/* 基础主题变量 */
:root {
  --bg: #0b1020;
  --bg-soft: #0f1730;
  --card: #111a33cc;
  --text: #e6ecff;
  --muted: #94a3b8;
  --primary: #4f8cff;
  --primary-600: #3b6fdb;
  --accent: #00e5ff;
  --border: #24324d;
  --glass: rgba(17, 26, 51, 0.55);
  --radius: 14px;
  --shadow: 0 8px 30px rgba(0, 0, 0, 0.45);
}

/* 亮色主题变量覆盖 */
html[data-theme="light"] {
  --bg: #f6f8fc;
  --bg-soft: #ffffff;
  --card: rgba(255,255,255,0.85);
  --text: #0b1020;
  --muted: #4b5563;
  --primary: #3b6fdb;
  --primary-600: #2f5ec1;
  --accent: #06b6d4;
  --border: #e5e7eb;
  --glass: rgba(255,255,255,0.7);
  --shadow: 0 8px 30px rgba(0,0,0,0.12);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, PingFang SC, Microsoft YaHei, Noto Sans CJK SC, Helvetica Neue, Arial, sans-serif;
  color: var(--text);
  background: radial-gradient(1200px 800px at 70% -10%, #1a2252 0%, #0b1020 60%), var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
/* 亮色主题下的背景覆盖 */
html[data-theme="light"] body {
  background: radial-gradient(1200px 800px at 70% -10%, #e8eefb 0%, #f6f8fc 60%), var(--bg);
}

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 20px;
}

.skip-link {
  position: absolute; left: -999px; top: auto;
  width: 1px; height: 1px; overflow: hidden;
}
.skip-link:focus { left: 16px; top: 16px; width: auto; height: auto; background: var(--bg-soft); padding: 8px 12px; border-radius: 8px; }

/* 头部 */
.site-header {
  position: sticky; top: 0; z-index: 1000;
  backdrop-filter: saturate(180%) blur(10px);
  background: linear-gradient(180deg, rgba(11,16,32,0.85), rgba(11,16,32,0.6));
  border-bottom: 1px solid var(--border);
}
html[data-theme="light"] .site-header {
  background: linear-gradient(180deg, rgba(255,255,255,0.85), rgba(255,255,255,0.7));
}
.site-header .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--text); text-decoration: none; font-weight: 600; letter-spacing: .4px; }
.brand img { filter: drop-shadow(0 2px 6px rgba(0,229,255,0.35)); }

.site-nav .menu { list-style: none; margin: 0; padding: 0; display: flex; gap: 18px; align-items: center; }
.site-nav a { color: var(--text); text-decoration: none; opacity: .8; }
.site-nav a:hover, .site-nav a:focus { opacity: 1; }
.menu-toggle { display: none; }

/* 主题切换按钮 */
.theme-toggle { display: inline-flex; align-items: center; justify-content: center; width: 36px; height: 36px; border-radius: 999px; border: 1px solid var(--border); background: #0d142a; color: var(--text); cursor: pointer; }
html[data-theme="light"] .theme-toggle { background: #ffffff; }
.theme-toggle:hover { background: #ffffff0f; }
html[data-theme="light"] .theme-toggle:hover { background: #f3f4f6; }

/* 按钮 */
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; padding: 12px 18px; border-radius: 999px; border: 1px solid var(--border); color: var(--text); text-decoration: none; backdrop-filter: blur(6px); transition: transform .2s ease, background .2s ease, border-color .2s ease; }
.btn.small { padding: 8px 14px; font-size: 14px; }
.btn.primary { background: linear-gradient(135deg, var(--primary), var(--accent)); border-color: transparent; box-shadow: 0 6px 24px rgba(79,140,255,.35); }
.btn.primary:hover { transform: translateY(-1px); }
.btn.ghost { background: transparent; }
.btn.ghost:hover { background: #ffffff0f; }
html[data-theme="light"] .btn.ghost:hover { background: #f3f4f6; }

/* 首屏 */
.hero { position: relative; min-height: 72vh; display: grid; place-items: center; overflow: clip; }
.hero-inner { text-align: center; padding: 120px 0 80px; }
.hero h1 { font-size: clamp(28px, 4vw, 48px); line-height: 1.2; margin: 0 0 12px; text-shadow: 0 10px 40px rgba(0,0,0,.35); }
.hero .lead { color: var(--muted); max-width: 820px; margin: 0 auto 24px; }
#particlesCanvas { position: absolute; inset: 0; width: 100%; height: 100%; z-index: -1; }

/* 版块通用 */
.section { padding: 80px 0; }
.section.alt { background: linear-gradient(180deg, transparent, #0c142b 40%, transparent); }
html[data-theme="light"] .section.alt { background: linear-gradient(180deg, transparent, #eef2ff 40%, transparent); }
.section-title { font-size: 28px; margin: 0 0 22px; letter-spacing: .3px; }
.grid { display: grid; gap: 18px; }
.grid.three { grid-template-columns: repeat(3, 1fr); }
.grid.four { grid-template-columns: repeat(4, 1fr); }

.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 18px 16px; box-shadow: var(--shadow); transition: transform .2s ease, border-color .2s ease, background .2s ease; }
.card:hover { transform: translateY(-3px); border-color: #2d3e66; }
.card h3 { margin: 6px 0 8px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); }
.card.glass { background: var(--glass); }

.logo-wall { display: grid; grid-template-columns: repeat(6, 1fr); gap: 10px; }
.logo { display: grid; place-items: center; height: 54px; border-radius: 12px; border: 1px dashed var(--border); color: var(--muted); }

.stack { display: flex; flex-wrap: wrap; gap: 10px; }
.badge { border: 1px solid var(--border); background: #0f1a35; color: var(--text); border-radius: 999px; padding: 8px 12px; font-size: 13px; opacity: .9; }
html[data-theme="light"] .badge { background: #eef2ff; }

/* 联系我们 */
.contact-grid { display: grid; grid-template-columns: 1.2fr .8fr; gap: 24px; }
.contact-list { margin: 12px 0 18px; padding-left: 18px; color: var(--muted); }
.contact-card { border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; background: linear-gradient(180deg, rgba(17,26,51,.65), rgba(10,15,30,.65)); box-shadow: var(--shadow); }
html[data-theme="light"] .contact-card { background: linear-gradient(180deg, rgba(255,255,255,.85), rgba(255,255,255,.75)); }
.contact-card form { display: flex; gap: 10px; margin-top: 8px; }
.contact-card input { flex: 1; min-width: 0; border-radius: 999px; border: 1px solid var(--border); background: #0d1733; color: var(--text); padding: 10px 12px; outline: none; }
html[data-theme="light"] .contact-card input { background: #ffffff; }
.contact-card input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(79,140,255,.18); }

.qrcode { display: inline-flex; flex-direction: column; align-items: center; gap: 8px; margin-top: 10px; }
.qrcode img { display: block; width: 160px; height: 160px; border: 1px solid var(--border); border-radius: 10px; background: #0b1228; box-shadow: 0 8px 20px rgba(0,0,0,.35); }

.site-footer { border-top: 1px solid var(--border); background: #0a1124; }
html[data-theme="light"] .site-footer { background: #f8fafc; }
.site-footer .container { display: flex; align-items: center; justify-content: space-between; padding: 18px 20px; }
/* 页脚增强 */
.footer-grid { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: 20px; padding: 22px 20px; }
.footer-brand p { margin: 6px 0 0; }
.footer-qr { justify-self: end; opacity: .95; }
.qr-chip { display: inline-flex; align-items: center; gap: 12px; padding: 10px 12px; border: 1px solid var(--border); border-radius: 999px; background: linear-gradient(180deg, rgba(17,26,51,.55), rgba(10,15,30,.55)); box-shadow: 0 8px 24px rgba(0,0,0,.35); backdrop-filter: blur(6px); }
html[data-theme="light"] .qr-chip { background: linear-gradient(180deg, rgba(255,255,255,.75), rgba(255,255,255,.65)); box-shadow: 0 8px 24px rgba(0,0,0,.08); }
.qr-chip img { width: 96px; height: 96px; border-radius: 10px; border: 1px solid #1c2a4a; background: #0b1228; box-shadow: 0 6px 18px rgba(0,0,0,.35); }
html[data-theme="light"] .qr-chip img { background: #fff; border-color: #e5e7eb; box-shadow: 0 6px 18px rgba(0,0,0,.08); }
.qr-caption { display: inline-flex; align-items: center; gap: 8px; color: var(--muted); font-size: 14px; padding-right: 6px; }
.qr-caption .dot { width: 6px; height: 6px; border-radius: 999px; background: linear-gradient(135deg, var(--primary), var(--accent)); box-shadow: 0 0 0 3px rgba(79,140,255,.22); }
.footer-qr:hover .qr-chip { transform: translateY(-1px); border-color: #2d3e66; transition: transform .2s ease, border-color .2s ease; }

.tiny { font-size: 12px; color: var(--muted); }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }

/* 动效与可访问性 */
.reveal { opacity: 0; transform: translateY(8px); transition: opacity .6s ease, transform .6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* 开场动画 */
.intro-overlay { position: fixed; inset: 0; z-index: 2000; display: grid; place-items: center; background: radial-gradient(800px 500px at 50% 30%, rgba(79,140,255,.12), transparent 60%), var(--bg); color: var(--text); transition: opacity .6s ease, visibility .6s ease; }
.intro-hidden { opacity: 0; visibility: hidden; }
.intro-card { display: grid; place-items: center; gap: 12px; padding: 22px; border: 1px solid var(--border); border-radius: 16px; background: linear-gradient(180deg, rgba(17,26,51,.65), rgba(10,15,30,.65)); box-shadow: var(--shadow); }
html[data-theme="light"] .intro-card { background: linear-gradient(180deg, rgba(255,255,255,.85), rgba(255,255,255,.75)); }
.intro-logo { width: 72px; height: 72px; filter: drop-shadow(0 8px 28px rgba(79,140,255,.35)); opacity: .98; }
.intro-title { margin: 0; font-size: 20px; letter-spacing: .6px; }
.intro-progress { height: 3px; width: 180px; background: #ffffff1a; border-radius: 999px; overflow: hidden; }
.intro-progress > span { display: block; height: 100%; width: 0%; background: linear-gradient(90deg, var(--primary), var(--accent)); box-shadow: 0 0 20px rgba(79,140,255,.4); transition: width .9s ease; }
.intro-actions { display: inline-flex; gap: 10px; }
.intro-skip { border: 1px solid var(--border); background: transparent; color: var(--text); border-radius: 999px; padding: 8px 14px; cursor: pointer; }
.intro-skip:hover { background: #ffffff0f; }
html[data-theme="light"] .intro-skip:hover { background: #f3f4f6; }

/* 响应式 */
@media (max-width: 1024px) {
  .grid.four { grid-template-columns: repeat(2, 1fr); }
  .logo-wall { grid-template-columns: repeat(3, 1fr); }
  .contact-grid { grid-template-columns: 1fr; }
}

@media (max-width: 760px) {
  .site-header .container { height: 60px; }
  .menu-toggle { display: inline-flex; align-items: center; justify-content: center; padding: 8px 12px; border-radius: 8px; border: 1px solid var(--border); background: #0d142a; color: var(--text); }
  html[data-theme="light"] .menu-toggle { background: #ffffff; }
  .site-nav .menu { position: fixed; inset: 60px 12px auto 12px; background: #0b1228f2; border: 1px solid var(--border); border-radius: 14px; padding: 12px; flex-direction: column; gap: 8px; transform: scale(.98); opacity: 0; pointer-events: none; transition: transform .2s ease, opacity .2s ease; }
  html[data-theme="light"] .site-nav .menu { background: #fffffff2; }
  .site-nav[data-open="true"] .menu { transform: scale(1); opacity: 1; pointer-events: auto; }
  .grid.three { grid-template-columns: 1fr; }
  .grid.four { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; justify-items: center; text-align: center; gap: 14px; }
  .footer-qr { justify-self: center; }
  .qr-chip { padding: 8px 10px; }
  .qr-chip img { width: 84px; height: 84px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}