/* ===== reset & base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  font-weight: 400; font-size: 1rem; line-height: 1.6;
  color: #FFFFFF; background: #0B1D3A;
  -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale;
}
ul, ol { list-style: none; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
button { font: inherit; cursor: pointer; border: none; background: none; color: inherit; }
:focus-visible { outline: 2px solid #FF6B35; outline-offset: 2px; border-radius: 2px; }

/* ===== css variables ===== */
:root {
  --color-primary: #FF6B35;
  --color-primary-hover: #e85a2a;
  --color-bg-dark: #0B1D3A;
  --color-bg-dark-alt: #11254a;
  --color-accent-red: #FF2A2A;
  --color-accent-green: #00C853;
  --color-accent-yellow: #FFC107;
  --color-surface: #FFF8F0;
  --color-text-muted: #3A4A6B;
  --color-border-light: rgba(255,255,255,0.08);
  --font-heading: Impact, 'Arial Black', 'Noto Sans SC', sans-serif;
  --font-body: -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
  --font-data: 'Fira Code', 'Consolas', 'Courier New', monospace;
  --sidebar-width: 220px;
  --sidebar-collapsed: 60px;
  --transition-base: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --reveal-duration: 0.5s;
}

/* ===== skip link ===== */
.skip-link {
  position: absolute; top: -100%; left: 1rem; z-index: 9999;
  padding: 0.5rem 1rem; background: var(--color-primary); color: #fff;
  font-weight: 700; border-radius: 0 0 4px 4px; transition: top 0.2s;
}
.skip-link:focus { top: 0; }

/* ===== sidebar (desktop fixed, mobile drawer) ===== */
.site-sidebar {
  position: fixed; top: 0; left: 0; width: var(--sidebar-width); height: 100vh;
  background: var(--color-bg-dark);
  display: flex; flex-direction: column; z-index: 800;
  border-right: 1px solid var(--color-border-light);
  transition: transform var(--transition-base);
  overflow-y: auto;
}
.sidebar-brand {
  display: flex; align-items: center; gap: 0.5rem;
  padding: 1.5rem 1.25rem 1rem;
  border-bottom: 1px solid var(--color-border-light);
}
.brand-icon { font-size: 1.6rem; line-height: 1; filter: drop-shadow(0 0 6px rgba(255,107,53,0.4)); }
.brand-text {
  font-family: var(--font-heading); font-weight: 900; font-size: 1.4rem;
  color: #FFFFFF; letter-spacing: 0.02em;
}
.sidebar-nav { flex: 1; padding: 1.25rem 0; }
.nav-list { display: flex; flex-direction: column; gap: 0.25rem; }
.nav-item { padding: 0 0.75rem; }
.nav-link {
  display: block; padding: 0.6rem 0.75rem; border-radius: 6px;
  font-family: var(--font-body); font-weight: 500; font-size: 0.95rem;
  color: rgba(255,255,255,0.75); transition: all var(--transition-base);
  position: relative; letter-spacing: 0.01em;
}
.nav-link:hover, .nav-link:focus-visible {
  color: #FFFFFF; background: rgba(255,107,53,0.18);
}
.nav-link[aria-current="page"] {
  color: var(--color-primary); background: rgba(255,107,53,0.10);
  font-weight: 700;
}
.nav-link[aria-current="page"]::before {
  content: ''; position: absolute; left: 0; top: 50%; transform: translateY(-50%);
  width: 3px; height: 60%; background: var(--color-primary); border-radius: 0 2px 2px 0;
}
.sidebar-decor {
  height: 6px; background: linear-gradient(135deg, transparent 50%, var(--color-primary) 50%);
  opacity: 0.6; margin-top: auto;
}

/* ===== nav toggle (mobile) ===== */
.nav-toggle {
  display: none; position: fixed; top: 0.75rem; right: 1rem; z-index: 900;
  width: 40px; height: 40px; flex-direction: column; align-items: center; justify-content: center;
  gap: 4px; background: rgba(11,29,58,0.85); border-radius: 8px;
  backdrop-filter: blur(4px); border: 1px solid var(--color-border-light);
  padding: 6px;
}
.hamburger-line {
  display: block; width: 22px; height: 2px; background: #FFFFFF;
  border-radius: 2px; transition: all var(--transition-base); transform-origin: center;
}
.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .hamburger-line:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ===== main content offset ===== */
#main-content { min-height: 70vh; }

/* ===== footer ===== */
.site-footer {
  background: var(--color-bg-dark);
  border-top: 1px solid var(--color-border-light);
  padding: 2.5rem 1.5rem 2rem;
  margin-left: var(--sidebar-width);
}
.footer-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: auto 1fr auto; gap: 1.5rem 2rem;
  align-items: start;
}
.footer-brand { display: flex; align-items: center; gap: 0.5rem; }
.footer-brand .brand-text { font-size: 1.2rem; }
.footer-motto { text-align: center; }
.footer-slogan {
  font-family: var(--font-heading); font-weight: 700; font-size: 1rem;
  color: var(--color-primary); letter-spacing: 0.04em; margin-bottom: 0.3rem;
}
.footer-trust { font-size: 0.85rem; color: rgba(255,255,255,0.55); max-width: 480px; margin: 0 auto; }
.footer-links { display: flex; align-items: center; gap: 0.6rem; justify-content: flex-end; }
.footer-link {
  font-size: 0.9rem; color: rgba(255,255,255,0.65); transition: color var(--transition-base);
}
.footer-link:hover, .footer-link:focus-visible { color: var(--color-primary); }
.footer-link-sep { color: rgba(255,255,255,0.25); font-size: 0.8rem; }
.footer-meta {
  grid-column: 1 / -1; text-align: center; padding-top: 1rem;
  border-top: 1px solid var(--color-border-light);
  display: flex; flex-wrap: wrap; gap: 1rem 2rem; justify-content: center;
  font-size: 0.8rem; color: rgba(255,255,255,0.4);
}
.footer-contact, .footer-icp { white-space: nowrap; }

/* ===== generic components ===== */

/* --切角面板-- */
.panel {
  background: var(--color-bg-dark-alt); border-radius: 8px;
  padding: 1.25rem; position: relative; overflow: hidden;
}
.panel--cut {
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 14px), calc(100% - 14px) 100%, 0 100%);
  border-radius: 0;
}
.panel--cut::after {
  content: ''; position: absolute; bottom: 0; right: 0;
  width: 14px; height: 14px;
  background: linear-gradient(135deg, var(--color-primary) 50%, transparent 50%);
  opacity: 0.3;
}

/* --按钮-- */
.btn {
  display: inline-flex; align-items: center; gap: 0.4rem;
  padding: 0.55rem 1.4rem; border-radius: 6px;
  font-family: var(--font-body); font-weight: 600; font-size: 0.9rem;
  transition: all var(--transition-base); border: 1px solid transparent;
  letter-spacing: 0.01em;
}
.btn--primary { background: var(--color-primary); color: #FFFFFF; }
.btn--primary:hover { background: var(--color-primary-hover); }
.btn--outline { background: transparent; color: #FFFFFF; border-color: rgba(255,255,255,0.25); }
.btn--outline:hover { border-color: var(--color-primary); color: var(--color-primary); }
.btn:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 2px; }

/* --标签-- */
.tag {
  display: inline-block; padding: 0.15rem 0.55rem; border-radius: 4px;
  font-family: var(--font-data); font-weight: 500; font-size: 0.75rem;
  line-height: 1.5; letter-spacing: 0.01em;
}
.tag--danger { background: rgba(255,42,42,0.18); color: var(--color-accent-red); }
.tag--success { background: rgba(0,200,83,0.15); color: var(--color-accent-green); }
.tag--warn { background: rgba(255,193,7,0.18); color: var(--color-accent-yellow); }
.tag--info { background: rgba(59,130,246,0.15); color: #60a5fa; }

/* --数据文本-- */
.data-text {
  font-family: var(--font-data); font-weight: 300; font-size: 0.9rem;
  color: rgba(255,255,255,0.85); letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

/* --网格-- */
.grid { display: grid; gap: 1.25rem; }
.grid--cols-2 { grid-template-columns: repeat(2, 1fr); }
.grid--cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid--cols-4 { grid-template-columns: repeat(4, 1fr); }

/* --滚动显现 (reveal) -- */
.reveal, [data-reveal] { opacity: 0; transform: translateY(18px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.is-visible, [data-reveal].is-visible { opacity: 1; transform: translateY(0); }
.reveal[data-reveal-delay="1"] { transition-delay: 0.1s; }
.reveal[data-reveal-delay="2"] { transition-delay: 0.2s; }
.reveal[data-reveal-delay="3"] { transition-delay: 0.3s; }
.reveal[data-reveal-delay="4"] { transition-delay: 0.4s; }
.reveal[data-reveal-delay="5"] { transition-delay: 0.5s; }

/* ===== responsive ===== */
@media (max-width: 767px) {
  .site-sidebar {
    transform: translateX(-100%); width: 280px;
    border-right: none; box-shadow: 4px 0 30px rgba(0,0,0,0.5);
  }
  .site-sidebar[data-open="true"] { transform: translateX(0); }
  .nav-toggle { display: flex; }
  .site-footer { margin-left: 0; padding: 2rem 1rem 1.5rem; }
  .footer-inner { grid-template-columns: 1fr; text-align: center; }
  .footer-links { justify-content: center; }
  .footer-meta { flex-direction: column; gap: 0.3rem; }
  .grid--cols-2, .grid--cols-3, .grid--cols-4 { grid-template-columns: 1fr; }
}

@media (min-width: 768px) and (max-width: 1023px) {
  :root { --sidebar-width: 180px; }
  .site-footer { margin-left: var(--sidebar-width); }
  .footer-inner { grid-template-columns: 1fr; text-align: center; }
  .footer-links { justify-content: center; }
  .grid--cols-3 { grid-template-columns: repeat(2, 1fr); }
  .grid--cols-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 1024px) {
  .site-sidebar { width: var(--sidebar-width); }
  .site-footer { margin-left: var(--sidebar-width); }
  .grid--cols-4 { grid-template-columns: repeat(4, 1fr); }
}

/* ===== reduced motion ===== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: 0.01ms !important; transition-duration: 0.01ms !important; }
  html { scroll-behavior: auto; }
  .reveal, [data-reveal] { opacity: 1; transform: none; transition: none; }
  .site-sidebar { transition: none; }
  .nav-toggle .hamburger-line { transition: none; }
  .nav-link { transition: none; }
  .btn { transition: none; }
  .footer-link { transition: none; }
}