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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Roboto', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  font-weight: 300;
  font-size: 16px;
  line-height: 1.7;
  color: #E0E6ED;
  background: linear-gradient(135deg, #0D1B2A 0%, #1B2838 100%);
  background-attachment: fixed;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: #FF8C00;
  text-decoration: none;
  transition: color 0.25s ease;
}

a:hover {
  color: #FFB74D;
}

a:focus-visible {
  outline: 2px solid #FF6F00;
  outline-offset: 2px;
  border-radius: 4px;
}

ul, ol {
  list-style: none;
}

/* ===== CSS Variables ===== */
:root {
  --color-primary: #1E3C72;
  --color-primary-light: #2A5298;
  --color-accent: #FF6F00;
  --color-accent-light: #FF8C00;
  --color-accent-glow: rgba(255, 111, 0, 0.35);
  --color-bg-start: #0D1B2A;
  --color-bg-end: #1B2838;
  --color-card-bg: #1E2D3D;
  --color-card-border: rgba(30, 60, 114, 0.5);
  --color-text-body: #E0E6ED;
  --color-text-heading: #FFFFFF;
  --color-text-muted: #A0AAB8;
  --color-link: #FF8C00;
  --color-link-hover: #FFB74D;
  --color-line: #FF6F00;
  --font-heading: 'Montserrat', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Roboto', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SFMono-Regular', 'Menlo', 'Consolas', monospace;
  --container-max: 1200px;
  --container-padding: 20px;
  --header-height: 68px;
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.35);
  --shadow-glow: 0 0 20px rgba(255, 111, 0, 0.15);
  --transition-fast: 0.2s ease;
  --transition-base: 0.35s ease;
  --transition-slow: 0.5s ease;
}

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

/* ===== Skip Link ===== */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  background: var(--color-accent);
  color: #fff;
  padding: 12px 24px;
  z-index: 10000;
  font-weight: 600;
  font-family: var(--font-heading);
  border-radius: 0 0 var(--radius-sm) 0;
  transition: top 0.25s ease;
}

.skip-link:focus {
  top: 0;
  outline: none;
}

/* ===== Header ===== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  background: transparent;
  transition: background var(--transition-base), box-shadow var(--transition-base);
  height: var(--header-height);
}

.site-header.scrolled {
  background: var(--color-primary);
  box-shadow: 0 2px 24px rgba(0, 0, 0, 0.45);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  position: relative;
}

.header-brand {
  flex-shrink: 0;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 10px;
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: 0.5px;
  text-decoration: none;
}

.brand-link:hover {
  color: #fff;
}

.brand-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
}

.brand-icon svg {
  width: 100%;
  height: 100%;
}

.brand-text {
  line-height: 1;
}

/* ===== Navigation ===== */
.nav-menu {
  display: flex;
  align-items: center;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: block;
  padding: 8px 16px;
  font-family: var(--font-heading);
  font-weight: 500;
  font-size: 14px;
  color: rgba(255, 255, 255, 0.8);
  letter-spacing: 0.3px;
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast), box-shadow var(--transition-fast);
  text-decoration: none;
  position: relative;
}

.nav-link:hover {
  color: #fff;
  background: rgba(255, 111, 0, 0.12);
  box-shadow: 0 0 12px rgba(255, 111, 0, 0.08);
}

.nav-link[aria-current="page"] {
  color: var(--color-accent);
  background: rgba(255, 111, 0, 0.08);
  box-shadow: inset 0 -2px 0 var(--color-accent), 0 0 16px rgba(255, 111, 0, 0.1);
}

.nav-link[aria-current="page"]::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 16px;
  right: 16px;
  height: 2px;
  background: var(--color-accent);
  border-radius: 1px;
  box-shadow: 0 0 8px var(--color-accent-glow);
}

/* ===== Nav Toggle (Mobile) ===== */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 44px;
  height: 44px;
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.2);
  border-radius: var(--radius-sm);
  cursor: pointer;
  padding: 10px;
  gap: 5px;
  transition: border-color var(--transition-fast), background var(--transition-fast);
}

.nav-toggle:hover {
  border-color: var(--color-accent);
  background: rgba(255, 111, 0, 0.06);
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

.nav-toggle-line {
  display: block;
  width: 22px;
  height: 2px;
  background: #fff;
  border-radius: 1px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ===== Header Lang ===== */
.header-lang {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-text-muted);
  letter-spacing: 0.5px;
  padding: 4px 12px;
  border-left: 1px solid rgba(255, 255, 255, 0.1);
  margin-left: 8px;
  flex-shrink: 0;
}

/* ===== Footer ===== */
.site-footer {
  background: #0A1520;
  border-top: 1px solid rgba(255, 111, 0, 0.12);
  padding: 60px 0 0 0;
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1.4fr;
  gap: 40px;
  padding-bottom: 40px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

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

.footer-brand-text {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 20px;
  color: #fff;
  letter-spacing: 0.5px;
}

.footer-trust {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-text-muted);
  max-width: 380px;
}

.footer-col-title {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 15px;
  color: #fff;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
  position: relative;
  padding-left: 14px;
}

.footer-col-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 4px;
  bottom: 4px;
  width: 3px;
  background: var(--color-accent);
  border-radius: 2px;
  box-shadow: 0 0 8px var(--color-accent-glow);
}

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

.footer-link {
  font-size: 14px;
  color: var(--color-text-muted);
  transition: color var(--transition-fast), padding-left var(--transition-fast);
  padding-left: 0;
}

.footer-link:hover {
  color: var(--color-accent-light);
  padding-left: 6px;
}

.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 14px;
  color: var(--color-text-muted);
}

.contact-label {
  color: var(--color-text-muted);
  font-weight: 400;
}

.contact-link {
  color: var(--color-link);
  transition: color var(--transition-fast);
}

.contact-link:hover {
  color: var(--color-link-hover);
}

.contact-text {
  color: var(--color-text-body);
}

.contact-note {
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--color-text-muted);
  background: rgba(255, 111, 0, 0.05);
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  border-left: 2px solid var(--color-accent);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 24px 0;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-bottom-left {
  display: flex;
  align-items: center;
  gap: 20px;
  font-size: 13px;
  color: var(--color-text-muted);
}

.footer-icp {
  font-family: var(--font-mono);
  font-size: 12px;
  color: rgba(255, 255, 255, 0.3);
}

.footer-bottom-links {
  display: flex;
  gap: 20px;
}

.footer-bottom-link {
  font-size: 13px;
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

.footer-bottom-link:hover {
  color: var(--color-accent-light);
}

/* ===== Shared Components ===== */

/* Buttons */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 32px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 15px;
  color: #fff;
  background: var(--color-accent);
  border: none;
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: background var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
  text-decoration: none;
  letter-spacing: 0.3px;
}

.btn-primary:hover {
  background: #E65C00;
  box-shadow: 0 0 24px var(--color-accent-glow), 0 0 48px rgba(255, 111, 0, 0.1);
  transform: translateY(-1px);
  color: #fff;
}

.btn-primary:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 11px 31px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 15px;
  color: var(--color-accent);
  background: transparent;
  border: 2px solid var(--color-accent);
  border-radius: var(--radius-lg);
  cursor: pointer;
  transition: background var(--transition-fast), box-shadow var(--transition-fast), color var(--transition-fast);
  text-decoration: none;
  letter-spacing: 0.3px;
}

.btn-secondary:hover {
  background: var(--color-accent);
  color: #fff;
  box-shadow: 0 0 20px var(--color-accent-glow);
}

.btn-secondary:focus-visible {
  outline: 2px solid #fff;
  outline-offset: 2px;
}

/* Cards */
.card {
  background: var(--color-card-bg);
  border: 1px solid var(--color-card-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-card);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
}

.card:hover {
  border-color: rgba(255, 111, 0, 0.2);
  box-shadow: var(--shadow-card), 0 0 20px rgba(255, 111, 0, 0.05);
  transform: translateY(-2px);
}

.card-glow {
  border-color: rgba(255, 111, 0, 0.15);
  box-shadow: 0 0 30px rgba(255, 111, 0, 0.06);
}

/* Section Title */
.section-title {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 28px;
  color: var(--color-text-heading);
  margin-bottom: 24px;
  position: relative;
  padding-left: 20px;
  letter-spacing: 0.3px;
}

.section-title::before {
  content: '';
  position: absolute;
  left: 0;
  top: 6px;
  bottom: 6px;
  width: 4px;
  background: var(--color-accent);
  border-radius: 2px;
  box-shadow: 0 0 12px var(--color-accent-glow);
}

/* Timeline */
.timeline {
  position: relative;
  padding-left: 32px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 10px;
  top: 0;
  bottom: 0;
  width: 2px;
  background: var(--color-primary);
  opacity: 0.4;
}

.timeline-item {
  position: relative;
  padding-bottom: 28px;
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -22px;
  top: 6px;
  width: 12px;
  height: 12px;
  background: var(--color-accent);
  border-radius: 50%;
  box-shadow: 0 0 12px var(--color-accent-glow);
}

.timeline-item:last-child {
  padding-bottom: 0;
}

/* Data Badge */
.data-badge {
  display: inline-flex;
  align-items: center;
  padding: 4px 14px;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 13px;
  color: #fff;
  background: var(--color-accent);
  border-radius: 20px;
  letter-spacing: 0.3px;
  box-shadow: 0 0 12px rgba(255, 111, 0, 0.15);
}

/* Progress Bar */
.progress-bar {
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 3px;
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: var(--color-accent);
  border-radius: 3px;
  box-shadow: 0 0 12px var(--color-accent-glow);
  transition: width 0.8s ease;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 16px 0;
  font-size: 13px;
  color: var(--color-text-muted);
  font-family: var(--font-body);
}

.breadcrumb a {
  color: var(--color-text-muted);
  transition: color var(--transition-fast);
}

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

.breadcrumb-sep {
  color: var(--color-accent);
  font-weight: 600;
  opacity: 0.6;
}

.breadcrumb-current {
  color: var(--color-text-body);
  font-weight: 400;
}

/* Page Content */
.page-content {
  padding-top: calc(var(--header-height) + 20px);
  padding-bottom: 60px;
  min-height: 60vh;
}

/* Image Container Placeholder */
.img-container {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-md);
  background: var(--color-card-bg);
}

.img-container::before {
  content: '';
  display: block;
  padding-top: 56.25%;
}

.img-placeholder {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-text-muted);
  font-size: 14px;
  background: linear-gradient(135deg, rgba(30, 60, 114, 0.2), rgba(255, 111, 0, 0.06));
  border: 1px dashed rgba(255, 255, 255, 0.08);
}

/* ===== Responsive ===== */

/* Tablet */
@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .footer-brand-col {
    grid-column: 1 / -1;
  }

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

/* Mobile */
@media (max-width: 768px) {
  :root {
    --container-padding: 16px;
    --header-height: 60px;
  }

  .header-inner {
    gap: 8px;
  }

  .brand-text {
    font-size: 18px;
  }

  .brand-icon {
    width: 30px;
    height: 30px;
  }

  .header-lang {
    display: none;
  }

  .nav-toggle {
    display: flex;
  }

  .nav-menu {
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--color-primary);
    border-top: 1px solid rgba(255, 255, 255, 0.06);
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.5);
    padding: 12px 20px 20px;
    transform: translateY(-8px);
    opacity: 0;
    visibility: hidden;
    transition: transform var(--transition-base), opacity var(--transition-base), visibility var(--transition-base);
    border-radius: 0 0 var(--radius-md) var(--radius-md);
  }

  .nav-menu[data-open] {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    gap: 2px;
  }

  .nav-link {
    padding: 12px 16px;
    font-size: 15px;
    width: 100%;
  }

  .nav-link[aria-current="page"]::after {
    display: none;
  }

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

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

  .footer-bottom-left {
    flex-direction: column;
    gap: 8px;
  }

  .section-title {
    font-size: 22px;
    padding-left: 16px;
  }

  .card {
    padding: 20px;
  }

  .btn-primary,
  .btn-secondary {
    padding: 10px 24px;
    font-size: 14px;
  }

  .page-content {
    padding-top: calc(var(--header-height) + 12px);
  }
}

/* Small Mobile */
@media (max-width: 480px) {
  .brand-text {
    font-size: 16px;
  }

  .brand-icon {
    width: 26px;
    height: 26px;
  }

  .section-title {
    font-size: 20px;
  }
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
  }

  .nav-menu {
    transition: none !important;
  }

  .card:hover {
    transform: none !important;
  }

  .btn-primary:hover,
  .btn-secondary:hover {
    transform: none !important;
  }

  .progress-bar-fill {
    transition: none !important;
  }
}

/* ===== Focus Visible ===== */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ===== Selection ===== */
::selection {
  background: var(--color-accent);
  color: #fff;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg-start);
}

::-webkit-scrollbar-thumb {
  background: var(--color-primary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-primary-light);
}