/* 
 * Core CSS Foundation - Zekt SaaS Landing Page
 * Dark theme with light green accents
 * CSS Custom Properties for maintainable design system
 */

/* ==========================================================================
   CSS Custom Properties (Design Tokens)
   ========================================================================== */

:root {
  /* Color Palette - Dark Theme */
  --color-bg-primary: #0a0a0a;
  --color-bg-secondary: #1a1a1a;
  --color-bg-tertiary: #2a2a2a;
  --color-bg-overlay: rgba(10, 10, 10, 0.95);
  
  /* Text Colors */
  --color-text-primary: #ffffff;
  --color-text-secondary: #b3b3b3;
  --color-text-tertiary: #808080;
  --color-text-muted: #666666;
  
  /* Accent Colors - Light Green Theme */
  --color-accent: #00ff88;
  --color-accent-hover: #00cc6a;
  --color-accent-light: #33ff99;
  --color-accent-dark: #00b85c;
  
  /* Status Colors */
  --color-success: #22c55e;
  --color-error: #ef4444;
  --color-warning: #f59e0b;
  --color-info: #3b82f6;
  
  /* Border and Surface Colors */
  --color-border: #333333;
  --color-border-light: #404040;
  --color-border-focus: var(--color-accent);
  --color-surface: #161616;
  --color-surface-hover: #202020;
  
  /* Typography */
  --font-family-primary: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'JetBrains Mono', 'SF Mono', Monaco, Inconsolata, 'Roboto Mono', Consolas, 'Courier New', monospace;
  
  /* Font Sizes - Responsive Typography Scale */
  --font-size-xs: 0.75rem;    /* 12px */
  --font-size-sm: 0.875rem;   /* 14px */
  --font-size-base: 1rem;     /* 16px */
  --font-size-lg: 1.125rem;   /* 18px */
  --font-size-xl: 1.25rem;    /* 20px */
  --font-size-2xl: 1.5rem;    /* 24px */
  --font-size-3xl: 1.875rem;  /* 30px */
  --font-size-4xl: 2.25rem;   /* 36px */
  --font-size-5xl: 3rem;      /* 48px */
  --font-size-6xl: 3.75rem;   /* 60px */
  
  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-base: 1.6;
  --line-height-relaxed: 1.75;
  
  /* Font Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  
  /* Spacing Scale */
  --space-xs: 0.25rem;   /* 4px */
  --space-sm: 0.5rem;    /* 8px */
  --space-md: 1rem;      /* 16px */
  --space-lg: 1.5rem;    /* 24px */
  --space-xl: 2rem;      /* 32px */
  --space-2xl: 3rem;     /* 48px */
  --space-3xl: 4rem;     /* 64px */
  --space-4xl: 6rem;     /* 96px */
  
  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 10px 10px -5px rgba(0, 0, 0, 0.2);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
  
  /* Z-Index Scale */
  --z-dropdown: 1500;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;
}

/* ==========================================================================
   Base Styles
   ========================================================================== */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  font-size: 16px;
  line-height: var(--line-height-base);
  -webkit-text-size-adjust: 100%;
  -moz-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-base);
  color: var(--color-text-primary);
  background-color: var(--color-bg-primary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ==========================================================================
   Typography
   ========================================================================== */

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-md) 0;
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--font-size-4xl);
}

h2 {
  font-size: var(--font-size-3xl);
}

h3 {
  font-size: var(--font-size-2xl);
}

h4 {
  font-size: var(--font-size-xl);
}

h5 {
  font-size: var(--font-size-lg);
}

h6 {
  font-size: var(--font-size-base);
}

p {
  margin: 0 0 var(--space-md) 0;
  color: var(--color-text-secondary);
}

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

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

a:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

strong, b {
  font-weight: var(--font-weight-semibold);
}

small {
  font-size: var(--font-size-sm);
  color: var(--color-text-tertiary);
}

/* ==========================================================================
   Lists
   ========================================================================== */

ul, ol {
  margin: 0 0 var(--space-md) 0;
  padding-left: var(--space-lg);
}

li {
  margin-bottom: var(--space-xs);
  color: var(--color-text-secondary);
}

/* ==========================================================================
   Images and Media
   ========================================================================== */

img, video, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

/* ==========================================================================
   Form Elements Base
   ========================================================================== */

input, textarea, select, button {
  font-family: inherit;
  font-size: inherit;
  line-height: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
  padding: 0;
  margin: 0;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.6;
}

/* ==========================================================================
   Focus Management
   ========================================================================== */

:focus {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

:focus:not(:focus-visible) {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* ==========================================================================
   Utility Classes
   ========================================================================== */

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.hidden {
  display: none !important;
}

.invisible {
  visibility: hidden;
}

/* Text Utilities */
.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

/* Color Utilities */
.text-primary {
  color: var(--color-text-primary);
}

.text-secondary {
  color: var(--color-text-secondary);
}

.text-accent {
  color: var(--color-accent);
}

.text-success {
  color: var(--color-success);
}

.text-error {
  color: var(--color-error);
}

/* ==========================================================================
   High Contrast Support
   ========================================================================== */

@media (prefers-contrast: high) {
  :root {
    --color-bg-primary: #000000;
    --color-bg-secondary: #111111;
    --color-text-primary: #ffffff;
    --color-text-secondary: #cccccc;
    --color-accent: #00ff00;
    --color-border: #444444;
  }
}

/* ==========================================================================
   Reduced Motion Support
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}