/* 第四爱官网 — 实机截图 + 完整内容版 */

:root {
  --ink: #1a1014;
  --ink-soft: #6b4452;
  --blush: #f15b78;
  --blush-deep: #dc4060;
  --rose: #fff1f4;
  --paper: #fffafb;
  --mist: #f7eef1;
  --line: #edd6de;
  --night: #140c10;
  --vip: #7a4a8c;
  --surface: #ffffff;
  --header-h: 70px;
  --container: 1120px;
  --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'Noto Serif SC', 'Songti SC', serif;
  --ease: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
  --phone-radius: 28px;
  --shadow-phone: 0 30px 80px rgba(26, 16, 20, 0.22);

  /* 兼容法律页 / 帖子落地 */
  --color-primary: var(--blush);
  --color-primary-light: #ff7a93;
  --color-primary-soft: rgba(241, 91, 120, 0.12);
  --color-text: var(--ink);
  --color-text-secondary: var(--ink-soft);
  --color-text-muted: #9a7383;
  --color-bg: var(--paper);
  --color-bg-alt: var(--mist);
  --color-surface: var(--surface);
  --color-border: var(--line);
  --color-vip: var(--vip);
  --gradient-primary: linear-gradient(135deg, #ff7a93, #f15b78);
  --gradient-hero: radial-gradient(ellipse at 70% 30%, #ffe0e8, var(--paper) 60%);
  --shadow-sm: 0 2px 10px rgba(26, 16, 20, 0.05);
  --shadow-md: 0 16px 48px rgba(26, 16, 20, 0.1);
  --shadow-lg: 0 28px 70px rgba(241, 91, 120, 0.18);
  --radius-sm: 12px;
  --radius-md: 20px;
  --radius-lg: 28px;
  --radius-full: 9999px;
  --font: var(--font-sans);
  --transition: var(--ease);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

img { display: block; max-width: 100%; height: auto; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }

.container {
  width: min(100% - 40px, var(--container));
  margin-inline: auto;
}

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

/* ---- Header ---- */

.site-header {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  height: var(--header-h);
  background: rgba(255, 250, 251, 0.8);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  border-bottom: 1px solid transparent;
  transition: border-color var(--ease), box-shadow var(--ease);
}

.site-header.scrolled {
  border-bottom-color: var(--line);
  box-shadow: 0 8px 30px rgba(26, 16, 20, 0.04);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: 0.04em;
}

.nav-brand img { border-radius: 10px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--ink-soft);
  transition: color var(--ease);
}

.nav-links a:hover { color: var(--blush); }

.nav-cta {
  padding: 9px 18px !important;
  background: var(--ink) !important;
  color: #fff !important;
  border-radius: 999px;
}

.nav-cta:hover { background: var(--blush-deep) !important; }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
}

/* ---- Buttons ---- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 30px;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 600;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  transition: transform var(--ease), background var(--ease), box-shadow var(--ease);
}

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

.btn-primary {
  background: var(--blush);
  color: #fff;
  box-shadow: 0 12px 32px rgba(241, 91, 120, 0.32);
}

.btn-primary:hover { background: var(--blush-deep); }

.btn-ghost {
  background: rgba(255, 255, 255, 0.55);
  color: var(--ink);
  border: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.btn-ghost:hover { border-color: var(--blush); color: var(--blush); }

.btn-sm { padding: 10px 22px; font-size: 14px; }

/* ---- Hero ---- */

.hero {
  position: relative;
  padding: calc(var(--header-h) + 56px) 0 80px;
  overflow: hidden;
  background:
    radial-gradient(ellipse 55% 50% at 85% 20%, rgba(241, 91, 120, 0.2), transparent 60%),
    radial-gradient(ellipse 40% 35% at 10% 90%, rgba(122, 74, 140, 0.08), transparent 55%),
    linear-gradient(180deg, #fff5f7 0%, var(--paper) 55%, #fff 100%);
}

.hero-glow {
  position: absolute;
  width: 520px;
  height: 520px;
  right: -80px;
  top: 10%;
  background: radial-gradient(circle, rgba(255, 150, 170, 0.35), transparent 70%);
  filter: blur(40px);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1.05fr;
  gap: 40px;
  align-items: center;
}

.hero-kicker {
  display: inline-block;
  margin-bottom: 16px;
  padding: 6px 14px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--blush);
  background: rgba(241, 91, 120, 0.1);
  border-radius: 999px;
}

.hero-brand {
  font-family: var(--font-serif);
  font-size: clamp(48px, 9vw, 80px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: 0.08em;
  margin-bottom: 14px;
}

.hero-title {
  font-family: var(--font-serif);
  font-size: clamp(24px, 3.2vw, 34px);
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 18px;
  color: var(--ink);
}

.hero-title em {
  font-style: normal;
  color: var(--blush);
}

.hero-desc {
  font-size: 16px;
  color: var(--ink-soft);
  max-width: 34em;
  margin-bottom: 28px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-bottom: 28px;
}

.hero-points {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
}

.hero-points li {
  font-size: 13px;
  font-weight: 500;
  color: var(--ink-soft);
  padding-left: 14px;
  position: relative;
}

.hero-points li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.55em;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--blush);
}

.hero-phones {
  position: relative;
  height: min(68vh, 620px);
  min-height: 480px;
}

.phone {
  position: absolute;
  margin: 0;
  border-radius: calc(var(--phone-radius) + 6px);
  background: #111;
  padding: 10px;
  box-shadow: var(--shadow-phone);
  overflow: hidden;
}

.phone img {
  width: 100%;
  border-radius: var(--phone-radius);
  display: block;
}

.phone-front {
  width: min(52%, 280px);
  right: 8%;
  bottom: 0;
  z-index: 2;
  transform: rotate(-2deg);
  animation: phone-float 5.5s ease-in-out infinite;
}

.phone-back {
  width: min(48%, 250px);
  left: 6%;
  top: 4%;
  z-index: 1;
  opacity: 0.95;
  transform: rotate(6deg);
  animation: phone-float 6.2s ease-in-out infinite reverse;
}

@keyframes phone-float {
  0%, 100% { translate: 0 0; }
  50% { translate: 0 -12px; }
}

/* ---- Intro ---- */

.intro {
  padding: 72px 0;
  background: var(--night);
  color: #fff;
}

.intro-inner {
  max-width: 40em;
}

.intro h2 {
  font-family: var(--font-serif);
  font-size: clamp(28px, 4.2vw, 42px);
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 20px;
}

.intro h2 strong {
  color: #ff8aa3;
  font-weight: 700;
}

.intro p {
  font-size: 17px;
  color: rgba(255, 255, 255, 0.72);
  line-height: 1.8;
}

/* ---- Sections ---- */

.section-head {
  max-width: 38em;
  margin-bottom: 56px;
}

.section-head-light .eyebrow { color: #ff8aa3; }

.eyebrow {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--blush);
  margin-bottom: 12px;
}

.section-head h2 {
  font-family: var(--font-serif);
  font-size: clamp(28px, 3.8vw, 38px);
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 12px;
}

.section-head p {
  color: var(--ink-soft);
  font-size: 16px;
}

/* ---- Features ---- */

.features {
  padding: 96px 0 40px;
}

.feature-row {
  display: grid;
  grid-template-columns: 1fr 0.9fr;
  gap: 56px;
  align-items: center;
  padding: 48px 0 72px;
  border-top: 1px solid var(--line);
}

.feature-row-reverse .feature-copy { order: 2; }
.feature-row-reverse .feature-shot { order: 1; }

.feature-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--blush);
  margin-bottom: 10px;
}

.feature-copy h3 {
  font-family: var(--font-serif);
  font-size: clamp(26px, 3vw, 34px);
  margin-bottom: 14px;
}

.feature-copy > p {
  color: var(--ink-soft);
  font-size: 16px;
  margin-bottom: 20px;
  max-width: 34em;
}

.feature-bullets li {
  position: relative;
  padding-left: 18px;
  margin-bottom: 10px;
  font-size: 15px;
  color: var(--ink-soft);
}

.feature-bullets li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.65em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--blush);
}

.feature-shot {
  margin: 0;
  justify-self: center;
  width: min(100%, 320px);
  border-radius: calc(var(--phone-radius) + 8px);
  background: #111;
  padding: 10px;
  box-shadow: var(--shadow-phone);
}

.feature-shot img {
  width: 100%;
  border-radius: var(--phone-radius);
}

.feature-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
  padding: 24px 0 72px;
  border-top: 1px solid var(--line);
}

.feature-mini {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 20px;
  align-items: center;
  padding: 24px;
  background: var(--mist);
  border-radius: 24px;
}

.feature-mini figure {
  margin: 0;
  border-radius: 18px;
  overflow: hidden;
  background: #111;
  padding: 6px;
  box-shadow: var(--shadow-sm);
}

.feature-mini img {
  width: 100%;
  border-radius: 14px;
}

.feature-mini h3 {
  font-family: var(--font-serif);
  font-size: 22px;
  margin-bottom: 8px;
}

.feature-mini p:last-child {
  font-size: 14px;
  color: var(--ink-soft);
}

/* ---- How ---- */

.how {
  padding: 96px 0;
  background: var(--night);
  color: #fff;
}

.how .section-head h2 { color: #fff; }
.how .section-head p { color: rgba(255, 255, 255, 0.65); }

.timeline {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.timeline li {
  padding: 28px 24px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.03);
}

.timeline-no {
  display: block;
  font-family: var(--font-serif);
  font-size: 28px;
  color: #ff8aa3;
  margin-bottom: 16px;
}

.timeline h3 {
  font-size: 20px;
  margin-bottom: 10px;
}

.timeline p {
  font-size: 14px;
  color: rgba(255, 255, 255, 0.65);
  line-height: 1.75;
}

/* ---- Community ---- */

.community {
  padding: 96px 0;
  background: var(--rose);
}

.community-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 48px;
  align-items: center;
}

.community-copy h2 {
  font-family: var(--font-serif);
  font-size: clamp(28px, 3.5vw, 36px);
  margin: 8px 0 16px;
}

.community-copy > p {
  color: var(--ink-soft);
  margin-bottom: 24px;
}

.check-list li {
  position: relative;
  padding-left: 28px;
  margin-bottom: 12px;
  font-size: 15px;
  color: var(--ink-soft);
}

.check-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  top: 0;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: rgba(241, 91, 120, 0.12);
  color: var(--blush);
  font-size: 11px;
  font-weight: 700;
  display: grid;
  place-items: center;
}

.community-card {
  padding: 40px 32px;
  background: var(--surface);
  border-radius: 28px;
  box-shadow: var(--shadow-md);
  text-align: center;
  border: 1px solid rgba(241, 91, 120, 0.08);
}

.community-card-label {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 18px;
  font-size: 12px;
  font-weight: 700;
  color: var(--vip);
  background: rgba(122, 74, 140, 0.1);
  border-radius: 999px;
}

.community-card h3 {
  font-family: var(--font-serif);
  font-size: 24px;
  margin-bottom: 8px;
}

.community-card > p {
  color: var(--ink-soft);
  font-size: 15px;
}

.community-card-line {
  width: 48px;
  height: 3px;
  margin: 22px auto;
  border-radius: 2px;
  background: var(--gradient-primary);
}

.community-card-tag {
  font-size: 13px;
  color: var(--color-text-muted);
  margin-bottom: 22px;
}

/* ---- Membership ---- */

.membership {
  padding: 96px 0;
}

.vip-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.vip-grid article {
  padding: 24px 20px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 18px;
  transition: transform var(--ease), box-shadow var(--ease), border-color var(--ease);
}

.vip-grid article:hover {
  transform: translateY(-3px);
  border-color: rgba(122, 74, 140, 0.25);
  box-shadow: var(--shadow-sm);
}

.vip-grid h4 {
  font-size: 16px;
  font-weight: 700;
  margin-bottom: 8px;
}

.vip-grid p {
  font-size: 13px;
  color: var(--ink-soft);
  line-height: 1.6;
}

/* ---- Download ---- */

.download {
  padding: 0 0 96px;
}

.download-panel {
  text-align: center;
  padding: 64px 40px;
  border-radius: 32px;
  background:
    radial-gradient(ellipse at 50% 0%, rgba(255, 255, 255, 0.2), transparent 55%),
    linear-gradient(145deg, #ff7a93, #e04564 55%, #c23d78);
  color: #fff;
  box-shadow: var(--shadow-lg);
}

.download-copy img {
  margin: 0 auto 20px;
  border-radius: 18px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.18);
}

.download-copy h2 {
  font-family: var(--font-serif);
  font-size: clamp(28px, 3.8vw, 36px);
  margin-bottom: 12px;
}

.download-copy p {
  max-width: 32em;
  margin: 0 auto 32px;
  opacity: 0.92;
}

.store-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 16px;
}

.store-btn {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 12px 22px;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.35);
  background: rgba(0, 0, 0, 0.18);
  color: #fff;
  font-weight: 600;
  font-size: 15px;
  transition: background var(--ease);
}

.store-btn-fill {
  background: rgba(0, 0, 0, 0.35);
}

.store-btn small {
  display: block;
  font-size: 10px;
  font-weight: 400;
  opacity: 0.8;
}

.store-btn:hover { background: rgba(0, 0, 0, 0.4); }

.download-note {
  font-size: 13px;
  opacity: 0.8;
}

/* ---- Footer ---- */

.site-footer {
  background: var(--night);
  color: rgba(255, 255, 255, 0.65);
  padding-top: 56px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 48px;
  padding-bottom: 40px;
}

.footer-brand {
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.footer-brand img { border-radius: 8px; }

.footer-brand strong {
  display: block;
  color: #fff;
  font-family: var(--font-serif);
  margin-bottom: 4px;
}

.footer-brand p { font-size: 13px; }

.footer-links {
  display: flex;
  gap: 56px;
}

.footer-links h4 {
  color: #fff;
  font-size: 13px;
  margin-bottom: 14px;
}

.footer-links a {
  display: block;
  font-size: 14px;
  margin-bottom: 10px;
  transition: color var(--ease);
}

.footer-links a:hover { color: #ff8aa3; }

.footer-bottom {
  padding: 20px 0;
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  text-align: center;
  font-size: 13px;
}

/* ---- Reveal ---- */

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

.fade-in {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .phone-front, .phone-back { animation: none; }
  .reveal, .fade-in { opacity: 1; transform: none; transition: none; }
  html { scroll-behavior: auto; }
}

/* ---- Post share ---- */

.post-share-page .site-header .nav-cta { margin-left: auto; }

.post-share {
  min-height: calc(100vh - var(--header-h) - 80px);
  padding: calc(var(--header-h) + 48px) 0 64px;
  background: var(--gradient-hero);
}

.post-share-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 40px;
  max-width: 520px;
}

.post-share-card {
  width: 100%;
  padding: 40px 32px;
  background: var(--surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  text-align: center;
}

.post-share-logo { margin: 0 auto 20px; border-radius: 18px; }

.post-share-badge {
  display: inline-block;
  margin-bottom: 12px;
  padding: 4px 12px;
  font-size: 13px;
  font-weight: 500;
  color: var(--blush);
  background: var(--color-primary-soft);
  border-radius: 999px;
}

.post-share-card h1 {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.35;
  margin-bottom: 12px;
}

.post-share-desc { color: var(--ink-soft); font-size: 15px; margin-bottom: 8px; }
.post-share-id { color: var(--color-text-muted); font-size: 13px; margin-bottom: 24px; }

.post-share-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 8px;
}

.post-share-actions .btn { min-width: 140px; }
.post-share-hint { margin-top: 16px; font-size: 13px; color: var(--color-text-muted); }

.post-share-download { width: 100%; text-align: center; }
.post-share-download h2 { font-size: 20px; font-weight: 600; margin-bottom: 8px; }
.post-share-download > p { color: var(--ink-soft); font-size: 14px; margin-bottom: 20px; }
.post-share-download .store-buttons { justify-content: center; }
.post-share-page .site-footer { padding: 0; }
.post-share-page .footer-bottom { padding: 24px 0; }
.post-share-page .footer-bottom a { color: #ff8aa3; }

/* ---- Legal ---- */

.legal-page { padding: calc(var(--header-h) + 48px) 0 96px; }
.legal-standalone .legal-page { padding: 32px 0 48px; }

.legal-page h1 {
  font-family: var(--font-serif);
  font-size: 32px;
  font-weight: 700;
  margin-bottom: 8px;
}

.legal-meta { color: var(--ink-soft); font-size: 14px; margin-bottom: 40px; }
.legal-content h2 { font-size: 20px; font-weight: 600; margin: 32px 0 12px; }
.legal-content h3 { font-size: 17px; font-weight: 600; margin: 24px 0 10px; }

.legal-content p,
.legal-content li {
  color: var(--ink-soft);
  font-size: 15px;
  line-height: 1.75;
  margin-bottom: 12px;
}

.legal-content ul {
  list-style: disc;
  padding-left: 24px;
  margin-bottom: 16px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 14px;
  font-weight: 500;
  color: var(--blush);
  margin-bottom: 32px;
}

/* ---- Responsive ---- */

@media (max-width: 980px) {
  .hero-grid,
  .feature-row,
  .community-grid,
  .feature-pair,
  .timeline {
    grid-template-columns: 1fr;
  }

  .feature-row-reverse .feature-copy,
  .feature-row-reverse .feature-shot {
    order: initial;
  }

  .hero-phones {
    height: 420px;
    min-height: 420px;
    margin-top: 12px;
  }

  .phone-front { width: 48%; right: 10%; }
  .phone-back { width: 42%; left: 12%; }

  .feature-shot { width: min(70%, 280px); }

  .feature-mini {
    grid-template-columns: 110px 1fr;
  }

  .vip-grid { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { flex-direction: column; }
}

@media (max-width: 640px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: rgba(255, 250, 251, 0.97);
    backdrop-filter: blur(16px);
    padding: 12px 24px 24px;
    border-bottom: 1px solid var(--line);
    transform: translateY(-110%);
    opacity: 0;
    pointer-events: none;
    transition: var(--ease);
  }

  .nav-links.open {
    transform: none;
    opacity: 1;
    pointer-events: auto;
  }

  .nav-links a {
    display: block;
    padding: 14px 0;
    border-bottom: 1px solid var(--line);
  }

  .nav-links li:last-child a {
    border-bottom: none;
    margin-top: 8px;
    text-align: center;
  }

  .vip-grid { grid-template-columns: 1fr; }
  .footer-links { flex-direction: column; gap: 28px; }
  .download-panel { padding: 48px 20px; }

  .feature-mini {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .feature-mini figure {
    width: 140px;
    margin-inline: auto;
  }

  .post-share-card { padding: 32px 20px; }
  .post-share-actions { flex-direction: column; }
  .post-share-actions .btn { width: 100%; }
}