/* ==================== Variables & Reset ==================== */
:root {
  --primary: #FF4757;
  --primary-light: #FF6B7A;
  --primary-dark: #E8384A;
  --primary-bg: #FFF5F5;
  --bg: #FFFAF8;
  --bg-white: #FFFFFF;
  --text: #2D2D2D;
  --text-secondary: #666666;
  --text-muted: #999999;
  --border: #F0E8E5;
  --shadow: 0 2px 20px rgba(255, 71, 87, 0.08);
  --shadow-hover: 0 8px 30px rgba(255, 71, 87, 0.15);
  --radius: 16px;
  --radius-sm: 10px;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --max-width: 1080px;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

a {
  color: var(--primary);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--primary-dark);
}

/* ==================== Top Navigation ==================== */
.top-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(240, 232, 229, 0.6);
  padding: 14px 0;
}

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

.nav-brand {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
}

.nav-brand:hover {
  color: var(--primary);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-links a {
  font-size: 0.95rem;
  color: var(--text-secondary);
  font-weight: 500;
  transition: color 0.2s;
}

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

/* ==================== Hero Section ==================== */
.hero {
  text-align: center;
  padding: 130px 0 60px;
  background: linear-gradient(180deg, var(--bg-white) 0%, var(--bg) 100%);
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.hero-subtitle {
  font-size: 1.25rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 32px;
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
  line-height: 1.8;
}

.cta-button {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 16px 36px;
  background: var(--primary);
  color: white;
  font-size: 1.1rem;
  font-weight: 600;
  border-radius: 50px;
  border: none;
  cursor: pointer;
  transition: all 0.25s;
  box-shadow: 0 4px 15px rgba(255, 71, 87, 0.3);
}

.cta-button:hover {
  background: var(--primary-dark);
  color: white;
  transform: translateY(-2px);
  box-shadow: 0 6px 25px rgba(255, 71, 87, 0.4);
}

.chrome-icon {
  flex-shrink: 0;
}

.hero-cost {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 28px;
}

.hero-note {
  margin-top: 16px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

/* Hero showcase: video (left) + workflow (right) */
.hero-showcase {
  margin-top: 48px;
  display: flex;
  align-items: center;
  gap: 40px;
}

.hero-demo {
  flex: 1;
  min-width: 0;
}

.hero-demo-img {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.12);
  display: block;
}

/* Vertical workflow steps (right side of hero) */
.hero-workflow {
  flex: 0 0 220px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.workflow-step-v {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  background: var(--bg-white);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow);
  width: 100%;
  transition: transform 0.3s;
}

.workflow-step-v:hover {
  transform: translateX(4px);
}

.workflow-step-v .step-icon {
  font-size: 1.6rem;
  margin-bottom: 0;
  flex-shrink: 0;
}

.workflow-step-v h3 {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 2px;
}

.workflow-step-v p {
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.4;
}

/* Screenshot images in selling points */
.sp-screenshot {
  width: 100%;
  border-radius: var(--radius);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
  display: block;
}

.workflow-arrow-v {
  font-size: 1.2rem;
  color: var(--primary);
  font-weight: 700;
}

/* Privacy data flow diagram (horizontal) */
.privacy-diagram {
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 20px 14px;
  box-shadow: var(--shadow);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.pd-node {
  text-align: center;
  padding: 12px 10px;
  border-radius: var(--radius-sm);
  flex: 1;
  min-width: 120px;
}

.pd-browser {
  background: linear-gradient(135deg, #EEF2FF, #E0E7FF);
  border: 1px solid #C7D2FE;
}

.pd-ai {
  background: linear-gradient(135deg, #FFF5F5, #FFF0ED);
  border: 1px solid var(--border);
}

.pd-icon {
  font-size: 1.4rem;
  margin-bottom: 3px;
}

.pd-label {
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 2px;
}

.pd-sub {
  font-size: 0.68rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.pd-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  flex-shrink: 0;
  padding: 0 2px;
}

.pd-arrow-line {
  width: 30px;
  height: 2px;
  background: var(--primary);
  border-radius: 1px;
  position: relative;
}

/* Right arrow (评论数据 → AI) */
.pd-arrow-line::after {
  content: '';
  position: absolute;
  right: -1px;
  top: -3px;
  border: 4px solid transparent;
  border-left: 5px solid var(--primary);
}

.pd-arrow-return {
  background: #6366F1;
}

/* Left arrow (结果 ← 浏览器) */
.pd-arrow-return::after {
  content: '';
  position: absolute;
  left: -1px;
  top: -3px;
  border: 4px solid transparent;
  border-right: 5px solid #6366F1;
  right: auto;
}

.pd-arrow-text {
  font-size: 0.6rem;
  color: var(--text-muted);
  font-weight: 500;
  white-space: nowrap;
}

.pd-block {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  padding: 6px 12px;
  background: #FEF2F2;
  border-radius: 20px;
  border: 1px dashed #FECACA;
  width: 100%;
}

.pd-block-icon {
  font-size: 0.8rem;
}

.pd-block-text {
  font-size: 0.72rem;
  font-weight: 600;
  color: #DC2626;
}

/* Video inside selling point */
.sp-video-wrap {
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.sp-video-wrap video {
  width: 100%;
  display: block;
}


/* ==================== Selling Points ==================== */
.selling-points {
  padding: 80px 0;
}

.selling-point {
  display: flex;
  align-items: center;
  gap: 60px;
  margin-bottom: 80px;
}

.selling-point:last-child {
  margin-bottom: 0;
}

.selling-point.reverse {
  flex-direction: row-reverse;
}

.sp-text {
  flex: 1;
}

.sp-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
  flex-wrap: wrap;
}

.sp-badge {
  display: inline-block;
  padding: 4px 14px;
  background: var(--primary-bg);
  color: var(--primary);
  font-size: 0.85rem;
  font-weight: 600;
  border-radius: 20px;
  flex-shrink: 0;
}

.sp-text h2 {
  font-size: 1.8rem;
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.01em;
  margin: 0;
  display: inline;
}

.sp-text p {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.8;
}

.sp-text p:last-child {
  margin-bottom: 0;
}

.sp-text strong {
  color: var(--text);
  font-weight: 600;
}

.sp-image {
  flex: 0 0 420px;
}

/* ==================== Placeholder Styles ==================== */
.placeholder {
  background: linear-gradient(135deg, #FFF5F5 0%, #FFF0ED 100%);
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  padding: 60px 30px;
  text-align: center;
  transition: all 0.3s;
}

.placeholder:hover {
  border-color: var(--primary-light);
  background: linear-gradient(135deg, #FFF0ED 0%, #FFE8E5 100%);
}

.placeholder-icon {
  font-size: 3rem;
  margin-bottom: 12px;
}

.placeholder p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

.placeholder .placeholder-hint {
  color: var(--text-muted);
  font-size: 0.8rem;
  font-weight: 400;
  margin-top: 8px;
}

/* ==================== Feature Highlights ==================== */
.features {
  padding: 80px 0;
  background: var(--bg-white);
}

.section-title {
  text-align: center;
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
  color: var(--text);
}

.section-desc {
  text-align: center;
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 48px;
}

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

.feature-card {
  background: var(--bg);
  border-radius: var(--radius);
  padding: 28px;
  transition: all 0.3s;
  border: 1px solid transparent;
}

.feature-card:hover {
  border-color: var(--border);
  box-shadow: var(--shadow-hover);
  transform: translateY(-4px);
}

.feature-placeholder {
  background: linear-gradient(135deg, #FFF5F5 0%, #FFF0ED 100%);
  border: 2px dashed var(--border);
  border-radius: var(--radius-sm);
  padding: 40px 20px;
  text-align: center;
  margin-bottom: 20px;
}

.feature-placeholder .placeholder-icon {
  font-size: 2.5rem;
  margin-bottom: 8px;
}

.feature-placeholder p {
  color: var(--text-muted);
  font-size: 0.85rem;
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text);
}

.feature-card p {
  font-size: 0.95rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ==================== Footer CTA ==================== */
.footer-cta {
  text-align: center;
  padding: 80px 0;
  background: linear-gradient(180deg, var(--bg-white) 0%, var(--primary-bg) 100%);
}

.footer-cta h2 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 28px;
  color: var(--text);
}

/* ==================== About Author ==================== */
.about {
  padding: 60px 0;
  background: var(--bg);
}

.about-card {
  max-width: 680px;
  margin: 0 auto;
  background: var(--bg-white);
  border-radius: var(--radius);
  padding: 40px;
  box-shadow: var(--shadow);
}

/* Clickable profile card */
.about-profile-card {
  display: flex;
  align-items: center;
  gap: 18px;
  padding: 16px 20px;
  margin-bottom: 16px;
  background: #F8F8F8;
  border-radius: var(--radius-sm);
  transition: all 0.2s;
  cursor: pointer;
  color: inherit;
}

.about-profile-card:hover {
  background: #F0F0F0;
  color: inherit;
}

.about-avatar-img {
  width: 60px;
  height: 60px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.about-profile-info {
  flex: 1;
}

.about-name {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 2px;
}

.about-bio {
  font-size: 0.88rem;
  color: var(--text-muted);
}

.about-xhs-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 0.85rem;
  color: var(--primary);
  font-weight: 500;
  padding: 4px 12px;
  margin-bottom: 24px;
  background: var(--primary-bg);
  border-radius: 20px;
  transition: all 0.2s;
}

.about-xhs-link:hover {
  background: #FFE8E5;
  color: var(--primary-dark);
}

.about-message p {
  font-size: 1rem;
  color: var(--text-secondary);
  line-height: 1.9;
  margin-bottom: 16px;
}

.about-message p:last-child {
  margin-bottom: 0;
}

.about-closing {
  font-weight: 600;
  color: var(--text);
  font-style: italic;
  margin-top: 8px;
}

/* ==================== Footer ==================== */
.footer {
  text-align: center;
  padding: 28px 0;
  background: var(--primary-bg);
  border-top: 1px solid var(--border);
}

.footer p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer a {
  font-weight: 600;
  color: var(--text-secondary);
}

/* ==================== Scroll Animations (CSS Keyframes) ==================== */

/* Initial hidden state — only active after JS marks body as ready */
body.animations-ready .fade-in,
body.animations-ready .slide-up {
  opacity: 0;
}

/* Fade-in animation */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

body.animations-ready .fade-in.visible {
  animation: fadeInUp 0.6s ease-out forwards;
}

/* Slide-up animation (more dramatic for workflow) */
@keyframes slideUpIn {
  from {
    opacity: 0;
    transform: translateY(50px) scale(0.95);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

body.animations-ready .slide-up.visible {
  animation: slideUpIn 0.7s cubic-bezier(0.25, 0.46, 0.45, 0.94) forwards;
}

/* Stagger delays for feature cards */
.feature-grid .fade-in:nth-child(1) { animation-delay: 0s !important; }
.feature-grid .fade-in:nth-child(2) { animation-delay: 0.15s !important; }
.feature-grid .fade-in:nth-child(3) { animation-delay: 0.3s !important; }

/* ==================== Responsive ==================== */
@media (max-width: 768px) {
  .hero {
    padding: 100px 0 40px;
  }

  .hero-title {
    font-size: 2.5rem;
  }

  .hero-subtitle {
    font-size: 1.1rem;
  }

  .hero-showcase {
    flex-direction: column;
    gap: 28px;
  }

  .hero-workflow {
    flex: none;
    width: 100%;
    max-width: 320px;
  }

  .selling-point,
  .selling-point.reverse {
    flex-direction: column;
    gap: 30px;
    margin-bottom: 50px;
  }

  .sp-image {
    flex: none;
    width: 100%;
  }

  .sp-header {
    gap: 8px;
  }

  .sp-text h2 {
    font-size: 1.4rem;
  }

  .sp-badge {
    font-size: 0.78rem;
    padding: 3px 10px;
  }

  .feature-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .section-title {
    font-size: 1.6rem;
  }

  .footer-cta h2 {
    font-size: 1.5rem;
  }

  .cta-button {
    padding: 14px 28px;
    font-size: 1rem;
  }

  .about-card {
    padding: 28px 20px;
  }

  .about-header {
    flex-direction: column;
    text-align: center;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 2rem;
  }

  .container {
    padding: 0 16px;
  }
}