/* ========================================
   法考主观题 AI 私教 - Landing Page Styles
   ======================================== */

/* CSS Variables */
:root {
  --primary: #1a365d;
  --primary-light: #2a4a7f;
  --primary-dark: #0f2440;
  --accent: #c9a84c;
  --accent-light: #ddc474;
  --accent-dark: #a88a32;
  --bg: #ffffff;
  --bg-alt: #f7f8fc;
  --bg-warm: #faf9f5;
  --text: #1a202c;
  --text-secondary: #4a5568;
  --text-muted: #718096;
  --border: #e2e8f0;
  --shadow-sm: 0 1px 3px rgba(26, 54, 93, 0.06);
  --shadow-md: 0 4px 20px rgba(26, 54, 93, 0.08);
  --shadow-lg: 0 8px 40px rgba(26, 54, 93, 0.12);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 20px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font-serif: 'Noto Serif SC', 'Georgia', serif;
  --font-sans: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  overflow-x: hidden;
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ========================================
   Buttons
   ======================================== */
.btn {
  display: inline-block;
  font-weight: 600;
  text-decoration: none;
  border-radius: var(--radius-sm);
  transition: var(--transition);
  cursor: pointer;
  border: none;
  font-family: var(--font-sans);
}

.btn-nav {
  background: var(--accent);
  color: var(--primary-dark);
  padding: 10px 24px;
  font-size: 14px;
  letter-spacing: 0.5px;
}

.btn-nav:hover {
  background: var(--accent-light);
  transform: translateY(-1px);
}

.btn-hero {
  background: var(--accent);
  color: var(--primary-dark);
  padding: 16px 48px;
  font-size: 17px;
  border-radius: var(--radius);
  letter-spacing: 1px;
  box-shadow: 0 4px 20px rgba(201, 168, 76, 0.35);
}

.btn-hero:hover {
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: 0 6px 28px rgba(201, 168, 76, 0.45);
}

.btn-cta {
  background: var(--accent);
  color: var(--primary-dark);
  padding: 18px 56px;
  font-size: 18px;
  border-radius: var(--radius);
  letter-spacing: 1px;
  box-shadow: 0 4px 24px rgba(201, 168, 76, 0.4);
}

.btn-cta:hover {
  background: var(--accent-light);
  transform: translateY(-2px);
  box-shadow: 0 8px 36px rgba(201, 168, 76, 0.5);
}

/* ========================================
   Navbar
   ======================================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 16px 0;
  transition: var(--transition);
  background: transparent;
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  box-shadow: var(--shadow-sm);
  padding: 10px 0;
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--bg);
  transition: var(--transition);
}

.scrolled .logo {
  color: var(--primary);
}

.logo-icon {
  font-size: 28px;
}

.logo-text {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 1px;
}

.nav-links {
  display: flex;
  list-style: none;
  gap: 36px;
}

.nav-links a {
  text-decoration: none;
  color: rgba(255, 255, 255, 0.85);
  font-size: 15px;
  font-weight: 500;
  transition: var(--transition);
  position: relative;
}

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent);
  transition: var(--transition);
}

.nav-links a:hover {
  color: #fff;
}

.nav-links a:hover::after {
  width: 100%;
}

.scrolled .nav-links a {
  color: var(--text-secondary);
}

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

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

.mobile-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: #fff;
  transition: var(--transition);
  border-radius: 2px;
}

.scrolled .mobile-toggle span {
  background: var(--primary);
}

.mobile-toggle.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.mobile-toggle.active span:nth-child(2) {
  opacity: 0;
}

.mobile-toggle.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ========================================
   Hero
   ======================================== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(160deg, var(--primary-dark) 0%, var(--primary) 50%, var(--primary-light) 100%);
  overflow: hidden;
  padding: 120px 0 80px;
}

.hero-bg-decor {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.hero-circle {
  position: absolute;
  border-radius: 50%;
  opacity: 0.06;
}

.hero-circle-1 {
  width: 600px;
  height: 600px;
  background: var(--accent);
  top: -200px;
  right: -150px;
}

.hero-circle-2 {
  width: 400px;
  height: 400px;
  background: var(--accent);
  bottom: -100px;
  left: -100px;
}

.hero-circle-3 {
  width: 200px;
  height: 200px;
  background: #fff;
  top: 40%;
  left: 60%;
}

.hero-content {
  position: relative;
  text-align: center;
  color: #fff;
  z-index: 1;
}

.hero-badge {
  display: inline-block;
  padding: 8px 24px;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 100px;
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 2px;
  margin-bottom: 32px;
  backdrop-filter: blur(10px);
}

.hero-title {
  font-family: var(--font-serif);
  font-size: 64px;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 24px;
  letter-spacing: 2px;
}

.hero-title .highlight {
  background: linear-gradient(135deg, var(--accent-light), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 20px;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.8);
  margin-bottom: 40px;
  font-weight: 300;
}

.hero-hint {
  margin-top: 16px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.5);
  letter-spacing: 0.5px;
}

/* ========================================
   Section Headers
   ======================================== */
.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-tag {
  display: inline-block;
  padding: 6px 20px;
  background: var(--bg-warm);
  border: 1px solid var(--border);
  border-radius: 100px;
  font-size: 13px;
  font-weight: 600;
  color: var(--accent-dark);
  letter-spacing: 2px;
  margin-bottom: 20px;
}

.section-title {
  font-family: var(--font-serif);
  font-size: 36px;
  font-weight: 700;
  color: var(--primary);
  line-height: 1.4;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 17px;
  color: var(--text-muted);
  max-width: 560px;
  margin: 0 auto;
}

/* ========================================
   Features
   ======================================== */
.features {
  padding: 100px 0;
  background: var(--bg);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  padding: 40px 32px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--accent), var(--accent-light));
  opacity: 0;
  transition: var(--transition);
}

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

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  font-size: 36px;
  margin-bottom: 20px;
}

.feature-card h3 {
  font-size: 19px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
}

.feature-card p {
  font-size: 15px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ========================================
   Methodology
   ======================================== */
.methodology {
  padding: 100px 0;
  background: var(--bg-alt);
}

.comparison {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 32px;
  margin-bottom: 80px;
}

.compare-card {
  flex: 1;
  max-width: 420px;
  padding: 40px 32px;
  border-radius: var(--radius-lg);
  position: relative;
}

.compare-traditional {
  background: #fff;
  border: 1px solid var(--border);
}

.compare-ai {
  background: var(--primary);
  color: #fff;
  box-shadow: var(--shadow-lg);
}

.compare-badge {
  display: inline-block;
  padding: 6px 20px;
  border-radius: 100px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 1px;
  margin-bottom: 28px;
}

.compare-traditional .compare-badge {
  background: #fef2f2;
  color: #b91c1c;
}

.compare-ai .compare-badge {
  background: rgba(201, 168, 76, 0.2);
  color: var(--accent-light);
}

.compare-list {
  list-style: none;
}

.compare-list li {
  padding: 12px 0;
  font-size: 15px;
  line-height: 1.6;
  display: flex;
  align-items: flex-start;
  gap: 12px;
}

.compare-list li::before {
  content: '';
  display: inline-block;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  flex-shrink: 0;
  margin-top: 2px;
}

.negative::before {
  background: #fef2f2;
  border: 2px solid #fca5a5;
}

.positive::before {
  background: rgba(201, 168, 76, 0.2);
  border: 2px solid var(--accent-light);
}

.compare-traditional .compare-list li {
  color: var(--text-secondary);
}

.compare-ai .compare-list li {
  color: rgba(255, 255, 255, 0.9);
}

.compare-vs {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 700;
  color: var(--text-muted);
  flex-shrink: 0;
}

/* Method Detail */
.method-detail {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 56px 48px;
  text-align: center;
}

.method-title {
  font-family: var(--font-serif);
  font-size: 28px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 16px;
}

.method-desc {
  font-size: 16px;
  color: var(--text-secondary);
  max-width: 680px;
  margin: 0 auto 48px;
  line-height: 1.8;
}

.method-steps {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
}

.method-step {
  flex: 1;
  max-width: 260px;
  padding: 28px 24px;
  background: var(--bg-alt);
  border-radius: var(--radius);
  transition: var(--transition);
}

.method-step:hover {
  background: var(--bg-warm);
  transform: translateY(-2px);
  box-shadow: var(--shadow-sm);
}

.step-number {
  font-family: var(--font-serif);
  font-size: 32px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 8px;
}

.step-label {
  font-size: 17px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}

.step-desc {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.6;
}

.method-arrow {
  font-size: 24px;
  color: var(--accent);
  flex-shrink: 0;
}

/* ========================================
   Audience
   ======================================== */
.audience {
  padding: 100px 0;
  background: var(--bg);
}

.audience-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.audience-card {
  padding: 36px 28px;
  background: var(--bg-alt);
  border-radius: var(--radius-lg);
  text-align: center;
  transition: var(--transition);
  border: 1px solid transparent;
}

.audience-card:hover {
  background: #fff;
  border-color: var(--border);
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
}

.audience-emoji {
  font-size: 40px;
  margin-bottom: 20px;
}

.audience-card h3 {
  font-size: 18px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 12px;
}

.audience-card p {
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.7;
}

/* ========================================
   CTA
   ======================================== */
.cta {
  padding: 100px 0;
  background: linear-gradient(160deg, var(--primary-dark), var(--primary));
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta::before {
  content: '';
  position: absolute;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  background: var(--accent);
  opacity: 0.05;
  top: -200px;
  right: -100px;
}

.cta::after {
  content: '';
  position: absolute;
  width: 300px;
  height: 300px;
  border-radius: 50%;
  background: var(--accent);
  opacity: 0.04;
  bottom: -100px;
  left: -80px;
}

.cta-content {
  position: relative;
  z-index: 1;
}

.cta-title {
  font-family: var(--font-serif);
  font-size: 40px;
  font-weight: 700;
  color: #fff;
  margin-bottom: 20px;
}

.cta-desc {
  font-size: 18px;
  color: rgba(255, 255, 255, 0.75);
  line-height: 1.8;
  margin-bottom: 40px;
}

.cta-hint {
  margin-top: 16px;
  font-size: 13px;
  color: rgba(255, 255, 255, 0.45);
}

/* ========================================
   Footer
   ======================================== */
.footer {
  padding: 48px 0 32px;
  background: var(--primary-dark);
  color: rgba(255, 255, 255, 0.6);
}

.footer-content {
  text-align: center;
}

.footer-brand {
  margin-bottom: 24px;
}

.footer-logo {
  font-family: var(--font-serif);
  font-size: 18px;
  font-weight: 700;
  color: rgba(255, 255, 255, 0.9);
  letter-spacing: 1px;
}

.footer-tagline {
  font-size: 13px;
  margin-top: 6px;
  color: rgba(255, 255, 255, 0.4);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 32px;
  margin-bottom: 32px;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.5);
  text-decoration: none;
  font-size: 14px;
  transition: var(--transition);
}

.footer-links a:hover {
  color: var(--accent-light);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.08);
  padding-top: 24px;
}

.footer-bottom p {
  font-size: 13px;
  margin-bottom: 4px;
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.4);
  text-decoration: none;
  transition: var(--transition);
}

.footer-bottom a:hover {
  color: rgba(255, 255, 255, 0.7);
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 1024px) {
  .hero-title {
    font-size: 48px;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .audience-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .comparison {
    flex-direction: column;
  }

  .compare-card {
    max-width: 100%;
    width: 100%;
  }

  .compare-vs {
    margin: -8px 0;
  }

  .method-steps {
    flex-direction: column;
    gap: 12px;
  }

  .method-step {
    max-width: 100%;
    width: 100%;
  }

  .method-arrow {
    transform: rotate(90deg);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    flex-direction: column;
    padding: 24px;
    gap: 0;
    box-shadow: var(--shadow-md);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links a {
    color: var(--text-secondary);
    padding: 12px 0;
    font-size: 16px;
    border-bottom: 1px solid var(--border);
  }

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

  .nav-links a::after {
    display: none;
  }

  .btn-nav {
    display: none;
  }

  .mobile-toggle {
    display: flex;
  }

  .hero {
    min-height: auto;
    padding: 140px 0 80px;
  }

  .hero-title {
    font-size: 36px;
  }

  .hero-subtitle {
    font-size: 17px;
  }

  .hero-badge {
    font-size: 12px;
    padding: 6px 16px;
  }

  .features-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .feature-card {
    padding: 28px 24px;
  }

  .audience-grid {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .section-title {
    font-size: 28px;
  }

  .cta-title {
    font-size: 30px;
  }

  .cta-desc {
    font-size: 16px;
  }

  .method-detail {
    padding: 36px 24px;
  }

  .compare-card {
    padding: 28px 24px;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 30px;
  }

  .btn-hero {
    padding: 14px 36px;
    font-size: 16px;
  }

  .btn-cta {
    padding: 16px 40px;
    font-size: 16px;
  }

  .section-header {
    margin-bottom: 40px;
  }
}

/* ========================================
   Animations (subtle)
   ======================================== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.hero-content > * {
  animation: fadeInUp 0.8s ease-out backwards;
}

.hero-badge { animation-delay: 0.1s; }
.hero-title { animation-delay: 0.2s; }
.hero-subtitle { animation-delay: 0.3s; }
.btn-hero { animation-delay: 0.4s; }
.hero-hint { animation-delay: 0.5s; }