/* ========== 全局变量 ========== */
:root {
  --primary: #e63946;
  --primary-dark: #c1121f;
  --primary-light: #ff6b6b;
  --accent: #ff8c42;
  --bg-dark: #0a0a0f;
  --bg-card: #12121a;
  --bg-card-hover: #1a1a25;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --text-muted: #606070;
  --border: rgba(255,255,255,0.06);
  --border-hover: rgba(255,255,255,0.12);
  --gradient-primary: linear-gradient(135deg, #e63946 0%, #ff8c42 100%);
  --gradient-hero: radial-gradient(ellipse at 50% 0%, rgba(230,57,70,0.15) 0%, transparent 60%);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.3);
  --shadow-glow: 0 0 40px rgba(230,57,70,0.2);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-xs: 6px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

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

body {
  font-family: var(--font);
  background: var(--bg-dark);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
  overflow-y: hidden;
  height: 100vh;
  -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;
}

/* ========== 导航栏 ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 10, 15, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  transition: var(--transition);
}

.navbar.scrolled {
  background: rgba(10, 10, 15, 0.95);
  box-shadow: 0 2px 20px rgba(0,0,0,0.3);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 48px;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 1.2rem;
  cursor: pointer;
}

.logo-icon {
  font-size: 1.5rem;
}

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

.logo-badge {
  font-size: 0.6rem;
  font-weight: 600;
  background: var(--gradient-primary);
  color: #fff;
  padding: 2px 6px;
  border-radius: 4px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

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

.nav-links a {
  font-size: 0.9rem;
  color: var(--text-secondary);
  transition: var(--transition);
  position: relative;
}

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

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

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

.nav-actions {
  display: flex;
  gap: 12px;
}

.btn-login {
  background: transparent;
  border: 1px solid var(--border-hover);
  color: var(--text-secondary);
  padding: 8px 20px;
  border-radius: var(--radius-xs);
  font-size: 0.85rem;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
}

.btn-login:hover {
  border-color: var(--primary);
  color: var(--primary);
}

.btn-register {
  background: var(--gradient-primary);
  border: none;
  color: #fff;
  padding: 8px 20px;
  border-radius: var(--radius-xs);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
}

.btn-register:hover {
  opacity: 0.9;
  transform: translateY(-1px);
}

/* 移动端菜单按钮 */
.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.mobile-menu-btn span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 1px;
  transition: var(--transition);
}

.mobile-menu-btn.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}
.mobile-menu-btn.active span:nth-child(2) {
  opacity: 0;
}
.mobile-menu-btn.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

.mobile-menu {
  display: none;
  padding: 16px 24px 24px;
  border-top: 1px solid var(--border);
}

.mobile-menu.active {
  display: block;
}

.mobile-menu ul {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 16px;
}

.mobile-menu a {
  font-size: 1rem;
  color: var(--text-secondary);
  padding: 8px 0;
  display: block;
}

.mobile-actions {
  display: flex;
  gap: 12px;
}

/* ========== Hero 区域 ========== */
.hero {
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  padding: 58px 24px 16px;
  overflow: hidden;
}

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

.gradient-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.4;
}

.orb-1 {
  width: 400px;
  height: 400px;
  background: rgba(230, 57, 70, 0.3);
  top: -15%;
  left: 20%;
  animation: float 8s ease-in-out infinite;
}

.orb-2 {
  width: 300px;
  height: 300px;
  background: rgba(255, 140, 66, 0.2);
  bottom: 10%;
  right: 10%;
  animation: float 10s ease-in-out infinite reverse;
}

.orb-3 {
  width: 250px;
  height: 250px;
  background: rgba(114, 9, 183, 0.15);
  top: 40%;
  left: -5%;
  animation: float 12s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -30px) scale(1.05); }
  66% { transform: translate(-20px, 20px) scale(0.95); }
}

.particles {
  position: absolute;
  inset: 0;
}

.particle {
  position: absolute;
  width: 3px;
  height: 3px;
  background: rgba(255,255,255,0.15);
  border-radius: 50%;
  animation: twinkle var(--duration) ease-in-out infinite;
  animation-delay: var(--delay);
}

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

.hero-content {
  max-width: 1200px;
  margin: 0 auto;
  text-align: center;
  width: 100%;
  position: relative;
  z-index: 1;
}

.hero-logo {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  animation: fadeInUp 0.8s ease-out 0.1s both;
}

.logo-svg {
  width: 160px;
  height: 160px;
  filter: drop-shadow(0 0 30px rgba(230, 57, 70, 0.3));
}

.title-sub {
  display: block;
  font-size: 1.4rem;
  font-weight: 300;
  color: var(--text-secondary);
  margin-top: 2px;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--gradient-primary);
  color: #fff;
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.btn-primary.btn-large {
  padding: 16px 40px;
  font-size: 1.1rem;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.05);
  color: var(--text-secondary);
  padding: 10px 24px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  border: 1px solid var(--border-hover);
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
}

.btn-secondary:hover {
  background: rgba(255,255,255,0.1);
  color: var(--text-primary);
  border-color: rgba(255,255,255,0.2);
}

.hero-stats {
  display: flex;
  align-items: center;
  gap: 24px;
  animation: fadeInUp 0.8s ease-out 0.4s both;
}

.stat-item {
  display: flex;
  flex-direction: column;
}

.stat-num {
  font-size: 1.2rem;
  font-weight: 700;
  background: var(--gradient-primary);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.stat-label {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.stat-divider {
  width: 1px;
  height: 24px;
  background: var(--border-hover);
}

/* Hero 右侧 Mockup（已移除） */
.hero-visual { display: none; }
.hero-stats { display: none; }

.hero-mockup {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

.mockup-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  background: rgba(255,255,255,0.02);
  border-bottom: 1px solid var(--border);
}

.mockup-dots {
  display: flex;
  gap: 6px;
}

.mockup-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.mockup-dots span:nth-child(1) { background: #ff5f57; }
.mockup-dots span:nth-child(2) { background: #ffbd2e; }
.mockup-dots span:nth-child(3) { background: #28c840; }

.mockup-title {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.mockup-body {
  display: flex;
  min-height: 220px;
}

.mockup-sidebar {
  width: 160px;
  border-right: 1px solid var(--border);
  padding: 12px 0;
  flex-shrink: 0;
}

.sidebar-item {
  padding: 10px 16px;
  font-size: 0.8rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: var(--transition);
  border-left: 2px solid transparent;
}

.sidebar-item:hover {
  color: var(--text-secondary);
  background: rgba(255,255,255,0.02);
}

.sidebar-item.active {
  color: var(--primary-light);
  background: rgba(230, 57, 70, 0.05);
  border-left-color: var(--primary);
}

.mockup-main {
  flex: 1;
  padding: 16px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.chat-bubble {
  display: flex;
  gap: 10px;
  animation: fadeInUp 0.6s ease-out both;
}

.chat-bubble:nth-child(2) { animation-delay: 0.8s; }
.chat-bubble:nth-child(3) { animation-delay: 1.6s; }

.chat-bubble.user {
  flex-direction: row-reverse;
}

.bubble-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: rgba(230, 57, 70, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
}

.bubble-content {
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 8px 12px;
  max-width: 250px;
}

.chat-bubble.user .bubble-content {
  background: rgba(230, 57, 70, 0.1);
  border-color: rgba(230, 57, 70, 0.15);
}

.bubble-content p {
  font-size: 0.75rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.progress-bar {
  height: 4px;
  background: rgba(255,255,255,0.1);
  border-radius: 2px;
  margin-top: 10px;
  overflow: hidden;
}

.progress-fill {
  width: 65%;
  height: 100%;
  background: var(--gradient-primary);
  border-radius: 2px;
  animation: progressAnim 2s ease-in-out infinite;
}

@keyframes progressAnim {
  0% { width: 20%; }
  50% { width: 80%; }
  100% { width: 20%; }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInRight {
  from { opacity: 0; transform: translateX(40px); }
  to { opacity: 1; transform: translateX(0); }
}

/* ========== 功能特性区域 ========== */
.features {
  padding: 16px 0 8px;
  position: relative;
}

.features::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 80%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-hover), transparent);
}

.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
}

.section-header-left {
  text-align: left;
}

.section-tag {
  display: inline-block;
  background: rgba(230, 57, 70, 0.1);
  color: var(--primary-light);
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.72rem;
  font-weight: 500;
  margin-bottom: 8px;
  border: 1px solid rgba(230, 57, 70, 0.15);
}

.section-title {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 6px;
  line-height: 1.3;
}

.section-desc {
  font-size: 0.82rem;
  color: var(--text-secondary);
  max-width: 600px;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
  flex: 1;
  min-width: 0;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 34px 30px;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--gradient-primary);
  opacity: 0;
  transition: var(--transition);
}

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

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

.feature-icon {
  position: relative;
  width: 48px;
  height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
}

.feature-icon svg {
  width: 28px;
  height: 28px;
}

.icon-bg {
  position: absolute;
  inset: 0;
  border-radius: 10px;
  opacity: 0.15;
}

.icon-bg-blue { background: #3b82f6; }
.icon-bg-green { background: #22c55e; }
.icon-bg-purple { background: #a855f7; }
.icon-bg-orange { background: #f97316; }

.feature-icon svg {
  position: relative;
  z-index: 1;
}

.feature-card:nth-child(1) .feature-icon svg { stroke: #3b82f6; }
.feature-card:nth-child(2) .feature-icon svg { stroke: #22c55e; }
.feature-card:nth-child(3) .feature-icon svg { stroke: #a855f7; }
.feature-card:nth-child(4) .feature-icon svg { stroke: #f97316; }

.feature-card h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 6px;
}

.feature-subtitle {
  font-size: 0.95rem;
  color: var(--primary-light);
  margin-bottom: 12px;
  font-weight: 500;
}

.feature-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.feature-list li {
  font-size: 0.92rem;
  color: var(--text-secondary);
  padding-left: 20px;
  position: relative;
  line-height: 1.65;
}

.feature-list li::before {
  content: '✓';
  position: absolute;
  left: 0;
  color: var(--primary-light);
  font-size: 0.8rem;
  font-weight: 700;
}

/* ========== 下载按钮 ========== */
.btn-download {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: linear-gradient(135deg, #ff4757 0%, #ff6b3a 40%, #ffa502 100%);
  color: #fff;
  padding: 14px 56px;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  border: none;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
  box-shadow: 0 0 30px rgba(255, 71, 87, 0.4), 0 4px 15px rgba(255, 107, 58, 0.3);
  text-shadow: 0 1px 2px rgba(0,0,0,0.2);
  position: relative;
  overflow: hidden;
  flex-shrink: 0;
  white-space: nowrap;
  text-decoration: none;
}

.btn-download::before {
  content: '';
  position: absolute;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: linear-gradient(45deg, transparent 40%, rgba(255,255,255,0.15) 50%, transparent 60%);
  animation: btnShine 3s ease-in-out infinite;
}

@keyframes btnShine {
  0% { transform: translateX(-100%) rotate(45deg); }
  100% { transform: translateX(100%) rotate(45deg); }
}

.btn-download:hover {
  transform: translateY(-3px) scale(1.03);
  box-shadow: 0 0 50px rgba(255, 71, 87, 0.5), 0 8px 25px rgba(255, 107, 58, 0.4);
}

/* ========== 响应式 ========== */
@media (max-width: 1024px) {
  body {
    overflow-y: auto;
    height: auto;
  }

  .logo-svg {
    width: 130px;
    height: 130px;
  }

  .title-sub {
    font-size: 1.1rem;
  }
}

@media (max-width: 768px) {
  .nav-links,
  .nav-actions {
    display: none;
  }

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

  .hero {
    padding-top: 56px;
    padding-bottom: 16px;
  }

  .logo-svg {
    width: 100px;
    height: 100px;
  }

  .title-sub {
    font-size: 1rem;
  }

  .section-title {
    font-size: 1.3rem;
  }

  .section-header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

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

  .feature-card {
    padding: 16px;
  }
}

@media (max-width: 480px) {
  .hero-actions {
    flex-direction: column;
    align-items: center;
  }

  .btn-primary,
  .btn-secondary {
    width: 100%;
    justify-content: center;
  }

  .logo-svg {
    width: 80px;
    height: 80px;
  }

  .btn-download {
    padding: 10px 24px;
    font-size: 0.85rem;
  }
}