/* Master CSS f Style 5: Deep Blue Tech (VN) */

/* CSS Variables */
:root {
  --color-primary: #0A4D68; /* deep blue */
  --color-secondary: #00D9FF; /* electric blue */
  --color-accent: #A7F3D0; /* mint accent for success hints */
  --color-background: #001524; /* blue-black */
  --color-surface: rgba(255,255,255,0.06);
  --color-text: #E6F3F8;
  --color-muted: #9FB6BF;

  --font-primary: "Roboto", system-ui, -apple-system, Segoe UI, Arial, sans-serif;
  --font-secondary: "Exo 2", "SF Pro Display", system-ui, sans-serif;

  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;

  --shadow-sm: 0 6px 18px rgba(0, 217, 255, 0.12);
  --border-glass: 1px solid rgba(255,255,255,0.15);
}

/* Reset & Base */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--font-primary);
  color: var(--color-text);
  background: linear-gradient(180deg, #001524 0%, #0A2130 100%);
  line-height: 1.65; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-secondary); text-decoration: none; }
a:hover { opacity: .9; }

/* Typography */
h1 { font-size: 2.4rem; font-family: var(--font-secondary); letter-spacing: 0.2px; }
h2 { font-size: 1.8rem; margin-bottom: var(--spacing-sm); font-family: var(--font-secondary); }
h3 { font-size: 1.25rem; margin: var(--spacing-sm) 0 var(--spacing-xs); }
p { margin: 0 0 var(--spacing-sm); color: var(--color-text); }
ul { margin: 0 0 var(--spacing-sm) 1.2rem; }

/* Layout */
.container { max-width: 1200px; margin: 0 auto; padding: 0 var(--spacing-md); }
.section { padding: var(--spacing-xl) 0; }
.surface { background: var(--color-surface); backdrop-filter: blur(10px); border: var(--border-glass); border-radius: var(--radius-md); }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 9999;
  background: rgba(0, 21, 36, 0.8);
  backdrop-filter: blur(12px);
  border-bottom: var(--border-glass);
  overflow: visible;
}

.header-inner {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-sm) 0;
}

.logo img {
  max-height: 48px;
  height: auto;
  width: auto;
}

.main-nav {
  flex: 1 1 auto;
  min-width: 0;
}

.main-nav > ul {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  list-style: none;
  white-space: nowrap;
}

/* Ensure dropdowns stay hidden by default (override top-level ul flex) */
.main-nav .dropdown { display: none; }

.main-nav li {
  position: relative;
}

.main-nav > ul > li > a {
  display: inline-block;
  padding: .4rem .5rem;
  color: var(--color-text);
  opacity: .9;
}

.main-nav a:hover {
  color: #fff;
}

.nav-group > a {
  position: relative;
  padding-right: .9rem;
}

.nav-group > a::after {
  content: "▾";
  font-size: .8rem;
  margin-left: .25rem;
  opacity: .8;
}

/* Dropdown menu */
.dropdown {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 220px;
  background: rgba(0, 21, 36, 0.92);
  backdrop-filter: blur(10px);
  border: var(--border-glass);
  border-radius: var(--radius-md);
  padding: .4rem 0;
  z-index: 1001;
}

.dropdown li {
  list-style: none;
}

.dropdown a {
  display: block;
  color: var(--color-text);
  padding: .5rem .75rem;
  white-space: nowrap;
}

.dropdown a:hover {
  background: rgba(0,217,255,0.08);
  color: #fff;
}

.nav-group:hover .dropdown,
.nav-group:focus-within .dropdown {
  display: block;
}

.cta-group {
  display: flex;
  gap: var(--spacing-sm);
  flex: 0 0 auto;
}

.menu-toggle {
  display: none;
  background: none;
  color: var(--color-text);
  font-size: 1.5rem;
  border: none;
  flex: 0 0 auto;
}

.mobile-nav {
  display: none;
  background: rgba(0, 21, 36, 0.95);
  padding: var(--spacing-sm);
  border-top: var(--border-glass);
}

.mobile-nav ul {
  list-style: none;
  display: grid;
  gap: .35rem;
}

.mobile-nav .cta-row {
  display: flex;
  gap: var(--spacing-sm);
  margin-top: .5rem;
}

.mobile-nav a { display:block; padding:.6rem .5rem; border-radius: 8px; }
.mobile-nav a:hover { background: rgba(0,217,255,0.08); }
.mobile-nav strong { display:block; margin:.75rem 0 .25rem; color:#fff; opacity:.95; }
.mobile-nav .cta-row .btn { flex:1; text-align:center; }

/* Buttons */
.btn { display: inline-block; padding: 0.65rem 1rem; border-radius: var(--radius-sm); transition: .2s ease; border: 1px solid transparent; }
.btn-primary { background: linear-gradient(90deg, var(--color-secondary), #4DE4FF); color: #00101A; box-shadow: var(--shadow-sm); font-weight: 600; }
.btn-primary:hover { transform: translateY(-1px); }
.btn-outline { border-color: var(--color-secondary); color: var(--color-secondary); }
.btn-outline:hover { background: rgba(0,217,255,0.1); }

/* Hero */
.hero-section { position: relative; min-height: 320px; padding: var(--spacing-xl) 0; background-size: cover; background-position: center; border-bottom: var(--border-glass); }
.hero-section .container { display: grid; gap: var(--spacing-sm); }
.hero-intro { max-width: 900px; color: var(--color-muted); }
.hero-section::after { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.35) 100%); pointer-events: none; }
.hero-section .container { position: relative; z-index: 1; }


/* Content Blocks */
.content-block { padding: var(--spacing-xl) 0; }
.content-block.horizontal .container { display: grid; grid-template-columns: 1.1fr .9fr; gap: var(--spacing-lg); align-items: center; }
.content-block.vertical .container { display: grid; grid-template-columns: 1fr; gap: var(--spacing-md); }
.block-text { background: var(--color-surface); padding: var(--spacing-lg); border-radius: var(--radius-md); border: var(--border-glass); }
.block-image { border-radius: var(--radius-md); overflow: hidden; border: var(--border-glass); }

/* Content Grid */
.content-grid-section { padding: var(--spacing-xl) 0; }
.content-grid { display: grid; gap: var(--spacing-md); }
.content-grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid-item { background: var(--color-surface); padding: var(--spacing-md); border-radius: var(--radius-md); border: var(--border-glass); }
.grid-item h3 { margin-top: var(--spacing-sm); }

/* Footer */
.site-footer { margin-top: var(--spacing-xl); background: #00101A; border-top: var(--border-glass); color: var(--color-muted); }
.footer-grid { display: grid; grid-template-columns: 1.3fr 1fr 1fr 1fr; gap: var(--spacing-lg); padding: var(--spacing-xl) 0; }
.footer-grid h3 { color: #fff; margin-bottom: var(--spacing-sm); font-family: var(--font-secondary); }
.footer-payments .payment-icons { display: flex; gap: var(--spacing-sm); flex-wrap: wrap; list-style: none; }
.footer-links ul { list-style: none; display: grid; gap: .4rem; }
.footer-compliance .legal-links { list-style: none; display: flex; gap: var(--spacing-sm); margin-top: .5rem; }
.footer-bottom { border-top: var(--border-glass); padding: var(--spacing-sm) 0; text-align: center; }

/* Utilities */
.muted { color: var(--color-muted); }
.card { background: var(--color-surface); border: var(--border-glass); border-radius: var(--radius-md); padding: var(--spacing-md); }

/* Responsive Breakpoints */
/* Large screens - tighten spacing */
@media (max-width: 1280px) {
  .header-inner { gap: var(--spacing-sm); }
  .main-nav > ul { gap: .75rem; }
  .main-nav > ul > li > a { padding: .35rem .4rem; font-size: .95rem; }
  .logo img { max-height: 42px; }
  .cta-group .btn { padding: .5rem .75rem; }
}

/* Medium screens - switch to mobile menu */
@media (max-width: 1200px) {
  .main-nav { display: none; }
  .menu-toggle { display: block; margin-left: auto; }
  .cta-group { display: none; }
  .header-inner { padding-left: var(--spacing-md); padding-right: var(--spacing-md); }

  /* 默认隐藏，点汉堡后移除 hidden 再显示 */
  .mobile-nav { display: none; }
  .mobile-nav:not([hidden]) { display: block; }
}

/* Tablet */
@media (max-width: 1024px) {
  .content-block.horizontal .container { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

/* Mobile */
@media (max-width: 768px) {
  .footer-grid { grid-template-columns: 1fr; }
  .content-grid.cols-3 { grid-template-columns: 1fr; }
  h1 { font-size: 1.6rem; line-height: 1.25; margin-bottom: .5rem; letter-spacing: 0; }
  .hero-section { min-height: 240px; padding: var(--spacing-lg) 0; }
}