/* PandaSlice Core Styles
   Base styles, variables, and utilities */

/* CSS Custom Properties (Variables) */
:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-dark: #1d4ed8;
  --color-secondary: #64748b;
  --color-accent: #059669;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  
  /* Neutrals */
  --color-white: #ffffff;
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-400: #94a3b8;
  --color-gray-500: #64748b;
  --color-gray-600: #475569;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;
  
  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, Inconsolata, 'Roboto Mono', monospace;
  
  /* Font Sizes */
  --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-normal: 1.5;
  --line-height-relaxed: 1.75;
  
  /* Spacing */
  --spacing-xs: 0.25rem;   /* 4px */
  --spacing-sm: 0.5rem;    /* 8px */
  --spacing-md: 1rem;      /* 16px */
  --spacing-lg: 1.5rem;    /* 24px */
  --spacing-xl: 2rem;      /* 32px */
  --spacing-2xl: 3rem;     /* 48px */
  --spacing-3xl: 4rem;     /* 64px */
  --spacing-4xl: 6rem;     /* 96px */
  
  /* Border Radius */
  --border-radius-sm: 0.25rem;
  --border-radius-md: 0.375rem;
  --border-radius-lg: 0.5rem;
  --border-radius-xl: 0.75rem;
  --border-radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;
  
  /* Container Sizes */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1280px;
  --container-2xl: 1536px;
}

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

html {
  font-size: 16px;
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-gray-900);
  background-color: var(--color-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Focus Management */
:focus {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

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

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

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: var(--line-height-tight);
  color: var(--color-gray-900);
}

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-bottom: var(--spacing-md);
  line-height: var(--line-height-relaxed);
}

/* Lists */
ul, ol {
  list-style: none;
}

/* Images */
img {
  max-width: 100%;
  height: auto;
  display: block;
}

/* Buttons */
button {
  background: none;
  border: none;
  font-family: inherit;
  cursor: pointer;
}

/* Form Elements */
input, textarea, select {
  font-family: inherit;
  font-size: inherit;
}

/* Utility Classes */
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

.visually-hidden-focusable:focus {
  position: static !important;
  width: auto !important;
  height: auto !important;
  padding: inherit !important;
  margin: inherit !important;
  overflow: visible !important;
  clip: auto !important;
  white-space: inherit !important;
}

.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;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

@media (min-width: 640px) {
  .container { padding: 0 var(--spacing-lg); }
}

@media (min-width: 1024px) {
  .container { padding: 0 var(--spacing-xl); }
}

/* Page Loader */
.page-loader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  opacity: 1;
  visibility: visible;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.page-loader.hidden {
  opacity: 0;
  visibility: hidden;
}

.loader-spinner {
  width: 40px;
  height: 40px;
  border: 4px solid var(--color-gray-200);
  border-top: 4px solid var(--color-primary);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

/* Skip to main content */
.skip-to-main {
  position: absolute;
  top: -100px;
  left: var(--spacing-md);
  background: var(--color-primary);
  color: var(--color-white);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  text-decoration: none;
  font-weight: 500;
  z-index: 1000;
  transition: top var(--transition-fast);
}

.skip-to-main:focus {
  top: var(--spacing-md);
}

/* Responsive Typography */
@media (min-width: 768px) {
  h1 { font-size: var(--font-size-5xl); }
  h2 { font-size: var(--font-size-4xl); }
  h3 { font-size: var(--font-size-3xl); }
}

@media (min-width: 1024px) {
  h1 { font-size: var(--font-size-6xl); }
  h2 { font-size: var(--font-size-5xl); }
}

/* Print Styles */
@media print {
  .page-loader,
  .mobile-menu-toggle,
  .mobile-menu-overlay,
  .back-to-top,
  .newsletter-form {
    display: none !important;
  }
  
  body {
    color: black;
    background: white;
  }
  
  a {
    color: black;
    text-decoration: underline;
  }
}

/* Dark Mode Support (Future Enhancement) */
@media (prefers-color-scheme: dark) {
  /* Will be implemented based on design requirements */
}