/* ============================================================
   BAIKA Technology — Global Design System v1
   Font: Space Grotesk (Display) + Inter (Body) + Lexend (UI)
   Design: Cosmic Dark x Neon Glow x AI
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Space+Grotesk:wght@400;500;600;700&family=Lexend:wght@300;400;500;600;700;800&display=swap');

:root {
  --bg-void:      #020612;
  --bg-primary:   #040918;
  --bg-secondary: #071224;
  --bg-tertiary:  #0b1830;
  --bg-elevated:  #0f1f3d;
  --bg-card:      rgba(255,255,255,0.035);
  --bg-card-hover:rgba(255,255,255,0.07);
  --bg-glass:     rgba(7,18,36,0.82);

  --border:       rgba(255,255,255,0.07);
  --border-glow:  rgba(0,183,255,0.25);
  --border-neon:  rgba(0,183,255,0.5);

  --neon-cyan:    #00b7ff;
  --neon-blue:    #3b82f6;
  --neon-violet:  #a855f7;
  --neon-green:   #10f5a0;
  --neon-amber:   #fbbf24;
  --neon-red:     #ff4d6d;

  --text-primary:   #e2eaf8;
  --text-secondary: #7b95c4;
  --text-muted:     #3d5278;
  --text-bright:    #ffffff;

  --gradient:       linear-gradient(135deg, #00b7ff 0%, #a855f7 50%, #3b82f6 100%);
  --gradient-text:  linear-gradient(135deg, #00b7ff, #7c3aed, #06b6d4);
  --gradient-card:  linear-gradient(135deg, rgba(0,183,255,0.08), rgba(168,85,247,0.05));

  --glow-cyan:    0 0 30px rgba(0,183,255,0.3), 0 0 60px rgba(0,183,255,0.1);
  --glow-violet:  0 0 30px rgba(168,85,247,0.3);
  --shadow:       0 8px 32px rgba(0,0,0,0.6);
  --shadow-xl:    0 24px 80px rgba(0,0,0,0.7);

  --radius-sm:  10px;
  --radius-md:  16px;
  --radius-lg:  24px;
  --radius-xl:  32px;
  --radius-full:9999px;

  --ease:       cubic-bezier(0.4, 0, 0.2, 1);
  --ease-spring:cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition: all 0.25s var(--ease);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 15px;
  font-weight: 400;
  line-height: 1.65;
  background: var(--bg-primary);
  color: var(--text-primary);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4, h5 {
  font-family: 'Space Grotesk', 'Inter', sans-serif;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
  color: var(--text-bright);
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
button { cursor: pointer; font-family: inherit; }
input, select, textarea { font-family: 'Inter', sans-serif; }
img { max-width: 100%; display: block; }
::selection { background: rgba(0,183,255,0.25); color: #fff; }

::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: var(--bg-void); }
::-webkit-scrollbar-thumb { background: linear-gradient(var(--neon-cyan), var(--neon-violet)); border-radius: 3px; }

/* === PAGE LOADER === */
.page-loader {
  position: fixed; inset: 0; background: var(--bg-void);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  z-index: 9999; gap: 20px; transition: opacity 0.6s;
}
.page-loader.fade-out { opacity: 0; pointer-events: none; }
.loader-logo {
  width: 64px; height: 64px; background: var(--gradient);
  border-radius: 16px; display: flex; align-items: center; justify-content: center;
  font-family: 'Space Grotesk', sans-serif; font-size: 28px; font-weight: 700; color: #fff;
  box-shadow: var(--glow-cyan); animation: loader-float 2s ease-in-out infinite;
}
.loader-bar { width: 220px; height: 3px; background: var(--border); border-radius: 2px; overflow: hidden; }
.loader-fill { width: 0; height: 100%; background: var(--gradient); border-radius: 2px; animation: load-fill 1.8s var(--ease) forwards; }
.page-loader p { font-family: 'Lexend', sans-serif; font-size: 11px; letter-spacing: 0.2em; text-transform: uppercase; color: var(--text-muted); }
@keyframes loader-float { 0%,100%{transform:translateY(0) rotate(0)}50%{transform:translateY(-8px) rotate(3deg)} }
@keyframes load-fill { 0%{width:0}100%{width:100%} }

/* === NAVBAR === */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  padding: 0 40px; height: 72px;
  display: flex; align-items: center; justify-content: space-between;
  background: rgba(4,9,24,0.6);
  backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid transparent;
  transition: var(--transition);
}
.nav.scrolled {
  background: rgba(4,9,24,0.92); border-bottom-color: var(--border);
  box-shadow: 0 4px 30px rgba(0,0,0,0.3);
}
.nav-brand {
  display: flex; align-items: center; gap: 12px; cursor: pointer;
}
.nav-logo-mark {
  width: 40px; height: 40px; background: var(--gradient); border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-family: 'Space Grotesk', sans-serif; font-size: 18px; font-weight: 700; color: #fff;
  box-shadow: 0 4px 16px rgba(0,183,255,0.4);
  transition: var(--transition);
}
.nav-brand:hover .nav-logo-mark { transform: rotate(5deg) scale(1.05); }
.nav-logo-text {
  font-family: 'Space Grotesk', sans-serif; font-size: 20px; font-weight: 700;
  letter-spacing: -0.02em;
}
.nav-logo-text span { color: var(--neon-cyan); }

.nav-links { display: flex; gap: 32px; }
.nav-link {
  font-size: 14px; font-weight: 500; color: var(--text-secondary);
  cursor: pointer; transition: var(--transition); position: relative;
  padding: 4px 0;
}
.nav-link::after {
  content: ''; position: absolute; bottom: -2px; left: 0; width: 0; height: 2px;
  background: var(--gradient); border-radius: 1px; transition: width 0.3s;
}
.nav-link:hover { color: var(--text-bright); }
.nav-link:hover::after { width: 100%; }
.nav-link.active { color: var(--neon-cyan); }
.nav-link.active::after { width: 100%; }

.nav-actions { display: flex; align-items: center; gap: 12px; }

/* === BUTTONS === */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 11px 24px; border-radius: var(--radius-sm);
  font-family: 'Inter', sans-serif; font-size: 14px; font-weight: 600;
  border: none; cursor: pointer; transition: var(--transition);
  position: relative; overflow: hidden; white-space: nowrap;
}
.btn:active { transform: scale(0.97); }

.btn-primary {
  background: var(--gradient); color: #fff;
  box-shadow: 0 4px 20px rgba(0,183,255,0.3);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 32px rgba(0,183,255,0.5), var(--glow-cyan); }

.btn-secondary {
  background: var(--bg-card); color: var(--text-primary);
  border: 1px solid var(--border); backdrop-filter: blur(10px);
}
.btn-secondary:hover { border-color: var(--border-neon); color: var(--neon-cyan); }

.btn-ghost { background: transparent; color: var(--text-secondary); border: 1px solid transparent; }
.btn-ghost:hover { color: var(--text-primary); background: var(--bg-card); border-color: var(--border); }

.btn-lg { padding: 15px 32px; font-size: 16px; border-radius: var(--radius-md); }
.btn-sm { padding: 7px 16px; font-size: 12px; }

/* === SECTION === */
.section {
  padding: 100px 40px;
  max-width: 1240px;
  margin: 0 auto;
}
.section-badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 16px; border-radius: var(--radius-full);
  background: rgba(0,183,255,0.08); border: 1px solid rgba(0,183,255,0.2);
  font-family: 'Lexend', sans-serif; font-size: 12px; font-weight: 500;
  color: var(--neon-cyan); letter-spacing: 0.06em; text-transform: uppercase;
  margin-bottom: 20px;
}
.section-badge .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--neon-cyan); box-shadow: 0 0 6px var(--neon-cyan); }
.section-title {
  font-size: clamp(2rem, 4vw, 3rem); margin-bottom: 16px;
}
.section-sub {
  font-size: 16px; color: var(--text-secondary); max-width: 600px; line-height: 1.7;
}
.text-gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* === CARDS === */
.card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: 32px;
  backdrop-filter: blur(16px); transition: var(--transition);
  position: relative; overflow: hidden;
}
.card::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(0,183,255,0.4), transparent);
  opacity: 0; transition: opacity 0.3s;
}
.card:hover {
  border-color: var(--border-glow); transform: translateY(-4px);
  box-shadow: 0 16px 48px rgba(0,0,0,0.3), 0 0 0 1px rgba(0,183,255,0.08);
}
.card:hover::before { opacity: 1; }

.card-icon {
  width: 56px; height: 56px; border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  font-size: 24px; margin-bottom: 20px;
  background: var(--gradient-card); border: 1px solid var(--border-glow);
}
.card-title { font-size: 18px; font-weight: 700; margin-bottom: 10px; }
.card-desc { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* === FOOTER === */
.footer {
  padding: 60px 40px 30px;
  border-top: 1px solid var(--border);
  background: var(--bg-void);
}
.footer-inner {
  max-width: 1240px; margin: 0 auto;
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
}
.footer-brand .nav-logo-text { margin-bottom: 12px; }
.footer-desc { font-size: 14px; color: var(--text-secondary); line-height: 1.7; max-width: 300px; }
.footer-title { font-family: 'Lexend', sans-serif; font-size: 12px; font-weight: 600; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-muted); margin-bottom: 16px; }
.footer-link { display: block; font-size: 14px; color: var(--text-secondary); padding: 6px 0; transition: var(--transition); cursor: pointer; }
.footer-link:hover { color: var(--neon-cyan); padding-left: 4px; }
.footer-bottom { max-width: 1240px; margin: 40px auto 0; padding-top: 24px; border-top: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; font-size: 13px; color: var(--text-muted); }

/* === GRID UTILS === */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.justify-center { justify-content: center; }
.text-center { text-align: center; }
.gap-8 { gap: 8px; } .gap-12 { gap: 12px; } .gap-16 { gap: 16px; } .gap-20 { gap: 20px; } .gap-24 { gap: 24px; }
.mt-12 { margin-top: 12px; } .mt-20 { margin-top: 20px; } .mt-32 { margin-top: 32px; } .mt-40 { margin-top: 40px; }
.mb-12 { margin-bottom: 12px; } .mb-20 { margin-bottom: 20px; } .mb-40 { margin-bottom: 40px; }

/* === FORM === */
.form-group { margin-bottom: 20px; }
.form-group label { display: block; font-size: 12px; font-weight: 600; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-muted); margin-bottom: 8px; }
.form-input {
  width: 100%; padding: 13px 16px;
  background: rgba(255,255,255,0.04); border: 1px solid var(--border);
  border-radius: var(--radius-sm); color: var(--text-primary);
  font-size: 14px; transition: var(--transition); outline: none;
}
.form-input::placeholder { color: var(--text-muted); }
.form-input:focus { border-color: var(--neon-cyan); background: rgba(0,183,255,0.05); box-shadow: 0 0 0 3px rgba(0,183,255,0.1); }
textarea.form-input { min-height: 120px; resize: vertical; }

/* === RESPONSIVE === */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .footer-inner { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
  .nav { padding: 0 20px; }
  .nav-links { display: none; }
  .section { padding: 60px 20px; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
  .section-title { font-size: 1.8rem; }
}