/* ================================================
   BASE.CSS - Design Tokens, Reset & Foundation
   Livro&Livro - Book Exchange Platform
   ================================================ */

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

html {
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  margin: 0;
  padding: 0;
  min-height: 100vh;
  line-height: 1.5;
}

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

input,
button,
textarea,
select {
  font: inherit;
}

p,
h1,
h2,
h3,
h4,
h5,
h6 {
  overflow-wrap: break-word;
}

/* ===== DESIGN TOKENS - CSS CUSTOM PROPERTIES ===== */
:root {
  /* COLOR PALETTE - Required by project specs */

  /* Primary */
  --color-primary: #1E3A8A;
  /* Dark Blue - headers, main buttons, icons, links */

  /* Secondary */
  --color-white: #FFFFFF;
  /* White - backgrounds */
  --color-gray-light: #F3F4F6;
  /* Light Gray - blocks/footers */

  /* Support */
  --color-gray-medium: #9CA3AF;
  /* Medium Gray - secondary text */
  --color-gray-dark: #374151;
  /* Dark Gray - main text */

  /* Accent */
  --color-accent: #3B82F6;
  /* Light Blue - hover/active states */
  --color-accent-light: #4187f7;
  /* Light Blue - active states */


  /* Semantic Colors */
  --color-success: #10B981;
  --color-warning: #F59E0B;
  --color-error: #EF4444;
  --color-info: #3B82F6;

  /* TYPOGRAPHY */
  --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  --font-family-heading: var(--font-family-base);

  /* Font Sizes - Mobile First */
  --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 Weights */
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.75;

  /* 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-sm: 0.25rem;
  /* 4px */
  --radius-md: 0.5rem;
  /* 8px */
  --radius-lg: 0.75rem;
  /* 12px */
  --radius-xl: 1rem;
  /* 16px */
  --radius-full: 9999px;
  /* circular */

  /* 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-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;

  /* Z-INDEX SCALE */
  --z-dropdown: 1000;
  --z-sticky: 1020;
  --z-fixed: 1030;
  --z-modal-backdrop: 1040;
  --z-modal: 1050;
  --z-popover: 1060;
  --z-tooltip: 1070;

  /* LAYOUT */
  --container-max-width: 1280px;
  --container-padding: var(--space-4);

  /* BREAKPOINTS (for reference in media queries) */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
}

/* ===== BASE STYLES ===== */
body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-gray-dark);
  background-color: var(--color-white);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-family: var(--font-family-heading);
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

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);
}

/* 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);
  }
}

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

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

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

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

/* ===== ACCESSIBILITY ===== */

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

/* Skip to main content link */
.skip-to-main {
  position: absolute;
  top: -100%;
  left: 0;
  z-index: var(--z-tooltip);
  padding: var(--space-3) var(--space-4);
  background-color: var(--color-primary);
  color: var(--color-white);
  font-weight: var(--font-weight-semibold);
  text-decoration: none;
  border-radius: var(--radius-md);
}

.skip-to-main:focus {
  top: var(--space-4);
  left: var(--space-4);
}

/* Screen reader only */
.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;
}

/* ===== UTILITY CLASSES ===== */

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

/* Visually hidden but accessible */
.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;
}