/* Modern CSS Utilities for Frontend Design Skill */

/* CSS Custom Properties - Design System */
:root {
  /* Colors - Primary Palette */
  --color-primary-50: #eff6ff;
  --color-primary-100: #dbeafe;
  --color-primary-200: #bfdbfe;
  --color-primary-300: #93c5fd;
  --color-primary-400: #60a5fa;
  --color-primary-500: #3b82f6;
  --color-primary-600: #2563eb;
  --color-primary-700: #1d4ed8;
  --color-primary-800: #1e40af;
  --color-primary-900: #1e3a8a;

  /* Colors - Neutral Palette */
  --color-neutral-50: #fafafa;
  --color-neutral-100: #f5f5f5;
  --color-neutral-200: #e5e5e5;
  --color-neutral-300: #d4d4d4;
  --color-neutral-400: #a3a3a3;
  --color-neutral-500: #737373;
  --color-neutral-600: #525252;
  --color-neutral-700: #404040;
  --color-neutral-800: #262626;
  --color-neutral-900: #171717;

  /* Colors - Semantic */
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --color-info: #3b82f6;

  /* Typography Scale */
  --text-xs: 0.75rem;      /* 12px */
  --text-sm: 0.875rem;     /* 14px */
  --text-base: 1rem;       /* 16px */
  --text-lg: 1.125rem;     /* 18px */
  --text-xl: 1.25rem;      /* 20px */
  --text-2xl: 1.5rem;      /* 24px */
  --text-3xl: 1.875rem;    /* 30px */
  --text-4xl: 2.25rem;     /* 36px */
  --text-5xl: 3rem;        /* 48px */
  --text-6xl: 3.75rem;     /* 60px */

  /* Spacing Scale */
  --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 */

  /* Border Radius */
  --radius-none: 0;
  --radius-sm: 0.125rem;   /* 2px */
  --radius-base: 0.25rem;  /* 4px */
  --radius-md: 0.375rem;   /* 6px */
  --radius-lg: 0.5rem;     /* 8px */
  --radius-xl: 0.75rem;    /* 12px */
  --radius-2xl: 1rem;      /* 16px */
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-base: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, var(--color-primary-500) 0%, var(--color-primary-600) 100%);
  --gradient-success: linear-gradient(135deg, #10b981 0%, #059669 100%);
  --gradient-warning: linear-gradient(135deg, #f59e0b 0%, #d97706 100%);
  --gradient-rainbow: linear-gradient(135deg, #667eea 0%, #764ba2 50%, #f093fb 100%);
  --gradient-sunset: linear-gradient(135deg, #ff9a9e 0%, #fecfef 50%, #fecfef 100%);

  /* Animation Timing */
  --duration-150: 150ms;
  --duration-200: 200ms;
  --duration-300: 300ms;
  --duration-500: 500ms;
  --duration-700: 700ms;
  --duration-1000: 1000ms;

  /* Easing Functions */
  --ease-linear: linear;
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in: cubic-bezier(0.4, 0, 1, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* Modern CSS Reset */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  line-height: 1.15;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Layout Utilities */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.container-fluid {
  width: 100%;
  padding: 0 var(--space-4);
}

/* Flexbox Utilities */
.flex { display: flex; }
.inline-flex { display: inline-flex; }
.flex-col { flex-direction: column; }
.flex-row { flex-direction: row; }
.flex-wrap { flex-wrap: wrap; }
.flex-nowrap { flex-wrap: nowrap; }

.items-start { align-items: flex-start; }
.items-center { align-items: center; }
.items-end { align-items: flex-end; }
.items-stretch { align-items: stretch; }

.justify-start { justify-content: flex-start; }
.justify-center { justify-content: center; }
.justify-end { justify-content: flex-end; }
.justify-between { justify-content: space-between; }
.justify-around { justify-content: space-around; }
.justify-evenly { justify-content: space-evenly; }

.flex-1 { flex: 1 1 0%; }
.flex-auto { flex: 1 1 auto; }
.flex-none { flex: none; }

.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* Grid Utilities */
.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)); }
.grid-cols-12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }

.col-span-1 { grid-column: span 1 / span 1; }
.col-span-2 { grid-column: span 2 / span 2; }
.col-span-3 { grid-column: span 3 / span 3; }
.col-span-4 { grid-column: span 4 / span 4; }
.col-span-6 { grid-column: span 6 / span 6; }
.col-span-12 { grid-column: span 12 / span 12; }

/* Spacing Utilities */
.p-0 { padding: 0; }
.p-1 { padding: var(--space-1); }
.p-2 { padding: var(--space-2); }
.p-3 { padding: var(--space-3); }
.p-4 { padding: var(--space-4); }
.p-6 { padding: var(--space-6); }
.p-8 { padding: var(--space-8); }

.px-1 { padding-left: var(--space-1); padding-right: var(--space-1); }
.px-2 { padding-left: var(--space-2); padding-right: var(--space-2); }
.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.px-6 { padding-left: var(--space-6); padding-right: var(--space-6); }

.py-1 { padding-top: var(--space-1); padding-bottom: var(--space-1); }
.py-2 { padding-top: var(--space-2); padding-bottom: var(--space-2); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.py-6 { padding-top: var(--space-6); padding-bottom: var(--space-6); }

.m-0 { margin: 0; }
.m-1 { margin: var(--space-1); }
.m-2 { margin: var(--space-2); }
.m-4 { margin: var(--space-4); }
.m-auto { margin: auto; }

.mx-auto { margin-left: auto; margin-right: auto; }
.my-4 { margin-top: var(--space-4); margin-bottom: var(--space-4); }
.my-8 { margin-top: var(--space-8); margin-bottom: var(--space-8); }

/* Typography Utilities */
.text-xs { font-size: var(--text-xs); }
.text-sm { font-size: var(--text-sm); }
.text-base { font-size: var(--text-base); }
.text-lg { font-size: var(--text-lg); }
.text-xl { font-size: var(--text-xl); }
.text-2xl { font-size: var(--text-2xl); }
.text-3xl { font-size: var(--text-3xl); }
.text-4xl { font-size: var(--text-4xl); }

.font-light { font-weight: 300; }
.font-normal { font-weight: 400; }
.font-medium { font-weight: 500; }
.font-semibold { font-weight: 600; }
.font-bold { font-weight: 700; }

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

.leading-tight { line-height: 1.25; }
.leading-snug { line-height: 1.375; }
.leading-normal { line-height: 1.5; }
.leading-relaxed { line-height: 1.625; }

/* Color Utilities */
.text-neutral-50 { color: var(--color-neutral-50); }
.text-neutral-100 { color: var(--color-neutral-100); }
.text-neutral-400 { color: var(--color-neutral-400); }
.text-neutral-600 { color: var(--color-neutral-600); }
.text-neutral-900 { color: var(--color-neutral-900); }

.text-primary-500 { color: var(--color-primary-500); }
.text-primary-600 { color: var(--color-primary-600); }

.bg-white { background-color: #ffffff; }
.bg-neutral-50 { background-color: var(--color-neutral-50); }
.bg-neutral-100 { background-color: var(--color-neutral-100); }
.bg-neutral-900 { background-color: var(--color-neutral-900); }

.bg-primary-500 { background-color: var(--color-primary-500); }
.bg-primary-600 { background-color: var(--color-primary-600); }

.bg-gradient-primary { background: var(--gradient-primary); }
.bg-gradient-rainbow { background: var(--gradient-rainbow); }

/* Border Utilities */
.border { border-width: 1px; border-style: solid; }
.border-0 { border-width: 0; }
.border-2 { border-width: 2px; }

.border-neutral-200 { border-color: var(--color-neutral-200); }
.border-neutral-300 { border-color: var(--color-neutral-300); }
.border-primary-500 { border-color: var(--color-primary-500); }

.rounded-none { border-radius: var(--radius-none); }
.rounded-sm { border-radius: var(--radius-sm); }
.rounded { border-radius: var(--radius-base); }
.rounded-md { border-radius: var(--radius-md); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-xl { border-radius: var(--radius-xl); }
.rounded-2xl { border-radius: var(--radius-2xl); }
.rounded-full { border-radius: var(--radius-full); }

/* Shadow Utilities */
.shadow-none { box-shadow: none; }
.shadow-sm { box-shadow: var(--shadow-sm); }
.shadow { box-shadow: var(--shadow-base); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }
.shadow-xl { box-shadow: var(--shadow-xl); }
.shadow-2xl { box-shadow: var(--shadow-2xl); }

/* Position Utilities */
.relative { position: relative; }
.absolute { position: absolute; }
.fixed { position: fixed; }
.sticky { position: sticky; }

.inset-0 { top: 0; right: 0; bottom: 0; left: 0; }
.top-0 { top: 0; }
.right-0 { right: 0; }
.bottom-0 { bottom: 0; }
.left-0 { left: 0; }

/* Size Utilities */
.w-full { width: 100%; }
.w-1\/2 { width: 50%; }
.w-1\/3 { width: 33.333333%; }
.w-2\/3 { width: 66.666667%; }
.w-auto { width: auto; }

.h-full { height: 100%; }
.h-screen { height: 100vh; }
.h-auto { height: auto; }

.min-h-screen { min-height: 100vh; }
.max-w-none { max-width: none; }
.max-w-sm { max-width: 24rem; }
.max-w-md { max-width: 28rem; }
.max-w-lg { max-width: 32rem; }
.max-w-xl { max-width: 36rem; }

/* Visibility Utilities */
.visible { visibility: visible; }
.invisible { visibility: hidden; }
.opacity-0 { opacity: 0; }
.opacity-50 { opacity: 0.5; }
.opacity-100 { opacity: 1; }

/* Overflow Utilities */
.overflow-hidden { overflow: hidden; }
.overflow-visible { overflow: visible; }
.overflow-scroll { overflow: scroll; }
.overflow-auto { overflow: auto; }

.overflow-x-hidden { overflow-x: hidden; }
.overflow-y-auto { overflow-y: auto; }

/* Transform Utilities */
.transform { transform: translateVar(--tw-translate-x) translateY(var(--tw-translate-y)) rotate(var(--tw-rotate)) skewX(var(--tw-skew-x)) skewY(var(--tw-skew-y)) scaleX(var(--tw-scale-x)) scaleY(var(--tw-scale-y)); }
.scale-95 { --tw-scale-x: .95; --tw-scale-y: .95; }
.scale-100 { --tw-scale-x: 1; --tw-scale-y: 1; }
.scale-105 { --tw-scale-x: 1.05; --tw-scale-y: 1.05; }

/* Transition Utilities */
.transition-none { transition-property: none; }
.transition-all { 
  transition-property: all; 
  transition-timing-function: var(--ease-in-out); 
  transition-duration: var(--duration-150); 
}
.transition-colors { 
  transition-property: color, background-color, border-color; 
  transition-timing-function: var(--ease-in-out); 
  transition-duration: var(--duration-150); 
}
.transition-transform { 
  transition-property: transform; 
  transition-timing-function: var(--ease-in-out); 
  transition-duration: var(--duration-150); 
}

.duration-75 { transition-duration: 75ms; }
.duration-100 { transition-duration: 100ms; }
.duration-150 { transition-duration: var(--duration-150); }
.duration-200 { transition-duration: var(--duration-200); }
.duration-300 { transition-duration: var(--duration-300); }
.duration-500 { transition-duration: var(--duration-500); }

.ease-linear { transition-timing-function: var(--ease-linear); }
.ease-in { transition-timing-function: var(--ease-in); }
.ease-out { transition-timing-function: var(--ease-out); }
.ease-in-out { transition-timing-function: var(--ease-in-out); }

/* Interactive States */
.hover\:scale-105:hover { transform: scale(1.05); }
.hover\:shadow-lg:hover { box-shadow: var(--shadow-lg); }
.hover\:bg-primary-600:hover { background-color: var(--color-primary-600); }
.hover\:text-primary-600:hover { color: var(--color-primary-600); }

.focus\:outline-none:focus { outline: 2px solid transparent; outline-offset: 2px; }
.focus\:ring-2:focus { box-shadow: var(--tw-ring-offset-shadow), var(--tw-ring-shadow), var(--tw-shadow, 0 0 #0000); }
.focus\:ring-primary-500:focus { --tw-ring-color: var(--color-primary-500); }

/* Animation Utilities */
@keyframes spin { to { transform: rotate(360deg); } }
@keyframes ping { 75%, 100% { transform: scale(2); opacity: 0; } }
@keyframes pulse { 50% { opacity: .5; } }
@keyframes bounce { 0%, 100% { transform: translateY(-25%); } 50% { transform: none; } }
@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { transform: translateY(30px); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

.animate-spin { animation: spin 1s linear infinite; }
.animate-ping { animation: ping 1s cubic-bezier(0, 0, 0.2, 1) infinite; }
.animate-pulse { animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite; }
.animate-bounce { animation: bounce 1s infinite; }
.animate-fade-in { animation: fadeIn 0.5s ease-out; }
.animate-slide-up { animation: slideUp 0.6s ease-out; }

/* Responsive Design */
@media (min-width: 640px) {
  .sm\:text-xl { font-size: var(--text-xl); }
  .sm\:px-6 { padding-left: var(--space-6); padding-right: var(--space-6); }
  .sm\:grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (min-width: 768px) {
  .md\:text-2xl { font-size: var(--text-2xl); }
  .md\:px-8 { padding-left: var(--space-8); padding-right: var(--space-8); }
  .md\:grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
  .md\:flex-row { flex-direction: row; }
}

@media (min-width: 1024px) {
  .lg\:text-3xl { font-size: var(--text-3xl); }
  .lg\:px-12 { padding-left: var(--space-12); padding-right: var(--space-12); }
  .lg\:grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
}