/**
 * AI Charter Design System
 * Institutional, minimal, grid-based aesthetic
 * Government/UN-grade portal styling
 */

/* ============================================
   ROOT VARIABLES & DESIGN TOKENS
   ============================================ */

:root {
  /* Color Palette */
  --color-bg-primary: #F8F9FA;
  --color-primary: #1B4332;
  --color-accent: #C5A059;
  --color-text: #2D3436;
  --color-text-light: #5F6368;
  --color-border: #E8EAED;
  --color-white: #FFFFFF;
  
  /* Typography */
  --font-serif: 'Playfair Display', serif;
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  
  /* Font Sizes */
  --fs-h1: 3.5rem;
  --fs-h2: 2.5rem;
  --fs-h3: 1.75rem;
  --fs-h4: 1.25rem;
  --fs-body: 1rem;
  --fs-small: 0.875rem;
  
  /* Line Heights */
  --lh-heading: 1.2;
  --lh-body: 1.6;
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --spacing-3xl: 5rem;
  --spacing-4xl: 6rem;
  --spacing-5xl: 8rem;
  
  /* Container */
  --container-max: 1280px;
  --container-padding: 2rem;
  
  /* Section Padding */
  --section-padding-y: 6rem;
  --section-padding-x: 2rem;
  
  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 300ms ease-in-out;
  --transition-slow: 500ms ease-in-out;
}

/* ============================================
   GLOBAL STYLES
   ============================================ */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-body);
  color: var(--color-text);
  background-color: var(--color-bg-primary);
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: var(--lh-heading);
  margin-bottom: var(--spacing-lg);
  color: var(--color-text);
  letter-spacing: -0.02em;
}

h1 {
  font-size: var(--fs-h1);
}

h2 {
  font-size: var(--fs-h2);
}

h3 {
  font-size: var(--fs-h3);
}

h4 {
  font-size: var(--fs-h4);
}

p {
  margin-bottom: var(--spacing-md);
  line-height: var(--lh-body);
}

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

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

/* ============================================
   BUTTONS
   ============================================ */

.btn, button, input[type="button"], input[type="submit"] {
  display: inline-block;
  padding: 1rem 2rem;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: 500;
  text-align: center;
  cursor: pointer;
  border: 2px solid transparent;
  background-color: var(--color-primary);
  color: var(--color-white);
  transition: all var(--transition-base);
  border-radius: 0;
}

.btn:hover, button:hover {
  background-color: var(--color-text);
  color: var(--color-white);
}

.btn-secondary {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.btn-accent {
  background-color: var(--color-accent);
  color: var(--color-white);
}

.btn-accent:hover {
  background-color: var(--color-text);
}

.btn-full-width {
  width: 100%;
  display: block;
}

/* ============================================
   CONTAINERS & LAYOUT
   ============================================ */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.section {
  padding: var(--section-padding-y) var(--section-padding-x);
}

.section-light {
  background-color: var(--color-white);
}

.section-dark {
  background-color: var(--color-primary);
  color: var(--color-white);
}

.section-dark h1, .section-dark h2, .section-dark h3, .section-dark h4 {
  color: var(--color-white);
}

/* ============================================
   GRID SYSTEM
   ============================================ */

.grid {
  display: grid;
  gap: var(--spacing-2xl);
}

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

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

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

.grid-50-50 {
  grid-template-columns: 1fr 1fr;
}

/* ============================================
   CARDS
   ============================================ */

.card {
  padding: var(--spacing-2xl);
  background-color: var(--color-white);
  border: 1px solid var(--color-border);
  border-radius: 0;
}

.card-icon {
  width: 3rem;
  height: 3rem;
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: center;
}

.card-icon svg {
  width: 100%;
  height: 100%;
  stroke: var(--color-primary);
  stroke-width: 1.5;
  fill: none;
}

.card-title {
  font-family: var(--font-serif);
  font-size: var(--fs-h4);
  margin-bottom: var(--spacing-md);
  color: var(--color-text);
}

.card-content {
  font-size: var(--fs-small);
  line-height: var(--lh-body);
  color: var(--color-text-light);
}

/* ============================================
   FORMS
   ============================================ */

form {
  display: flex;
  flex-direction: column;
}

.form-group {
  margin-bottom: var(--spacing-lg);
}

label {
  display: block;
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  font-size: var(--fs-small);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text);
}

input[type="text"],
input[type="email"],
input[type="tel"],
textarea,
select {
  width: 100%;
  padding: 0.75rem;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  border: 1px solid var(--color-border);
  background-color: var(--color-white);
  color: var(--color-text);
  border-radius: 0;
  transition: border-color var(--transition-base);
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="tel"]:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: none;
}

textarea {
  resize: vertical;
  min-height: 150px;
}

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

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

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

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

.text-uppercase {
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.text-muted {
  color: var(--color-text-light);
}

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

.py-1 { padding-top: var(--spacing-sm); padding-bottom: var(--spacing-sm); }
.py-2 { padding-top: var(--spacing-md); padding-bottom: var(--spacing-md); }
.py-3 { padding-top: var(--spacing-lg); padding-bottom: var(--spacing-lg); }
.py-4 { padding-top: var(--spacing-xl); padding-bottom: var(--spacing-xl); }

.px-1 { padding-left: var(--spacing-sm); padding-right: var(--spacing-sm); }
.px-2 { padding-left: var(--spacing-md); padding-right: var(--spacing-md); }
.px-3 { padding-left: var(--spacing-lg); padding-right: var(--spacing-lg); }
.px-4 { padding-left: var(--spacing-xl); padding-right: var(--spacing-xl); }

.hidden {
  display: none !important;
}

.visible {
  display: block !important;
}

/* ============================================
   HEADER POSITION FIX
   ============================================ */

.site-header {
  position: relative;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 768px) {
  :root {
    --fs-h1: 2.5rem;
    --fs-h2: 1.75rem;
    --fs-h3: 1.25rem;
    --section-padding-y: 3rem;
  }

  .grid-2,
  .grid-3,
  .grid-4,
  .grid-50-50 {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  :root {
    --fs-h1: 1.75rem;
    --fs-h2: 1.25rem;
    --fs-h3: 1rem;
    --section-padding-y: 2rem;
    --container-padding: 1rem;
  }
}