/* Variables */
:root {
  /* Colors */
  --color-background: #ffffff; /* White */
  --color-text: #2c3e50; /* Navy Blue */
  --color-primary: #007bff; /* Electric Blue */
  --color-success: #28a745;
  --color-warning: #ffc107;
  --color-danger: #dc3545;
  --color-neutral-100: #f8f9fa; /* Light Graphite */
  --color-neutral-200: #e9ecef;
  --color-neutral-300: #dee2e6;
  --color-neutral-400: #ced4da;
  --color-neutral-500: #adb5bd; /* Chrome Silver */
  --color-neutral-600: #6c757d;
  --color-neutral-700: #495057; /* Graphite Gray */
  --color-neutral-800: #343a40;
  --color-neutral-900: #212529;

  /* Typography */
  --font-family-primary: 'Roboto', sans-serif; /* Modern sans-serif */
  --font-family-secondary: 'Montserrat', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;

  /* Spacing */
  --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-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, 0.05);
  --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);

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;
}

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

* {
  margin: 0;
}

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

html {
  scroll-behavior: smooth;
}

body {
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

input, button, select, optgroup, textarea {
  font-family: inherit;
  font-size: 100%;
  line-height: 1.15;
  margin: 0;
}

button, input {
  overflow: visible;
}

button, select {
  text-transform: none;
}

button, [type="button"], [type="reset"], [type="submit"] {
  -webkit-appearance: button;
}

fieldset {
  padding: 0.35em 0.75em 0.625em;
}

legend {
  padding: 0;
}

progress {
  vertical-align: baseline;
}

textarea {
  overflow: auto;
}

[type="checkbox"], [type="radio"] {
  padding: 0;
}

[type="number"]::-webkit-inner-spin-button, [type="number"]::-webkit-outer-spin-button {
  height: auto;
}

[type="search"] {
  -webkit-appearance: textfield;
  outline-offset: -2px;
}

[type="search"]::-webkit-search-decoration {
  -webkit-appearance: none;
}

details {
  display: block;
}

summary {
  display: list-item;
}

template {
  display: none;
}

[hidden] {
  display: none;
}

/* Base styles */
body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  background-color: var(--color-background);
  color: var(--color-text);
  line-height: var(--line-height-normal);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-family-secondary);
  font-weight: 700;
  line-height: var(--line-height-tight);
  margin: 0 0 var(--space-4) 0;
}

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);
}

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

a:hover, a:focus {
  color: var(--color-neutral-700);
}

p {
  margin: 0 0 var(--space-4) 0;
}

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

.flex {
  display: flex;
}

.items-center {
  align-items: center;
}

.justify-between {
  justify-content: space-between;
}

.grid {
  display: grid;
}

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

.grid-cols-2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid-cols-3 {
  grid-template-columns: repeat(3, 1fr);
}

.py-8 {
  padding-top: var(--space-8);
  padding-bottom: var(--space-8);
}

.gap-6 {
  gap: var(--space-6);
}

@media (max-width: 768px) {
  .grid-cols-2 {
    grid-template-columns: 1fr;
  }

  .grid-cols-3 {
    grid-template-columns: 1fr;
  }
}

.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;
}

/* Components */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-6);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: 500;
  line-height: var(--line-height-tight);
  background-color: var(--color-primary);
  color: var(--color-background);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn:hover {
  background-color: var(--color-neutral-700);
  border-color: var(--color-neutral-700);
}

.btn:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}

.btn:disabled {
  background-color: var(--color-neutral-400);
  border-color: var(--color-neutral-400);
  cursor: not-allowed;
}

.input {
  display: block;
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  background-color: var(--color-background);
  color: var(--color-text);
  border: 1px solid var(--color-neutral-400);
  border-radius: var(--radius-md);
  transition: border-color var(--transition-fast);
}

.input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}

.card {
  background-color: var(--color-background);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  padding: var(--space-6);
  transition: box-shadow var(--transition-normal);
}

.card:hover {
  box-shadow: var(--shadow-lg);
}

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

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