================================================
   NAV
   ============================================================ */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  z-index: 100;
  background: transparent;
  transition: background .3s, border-color .3s;
}
.nav.scrolled {
  background: rgba(250,246,240,.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 40px;
  height: 100%;
  display: flex;
  align-items: center;
  gap: 40px;
}
.nav-logo {
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  color: var(--on-dark);
  letter-spacing: .01em;
  transition: color .3s;
  flex-shrink: 0;
}
.nav-logo span { color: var(--highlight); }
.nav.scrolled .nav-logo { color: var(--ink); }
.nav-links {
  display: flex;
  gap: 32px;
  margin-left: auto;
}
.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: rgba(244,236,224,.75);
  transition: color .2s;
}
.nav-links a:hover { color: var(--on-dark); }
.nav.scrolled .nav-links a { color: var(--ink-dim); }
.nav.scrolled .nav-links a:hover { color: var(--ink); }
.nav-cta {
  font-size: 13px;
  font-weight: 600;
  padding: 8px 20px;
  border-radius: 6px;
  background: var(--accent);
  color: #fff;
  letter-spacing: .02em;
  transition: background .2s;
  flex-shrink: 0;
}
.nav-cta:hover { background: var(--accent-hover); }
@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-inner { padding: 0 24px; }
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  position: relative;
  min-height: 100svh;
  background: var(--night);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: calc(var(--nav-h) + 80px) 40px 100px;
}
.hero-grain {
  position: absolute;
  inset: 0;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.75' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.04'/%3E%3C/svg%3E");
  background-size: 200px;
  pointer-events: none;
  opacity: .6;
}
/* subtle warm glow */
.hero::before {
  content: '';
  position: absolute;
  width: 600px; height: 600px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(74,104,80,.25) 0%, transparent 70%);
  top: 20%; left: 55%;
  transform: translate(-50%, -50%);
  pointer-events: none;
}
.hero-inner {
  position: relative;
  text-align: center;
  max-width: 800px;
}
.hero-eyebrow {
  color: var(--night-dim);
  margin-bottom: 28px;
  text-transform: none;
  letter-spacing: .04em;
  font-size: 13px;
}
.hero-title {
  font-family: var(--font-display);
  font-size: clamp(52px, 8vw, 96px);
  font-weight: 600;
  line-height: 1.08;
  color: var(--night-ink);
  letter-spacing: -.02em;
  margin-bottom: 28px;
}
.hero-title .ink-mark {
  color: var(--highlight);
  font-style: italic;
}
.hero-sub {
  font-size: clamp(16px, 2vw, 20px);
  color: var(--night-dim);
  margin-bottom: 48px;
  font-weight: 300;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}
.btn {
  display: inline-flex;
  align-items: center;
  padding: 14px 32px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .02em;
  transition: all .2s;
}
.btn-primary {
  background: var(--accent);
  color: #fff;
}
.btn-primary:hover { background: var(--accent-hover); }
.btn-ghost {
  background: transparent;
  color: var(--night-ink);
  border: 1px solid var(--night-line);
}
.btn-ghost:hover { border-color: var(--night-dim); }

.hero-scroll-hint {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}
.hero-scroll-hint span {
  width: 1px;
  height: 40px;
  background: linear-gradient(to bottom, transparent, var(--night-line));
  animation: scrollline 2s ease-in-out infinite;
}
@keyframes scrollline {
  0%,100% { opacity: .3; transform: scaleY(1); }
  50% { opacity: .8; }
}

/* ============================================================
   命题
   ============================================================ */
.thesis {
  padding: 120px 0;
  background: var(--paper);
}
.thesis .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 80px;
  align-items: start;
}
.thesis-pull {
  font-family: var(--font-display);
  font-size: clamp(36px, 4.5vw, 58px);
  font-weight: 600;
  line-height: 1.15;
  color: var(--ink);
  border: none;
  quotes: none;
  letter-spacing: -.01em;
}
.thesis-pull::before, .thesis-pull::after { content: none; }
.thesis-body {
  padding-top: 8px;
}
.thesis-body p {
  font-size: 17px;
  color: var(--ink-dim);
  line-height: 1.8;
  margin-bottom: 20px;
}
.thesis-body p:last-child { margin-bottom: 0; }
@media (max-width: 900px) {
  .thesis .container { grid-template-columns: 1fr; gap: 32px; }
}

/* ============================================================
   分水岭
   ============================================================ */
.divide {
  background: var(--night);
  padding: 120px 0;
  color: var(--night-ink);
}
.divide-eyebrow {
  color: var(--night-dim);
  margin-bottom: 16px;
}
.divide-title {
  font-family: var(--font-display);
  font-size: clamp(28px, 3.5vw, 44px);
  font-weight: 600;
  color: var(--night-ink);
  margin-bottom: 56px;
  letter-spacing: -.01em;
}
.contrast-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  background: var(--night-line);
  border: 1px solid var(--night-line);
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 48px;
}
.contrast-head {
  padding: 16px 28px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.contrast-head--dim { background: rgba(255,255,255,.04); color: var(--night-dim); }
.contrast-head--lit { background: rgba(74,104,80,.2); color: var(--on-dark-dim); }
.contrast-item {
  padding: 18px 28px;
  font-size: 15px;
  line-height: 1.5;
  background: var(--night);
}
.contrast-item--dim { color: var(--night-dim); }
.contrast-item--lit { color: var(--night-ink); border-left: 2px solid var(--accent); }
.divide-note {
  font-size: 22px;
  font-family: var(--font-display);
  font-style: italic;
  color: var(--night-dim);
  text-align: center;
}
@media (max-width: 640px) {
  .contrast-grid { grid-template-columns: 1fr; }
  .contrast-head--dim { display: none; }
}

/* ============================================================
   转型路径
   ============================================================ */
.maturity {
  padding: 120px 0;
  background: var(--paper-deep);
}
.ladder {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0;
  padding-left: 0;
}
.ladder::before {
  content: '';
  position: absolute;
  left: 28px;
  top: 28px;
  bottom: 28px;
  width: 2px;
  background: var(--line);
}
.rung {
  display: flex;
  align-items: flex-start;
  gap: 28px;
  padding: 32px 0;
  position: relative;
}
.rung + .rung {
  border-top: 1px solid var(--line-soft);
}
.rung-level {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: var(--paper-elevated);
  border: 2px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 600;
  color: var(--ink-dim);
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}
.rung--top .rung-level {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.rung-body h3 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 8px;
  padding-top: 12px;
}
.rung-body p {
  font-size: 16px;
  color: var(--ink-dim);
  max-width: 560px;
}
.rung--top .rung-body h3 { color: var(--accent-deep); }

/* ============================================================
   我们做什么
   ============================================================ */
.approach {
  padding: 120px 0;
  background: var(--paper);
}
.pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 48px;
}
.pillar {
  background: var(--paper-elevated);
  padding: 40px 32px;
}
.pillar-no {
  display: block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .1em;
  color: var(--highlight);
  margin-bottom: 16px;
}
.pillar h3 {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 12px;
  line-height: 1.3;
}
.pillar p {
  font-size: 15px;
  color: var(--ink-dim);
  line-height: 1.7;
}
.approach-note {
  font-size: 17px;
  color: var(--ink-dim);
  border-left: 3px solid var(--accent-soft);
  padding-left: 20px;
  max-width: 600px;
}
.approach-note strong { color: var(--ink); }
@media (max-width: 900px) {
  .pillars { grid-template-columns: 1fr; }
}

/* ============================================================
   定价
   ============================================================ */
.pricing {
  padding: 120px 0;
  background: var(--paper-deep);
}
.pricing .section-intro { margin-bottom: 16px; }
.pricing-trust {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 56px;
}
.trust-tag {
  font-size: 12px;
  font-weight: 500;
  color: var(--ink-dim);
  background: var(--paper-elevated);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 5px 14px;
}
.plans {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 48px;
}
.plan-card {
  background: var(--paper-elevated);
  border: 1px solid var(--line);
  border-radius: 16px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
.plan-card--featured {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}
.plan-head {
  padding: 28px 28px 20px;
  border-bottom: 1px solid var(--line-soft);
}
.plan-product-logo {
  width: 28px;
  height: 28px;
  object-fit: contain;
  margin-bottom: 12px;
}
.plan-name {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 6px;
}
.plan-tag {
  display: inline-block;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  background: var(--accent-soft);
  color: var(--accent-deep);
  border-radius: 4px;
  padding: 3px 8px;
  margin-bottom: 10px;
}
.plan-tagline {
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.5;
}
.plan-body {
  padding: 24px 28px;
  flex: 1;
}
.plan-tiers { display: flex; flex-direction: column; gap: 12px; }
.plan-tier {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 14px 16px;
  border-radius: 8px;
  background: var(--paper);
  border: 1px solid var(--line-soft);
  gap: 12px;
}
.plan-tier--rec {
  background: var(--accent-soft);
  border-color: rgba(74,104,80,.2);
}
.plan-tier-label {
  font-size: 14px;
  font-weight: 500;
  color: var(--ink);
}
.plan-tier--rec .plan-tier-label { color: var(--accent-deep); }
.plan-tier-rec-badge {
  font-size: 10px;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--accent);
  display: block;
}
.plan-tier-price {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 600;
  color: var(--ink);
  white-space: nowrap;
}
.plan-tier--rec .plan-tier-price { color: var(--accent-deep); }
.plan-tier-unit {
  font-size: 12px;
  color: var(--ink-soft);
  font-family: var(--font-sans);
  font-weight: 400;
}
.plan-tier-meta {
  font-size: 11px;
  color: var(--ink-soft);
  margin-top: 2px;
}
.plan-cta {
  padding: 0 28px 28px;
}
.plan-cta a {
  display: block;
  text-align: center;
  padding: 13px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 600;
  background: var(--ink);
  color: var(--paper);
  transition: background .2s;
}
.plan-card--featured .plan-cta a {
  background: var(--accent);
  color: #fff;
}
.plan-card--featured .plan-cta a:hover { background: var(--accent-hover); }
.plan-cta a:hover { background: var(--accent); color: #fff; }
.pricing-footnote {
  font-size: 13px;
  color: var(--ink-soft);
  text-align: center;
}
@media (max-width: 900px) {
  .plans { grid-template-columns: 1fr; max-width: 480px; }
}

/* ============================================================
   合作伙伴
   ============================================================ */
.partners {
  padding: 120px 0;
  background: var(--paper);
}
.logo-wall {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 2px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
  margin-bottom: 32px;
}
.logo-wall-row2 {
  grid-template-columns: repeat(4, 1fr);
  max-width: calc(100% * 4/5);
  margin-left: auto;
  margin-right: auto;
}
.logo-item {
  background: var(--paper-elevated);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 28px 20px;
  min-height: 88px;
}
.logo-item img {
  max-height: 32px;
  max-width: 100%;
  width: auto;
  object-fit: contain;
  opacity: .7;
  filter: grayscale(1);
  transition: opacity .2s, filter .2s;
}
.logo-item:hover img { opacity: 1; filter: none; }
.logo-item-text {
  font-size: 13px;
  font-weight: 600;
  color: var(--ink-dim);
  letter-spacing: .02em;
}
.partners-caption {
  font-size: 13px;
  color: var(--ink-soft);
  text-align: center;
  margin-bottom: 40px;
}
.sectors-strip {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}
.sectors-label {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  flex-shrink: 0;
}
.sectors-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.sectors-tags li {
  font-size: 13px;
  color: var(--ink-dim);
  background: var(--paper-deep);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 5px 14px;
}
@media (max-width: 768px) {
  .logo-wall { grid-template-columns: repeat(3, 1fr); }
  .logo-wall-row2 { max-width: 100%; grid-template-columns: repeat(3, 1fr); }
}

/* ============================================================
   联系 / CTA
   ============================================================ */
.contact {
  padding: 120px 0;
  background: var(--night);
  color: var(--night-ink);
}
.contact-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 80px;
  align-items: center;
}
.contact .eyebrow { color: var(--night-dim); }
.contact-title {
  font-family: var(--font-display);
  font-size: clamp(32px, 4vw, 52px);
  font-weight: 600;
  line-height: 1.15;
  color: var(--night-ink);
  margin-bottom: 20px;
  letter-spacing: -.01em;
}
.contact-sub {
  font-size: 17px;
  color: var(--night-dim);
  max-width: 480px;
  margin-bottom: 40px;
}
.contact-note {
  font-size: 13px;
  color: var(--night-dim);
  opacity: .6;
  margin-top: 16px;
}
.wechat-card {
  background: var(--night-elevated);
  border: 1px solid var(--night-line);
  border-radius: 16px;
  padding: 32px;
  text-align: center;
  flex-shrink: 0;
  width: 200px;
}
.wechat-qr {
  width: 140px;
  height: 140px;
  border-radius: 8px;
  margin: 0 auto 16px;
  overflow: hidden;
}
.wechat-qr img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.wechat-qr-placeholder {
  font-size: 11px;
  color: var(--ink-soft);
  text-align: center;
  padding: 8px;
}
.wechat-label {
  font-size: 12px;
  color: var(--night-dim);
  font-weight: 500;
}
@media (max-width: 768px) {
  .contact-inner { grid-template-columns: 1fr; gap: 48px; }
  .wechat-card { width: 100%; max-width: 240px; }
}

/* ============================================================
   FOOTER
   ============================================================ */
.footer {
  background: var(--night);
  border-top: 1px solid var(--night-line);
  padding: 40px 0;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}
.footer-logo {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 600;
  color: var(--night-dim);
}
.footer-logo span { color: var(--highlight); }
.footer-copy {
  font-size: 12px;
  color: var(--night-dim);
  opacity: .5;
}
.footer-icp {
  font-size: 12px;
  color: var(--night-dim);
  opacity: .4;
}
.footer-icp a { opacity: .8; }
.footer-icp a:hover { opacity: 1; }