:root {
  --color-primary: #0B1D3A;
  --color-accent: #F5C518;
  --color-red: #E63946;
  --color-dark: #0D1117;
  --color-card: #1A2332;
  --color-white: #FFFFFF;
  --color-gray: #B0B8C4;
  --color-border: #2D3A4A;

  --font-heading: 'Montserrat', 'Impact', 'Arial Black', sans-serif;
  --font-body: 'Noto Sans SC', 'Microsoft YaHei', 'PingFang SC', sans-serif;
  --font-number: 'Montserrat', 'Arial Black', sans-serif;

  --text-h1: 3rem;
  --text-h2: 2.25rem;
  --text-h3: 1.75rem;
  --text-body: 1rem;
  --text-small: 0.875rem;

  --line-height-heading: 1.1;
  --line-height-body: 1.7;

  --max-width: 1200px;
  --header-height: 4rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-body);
  line-height: var(--line-height-body);
  color: var(--color-white);
  background-color: var(--color-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 900;
  font-style: italic;
  line-height: var(--line-height-heading);
  color: var(--color-white);
}

h1 { font-size: var(--text-h1); }
h2 { font-size: var(--text-h2); }
h3 { font-size: var(--text-h3); }

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--color-white);
}

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 4px;
  border-radius: 4px;
}

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

ul {
  list-style: none;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -100%;
  left: 0;
  z-index: 1000;
  padding: 0.75rem 1.5rem;
  background-color: var(--color-accent);
  color: var(--color-primary);
  font-weight: bold;
}

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

/* Header & Navigation (Command Bar) */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(11, 29, 58, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-height);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.brand-link {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  color: var(--color-white);
}

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

.brand-name {
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: 900;
  font-style: italic;
  letter-spacing: 0.05em;
}

.brand-slogan {
  font-size: var(--text-small);
  color: var(--color-gray);
  display: none;
}

@media (min-width: 640px) {
  .brand-slogan {
    display: inline;
  }
}

/* Navigation Toggle (Mobile) */
.nav-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  background: none;
  border: 1px solid var(--color-border);
  color: var(--color-white);
  padding: 0.5rem 1rem;
  cursor: pointer;
  font-size: var(--text-small);
  border-radius: 4px;
  transition: background-color 0.2s ease;
}

.nav-toggle:hover {
  background-color: var(--color-card);
}

.nav-toggle-icon {
  display: block;
  width: 1.25rem;
  height: 2px;
  background-color: var(--color-accent);
  position: relative;
  transition: background-color 0.2s ease;
}

.nav-toggle-icon::before,
.nav-toggle-icon::after {
  content: '';
  display: block;
  width: 1.25rem;
  height: 2px;
  background-color: var(--color-accent);
  position: absolute;
  left: 0;
  transition: transform 0.3s ease;
}

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

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

[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon::before {
  transform: translateY(6px) rotate(45deg);
}

[data-nav-toggle][aria-expanded="true"] .nav-toggle-icon::after {
  transform: translateY(-6px) rotate(-45deg);
}

.nav-toggle-label {
  font-family: var(--font-body);
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
}

/* Primary Navigation */
.primary-nav {
  display: none;
  position: absolute;
  top: var(--header-height);
  left: 0;
  right: 0;
  background-color: var(--color-primary);
  border-bottom: 2px solid var(--color-accent);
  padding: 1rem 0;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
}

.primary-nav[data-open] {
  display: block;
}

.primary-nav .nav-list {
  display: flex;
  flex-direction: column;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.primary-nav .nav-item {
  border-bottom: 1px solid var(--color-border);
}

.primary-nav .nav-item:last-child {
  border-bottom: none;
}

.primary-nav .nav-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 0;
  color: var(--color-gray);
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  transition: color 0.2s ease, background-color 0.2s ease;
}

.primary-nav .nav-link:hover {
  color: var(--color-accent);
}

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

.nav-index {
  font-family: var(--font-number);
  color: var(--color-border);
  font-size: var(--text-small);
  min-width: 2rem;
}

@media (min-width: 768px) {
  .primary-nav {
    display: flex !important;
    position: static;
    background-color: transparent;
    border-bottom: none;
    box-shadow: none;
    padding: 0;
  }

  .primary-nav .nav-list {
    flex-direction: row;
    gap: 0.25rem;
    padding: 0;
  }

  .primary-nav .nav-item {
    border-bottom: none;
  }

  .primary-nav .nav-link {
    padding: 0.5rem 0.75rem;
    font-size: var(--text-small);
    border-radius: 4px;
    letter-spacing: 0.02em;
  }

  .primary-nav .nav-link[aria-current="page"] {
    background-color: rgba(245, 197, 24, 0.1);
    color: var(--color-accent);
  }

  .nav-index {
    font-size: 0.7rem;
    min-width: 1.5rem;
  }
}

/* Footer */
.site-footer {
  background-color: var(--color-dark);
  border-top: 1px solid var(--color-border);
  padding: 3rem 1.5rem 2rem;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 1.5fr 2fr 1fr;
  }
}

.footer-brand .brand-name {
  display: block;
  font-size: 1.75rem;
  margin-bottom: 0.25rem;
}

.footer-brand .brand-slogan {
  color: var(--color-gray);
  font-size: var(--text-small);
}

.footer-contact {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.contact-item {
  color: var(--color-gray);
  font-size: var(--text-small);
}

.footer-links {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  gap: 1rem;
}

@media (min-width: 768px) {
  .footer-links {
    flex-direction: column;
  }
}

.footer-link {
  color: var(--color-accent);
  font-size: var(--text-small);
  font-weight: 600;
}

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

.footer-legal {
  border-top: 1px solid var(--color-border);
  padding-top: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  align-items: flex-start;
}

.icp {
  color: var(--color-gray);
  font-size: var(--text-small);
}

.trust-statement {
  color: var(--color-gray);
  font-size: var(--text-small);
  max-width: 600px;
}

/* Panels (Stacked Canvas Layout) */
.panel {
  padding: 4rem 1.5rem;
  border-bottom: 1px solid var(--color-border);
  background-color: var(--color-primary);
  position: relative;
}

.panel:nth-child(even) {
  background-color: var(--color-dark);
}

.panel:last-child {
  border-bottom: none;
}

.panel-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

/* Cards */
.card {
  background-color: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.5rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.card__title {
  font-family: var(--font-heading);
  font-size: var(--text-h3);
  font-weight: 900;
  font-style: italic;
  margin-bottom: 0.75rem;
}

.card__body {
  color: var(--color-gray);
  font-size: var(--text-body);
  line-height: var(--line-height-body);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: var(--text-body);
  border: 2px solid transparent;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

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

.btn-primary:hover {
  background-color: transparent;
  color: var(--color-accent);
}

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

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

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

/* Tags */
.tag {
  display: inline-block;
  padding: 0.2rem 0.75rem;
  font-size: var(--text-small);
  font-weight: 700;
  border-radius: 4px;
  background-color: var(--color-red);
  color: var(--color-white);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.tag--live {
  background-color: var(--color-red);
  animation: pulse 1.5s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.6; }
}

/* Image Placeholder */
.img-placeholder {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  background-color: var(--color-card);
  background-image:
    linear-gradient(45deg, var(--color-border) 25%, transparent 25%),
    linear-gradient(-45deg, var(--color-border) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, var(--color-border) 75%),
    linear-gradient(-45deg, transparent 75%, var(--color-border) 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
  border: 2px dashed var(--color-border);
  border-radius: 4px;
}

/* Utility / Layout Helpers */
.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-2 { grid-template-columns: 1fr; }
.grid-3 { grid-template-columns: 1fr; }

@media (min-width: 640px) {
  .grid-2 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
}

/* Back to Top */
[data-back-to-top] {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  z-index: 50;
  width: 3rem;
  height: 3rem;
  border-radius: 50%;
  background-color: var(--color-accent);
  color: var(--color-primary);
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease, transform 0.2s ease;
}

[data-back-to-top][data-visible] {
  opacity: 1;
  visibility: visible;
}

[data-back-to-top]:hover {
  transform: scale(1.1);
}

[data-back-to-top]:focus-visible {
  outline: 2px solid var(--color-white);
  outline-offset: 4px;
}

/* Section Navigation Highlighting */
.section-nav {
  position: sticky;
  top: var(--header-height);
  z-index: 10;
  background-color: rgba(11, 29, 58, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
  padding: 0.5rem 1.5rem;
}

.section-nav-list {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  max-width: var(--max-width);
  margin: 0 auto;
}

.section-nav-link {
  font-size: var(--text-small);
  color: var(--color-gray);
  white-space: nowrap;
  padding: 0.25rem 0.5rem;
  border-bottom: 2px solid transparent;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.section-nav-link[data-active] {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

/* 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;
  }

  html {
    scroll-behavior: auto;
  }

  .card:hover {
    transform: none;
  }
}

/* Responsive adjustments */
@media (max-width: 480px) {
  :root {
    --text-h1: 2rem;
    --text-h2: 1.75rem;
    --text-h3: 1.25rem;
  }

  .panel {
    padding: 2rem 1rem;
  }

  .site-header {
    --header-height: 3.5rem;
  }
}

@media (min-width: 481px) and (max-width: 768px) {
  .panel {
    padding: 3rem 1.5rem;
  }
}