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

:root {
  --primary-deep-blue: #0B1D3A;
  --secondary-navy: #13294B;
  --accent-gold: #D4AF37;
  --vivid-red: #C3272B;
  --ivory-white: #FFFFF0;
  --misty-blue: #A8B8D0;
  --pale-gold: #E8D18C;
  --ink-blue: #1A2B4C;
  --heading-font: "Source Han Serif SC", "Source Han Serif", "Noto Serif CJK SC", "STSong", "SimSun", serif;
  --body-font: "Source Han Sans SC", "Source Han Sans", "Noto Sans CJK SC", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --mono-font: "JetBrains Mono", "SF Mono", "Roboto Mono", "Courier New", monospace;
  --content-max-width: 1200px;
  --header-height: 80px;
  --transition-fast: 0.15s ease-out;
  --transition-medium: 0.3s ease-out;
  --transition-slow: 0.6s ease-out;
}

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

body {
  font-family: var(--body-font);
  font-size: 1rem;
  line-height: 1.8;
  color: var(--ivory-white);
  background: var(--primary-deep-blue);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--heading-font);
  color: var(--ivory-white);
  line-height: 1.3;
  letter-spacing: 0.05em;
  margin: 0 0 0.5em;
}

p {
  margin: 0 0 1em;
}

a {
  color: var(--accent-gold);
  text-decoration: none;
  transition: color var(--transition-medium);
}

a:hover {
  color: var(--pale-gold);
}

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

ul, ol {
  list-style: none;
}

#main-content {
  display: block;
  outline: none;
  min-height: 60vh;
}

.nav-list, .footer-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.mono-num {
  font-family: var(--mono-font);
  letter-spacing: 0.02em;
}

/* ========== Content Width & Section ========== */
.container {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 32px;
}

.section {
  padding: 80px 0;
}

.section-heading {
  font-family: var(--heading-font);
  font-size: 1.875rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  position: relative;
  padding-bottom: 18px;
  margin-bottom: 16px;
}

.section-heading::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 56px;
  height: 3px;
  border-radius: 3px;
  background: var(--accent-gold);
}

.section-subheading {
  font-size: 0.9375rem;
  color: var(--misty-blue);
  letter-spacing: 0.04em;
  max-width: 640px;
  margin-bottom: 40px;
}

/* ========== Skip Link ========== */
.skip-link {
  position: absolute;
  top: -100px;
  left: 16px;
  z-index: 2000;
  padding: 14px 28px;
  background: var(--accent-gold);
  color: var(--primary-deep-blue);
  border-radius: 0 0 14px 14px;
  font-weight: 700;
  font-size: 0.925rem;
  transition: top var(--transition-fast);
  clip: auto;
  white-space: nowrap;
}

.skip-link:focus {
  top: 0;
}

/* ========== Scroll Progress ========== */
.scroll-progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 2px;
  width: 0;
  background: linear-gradient(90deg, var(--accent-gold), var(--pale-gold));
  z-index: 10;
  pointer-events: none;
}

/* ========== Header ========== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: rgba(11, 29, 58, 0.92);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(212, 175, 55, 0.12);
  -webkit-transition: box-shadow var(--transition-medium);
  transition: box-shadow var(--transition-medium);
}

.site-header::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, rgba(212, 175, 55, 0.7), transparent);
  pointer-events: none;
}

.header-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  min-height: 76px;
}

/* Brand */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  flex-shrink: 0;
}

.brand-mark {
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--accent-gold), #A8852A);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--heading-font);
  font-weight: 900;
  font-size: 1.35rem;
  color: var(--primary-deep-blue);
  letter-spacing: 0;
  box-shadow: 0 0 24px rgba(212, 175, 55, 0.18);
}

.brand-text {
  font-family: var(--heading-font);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--ivory-white);
  letter-spacing: 0.1em;
  line-height: 1.2;
}

.brand-text small {
  display: block;
  font-family: var(--body-font);
  font-size: 0.65rem;
  font-weight: 500;
  letter-spacing: 0.35em;
  color: var(--pale-gold);
  margin-top: 2px;
}

/* Navigation */
.site-nav {
  display: flex;
  align-items: center;
  gap: 8px;
}

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

.nav-item {
  margin: 0;
}

.nav-link {
  display: block;
  padding: 10px 14px;
  font-family: var(--body-font);
  font-size: 0.9125rem;
  font-weight: 500;
  color: var(--ivory-white);
  position: relative;
  text-decoration: none;
  letter-spacing: 0.04em;
  transition: color var(--transition-medium);
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 4px;
  left: 14px;
  right: 14px;
  height: 2px;
  background: var(--accent-gold);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition-medium);
}

.nav-link:hover {
  color: var(--pale-gold);
}

.nav-link:hover::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--accent-gold);
}

.nav-cta {
  margin-left: 8px;
}

/* ========== Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 26px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--body-font);
  font-size: 0.9125rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-decoration: none;
  cursor: pointer;
  line-height: 1.4;
  transition: background var(--transition-medium), color var(--transition-medium), border-color var(--transition-medium), transform var(--transition-fast), box-shadow var(--transition-medium);
}

.btn-gold {
  background: var(--accent-gold);
  color: var(--primary-deep-blue);
  border-color: var(--accent-gold);
}

.btn-gold:hover {
  background: var(--pale-gold);
  border-color: var(--pale-gold);
  color: var(--primary-deep-blue);
  transform: translateY(-2px);
  box-shadow: 0 6px 24px rgba(212, 175, 55, 0.28);
}

.btn-outline {
  background: transparent;
  color: var(--pale-gold);
  border-color: rgba(212, 175, 55, 0.6);
}

.btn-outline:hover {
  background: rgba(212, 175, 55, 0.1);
  border-color: var(--accent-gold);
  color: var(--ivory-white);
}

/* Nav toggle */
.nav-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border-radius: 14px;
  background: transparent;
  border: 1px solid rgba(212, 175, 55, 0.4);
  cursor: pointer;
  position: relative;
  z-index: 10;
  transition: border-color var(--transition-medium), background var(--transition-medium);
}

.nav-toggle:hover {
  border-color: var(--accent-gold);
  background: rgba(212, 175, 55, 0.06);
}

.nav-toggle-icon {
  position: relative;
  width: 18px;
  height: 2px;
  background: var(--accent-gold);
  border-radius: 2px;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: '';
  position: absolute;
  left: 0;
  width: 100%;
  height: 2px;
  background: var(--accent-gold);
  border-radius: 2px;
  transition: transform var(--transition-medium), top var(--transition-medium);
}

.nav-toggle-icon::before {
  top: -6px;
}

.nav-toggle-icon::after {
  top: 6px;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon {
  background: transparent;
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::before {
  top: 0;
  transform: rotate(45deg);
}

.nav-toggle[aria-expanded="true"] .nav-toggle-icon::after {
  top: 0;
  transform: rotate(-45deg);
}

/* ========== Footer ========== */
.site-footer {
  background: linear-gradient(180deg, var(--secondary-navy), #0B1D3A);
  border-top: 1px solid rgba(212, 175, 55, 0.2);
  padding-top: 64px;
  color: var(--ivory-white);
}

.footer-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 0 32px 48px;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 56px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-logo {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--heading-font);
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  color: var(--ivory-white);
  text-decoration: none;
}

.footer-logo:hover {
  color: var(--pale-gold);
}

.footer-logo-mark {
  width: 38px;
  height: 38px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent-gold), #A8852A);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--heading-font);
  font-weight: 900;
  font-size: 1.15rem;
  color: var(--primary-deep-blue);
}

.footer-logo-text {
  letter-spacing: 0.1em;
}

.footer-desc {
  font-size: 0.875rem;
  color: var(--misty-blue);
  max-width: 420px;
  line-height: 1.8;
}

.footer-trust {
  font-size: 0.8125rem;
  color: var(--pale-gold);
  border-left: 3px solid var(--accent-gold);
  padding-left: 14px;
  background: rgba(212, 175, 55, 0.04);
  border-radius: 0 12px 12px 0;
  line-height: 1.7;
  max-width: 420px;
}

.footer-col {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-title {
  font-family: var(--heading-font);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--pale-gold);
  letter-spacing: 0.12em;
  padding-bottom: 8px;
  position: relative;
}

.footer-title::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 24px;
  height: 2px;
  background: var(--accent-gold);
  border-radius: 2px;
}

.footer-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-item {
  font-size: 0.875rem;
  color: var(--misty-blue);
  line-height: 1.7;
}

.footer-link {
  color: var(--misty-blue);
  text-decoration: none;
  font-size: 0.875rem;
  transition: color var(--transition-medium), padding-left var(--transition-medium);
}

.footer-link:hover {
  color: var(--accent-gold);
  padding-left: 4px;
}

.footer-bottom {
  border-top: 1px solid rgba(212, 175, 55, 0.15);
}

.footer-bottom-inner {
  max-width: var(--content-max-width);
  margin: 0 auto;
  padding: 20px 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.footer-icp,
.footer-copyright {
  font-family: var(--mono-font);
  font-size: 0.8125rem;
  color: var(--misty-blue);
}

/* ========== Back to Top ========== */
.back-top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  z-index: 999;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: var(--accent-gold);
  color: var(--primary-deep-blue);
  border: 1px solid rgba(212, 175, 55, 0.5);
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity var(--transition-medium), transform var(--transition-medium), visibility var(--transition-medium), background var(--transition-medium);
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
}

.back-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-top:hover {
  background: var(--pale-gold);
  box-shadow: 0 6px 24px rgba(212, 175, 55, 0.3);
}

/* ========== Breadcrumb ========== */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 20px 0;
  font-family: var(--body-font);
  font-size: 0.875rem;
  color: var(--misty-blue);
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 8px;
}

.breadcrumb li + li::before {
  content: '›';
  color: var(--accent-gold);
  font-size: 1.1rem;
}

.breadcrumb a {
  color: var(--misty-blue);
  text-decoration: none;
  transition: color var(--transition-medium);
}

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

.breadcrumb .current {
  color: var(--ivory-white);
}

/* ========== Card & Grid ========== */
.card {
  background: var(--ink-blue);
  border-radius: 20px;
  padding: 28px;
  position: relative;
  border: 1px solid rgba(232, 209, 140, 0.08);
  transition: border-color var(--transition-medium), box-shadow var(--transition-medium), transform var(--transition-medium);
}

.card:hover {
  border-color: rgba(212, 175, 55, 0.25);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
}

.grid-2,
.grid-3,
.grid-4 {
  display: grid;
  gap: 24px;
}

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

/* ========== Tag ========== */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 14px;
  border-radius: 999px;
  font-size: 0.8125rem;
  font-weight: 500;
  font-family: var(--body-font);
  background: rgba(212, 175, 55, 0.1);
  color: var(--pale-gold);
  border: 1px solid rgba(212, 175, 55, 0.25);
  white-space: nowrap;
}

.tag-red {
  background: rgba(195, 39, 43, 0.12);
  color: #F0B0B2;
  border-color: rgba(195, 39, 43, 0.35);
}

/* ========== Image Frame ========== */
.img-frame {
  position: relative;
  border-radius: 24px;
  overflow: hidden;
  background: var(--ink-blue);
  border: 1px solid rgba(212, 175, 55, 0.15);
}

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

.img-frame img,
.img-frame .img-placeholder {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.img-frame .img-placeholder {
  background: linear-gradient(135deg, rgba(212, 175, 55, 0.08), rgba(11, 29, 58, 0.2));
}

.img-frame.is-portrait::before {
  padding-top: 120%;
}

.img-frame.is-square::before {
  padding-top: 100%;
}

/* ========== Utility ========== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

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

.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.mt-2 { margin-top: 16px; }
.mb-2 { margin-bottom: 16px; }

/* ========== Accessibility ========== */
:focus-visible {
  outline: 3px solid var(--accent-gold);
  outline-offset: 3px;
  border-radius: 4px;
}

:focus:not(:focus-visible) {
  outline: none;
}

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

/* ========== Responsive ========== */
@media (min-width: 769px) and (max-width: 1024px) {
  .nav-link {
    padding: 10px 10px;
    font-size: 0.875rem;
  }

  .grid-3 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .grid-4 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 768px) {
  .site-header::before {
    height: 1px;
  }

  .header-inner {
    flex-wrap: wrap;
    padding: 0 20px;
    min-height: 64px;
    padding-top: 8px;
    padding-bottom: 8px;
  }

  .brand-mark {
    width: 38px;
    height: 38px;
    font-size: 1.1rem;
  }

  .brand-text {
    font-size: 1.15rem;
  }

  .brand-text small {
    font-size: 0.55rem;
    letter-spacing: 0.3em;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .site-nav {
    display: none;
    order: 3;
    flex-basis: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 12px;
    padding: 16px 0 8px;
    border-top: 1px solid rgba(212, 175, 55, 0.12);
  }

  .site-nav[data-open] {
    display: flex;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
  }

  .nav-link {
    padding: 12px 14px;
    border-radius: 12px;
    font-size: 0.95rem;
  }

  .nav-link::after {
    left: 14px;
    right: auto;
    width: 0;
  }

  .nav-link:hover::after,
  .nav-link[aria-current="page"]::after {
    width: 24px;
    transform: scaleX(1);
  }

  .nav-link:hover,
  .nav-link[aria-current="page"] {
    background: rgba(212, 175, 55, 0.08);
  }

  .nav-cta {
    margin-left: 14px;
    margin-top: 4px;
  }

  .section {
    padding: 48px 0;
  }

  .section-heading {
    font-size: 1.5rem;
  }

  .container {
    padding: 0 20px;
  }

  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
    gap: 20px;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 36px;
    padding: 0 20px 40px;
  }

  .footer-bottom-inner {
    padding: 16px 20px;
    flex-direction: column;
    align-items: flex-start;
  }

  .back-top {
    right: 16px;
    bottom: 16px;
    width: 44px;
    height: 44px;
    font-size: 1.1rem;
  }

  .breadcrumb {
    padding: 16px 20px;
  }
}

@media (max-width: 480px) {
  .header-inner {
    padding: 6px 16px;
  }

  .brand-text {
    font-size: 1.05rem;
  }

  .brand-mark {
    width: 34px;
    height: 34px;
    border-radius: 10px;
  }

  .footer-icp,
  .footer-copyright {
    font-size: 0.75rem;
  }
}