/* YunxiVPN — Deep Space Dark Theme */
@import url('https://cdnjs.cloudflare.com/ajax/libs/font-awesome/6.5.0/css/all.min.css');

:root {
  /* Brand palette from DESIGN.md */
  --primary:        #3b82f6;
  --primary-dark:   #2563eb;
  --accent-cyan:    #06b6d4;
  --accent-purple:  #8b5cf6;
  --gold:           #fbbf24;

  --bg:             #070b14;
  --surface:        #0f1829;
  --surface-2:      #141f35;
  --header-bg:      #0a1120;
  --text:           #f0f4ff;
  --text-secondary: #b0c4de;
  --text-muted:     #6a8bb0;
  --border:         #2a3f5e;

  --dark:           #040710;

  --radius-sm:  8px;
  --radius-md:  10px;
  --radius-lg:  16px;
  --radius-xl:  50px;

  --shadow-card: 0 4px 20px rgba(59,130,246,.15);
  --shadow-lg:   0 8px 32px rgba(0,0,0,.4);
  --transition:  0.2s ease;

  --space-xs: 8px;
  --space-sm: 16px;
  --space-md: 24px;
  --space-lg: 48px;
  --space-xl: 80px;
}

*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; overflow-x: hidden; max-width: 100%; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'PingFang SC', 'Microsoft YaHei', sans-serif;
  font-size: 16px; line-height: 1.7;
  color: var(--text); background: var(--bg);
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
ul { list-style: none; padding: 0; margin: 0; }
h1, h2, h3, h4 { margin-top: 0; line-height: 1.25; color: var(--text); }

/* ─── HEADER ─── */
.site-header {
  position: sticky; top: 0; z-index: 1000;
  background: rgba(7,11,20,.92);
  backdrop-filter: blur(16px) saturate(1.2);
  border-bottom: 1px solid var(--border);
}
.nav {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center;
  padding: 0 var(--space-sm);
  height: 64px; gap: var(--space-sm);
}
.brand { display: flex; align-items: center; flex-shrink: 0; }
.logo { height: 40px; width: auto; max-width: 160px; object-fit: contain; }

.nav-links {
  display: flex; align-items: center; gap: 4px;
  flex: 1; justify-content: center;
}
.nav-links > li > a {
  color: var(--text-secondary); font-size: 14px; font-weight: 500;
  padding: 8px 12px; border-radius: var(--radius-sm);
  transition: color var(--transition), background var(--transition);
  white-space: nowrap;
}
.nav-links > li > a:hover { color: var(--text); background: rgba(59,130,246,.12); text-decoration: none; }

.nav-right {
  display: flex; align-items: center; gap: var(--space-sm);
  flex-shrink: 0; margin-left: auto;
}

.mobile-lang { display: none; }

/* ─── DROPDOWN ─── */
.dropdown { position: relative; }
.dropdown-panel {
  position: absolute; top: 100%; right: 0;
  margin-top: 0; padding-top: 8px;
  display: none; min-width: 160px; z-index: 1000;
}
.dropdown-panel-inner {
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--radius-md); overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.dropdown:hover .dropdown-panel,
.dropdown:focus-within .dropdown-panel { display: block; }
.dropdown-panel a {
  display: block; padding: 10px 16px;
  color: var(--text-secondary); font-size: 14px;
  transition: background var(--transition);
  white-space: nowrap;
}
.dropdown-panel a:hover { background: var(--surface); color: var(--text); text-decoration: none; }

.lang-btn {
  background: none; border: 1px solid var(--border);
  color: var(--text-secondary); padding: 6px 12px;
  border-radius: var(--radius-sm); cursor: pointer;
  font-size: 13px; display: flex; align-items: center; gap: 6px;
  transition: border-color var(--transition), color var(--transition);
}
.lang-btn:hover { border-color: var(--primary); color: var(--text); }
.lang-btn i { font-size: 11px; }

/* ─── CTA BUTTON ─── */
.btn-cta {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  color: #fff; padding: 10px 22px; border-radius: var(--radius-xl);
  font-size: 14px; font-weight: 600;
  box-shadow: 0 4px 20px rgba(59,130,246,.4);
  transition: transform var(--transition), box-shadow var(--transition);
  white-space: nowrap; display: inline-block;
}
.btn-cta:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(59,130,246,.5); text-decoration: none; color: #fff; }
.btn-cta.btn-lg { padding: 16px 40px; font-size: 18px; font-weight: 700; border-radius: var(--radius-xl); }

/* ─── HAMBURGER ─── */
.nav-toggle {
  display: none;
  background: none; border: none; cursor: pointer;
  color: var(--text); font-size: 22px; padding: 6px;
  order: 99;
}

/* ─── HERO ─── */
.hero {
  background: var(--surface);
  color: var(--text);
  padding: 100px var(--space-sm) var(--space-xl);
  position: relative; overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute; inset: 0;
  background: radial-gradient(ellipse at 70% 50%, rgba(59,130,246,.15) 0%, transparent 60%),
              radial-gradient(ellipse at 20% 80%, rgba(139,92,246,.12) 0%, transparent 50%);
}
.hero-inner {
  position: relative; max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-lg); align-items: center;
}
.hero-text { text-align: left; }
.badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(59,130,246,.15); border: 1px solid rgba(59,130,246,.35);
  color: var(--accent-cyan); padding: 6px 16px; border-radius: 100px;
  font-size: 13px; font-weight: 600; margin-bottom: var(--space-md);
}
.hero h1 {
  font-size: clamp(28px, 4vw, 52px); font-weight: 700;
  margin-bottom: var(--space-sm); color: var(--text);
  letter-spacing: -0.5px; line-height: 1.15;
}
.hero h1 em { font-style: normal; color: var(--accent-cyan); }
.hero p {
  font-size: clamp(15px, 2vw, 18px); color: var(--text-secondary);
  margin-bottom: var(--space-md);
}
.hero-cta { margin-bottom: var(--space-sm); }
.hero-trust {
  display: flex; align-items: center; gap: var(--space-sm);
  font-size: 14px; color: var(--text-muted); flex-wrap: wrap;
}
.hero-image { border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-lg); }
.hero-image img { width: 100%; height: 380px; object-fit: cover; }

/* ─── FEATURES ─── */
.features {
  padding: var(--space-xl) var(--space-sm);
  background: var(--bg);
}
.section-head { max-width: 1200px; margin: 0 auto var(--space-lg); text-align: center; }
.section-head h2 { font-size: clamp(24px, 3.5vw, 38px); font-weight: 700; letter-spacing: -0.5px; }
.section-head p { font-size: 17px; color: var(--text-secondary); max-width: 600px; margin: var(--space-xs) auto 0; }
.feature-grid {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--space-md);
}
.feature-card {
  background: var(--surface-2); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: var(--space-md);
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
}
.feature-card:hover { border-color: var(--primary); transform: translateY(-3px); box-shadow: var(--shadow-card); }
.feature-card i {
  font-size: 28px; color: var(--primary); margin-bottom: var(--space-sm); display: block;
}
.feature-card h3 { font-size: 17px; font-weight: 600; margin-bottom: 8px; }
.feature-card p { font-size: 14px; color: var(--text-muted); margin: 0; line-height: 1.7; }

/* ─── SPLIT ROW ─── */
.split-row { padding: var(--space-xl) var(--space-sm); background: var(--surface); }
.split-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-lg); align-items: center;
}
.split-text h2 { font-size: clamp(22px, 3vw, 34px); font-weight: 700; letter-spacing: -0.5px; margin-bottom: var(--space-sm); }
.split-text p { color: var(--text-secondary); margin-bottom: var(--space-sm); }
.split-img { border-radius: var(--radius-lg); overflow: hidden; box-shadow: var(--shadow-lg); }
.split-img img { width: 100%; height: 320px; object-fit: cover; }

/* ─── IMAGE STRIP ─── */
.image-strip { padding: 0; background: var(--bg); }
.image-strip-inner {
  max-width: 1200px; margin: 0 auto; padding: var(--space-lg) var(--space-sm);
  display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-sm);
}
.img-col { border-radius: var(--radius-lg); overflow: hidden; }
.img-col img { width: 100%; height: 200px; object-fit: cover; }

/* ─── FAQ ─── */
.faq { padding: var(--space-xl) var(--space-sm); background: var(--surface); }
.faq-list { max-width: 760px; margin: 0 auto; }
.faq-item { border-bottom: 1px solid var(--border); }
.faq-q {
  width: 100%; background: none; border: none; text-align: left;
  padding: var(--space-sm) 0; font-size: 16px; font-weight: 600;
  cursor: pointer; display: flex; justify-content: space-between; align-items: center;
  color: var(--text); font-family: inherit;
}
.faq-q::after { content: '+'; color: var(--primary); font-size: 20px; flex-shrink: 0; transition: transform var(--transition); }
.faq-item.open .faq-q::after { transform: rotate(45deg); }
.faq-a { display: none; padding: 0 0 var(--space-sm); font-size: 15px; color: var(--text-secondary); line-height: 1.8; }
.faq-item.open .faq-a { display: block; }

/* ─── PAGE HERO ─── */
.page-hero {
  background: var(--surface);
  color: var(--text); text-align: center;
  padding: 80px var(--space-sm) var(--space-xl);
  border-bottom: 1px solid var(--border);
}
.page-hero-inner { max-width: 700px; margin: 0 auto; }
.page-hero h1 { font-size: clamp(26px, 4vw, 44px); font-weight: 700; margin-bottom: var(--space-sm); }
.page-hero p { font-size: 18px; color: var(--text-secondary); }

/* ─── PROSE ─── */
.prose { padding: var(--space-xl) var(--space-sm); }
.prose-inner { max-width: 800px; margin: 0 auto; font-size: 15px; line-height: 1.85; }
.prose-inner p { color: var(--text-secondary); margin-bottom: 20px; }

/* ─── FOOTER ─── */
.site-footer {
  background: var(--dark); color: var(--text-secondary);
  padding: var(--space-xl) var(--space-sm) var(--space-md);
  border-top: 1px solid var(--border);
}
.footer-grid {
  max-width: 1100px; margin: 0 auto;
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-lg); margin-bottom: var(--space-xl);
}
.footer-brand .logo-footer { height: 40px; width: auto; margin-bottom: var(--space-sm); }
.footer-brand p { font-size: 14px; line-height: 1.7; max-width: 280px; color: var(--text-muted); }
.footer-col h4 { color: var(--text); font-size: 13px; font-weight: 700; margin-bottom: var(--space-sm); text-transform: uppercase; letter-spacing: .5px; }
.footer-col ul li { margin-bottom: 8px; }
.footer-col ul li a { color: var(--text-muted); font-size: 14px; transition: color var(--transition); }
.footer-col ul li a:hover { color: var(--text); text-decoration: none; }
.footer-bottom {
  max-width: 1100px; margin: 0 auto;
  border-top: 1px solid rgba(255,255,255,.07); padding-top: var(--space-sm);
}
.footer-bottom p { font-size: 13px; margin: 0; color: var(--text-muted); }

/* ─── MOBILE ─── */
@media (max-width: 768px) {
  .nav { padding: 0 8px; }
  .nav-links {
    display: none;
    position: absolute; top: 100%;
    left: 0; right: 0;
    flex-direction: column;
    align-items: center;
    background: var(--header-bg);
    box-shadow: 0 8px 24px rgba(0,0,0,.4);
    padding: 12px 0;
    z-index: 999;
    overflow: visible;
    height: auto; max-height: none;
  }
  .nav-links.open { display: flex; }
  .nav-links > li { width: 100%; text-align: center; }
  .nav-links > li > a { display: block; width: 100%; padding: 14px 0; font-size: 17px; }

  .nav-right .lang-switcher { display: none; }
  .nav-right .btn-cta { display: none; }
  .nav-toggle { display: block; }

  .mobile-lang {
    display: flex; justify-content: center; gap: 16px;
    padding: 14px 0; border-top: 1px solid rgba(255,255,255,.1);
    width: 100%;
  }
  .nav-links li.mobile-lang a {
    display: inline-block; width: auto;
    padding: 4px 10px; font-size: 15px; line-height: 1.4;
    white-space: nowrap; color: var(--text-muted);
  }
  .nav-links li.mobile-lang a.active { color: var(--accent-cyan); font-weight: 700; }

  .hero { padding: 60px var(--space-sm) var(--space-lg); }
  .hero-inner { grid-template-columns: 1fr; }
  .hero-image { display: none; }
  .hero-text { text-align: center; }
  .hero-trust { justify-content: center; }

  .split-inner { grid-template-columns: 1fr; }
  .split-img { display: none; }

  .image-strip-inner { grid-template-columns: 1fr; }

  .footer-grid { grid-template-columns: 1fr 1fr; }

  .btn-cta, .btn-cta.btn-lg, .hero-cta a {
    display: block; margin-left: auto; margin-right: auto;
    text-align: center; width: max-content; max-width: 90%;
  }
}

@media (max-width: 480px) {
  .footer-grid { grid-template-columns: 1fr; }
}