/* ============================================
   BASE CSS - Athletic E-commerce Platform
   Poland | Active Lifestyle | Premium Fitness
   ============================================ */

/* ============================================
   VARIABLES
   ============================================ */
:root {
  /* Brand Colors */
  --color-primary: #E63946;        /* Vibrant Red - Energy */
  --color-secondary: #00B4D8;      /* Electric Blue - Performance */
  --color-accent: #CCFF00;         /* Lime Green - Dynamic */
  --color-charcoal: #2B2D42;       /* Charcoal Gray - Premium */
  
  /* Semantic Colors */
  --color-bg: #FFFFFF;
  --color-bg-alt: #F8F9FA;
  --color-text: #2B2D42;
  --color-text-inverse: #FFFFFF;
  --color-success: #2ECC71;
  --color-warning: #FFB703;
  --color-danger: #E63946;
  
  /* Neutral Grays */
  --color-gray-50: #F8F9FA;
  --color-gray-100: #F1F3F5;
  --color-gray-200: #E9ECEF;
  --color-gray-300: #DEE2E6;
  --color-gray-400: #CED4DA;
  --color-gray-500: #ADB5BD;
  --color-gray-600: #6C757D;
  --color-gray-700: #495057;
  --color-gray-800: #343A40;
  --color-gray-900: #212529;
  
  /* Typography */
  --font-family-base: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans', sans-serif;
  --font-family-heading: var(--font-family-base);
  
  --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 */
  
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;
  
  --line-height-none: 1;
  --line-height-tight: 1.25;
  --line-height-snug: 1.375;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --line-height-loose: 2;
  
  --letter-spacing-tight: -0.025em;
  --letter-spacing-normal: 0;
  --letter-spacing-wide: 0.025em;
  --letter-spacing-wider: 0.05em;
  --letter-spacing-widest: 0.1em;
  
  /* Spacing Scale (0-96px) */
  --space-0: 0;
  --space-1: 0.25rem;     /* 4px */
  --space-2: 0.5rem;      /* 8px */
  --space-3: 0.75rem;     /* 12px */
  --space-4: 1rem;        /* 16px */
  --space-5: 1.25rem;     /* 20px */
  --space-6: 1.5rem;      /* 24px */
  --space-8: 2rem;        /* 32px */
  --space-10: 2.5rem;     /* 40px */
  --space-12: 3rem;       /* 48px */
  --space-16: 4rem;       /* 64px */
  --space-20: 5rem;       /* 80px */
  --space-24: 6rem;       /* 96px */
  
  /* Radius */
  --radius-none: 0;
  --radius-sm: 0.25rem;   /* 4px */
  --radius-md: 0.5rem;    /* 8px */
  --radius-lg: 0.75rem;   /* 12px */
  --radius-xl: 1rem;      /* 16px */
  --radius-2xl: 1.5rem;   /* 24px */
  --radius-full: 9999px;
  
  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(43, 45, 66, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(43, 45, 66, 0.1), 0 2px 4px -1px rgba(43, 45, 66, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(43, 45, 66, 0.1), 0 4px 6px -2px rgba(43, 45, 66, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(43, 45, 66, 0.1), 0 10px 10px -5px rgba(43, 45, 66, 0.04);
  --shadow-2xl: 0 25px 50px -12px rgba(43, 45, 66, 0.25);
  --shadow-inner: inset 0 2px 4px 0 rgba(43, 45, 66, 0.06);
  --shadow-accent: 0 0 20px rgba(204, 255, 0, 0.3);
  
  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
  
  /* Layout */
  --container-max: 1280px;
  --container-padding: var(--space-4);
}

/* ============================================
   RESET & NORMALIZE
   ============================================ */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

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

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-height: 100vh;
  overflow-x: hidden;
}

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

input, button, textarea, select {
  font: inherit;
  color: inherit;
  letter-spacing: inherit;
}

button {
  cursor: pointer;
  background: none;
  border: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

/* ============================================
   BASE STYLES
   ============================================ */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-heading);
  font-weight: var(--font-weight-extrabold);
  line-height: var(--line-height-tight);
  letter-spacing: var(--letter-spacing-tight);
  color: var(--color-charcoal);
  text-transform: uppercase;
  margin-bottom: var(--space-4);
}

h1 { font-size: var(--font-size-5xl); }
h2 { font-size: var(--font-size-4xl); }
h3 { font-size: var(--font-size-3xl); }
h4 { font-size: var(--font-size-2xl); }
h5 { font-size: var(--font-size-xl); }
h6 { font-size: var(--font-size-lg); }

@media (min-width: 768px) {
  h1 { font-size: var(--font-size-6xl); }
  h2 { font-size: var(--font-size-5xl); }
}

p {
  margin-bottom: var(--space-4);
  line-height: var(--line-height-relaxed);
  color: var(--color-gray-700);
}

a {
  transition: color var(--transition-fast);
}

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

/* Focus Visible Accessibility */
:focus-visible {
  outline: 3px solid var(--color-secondary);
  outline-offset: 2px;
}

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

/* ============================================
   UTILITIES
   ============================================ */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--container-padding);
  padding-right: var(--container-padding);
}

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

/* Flex Helpers */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-around { justify-content: space-around; }
.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* Grid Helpers */
.grid { display: grid; }
.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }
.grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

@media (min-width: 768px) {
  .md\:grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .md\:grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .md\:grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}

/* ============================================
   COMPONENTS
   ============================================ */

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wider);
  border-radius: var(--radius-md);
  border: 2px solid transparent;
  transition: all var(--transition-base);
  cursor: pointer;
  position: relative;
  overflow: hidden;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse)!important;
  box-shadow: var(--shadow-md);
}

.btn-primary:hover:not(:disabled) {
  background-color: #D62839;
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.btn-secondary {
  background-color: var(--color-secondary);
  color: var(--color-text-inverse)!important;
}

.btn-secondary:hover:not(:disabled) {
  background-color: #0096C7;
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
}

.btn-accent {
  background-color: var(--color-accent);
  color: var(--color-charcoal);
  font-weight: var(--font-weight-extrabold);
}

.btn-accent:hover:not(:disabled) {
  background-color: #B8E600;
  transform: translateY(-2px);
  box-shadow: var(--shadow-accent);
}

.btn-outline {
  background-color: transparent;
  border-color: var(--color-charcoal);
  color: var(--color-charcoal);
}

.btn-outline:hover:not(:disabled) {
  background-color: var(--color-charcoal);
  color: var(--color-text-inverse);
  transform: translateY(-2px);
}

/* Form Inputs */
.input {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-normal);
  color: var(--color-text);
  background-color: var(--color-bg);
  border: 2px solid var(--color-gray-200);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.input:hover {
  border-color: var(--color-gray-300);
}

.input:focus {
  outline: none;
  border-color: var(--color-secondary);
  box-shadow: 0 0 0 4px rgba(0, 180, 216, 0.15);
}

.input::placeholder {
  color: var(--color-gray-400);
  font-weight: var(--font-weight-normal);
}

.input:disabled {
  background-color: var(--color-gray-100);
  cursor: not-allowed;
  opacity: 0.7;
}

/* Cards */
.card {
  background-color: var(--color-bg);
  border-radius: var(--radius-xl);
  padding: var(--space-6);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--color-gray-100);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  display: flex;
  flex-direction: column;
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-xl);
  border-color: var(--color-gray-200);
}

.card-energetic {
  border-top: 4px solid var(--color-primary);
}

.card-premium {
  border-top: 4px solid var(--color-accent);
}

/* Athletic Badge */
.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-bold);
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wider);
  border-radius: var(--radius-full);
  background-color: var(--color-gray-100);
  color: var(--color-gray-700);
}

.badge-primary {
  background-color: var(--color-primary);
  color: var(--color-text-inverse);
}

.badge-accent {
  background-color: var(--color-accent);
  color: var(--color-charcoal);
}

/* ============================================
   ACCESSIBILITY EXTRAS
   ============================================ */
@media (prefers-contrast: high) {
  :root {
    --color-primary: #CC0000;
    --color-secondary: #0066CC;
  }
  
  .btn, .input, .card {
    border-width: 3px;
  }
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-charcoal);
  color: var(--color-text-inverse);
  padding: 8px;
  text-decoration: none;
  z-index: 100;
}

.skip-link:focus {
  top: 0;
}