/* ===== 全局重置与变量 ===== */
:root {
  --bg: #f0f2f5;
  --surface: #ffffff;
  --text: #1a1a2e;
  --text2: #4a4a6a;
  --accent: #e94560;
  --accent2: #0f3460;
  --grad: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  --glass: rgba(255,255,255,0.25);
  --shadow: 0 8px 32px rgba(0,0,0,0.08);
  --radius: 20px;
  --transition: 0.3s ease;
}

.dark {
  --bg: #0d0d1a;
  --surface: #1a1a2e;
  --text: #e0e0e0;
  --text2: #a0a0c0;
  --glass: rgba(255,255,255,0.08);
  --shadow: 0 8px 32px rgba(0,0,0,0.4);
}

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

body {
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  transition: background var(--transition), color var(--transition);
  overflow-x: hidden;
}

a {
  color: inherit;
  text-decoration: none;
}

img, svg {
  display: block;
  max-width: 100%;
  height: auto;
}

.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}

.glass {
  background: var(--glass);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-radius: var(--radius);
  border: 1px solid rgba(255,255,255,0.1);
  box-shadow: var(--shadow);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent);
  color: #fff;
  padding: 14px 32px;
  border-radius: 50px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 12px 24px rgba(233,69,96,0.3);
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--accent);
  color: var(--accent);
}

.btn-outline:hover {
  background: var(--accent);
  color: #fff;
}

.section {
  padding: 80px 0;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
}

.section-sub {
  font-size: 1.1rem;
  color: var(--text2);
  max-width: 640px;
  margin-bottom: 48px;
}

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3,1fr);
  gap: 32px;
}

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

.card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 32px;
  box-shadow: var(--shadow);
  transition: transform var(--transition);
}

.card:hover {
  transform: translateY(-4px);
}

.dark-toggle {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 999;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--surface);
  border: 1px solid rgba(255,255,255,0.2);
  box-shadow: var(--shadow);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  transition: background var(--transition);
}

.back-top {
  position: fixed;
  bottom: 84px;
  right: 24px;
  z-index: 999;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  border: none;
  box-shadow: var(--shadow);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition), visibility var(--transition);
}

.back-top.show {
  opacity: 1;
  visibility: visible;
}

@media (max-width: 768px) {
  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }
  .section-title {
    font-size: 2rem;
  }
  .section {
    padding: 48px 0;
  }
}

/* ===== Hero ===== */
.hero {
  min-height: 80vh;
  display: flex;
  align-items: center;
  background: var(--grad);
  color: #fff;
  border-radius: 0 0 40px 40px;
  position: relative;
  overflow: hidden;
}

.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 30% 70%, rgba(233,69,96,0.2) 0%, transparent 60%);
}

.hero-content {
  position: relative;
  z-index: 2;
}

.hero h1 {
  font-size: 4rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 20px;
}

.hero p {
  font-size: 1.25rem;
  opacity: 0.85;
  max-width: 540px;
  margin-bottom: 32px;
}

.hero-btns {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

/* ===== Carousel ===== */
.carousel {
  position: relative;
  width: 100%;
  overflow: hidden;
}

.carousel-inner {
  display: flex;
  transition: transform 0.6s ease;
}

.carousel-item {
  min-width: 100%;
}

.carousel-controls {
  position: absolute;
  top: 50%;
  width: 100%;
  display: flex;
  justify-content: space-between;
  transform: translateY(-50%);
  pointer-events: none;
}

.carousel-btn {
  pointer-events: auto;
  background: rgba(255,255,255,0.2);
  border: none;
  color: #fff;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.5rem;
  backdrop-filter: blur(4px);
  transition: background var(--transition);
}

.carousel-btn:hover {
  background: rgba(255,255,255,0.4);
}

/* ===== Fade In Animation ===== */
.fade-in {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ===== Count Up ===== */
.count-up {
  font-size: 3rem;
  font-weight: 700;
  color: var(--accent);
}

/* ===== Navigation ===== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--glass);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid rgba(255,255,255,0.1);
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 0;
}

.nav-logo {
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--accent);
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links {
  display: flex;
  gap: 24px;
  list-style: none;
}

.nav-links a {
  font-weight: 500;
  position: relative;
  transition: color var(--transition);
}

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

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

.nav-search {
  background: transparent;
  border: 1px solid var(--text2);
  border-radius: 50px;
  padding: 8px 16px;
  color: var(--text);
  outline: none;
  width: 180px;
  transition: border var(--transition);
}

.nav-search:focus {
  border-color: var(--accent);
}

.mobile-menu {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.8rem;
  cursor: pointer;
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    flex-direction: column;
    background: var(--surface);
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    padding: 16px;
    box-shadow: var(--shadow);
  }
  .nav-links.open {
    display: flex;
  }
  .mobile-menu {
    display: block;
  }
  .nav-search {
    width: 120px;
  }
}

/* ===== FAQ ===== */
.faq-item {
  border-bottom: 1px solid rgba(255,255,255,0.1);
  padding: 16px 0;
  cursor: pointer;
}

.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 600;
  font-size: 1.1rem;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.4s ease;
  color: var(--text2);
}

.faq-item.open .faq-answer {
  max-height: 300px;
  padding-top: 12px;
}

.faq-item.open .faq-icon {
  transform: rotate(180deg);
}

/* ===== Breadcrumb ===== */
.breadcrumb {
  display: flex;
  gap: 8px;
  list-style: none;
  padding: 16px 0;
  font-size: 0.9rem;
  color: var(--text2);
}

.breadcrumb li+li::before {
  content: '/';
  margin-right: 8px;
  color: var(--text2);
}

/* ===== Footer ===== */
.footer {
  background: var(--grad);
  color: #fff;
  padding: 48px 0 24px;
  border-radius: 40px 40px 0 0;
}

.footer a {
  opacity: 0.8;
  transition: opacity var(--transition);
}

.footer a:hover {
  opacity: 1;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr 1fr;
  gap: 32px;
}

@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}