/* ========== CSS Variables ========== */
:root {
  --color-primary: #0A1628; /* Brand Dark Blue */
  --color-secondary: #FFFFFF; /* Card Backgrounds */
  --color-bg-light: #F8FAFC; /* Main Light Background */
  --color-accent: #2563EB;
  --color-accent-light: #3B82F6;
  --color-text: #1E293B; /* Dark Text */
  --color-text-secondary: #64748B;
  --color-border: #E2E8F0;
  --font-main: "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-number: "DIN Alternate", "Helvetica Neue", sans-serif;
  --max-width: 1200px;
  --nav-height: 72px;
  --transition: 0.3s ease;
  --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.05);
  --shadow-card-hover: 0 12px 40px rgba(0, 0, 0, 0.1);
  --radius: 8px;
}

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

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

body {
  font-family: var(--font-main);
  color: var(--color-text);
  background: var(--color-bg-light);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ========== Hide Scrollbar for all pages ========== */
html, body {
  -ms-overflow-style: none; /* IE and Edge */
  scrollbar-width: none; /* Firefox */
}
::-webkit-scrollbar {
  display: none; /* Chrome, Safari and Opera */
  width: 0;
  height: 0;
}

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

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  display: block;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  font-family: inherit;
}

/* ========== Typography ========== */
h1 { font-size: 3rem; font-weight: 700; line-height: 1.2; }
h2 { font-size: 2.25rem; font-weight: 700; line-height: 1.3; }
h3 { font-size: 1.5rem; font-weight: 600; line-height: 1.4; }
h4 { font-size: 1.125rem; font-weight: 600; line-height: 1.4; }

.section-title {
  text-align: center;
  margin-bottom: 1rem;
}

.section-subtitle {
  text-align: center;
  color: var(--color-text-secondary);
  margin-bottom: 3rem;
  font-size: 1rem;
}

/* ========== Layout ========== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 80px 0;
}

.section--dark {
  background: var(--color-secondary);
}

.section--light {
  background: var(--color-bg-light);
}

.section--light .section-subtitle {
  color: var(--color-text-secondary);
}

/* ========== Navigation ========== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--nav-height);
  z-index: 1000;
  transition: background var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.05);
}

.navbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.navbar__logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 700;
  color: #FFFFFF;
  transition: color var(--transition);
}

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

.navbar__logo img {
  height: 36px;
}

.navbar__logo-text {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  line-height: 1.1;
}

.logo-title {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 1px;
}

.logo-subtitle {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 2.5px;
}

.navbar__menu {
  display: flex;
  align-items: center;
  gap: 36px;
}

.navbar__link {
  font-size: 0.9375rem;
  color: rgba(255, 255, 255, 0.8);
  transition: color var(--transition);
  position: relative;
}

.navbar.scrolled .navbar__link {
  color: var(--color-text-secondary);
}

.navbar__link::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-accent);
  transition: width var(--transition);
}

.navbar__link:hover,
.navbar__link.active {
  color: #FFFFFF;
}

.navbar.scrolled .navbar__link:hover,
.navbar.scrolled .navbar__link.active {
  color: var(--color-primary);
}

.navbar__link:hover::after,
.navbar__link.active::after {
  width: 100%;
}

.navbar__toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 4px;
}

.navbar__toggle span {
  width: 24px;
  height: 2px;
  background: #FFFFFF;
  transition: var(--transition);
}

.navbar.scrolled .navbar__toggle span {
  background: var(--color-primary);
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 32px;
  border-radius: var(--radius);
  font-size: 0.9375rem;
  font-weight: 600;
  transition: all var(--transition);
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-accent), var(--color-accent-light));
  color: #FFFFFF;
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(45, 124, 255, 0.4);
}

.btn--outline {
  border: 1px solid var(--color-accent);
  color: var(--color-accent);
}

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

/* ========== Footer ========== */
.footer {
  background: var(--color-primary);
  border-top: 1px solid var(--color-border);
  padding: 60px 0 30px;
}

.footer__grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.5fr;
  gap: 40px;
  margin-bottom: 40px;
}

.footer__brand-desc {
  color: #A0B4CC;
  font-size: 0.875rem;
  margin-top: 12px;
  line-height: 1.7;
}

.footer__title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: #FFFFFF;
}

.footer__links {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer__link {
  color: #A0B4CC;
  font-size: 0.875rem;
  transition: color var(--transition);
}

.footer__link:hover {
  color: var(--color-accent);
}

.footer__contact-item {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #A0B4CC;
  font-size: 0.875rem;
  margin-bottom: 12px;
}

.footer__contact-item svg {
  width: 18px;
  height: 18px;
  fill: var(--color-accent);
  flex-shrink: 0;
}

.footer__contact-item.align-start {
  align-items: flex-start;
}

.footer__contact-item.align-start svg {
  margin-top: 4px;
}

.footer__bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8125rem;
  color: #A0B4CC;
}

.footer__record {
  display: flex;
  align-items: center;
  gap: 16px;
}

.footer__icp a, .footer__gwa a {
  color: #A0B4CC;
  transition: color var(--transition);
}

.footer__icp a:hover, .footer__gwa a:hover {
  color: var(--color-accent);
}

.footer__gwa a {
  display: flex;
  align-items: center;
  gap: 4px;
}

.footer__gwa img {
  width: 14px;
  height: 14px;
}

/* ========== Scroll 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);
}

/* ========== Back to Top ========== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: var(--color-accent);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition);
  z-index: 999;
}

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

.back-to-top:hover {
  background: var(--color-accent-light);
  transform: translateY(-3px);
}

.back-to-top svg {
  width: 20px;
  height: 20px;
  fill: var(--color-text);
}

/* ========== Page Banner (子页面通用) ========== */
.page-banner {
  padding-top: calc(var(--nav-height) + 80px);
  padding-bottom: 80px;
  background: linear-gradient(135deg, var(--color-primary), #1A3A5C);
  text-align: center;
  color: #FFFFFF;
}

.page-banner h1 {
  margin-bottom: 12px;
  color: #FFFFFF;
}

.page-banner p {
  color: #A0B4CC;
  font-size: 1.0625rem;
}

/* ========== Responsive ========== */
@media (max-width: 1199px) {
  .footer__grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 767px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  h3 { font-size: 1.25rem; }

  .section { padding: 60px 0; }

  .navbar__menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 24px;
    gap: 20px;
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition);
  }

  .navbar__menu.open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .navbar__link {
    color: var(--color-text);
  }

  .navbar__link:hover,
  .navbar__link.active {
    color: var(--color-primary);
  }

  .navbar__toggle {
    display: flex;
  }

  .footer__grid {
    grid-template-columns: 1fr;
    gap: 30px;
  }

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