/* ============================================
   夜色AI — 暗夜星空主题下载页样式
   配色：深空蓝黑底 + 月光银 + 紫罗兰霓虹
   ============================================ */

/* --- CSS Variables --- */
:root {
  --bg-deep: #050510;
  --bg-surface: #0a0a20;
  --bg-card: rgba(20, 20, 50, 0.6);
  --text-primary: #e8e6f0;
  --text-secondary: #a09ab8;
  --text-muted: #6e6888;
  --accent-purple: #a855f7;
  --accent-indigo: #6366f1;
  --accent-pink: #ec4899;
  --accent-gold: #fbbf24;
  --accent-cyan: #06b6d4;
  --gradient-primary: linear-gradient(135deg, #6366f1, #a855f7, #ec4899);
  --gradient-gold: linear-gradient(135deg, #fbbf24, #f59e0b);
  --glass-bg: rgba(255, 255, 255, 0.03);
  --glass-border: rgba(255, 255, 255, 0.06);
  --glass-hover: rgba(255, 255, 255, 0.06);
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --shadow-glow: 0 0 40px rgba(168, 85, 247, 0.15);
  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
  --transition-fast: 0.2s ease;
  --transition-smooth: 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  background: var(--bg-deep);
  color: var(--text-primary);
  line-height: 1.7;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

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

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* --- Starfield Background --- */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(99, 102, 241, 0.08), transparent 60%),
    radial-gradient(ellipse 60% 40% at 20% 80%, rgba(168, 85, 247, 0.06), transparent 60%),
    radial-gradient(ellipse 50% 50% at 80% 30%, rgba(236, 72, 153, 0.05), transparent 60%),
    radial-gradient(ellipse at center, rgba(10, 10, 30, 0.3), var(--bg-deep));
  z-index: -1;
  pointer-events: none;
}

/* ============================================
   ANNOUNCEMENT BAR
   ============================================ */
.announcement-bar {
  position: fixed;
  top: 70px;
  left: 0;
  right: 0;
  z-index: 9999;
  background: linear-gradient(135deg, rgba(99, 102, 241, 0.95), rgba(168, 85, 247, 0.95));
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  padding: 12px 0;
  backdrop-filter: blur(12px);
  box-shadow: 0 4px 24px rgba(99, 102, 241, 0.35);
}

.announcement-inner {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  text-align: center;
}

.announcement-icon {
  flex-shrink: 0;
  color: #fef08a;
  animation: iconPulse 2s ease-in-out infinite;
}

@keyframes iconPulse {
  0%, 100% { opacity: 0.7; transform: scale(1); }
  50% { opacity: 1; transform: scale(1.1); }
}

.announcement-text {
  color: #fff;
  font-size: 14px;
  font-weight: 500;
  line-height: 1.5;
}

.announcement-text strong {
  color: #fef08a;
  font-weight: 700;
}

.announcement-bar ~ main .hero {
  padding-top: 200px;
}

/* ============================================
   NAVBAR
   ============================================ */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  padding: 16px 0;
  transition: background 0.3s ease, padding 0.3s ease, box-shadow 0.3s ease;
  background: rgba(5, 5, 16, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(255, 255, 255, 0.04);
}

.navbar.scrolled {
  padding: 10px 0;
  background: rgba(5, 5, 16, 0.95);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 20px;
  letter-spacing: -0.3px;
  z-index: 1001;
}

.logo-icon {
  display: flex;
  align-items: center;
}

.logo-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast);
  position: relative;
}

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

.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--gradient-primary);
  border-radius: 1px;
  transform: scaleX(0);
  transition: transform var(--transition-fast);
}

.nav-links a:hover::after {
  transform: scaleX(1);
}

.nav-download-btn {
  background: var(--gradient-primary);
  padding: 8px 20px !important;
  border-radius: 20px;
  color: #fff !important;
  font-weight: 600 !important;
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

.nav-download-btn:hover {
  box-shadow: 0 4px 20px rgba(168, 85, 247, 0.4);
  transform: translateY(-1px);
}

.nav-download-btn::after { display: none !important; }

/* Mobile menu button */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  z-index: 1001;
}

.mobile-menu-btn span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: var(--transition-smooth);
}

.mobile-menu-btn.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

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

.mobile-menu-btn.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ============================================
   HERO
   ============================================ */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  padding: 140px 0 100px;
  overflow: hidden;
  z-index: 0;
}

.hero-stars {
  position: absolute;
  inset: 0;
  overflow: hidden;
}

.star {
  position: absolute;
  background: white;
  border-radius: 50%;
  animation: twinkle var(--duration) ease-in-out infinite;
  animation-delay: var(--delay);
}

@keyframes twinkle {
  0%, 100% { opacity: var(--opacity-min); transform: scale(1); }
  50% { opacity: var(--opacity-max); transform: scale(1.5); }
}

.hero-moon {
  position: absolute;
  top: 15%;
  right: 10%;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  background: radial-gradient(circle at 60% 40%, rgba(251, 191, 36, 0.25), rgba(168, 85, 247, 0.08) 50%, transparent 70%);
  filter: blur(40px);
  animation: moonGlow 4s ease-in-out infinite alternate;
}

@keyframes moonGlow {
  0% { opacity: 0.5; transform: scale(1); }
  100% { opacity: 0.9; transform: scale(1.15); }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 720px;
  margin: 0 auto;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(168, 85, 247, 0.1);
  border: 1px solid rgba(168, 85, 247, 0.2);
  padding: 8px 18px;
  border-radius: 20px;
  font-size: 13px;
  font-weight: 500;
  color: #c4b5fd;
  margin-bottom: 28px;
}

.badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent-purple);
  animation: dotPulse 2s ease-in-out infinite;
}

@keyframes dotPulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(168, 85, 247, 0.5); }
  50% { box-shadow: 0 0 0 8px rgba(168, 85, 247, 0); }
}

.hero-title {
  font-family: 'Noto Serif SC', 'Inter', serif;
  font-size: 56px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -1.5px;
  margin-bottom: 24px;
}

.gradient-text {
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-desc {
  font-size: 17px;
  color: var(--text-secondary);
  line-height: 1.8;
  margin-bottom: 36px;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
  margin-bottom: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 36px;
  border-radius: 50px;
  font-size: 16px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: all var(--transition-smooth);
  white-space: nowrap;
}

.btn-primary {
  background: var(--gradient-primary);
  color: #fff;
  box-shadow: 0 4px 24px rgba(168, 85, 247, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px rgba(168, 85, 247, 0.5);
}

.btn-large {
  padding: 18px 48px;
  font-size: 18px;
}

.pulse-anim {
  animation: downloadPulse 2.5s ease-in-out infinite;
}

@keyframes downloadPulse {
  0%, 100% { box-shadow: 0 4px 24px rgba(168, 85, 247, 0.35); }
  50% { box-shadow: 0 8px 40px rgba(168, 85, 247, 0.6), 0 0 60px rgba(99, 102, 241, 0.3); }
}

.download-hint {
  font-size: 13px;
  color: var(--text-muted);
}

.hero-scroll-indicator {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  color: var(--text-muted);
  font-size: 12px;
  animation: scrollFade 2s ease-in-out infinite;
}

@keyframes scrollFade {
  0%, 100% { opacity: 0.4; transform: translateX(-50%) translateY(0); }
  50% { opacity: 1; transform: translateX(-50%) translateY(6px); }
}

/* ============================================
   SECTION HEADERS
   ============================================ */
.section-header {
  text-align: center;
  margin-bottom: 60px;
}

.section-tag {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 2px;
  text-transform: uppercase;
  color: var(--accent-purple);
  background: rgba(168, 85, 247, 0.1);
  padding: 6px 16px;
  border-radius: 12px;
  margin-bottom: 16px;
}

.section-title {
  font-family: 'Noto Serif SC', 'Inter', serif;
  font-size: 40px;
  font-weight: 700;
  line-height: 1.3;
  letter-spacing: -0.8px;
  margin-bottom: 12px;
}

.section-desc {
  font-size: 16px;
  color: var(--text-secondary);
}

/* ============================================
   FEATURES — 功能介绍
   ============================================ */
.features {
  padding: 100px 0;
  position: relative;
}

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

.feature-card {
  position: relative;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 36px 28px;
  transition: all var(--transition-smooth);
  overflow: hidden;
  backdrop-filter: blur(10px);
}

.feature-card-glow {
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle at 50% 0%, rgba(168, 85, 247, 0.08), transparent 60%);
  opacity: 0;
  transition: opacity var(--transition-smooth);
  pointer-events: none;
}

.feature-card:hover {
  transform: translateY(-4px);
  border-color: rgba(168, 85, 247, 0.3);
  box-shadow: var(--shadow-card), 0 0 40px rgba(168, 85, 247, 0.1);
}

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

.feature-icon {
  font-size: 40px;
  margin-bottom: 20px;
  display: block;
}

.feature-card h3 {
  font-size: 19px;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

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

/* ============================================
   GUIDE — 使用说明
   ============================================ */
.guide {
  padding: 100px 0;
  position: relative;
}

.guide-steps {
  display: flex;
  flex-direction: column;
  gap: 0;
  max-width: 760px;
  margin: 0 auto 50px;
}

.guide-step {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  position: relative;
}

.step-connector {
  position: absolute;
  left: 28px;
  top: 60px;
  width: 2px;
  height: calc(100% - 20px);
  background: linear-gradient(to bottom, rgba(168, 85, 247, 0.4), rgba(168, 85, 247, 0.05));
}

.step-number {
  position: relative;
  width: 58px;
  height: 58px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--bg-surface);
  border: 2px solid rgba(168, 85, 247, 0.3);
  z-index: 1;
}

.step-number span {
  font-size: 18px;
  font-weight: 700;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.step-ring {
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  border: 2px solid rgba(168, 85, 247, 0.2);
  animation: ringPulse 3s ease-in-out infinite;
}

@keyframes ringPulse {
  0%, 100% { transform: scale(1); opacity: 0.3; }
  50% { transform: scale(1.1); opacity: 0.7; }
}

.step-card {
  flex: 1;
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-bottom: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  transition: all var(--transition-smooth);
  backdrop-filter: blur(10px);
}

.step-card:hover {
  border-color: rgba(168, 85, 247, 0.25);
  box-shadow: var(--shadow-card);
}

.step-tag {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--accent-purple);
  margin-bottom: 6px;
  display: block;
}

.step-card-header h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: 8px;
}

.step-card p {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 480px;
}

.step-visual {
  flex-shrink: 0;
  color: var(--accent-purple);
  opacity: 0.7;
}

.guide-cta {
  text-align: center;
}

/* ============================================
   FAQ — 常见问题
   ============================================ */
.faq {
  padding: 100px 0;
}

.faq-list {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: all var(--transition-smooth);
  backdrop-filter: blur(10px);
}

.faq-item:hover {
  border-color: rgba(168, 85, 247, 0.2);
}

.faq-item.active {
  border-color: rgba(168, 85, 247, 0.3);
  box-shadow: 0 4px 20px rgba(168, 85, 247, 0.1);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 20px 24px;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 15px;
  font-weight: 600;
  text-align: left;
  cursor: pointer;
  font-family: inherit;
  transition: color var(--transition-fast);
}

.faq-q-icon {
  flex-shrink: 0;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(168, 85, 247, 0.15);
  border-radius: 8px;
  font-size: 13px;
  font-weight: 800;
  color: var(--accent-purple);
}

.faq-question span:nth-child(2) {
  flex: 1;
}

.faq-arrow {
  flex-shrink: 0;
  color: var(--text-muted);
  transition: transform var(--transition-smooth);
}

.faq-item.active .faq-arrow {
  transform: rotate(180deg);
  color: var(--accent-purple);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-item.active .faq-answer {
  max-height: 300px;
}

.faq-answer p {
  padding: 0 24px 20px 64px;
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.8;
}

.faq-answer strong {
  color: var(--accent-purple);
}

/* ============================================
   CTA — 底部召唤区
   ============================================ */
.cta {
  position: relative;
  padding: 100px 0;
  text-align: center;
  overflow: hidden;
}

.cta-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 60% 80% at 50% 50%, rgba(99, 102, 241, 0.1), transparent 60%),
    radial-gradient(ellipse 40% 50% at 20% 30%, rgba(168, 85, 247, 0.08), transparent 60%);
  pointer-events: none;
}

.cta-content {
  position: relative;
  z-index: 1;
  max-width: 600px;
  margin: 0 auto;
}

.cta-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 3px;
  text-transform: uppercase;
  color: var(--accent-gold);
  margin-bottom: 20px;
}

.cta h2 {
  font-family: 'Noto Serif SC', 'Inter', serif;
  font-size: 44px;
  font-weight: 700;
  line-height: 1.3;
  margin-bottom: 16px;
}

.cta p {
  font-size: 16px;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.cta-actions {
  margin-bottom: 16px;
}

.cta-hint {
  font-size: 13px;
  color: var(--text-muted);
  letter-spacing: 0.5px;
}

/* ============================================
   FOOTER
   ============================================ */
.footer {
  padding: 60px 0 30px;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  background: rgba(5, 5, 16, 0.6);
  text-align: center;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 30px;
}

.footer-brand p {
  margin-top: 12px;
  font-size: 14px;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 18px;
  font-weight: 700;
}

.footer-bottom {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 20px;
  padding-top: 24px;
  border-top: 1px solid rgba(255, 255, 255, 0.04);
  font-size: 13px;
  color: var(--text-muted);
}

.beian-link {
  color: var(--text-muted);
  transition: color var(--transition-fast);
}

.beian-link:hover {
  color: var(--text-primary);
}

/* ============================================
   SCROLL ANIMATIONS
   ============================================ */
[data-aos="fade-up"] {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease, transform 0.8s ease;
}

[data-aos="fade-up"].aos-visible {
  opacity: 1;
  transform: translateY(0);
}

/* ============================================
   RESPONSIVE — 平板
   ============================================ */
@media (max-width: 1024px) {
  .hero-title { font-size: 44px; }
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .section-title { font-size: 34px; }
}

@media (max-width: 768px) {
  /* Nav */
  .nav-links {
    position: fixed;
    top: 0;
    right: -100%;
    width: 280px;
    height: 100vh;
    flex-direction: column;
    justify-content: center;
    gap: 24px;
    background: rgba(10, 10, 30, 0.98);
    backdrop-filter: blur(20px);
    padding: 40px;
    transition: right var(--transition-smooth);
    border-left: 1px solid var(--glass-border);
  }

  .nav-links.active {
    right: 0;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .nav-download-btn {
    display: inline-flex;
    justify-content: center;
    width: 100%;
  }

  /* Announcement */
  .announcement-bar {
    top: 58px;
    padding: 10px 0;
  }

  .announcement-text {
    font-size: 12px;
  }

  .announcement-bar ~ main .hero {
    padding-top: 180px;
  }

  /* Hero */
  .hero {
    padding: 120px 0 80px;
  }

  .hero-title {
    font-size: 34px;
    letter-spacing: -1px;
  }

  .hero-desc {
    font-size: 15px;
  }

  /* Features */
  .features-grid {
    grid-template-columns: 1fr;
    max-width: 460px;
    margin: 0 auto;
  }

  /* Guide */
  .step-card {
    flex-direction: column;
    text-align: center;
    padding: 24px;
  }

  .step-card p {
    max-width: 100%;
  }

  .step-visual {
    order: -1;
  }

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

  /* CTA */
  .cta h2 {
    font-size: 30px;
  }

  /* Footer */
  .footer-bottom {
    flex-direction: column;
    gap: 8px;
  }
}

@media (max-width: 480px) {
  .announcement-bar {
    top: 54px;
    padding: 8px 0;
  }

  .announcement-text {
    font-size: 11px;
  }

  .announcement-icon {
    display: none;
  }

  .announcement-bar ~ main .hero {
    padding-top: 170px;
  }

  .hero {
    padding: 100px 0 60px;
  }

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

  .hero-badge {
    font-size: 12px;
    padding: 6px 14px;
  }

  .btn {
    padding: 14px 28px;
    font-size: 15px;
    width: 100%;
    justify-content: center;
  }

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

  .section-title {
    font-size: 24px;
  }

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

  .faq-question {
    font-size: 14px;
    padding: 16px 18px;
  }

  .faq-answer p {
    padding: 0 18px 16px 50px;
  }

  .cta h2 {
    font-size: 26px;
  }

  .footer-bottom {
    flex-direction: column;
    gap: 8px;
    text-align: center;
  }

  .hero-scroll-indicator {
    display: none;
  }
}