/* =====================================================
   ValU AI — Professional Finance Dark Theme
   Global Styles: Variables, Reset, Typography
   ===================================================== */

/* --- CSS Custom Properties --- */
:root {
  /* Colors */
  --bg-primary: #0c111c;
  --bg-secondary: #131a2e;
  --bg-card: #171f35;
  --bg-elevated: #1e2a45;
  --bg-input: #1a2340;
  
  --text-primary: #e8ecf4;
  --text-secondary: #8a95ad;
  --text-muted: #5e6a82;
  
  --accent-primary: #3b82f6;
  --accent-primary-hover: #2563eb;
  --accent-success: #10b981;
  --accent-warning: #f59e0b;
  --accent-danger: #ef4444;
  
  --border-subtle: rgba(255, 255, 255, 0.06);
  --border-card: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(59, 130, 246, 0.5);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* Typography */
  --font-display: 'Noto Serif SC', 'Source Han Serif SC', serif;
  --font-body: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
  
  /* Layout */
  --max-width: 1200px;
  --nav-height: 70px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 400ms ease;
}

/* --- Reset --- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

/* --- Typography --- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.3;
  color: var(--text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
  margin-bottom: var(--spacing-md);
  color: var(--text-secondary);
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--accent-primary-hover);
}

strong, b {
  font-weight: 600;
  color: var(--text-primary);
}

/* --- Data/Numbers --- */
.number-display {
  font-family: var(--font-mono);
  font-size: 2rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.number-positive { color: var(--accent-success); }
.number-negative { color: var(--accent-danger); }
.number-neutral { color: var(--accent-warning); }

/* --- Container --- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-xl);
}

/* --- Sections --- */
.section {
  padding: var(--spacing-3xl) 0;
}

.section-header {
  text-align: center;
  margin-bottom: var(--spacing-2xl);
}

.section-header h2 {
  margin-bottom: var(--spacing-md);
}

.section-header p {
  max-width: 600px;
  margin: 0 auto;
}

/* --- Fade-in animation --- */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* --- Utility --- */
.text-center { text-align: center; }
.text-right { text-align: right; }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mt-xl { margin-top: var(--spacing-xl); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.mb-xl { margin-bottom: var(--spacing-xl); }

/* --- Responsive --- */
@media (max-width: 768px) {
  :root {
    --spacing-3xl: 2.5rem;
  }
  
  h1 { font-size: 2rem; }
  h2 { font-size: 1.5rem; }
  
  .container {
    padding: 0 var(--spacing-md);
  }
}