/* ======================================================
   公共样式表 — 南阳中豫航空产业发展研究院
   覆盖：导航栏、页脚、移动端菜单、页面过渡、滚动动画
   ====================================================== */

/* --- 1. 全局重置 --- */
* { margin: 0; padding: 0; box-sizing: border-box; }

body, html {
    font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

a { text-decoration: none; color: inherit; cursor: pointer; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* --- 2. 导航栏 --- */
header {
    position: fixed; top: 0; left: 0; width: 100%; height: 80px;
    z-index: 999;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(0,0,0,0.05);
    transition: all 0.3s;
}

/* 深色主题导航 */
body.theme-dark header {
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: saturate(180%) blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(255,255,255,0.08);
}
body.theme-dark .nav-links a { color: #ccc; }
body.theme-dark .nav-links a:hover { color: var(--accent, #0071e3); }
body.theme-dark .nav-logo .logo-cn { color: #fff; }
body.theme-dark .nav-logo .logo-en { color: #999; }

header.scrolled .nav-inner { height: 70px; }

.nav-inner {
    display: flex; justify-content: space-between; align-items: center;
    max-width: 1400px; margin: 0 auto; padding: 0 30px;
    height: 80px; transition: height 0.3s;
}

.nav-logo { display: flex; flex-direction: column; justify-content: center; line-height: 1.2; margin-right: 40px; flex-shrink: 0; }
.nav-logo .logo-cn { font-size: 20px; font-weight: 800; color: #1d1d1f; letter-spacing: 1px; white-space: nowrap; }
.nav-logo .logo-en { font-size: 10px; color: #666; text-transform: uppercase; transform: scale(0.8); transform-origin: left center; white-space: nowrap; margin-top: 2px; }

.nav-links { display: flex; gap: 20px; align-items: center; flex-shrink: 0; }
.nav-links a { display: flex; flex-direction: column; align-items: center; color: #333; font-size: 15px; font-weight: 500; white-space: nowrap; padding: 8px 12px; transition: all 0.3s; border-radius: 8px; }
.nav-links a small { font-size: 9px; color: #999; margin-top: 4px; text-transform: uppercase; font-weight: 700; letter-spacing: 0.5px; font-family: Arial, sans-serif; }
.nav-links a:hover, .nav-links a.active { color: var(--accent, #0071e3); }
.nav-links a:hover small, .nav-links a.active small { color: #5baafc; }

/* --- 3. 移动端菜单 --- */
.mobile-menu-btn { display: none; position: fixed; top: 0; right: 0; height: 60px; padding: 0 20px; z-index: 2000; align-items: center; background: transparent; border: none; font-size: 14px; color: #1d1d1f; font-weight: 500; cursor: pointer; }
body.theme-dark .mobile-menu-btn { color: #fff; }

.mobile-nav-overlay { position: fixed; top: 0; left: 0; width: 100%; height: 100vh; background: rgba(255, 255, 255, 0.95); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); z-index: 1999; display: flex; flex-direction: column; padding: 100px 40px; opacity: 0; pointer-events: none; transition: 0.4s; transform: translateY(-20px); }
.mobile-nav-overlay.active { opacity: 1; pointer-events: auto; transform: translateY(0); }
.mobile-nav-link { font-size: 24px; font-weight: 600; color: #1d1d1f; margin-bottom: 24px; text-decoration: none; opacity: 0; transform: translateY(10px); transition: 0.4s; }
.mobile-nav-overlay.active .mobile-nav-link { opacity: 1; transform: translateY(0); }
.mobile-nav-link:nth-child(1) { transition-delay: 0.1s; }
.mobile-nav-link:nth-child(2) { transition-delay: 0.15s; }
.mobile-nav-link:nth-child(3) { transition-delay: 0.2s; }
.mobile-nav-link:nth-child(4) { transition-delay: 0.25s; }
.mobile-nav-link:nth-child(5) { transition-delay: 0.3s; }
.mobile-nav-link:nth-child(6) { transition-delay: 0.35s; }
.mobile-nav-link:nth-child(7) { transition-delay: 0.4s; }

/* --- 4. 页面过渡遮罩 --- */
#page-transition-mask { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: #fff; z-index: 9999; pointer-events: none; opacity: 1; transition: opacity 0.6s; }
body.is-leaving { transform: scale(0.98); filter: blur(10px); transition: 0.6s; }

/* --- 5. 滚动动画 --- */
.reveal-on-scroll { opacity: 0; transform: translateY(40px); transition: all 0.8s cubic-bezier(0.25, 1, 0.5, 1); }
.reveal-on-scroll.is-visible { opacity: 1; transform: translateY(0); }

.scroll-reveal { opacity: 0; transform: translateY(40px); transition: 0.8s cubic-bezier(0.2, 0.8, 0.2, 1); }
.scroll-reveal.visible { opacity: 1; transform: translateY(0); }

/* --- 6. 页脚 --- */
.pro-footer { background: #1d1d1f; color: #f5f5f7; padding: 60px 0 30px; font-size: 14px; }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1.5fr; gap: 40px; margin-bottom: 50px; max-width: 1200px; margin: 0 auto 50px; padding: 0 20px; }
.footer-brand h4 { color: #fff; font-size: 18px; margin-bottom: 15px; font-weight: 700; }
.footer-brand p { font-size: 13px; line-height: 1.6; max-width: 300px; color: #a1a1a6; }
.footer-links h5, .footer-contact h5 { color: #fff; margin-bottom: 20px; font-size: 14px; font-weight: 600; }
.footer-links a { display: block; margin-bottom: 12px; color: #a1a1a6; transition: 0.3s; }
.footer-links a:hover { color: #fff; }
.footer-contact p { color: #a1a1a6; margin-bottom: 12px; line-height: 1.4; }
.footer-social { margin-top: 20px; }
.social-icon { display: inline-block; padding: 4px 10px; background: #333; border-radius: 4px; font-size: 10px; margin-right: 8px; cursor: pointer; color: #ccc; }
.footer-bottom { border-top: 1px solid #333; padding-top: 30px; text-align: center; color: #6e6e73; font-size: 12px; max-width: 1200px; margin: 0 auto; }

/* 页脚联系方式 */
.footer-contact p { color: #a1a1a6; margin-bottom: 12px; line-height: 1.4; }

/* --- 7. 移动端适配 --- */
@media (max-width: 768px) {
    header { height: 60px; }
    .nav-links { display: none; }
    .nav-inner { justify-content: center; }
    .nav-logo { margin-right: 0; align-items: center; }
    .mobile-menu-btn { display: flex; }
    .footer-grid { grid-template-columns: 1fr; gap: 30px; }
    .nav-inner { height: 60px; }
}

/* 跳过导航（无障碍） */
.skip-nav { position: absolute; top: -100px; left: 10px; background: #0071e3; color: #fff; padding: 8px 16px; border-radius: 0 0 8px 8px; z-index: 10000; font-size: 14px; transition: top 0.3s; }
.skip-nav:focus { top: 0; }