/* ===== Reset ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body { min-height: 100vh; line-height: 1.6; -webkit-font-smoothing: antialiased; }
img, picture, video, canvas, svg { display: block; max-width: 100%; }
input, button, textarea, select { font: inherit; }
ul, ol { list-style: none; }
a { text-decoration: none; color: inherit; }
button { background: none; border: none; cursor: pointer; }
:focus-visible { outline: 2px solid #00D4FF; outline-offset: 2px; }

/* ===== Variables ===== */
:root {
  --color-primary-bg: #0B1D3A;
  --color-secondary-bg: #1A2D4A;
  --color-card-bg: #14283F;
  --color-accent-orange: #FF6B35;
  --color-accent-blue: #00D4FF;
  --color-text-primary: #FFFFFF;
  --color-text-secondary: #B0B0B8;
  --color-border: #2A3F5A;
  --color-success: #34C759;
  --color-warning: #FFD60A;
  --font-heading: 'Arial Black', 'Helvetica Neue', sans-serif;
  --font-body: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-digit: 'Courier New', monospace;
  --h1-size: clamp(2.25rem, 5vw, 3rem);
  --h2-size: clamp(1.5rem, 3.5vw, 2.25rem);
  --h3-size: clamp(1.125rem, 2vw, 1.5rem);
  --body-size: clamp(0.875rem, 1.2vw, 1rem);
  --small-size: 0.875rem;
  --max-width: 1280px;
  --header-height: 60px;
  --side-menu-width: 220px;
  --side-menu-collapsed: 56px;
  --transition-fast: 0.2s ease;
  --transition-base: 0.3s ease;
  --glass-bg: rgba(11, 29, 58, 0.85);
  --glass-border: rgba(0, 212, 255, 0.15);
}

/* ===== Global ===== */
body {
  font-family: var(--font-body);
  font-size: var(--body-size);
  color: var(--color-text-primary);
  background-color: var(--color-primary-bg);
}
::selection { background: var(--color-accent-orange); color: #fff; }

/* ===== Skip Link ===== */
.skip-link {
  position: absolute; top: -100%; left: 0; z-index: 1000;
  padding: 12px 24px; background: var(--color-accent-orange); color: #fff;
  font-weight: 700; font-size: var(--small-size);
  transition: top var(--transition-fast);
}
.skip-link:focus { top: 0; outline: none; }

/* ===== Header ===== */
.site-header { position: relative; z-index: 100; }
.header-top {
  position: fixed; top: 0; left: 0; right: 0; z-index: 200;
  height: var(--header-height);
  background: var(--color-primary-bg);
  border-bottom: 1px solid var(--color-border);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  max-width: var(--max-width); margin: 0 auto;
  padding: 0 24px; height: 100%;
}

/* Brand */
.header-brand { flex-shrink: 0; }
.brand-link { display: flex; align-items: center; gap: 2px; font-family: var(--font-heading); font-size: 1.375rem; letter-spacing: -0.5px; }
.brand-num { color: var(--color-accent-orange); }
.brand-text { color: var(--color-text-primary); }

/* Nav - desktop */
.header-nav { display: none; }
@media (min-width: 769px) {
  .header-nav { display: flex; align-items: center; }
}
.nav-list { display: flex; align-items: center; gap: 4px; }
.nav-item { position: relative; }
.nav-link {
  display: block; padding: 8px 14px;
  font-size: 0.8125rem; font-weight: 600; letter-spacing: 0.3px;
  color: var(--color-text-secondary); border-radius: 4px;
  transition: color var(--transition-fast), background var(--transition-fast);
}
.nav-link:hover, .nav-link:focus-visible { color: var(--color-accent-blue); background: rgba(0, 212, 255, 0.08); }
.nav-link[aria-current="page"] { color: var(--color-accent-orange); background: rgba(255, 107, 53, 0.1); }
.nav-link[aria-current="page"]::after {
  content: ''; position: absolute; bottom: 0; left: 14px; right: 14px;
  height: 2px; background: var(--color-accent-orange); border-radius: 1px;
}

/* Toggle button */
.nav-toggle {
  display: flex; flex-direction: column; justify-content: center; gap: 4px;
  width: 36px; height: 36px; padding: 6px;
  background: transparent; border: 1px solid var(--color-border); border-radius: 4px;
  transition: border-color var(--transition-fast);
}
.nav-toggle:hover, .nav-toggle:focus-visible { border-color: var(--color-accent-blue); }
.toggle-bar { display: block; width: 100%; height: 2px; background: var(--color-text-primary); border-radius: 1px; transition: transform var(--transition-base), opacity var(--transition-base); }
.nav-toggle[aria-expanded="true"] .toggle-bar:nth-child(1) { transform: rotate(45deg) translate(4px, 4px); }
.nav-toggle[aria-expanded="true"] .toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .toggle-bar:nth-child(3) { transform: rotate(-45deg) translate(4px, -4px); }
@media (min-width: 769px) { .nav-toggle { display: none; } }

/* ===== Side Menu ===== */
.side-menu {
  position: fixed; top: var(--header-height); left: 0; bottom: 0; z-index: 150;
  width: var(--side-menu-width);
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-right: 1px solid var(--glass-border);
  display: flex; flex-direction: column;
  transition: width var(--transition-base), transform var(--transition-base), opacity var(--transition-base);
  overflow: hidden;
}
.side-menu[data-side-open="false"] { width: var(--side-menu-collapsed); }
.side-menu[data-side-open="false"] .side-label { display: none; }
.side-menu[data-side-open="false"] .side-link { justify-content: center; padding: 12px 0; }
.side-menu[data-side-open="false"] .side-num { font-size: 1rem; }

/* Mobile: hidden by default, toggle via data-open */
@media (max-width: 768px) {
  .side-menu { transform: translateX(-100%); opacity: 0; width: 280px; }
  .side-menu[data-open="true"] { transform: translateX(0); opacity: 1; }
  .side-menu[data-side-open="false"] .side-label { display: inline; }
  .side-menu[data-side-open="false"] .side-link { justify-content: flex-start; padding: 12px 20px; }
  .side-menu[data-side-open="false"] .side-num { font-size: 0.875rem; }
}
@media (min-width: 769px) {
  .side-menu { transform: translateX(0); opacity: 1; }
}

/* Side toggle */
.side-toggle {
  flex-shrink: 0; display: flex; align-items: center; justify-content: center;
  width: 100%; padding: 14px 0; margin-bottom: 4px;
  color: var(--color-accent-blue); font-size: 1.125rem;
  transition: color var(--transition-fast), background var(--transition-fast);
  border-bottom: 1px solid var(--glass-border);
}
.side-toggle:hover, .side-toggle:focus-visible { color: var(--color-accent-orange); background: rgba(255, 107, 53, 0.06); }
.side-toggle-icon { display: inline-block; transition: transform var(--transition-base); }
.side-menu[data-side-open="false"] .side-toggle-icon { transform: rotate(180deg); }

/* Side nav list */
.side-nav-list { flex: 1; overflow-y: auto; padding: 4px 0; }
.side-link {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 20px;
  font-size: 0.875rem; font-weight: 500; letter-spacing: 0.2px;
  color: var(--color-text-secondary); border-radius: 0;
  transition: color var(--transition-fast), background var(--transition-fast), padding var(--transition-base);
}
.side-link:hover, .side-link:focus-visible { color: var(--color-accent-blue); background: rgba(0, 212, 255, 0.06); }
.side-link[aria-current="page"] { color: var(--color-accent-orange); background: rgba(255, 107, 53, 0.08); border-right: 3px solid var(--color-accent-orange); }
.side-num { font-family: var(--font-digit); font-size: 0.875rem; min-width: 28px; color: var(--color-accent-blue); opacity: 0.7; }
.side-link[aria-current="page"] .side-num { color: var(--color-accent-orange); opacity: 1; }
.side-label { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* ===== Main Content Push ===== */
#main-content { padding-top: var(--header-height); }
@media (min-width: 769px) {
  #main-content { padding-left: var(--side-menu-width); transition: padding-left var(--transition-base); }
  .side-menu[data-side-open="false"] ~ #main-content,
  .side-menu[data-side-open="false"] + * #main-content { padding-left: var(--side-menu-collapsed); }
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-secondary-bg);
  border-top: 1px solid var(--color-border);
  padding: 48px 24px 0;
  margin-top: 64px;
}
.footer-inner {
  max-width: var(--max-width); margin: 0 auto;
  display: grid; grid-template-columns: 1fr; gap: 36px;
}
@media (min-width: 640px) { .footer-inner { grid-template-columns: 1fr 1fr; } }
@media (min-width: 960px) { .footer-inner { grid-template-columns: 2fr 1fr 1fr; } }

.footer-section { display: flex; flex-direction: column; gap: 12px; }
.footer-brand { margin-bottom: 4px; }
.footer-brand-link { display: inline-flex; align-items: center; gap: 2px; font-family: var(--font-heading); font-size: 1.25rem; letter-spacing: -0.5px; }
.footer-tagline { color: var(--color-text-secondary); font-size: var(--small-size); line-height: 1.7; max-width: 360px; }
.footer-contact { display: flex; flex-direction: column; gap: 6px; margin-top: 4px; }
.footer-contact-item { color: var(--color-text-secondary); font-size: var(--small-size); display: flex; flex-wrap: wrap; gap: 4px; }
.contact-label { color: var(--color-text-secondary); opacity: 0.7; }
.contact-link { color: var(--color-accent-blue); transition: color var(--transition-fast); }
.contact-link:hover, .contact-link:focus-visible { color: var(--color-accent-orange); }

.footer-heading { font-family: var(--font-heading); font-size: 0.9375rem; color: var(--color-text-primary); letter-spacing: 0.5px; margin-bottom: 4px; position: relative; padding-bottom: 8px; }
.footer-heading::after { content: ''; position: absolute; bottom: 0; left: 0; width: 28px; height: 2px; background: var(--color-accent-orange); border-radius: 1px; }

.footer-nav-list, .footer-legal-list { display: flex; flex-direction: column; gap: 6px; }
.footer-link { color: var(--color-text-secondary); font-size: var(--small-size); transition: color var(--transition-fast); display: inline-block; padding: 2px 0; }
.footer-link:hover, .footer-link:focus-visible { color: var(--color-accent-blue); }
.footer-note { color: var(--color-text-secondary); font-size: 0.8125rem; line-height: 1.7; margin-top: 8px; padding: 12px; background: rgba(0, 212, 255, 0.04); border-left: 3px solid var(--color-accent-blue); border-radius: 2px; }

.footer-bottom {
  margin-top: 36px; padding: 16px 0;
  border-top: 1px solid var(--color-border);
  display: flex; flex-direction: column; align-items: center; gap: 4px;
  text-align: center;
}
.footer-copyright { color: var(--color-text-secondary); font-size: 0.75rem; }
.footer-icp { color: var(--color-text-secondary); font-size: 0.75rem; opacity: 0.6; font-family: var(--font-digit); }
@media (min-width: 640px) { .footer-bottom { flex-direction: row; justify-content: space-between; text-align: left; } }

/* ===== Common Components ===== */

/* Buttons */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 10px 24px; border-radius: 4px;
  font-size: var(--small-size); font-weight: 600; letter-spacing: 0.3px;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast), transform var(--transition-fast);
  cursor: pointer; border: 1px solid transparent;
}
.btn:active { transform: scale(0.97); }
.btn-primary { background: var(--color-accent-orange); color: #fff; border-color: var(--color-accent-orange); }
.btn-primary:hover, .btn-primary:focus-visible { background: #e85d2a; border-color: #e85d2a; }
.btn-outline { background: transparent; color: var(--color-accent-blue); border-color: var(--color-accent-blue); }
.btn-outline:hover, .btn-outline:focus-visible { background: rgba(0, 212, 255, 0.08); color: var(--color-accent-orange); border-color: var(--color-accent-orange); }

/* Breadcrumb */
.breadcrumb { padding: 16px 24px; max-width: var(--max-width); margin: 0 auto; }
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: 4px 8px; align-items: center; }
.breadcrumb li { display: flex; align-items: center; gap: 8px; color: var(--color-text-secondary); font-size: var(--small-size); }
.breadcrumb li + li::before { content: '/'; color: var(--color-border); }
.breadcrumb a { color: var(--color-accent-blue); transition: color var(--transition-fast); }
.breadcrumb a:hover, .breadcrumb a:focus-visible { color: var(--color-accent-orange); }
.breadcrumb [aria-current="page"] { color: var(--color-text-primary); font-weight: 600; }

/* Content Container */
.content-container { max-width: var(--max-width); margin: 0 auto; padding: 24px; }
.content-container h1 { font-family: var(--font-heading); font-size: var(--h1-size); color: var(--color-text-primary); margin-bottom: 20px; line-height: 1.15; }
.content-container h2 { font-family: var(--font-heading); font-size: var(--h2-size); color: var(--color-text-primary); margin-top: 40px; margin-bottom: 16px; line-height: 1.2; }
.content-container h3 { font-family: var(--font-heading); font-size: var(--h3-size); color: var(--color-text-primary); margin-top: 28px; margin-bottom: 12px; line-height: 1.25; }
.content-container p { color: var(--color-text-secondary); line-height: 1.8; margin-bottom: 16px; }
.content-container a { color: var(--color-accent-blue); border-bottom: 1px solid transparent; transition: color var(--transition-fast), border-color var(--transition-fast); }
.content-container a:hover, .content-container a:focus-visible { color: var(--color-accent-orange); border-color: var(--color-accent-orange); }

/* Card */
.card { background: var(--color-card-bg); border: 1px solid var(--color-border); border-radius: 6px; overflow: hidden; transition: transform var(--transition-fast), box-shadow var(--transition-fast), border-color var(--transition-fast); }
.card:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3); border-color: var(--color-accent-blue); }
.card-header { padding: 16px 20px 8px; border-bottom: 1px solid var(--color-border); font-family: var(--font-heading); font-size: 1rem; color: var(--color-text-primary); display: flex; align-items: center; gap: 8px; }
.card-body { padding: 16px 20px; color: var(--color-text-secondary); font-size: var(--small-size); line-height: 1.7; }
.card-footer { padding: 12px 20px; border-top: 1px solid var(--color-border); font-size: var(--small-size); color: var(--color-text-secondary); display: flex; justify-content: flex-end; gap: 8px; }

/* Image Container */
.img-container { position: relative; width: 100%; overflow: hidden; border-radius: 4px; background: var(--color-secondary-bg); }
.img-container img { width: 100%; height: auto; object-fit: cover; transition: opacity var(--transition-fast); }
.img-container::before { content: ''; display: block; padding-bottom: 56.25%; }
.img-container img { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
.img-container--portrait::before { padding-bottom: 125%; }
.img-container--square::before { padding-bottom: 100%; }

/* Grid utilities */
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: 1fr; }
@media (min-width: 640px) { .grid-2 { grid-template-columns: 1fr 1fr; } }
.grid-3 { grid-template-columns: 1fr; }
@media (min-width: 640px) { .grid-3 { grid-template-columns: 1fr 1fr; } }
@media (min-width: 960px) { .grid-3 { grid-template-columns: 1fr 1fr 1fr; } }

/* Back to Top */
[data-back-top] {
  position: fixed; bottom: 32px; right: 32px; z-index: 300;
  width: 44px; height: 44px; border-radius: 50%;
  background: var(--color-accent-orange); color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.15);
  font-size: 1.25rem; display: flex; align-items: center; justify-content: center;
  opacity: 0; pointer-events: none; transform: translateY(12px);
  transition: opacity var(--transition-base), transform var(--transition-base), background var(--transition-fast);
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.4);
}
[data-back-top].is-visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
[data-back-top]:hover, [data-back-top]:focus-visible { background: #e85d2a; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .header-inner { padding: 0 16px; }
  .content-container { padding: 16px; }
  .side-menu { width: 280px; }
  .site-footer { padding: 32px 16px 0; }
}

/* ===== Accessibility ===== */
@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; }
  .card:hover { transform: none; }
  .side-menu { transition: none; }
  .nav-toggle .toggle-bar { transition: none; }
  [data-back-top] { transition: none; }
}