/* ============================================
   HORLUX - Educational Panel System
   Design System & Global Styles
   ============================================ */

:root {
  /* Primary Color */
  --color-primary: #1a3a52;
  
  /* Neutral Colors */
  --color-neutral-light: #f5f5f5;
  --color-neutral-medium: #cccccc;
  --color-neutral-dark: #333333;
  
  /* Accent Colors */
  --color-accent-terracotta: #c97a5c;
  --color-accent-green: #6b8e6f;
  
  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  --font-serif: 'Georgia', 'Garamond', serif;
  
  /* Spacing System (8px base) */
  --spacing-xs: 8px;
  --spacing-sm: 16px;
  --spacing-md: 24px;
  --spacing-lg: 32px;
  --spacing-xl: 48px;
  --spacing-2xl: 64px;
  
  /* Border Radius */
  --radius: 4px;
  
  /* Transitions */
  --transition-smooth: 0.2s ease-in-out;
}

/* ============================================
   RESET & BASE STYLES
   ============================================ */

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-neutral-light);
  color: var(--color-neutral-dark);
  line-height: 1.6;
  letter-spacing: 0.3px;
}

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

h1 {
  font-family: var(--font-sans);
  font-size: 3.5rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--spacing-lg);
  color: var(--color-primary);
  letter-spacing: -0.5px;
}

h2 {
  font-family: var(--font-sans);
  font-size: 2.5rem;
  font-weight: 600;
  line-height: 1.3;
  margin-bottom: var(--spacing-md);
  color: var(--color-primary);
  letter-spacing: -0.3px;
}

h3 {
  font-family: var(--font-sans);
  font-size: 1.5rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: var(--spacing-sm);
  color: var(--color-neutral-dark);
}

p {
  font-size: 1rem;
  line-height: 1.6;
  margin-bottom: var(--spacing-md);
  text-align: justify;
}

a {
  color: var(--color-accent-terracotta);
  text-decoration: none;
  transition: var(--transition-smooth);
  border-bottom: 1px solid transparent;
}

a:hover {
  border-bottom: 1px solid var(--color-accent-terracotta);
}

/* ============================================
   CONTAINER & LAYOUT
   ============================================ */

.container {
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.container-wide {
  width: 100%;
}

section {
  padding: var(--spacing-2xl) 0;
}

section.full-width {
  padding: var(--spacing-2xl) var(--spacing-lg);
}

/* ============================================
   GRID SYSTEM (12 columns)
   ============================================ */

.grid {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  gap: var(--spacing-lg);
}

.grid-col-6 {
  grid-column: span 6;
}

.grid-col-4 {
  grid-column: span 4;
}

.grid-col-8 {
  grid-column: span 8;
}

.grid-col-12 {
  grid-column: span 12;
}

/* ============================================
   PANEL SYSTEM
   ============================================ */

.panel {
  background-color: white;
  border: 1px solid #e0e0e0;
  border-radius: var(--radius);
  padding: var(--spacing-lg);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  transition: var(--transition-smooth);
}

.panel:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.12);
}

.panel-content {
  display: flex;
  flex-direction: column;
}

.panel-image {
  width: 100%;
  height: 300px;
  object-fit: cover;
  border-radius: var(--radius);
  margin-bottom: var(--spacing-md);
}

.panel-header {
  color: var(--color-primary);
  margin-bottom: var(--spacing-sm);
}

/* ============================================
   HEADER & NAVIGATION
   ============================================ */

header {
  background-color: var(--color-primary);
  color: white;
  padding: var(--spacing-md) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1440px;
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

.logo {
  font-size: 1.75rem;
  font-weight: 700;
  letter-spacing: 2px;
  color: white;
}

nav ul {
  display: flex;
  list-style: none;
  gap: var(--spacing-md);
}

nav a {
  color: white;
  font-size: 0.95rem;
  font-weight: 500;
  padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius);
  transition: var(--transition-smooth);
  border-bottom: none;
}

nav a:hover {
  background-color: rgba(255, 255, 255, 0.1);
  border-bottom: none;
}

/* ============================================
   FOOTER
   ============================================ */

footer {
  background-color: var(--color-primary);
  color: white;
  padding: var(--spacing-2xl) var(--spacing-lg);
  margin-top: var(--spacing-2xl);
}

.footer-content {
  max-width: 1440px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.footer-section h3 {
  color: white;
  margin-bottom: var(--spacing-sm);
}

.footer-section p, .footer-section a {
  font-size: 0.9rem;
  line-height: 1.8;
  color: rgba(255, 255, 255, 0.9);
}

.footer-section a {
  color: var(--color-accent-terracotta);
  border-bottom: 1px solid transparent;
}

.footer-section a:hover {
  border-bottom: 1px solid var(--color-accent-terracotta);
}

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.2);
  padding-top: var(--spacing-md);
  text-align: center;
  font-size: 0.85rem;
  color: rgba(255, 255, 255, 0.7);
}

/* ============================================
   FORMS & BUTTONS
   ============================================ */

.button {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-md);
  background-color: var(--color-accent-terracotta);
  color: white;
  border: none;
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition-smooth);
  text-decoration: none;
}

.button:hover {
  background-color: #b5694d;
}

.button-secondary {
  background-color: var(--color-accent-green);
}

.button-secondary:hover {
  background-color: #5a776f;
}

form {
  max-width: 600px;
  margin: var(--spacing-lg) auto;
}

.form-group {
  margin-bottom: var(--spacing-md);
  display: flex;
  flex-direction: column;
}

label {
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--color-primary);
}

input, textarea, select {
  padding: var(--spacing-sm);
  border: 1px solid #d0d0d0;
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 0.95rem;
  line-height: 1.5;
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--color-accent-terracotta);
  box-shadow: 0 0 0 3px rgba(201, 122, 92, 0.1);
}

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

/* ============================================
   LISTS
   ============================================ */

ul, ol {
  margin-left: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

li {
  margin-bottom: var(--spacing-sm);
  line-height: 1.7;
}

/* ============================================
   HERO SECTION
   ============================================ */

.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, #0f2638 100%);
  color: white;
  padding: var(--spacing-2xl) var(--spacing-lg);
  text-align: center;
}

.hero h1 {
  color: white;
  font-size: 4rem;
  margin-bottom: var(--spacing-lg);
}

.hero p {
  font-size: 1.25rem;
  max-width: 800px;
  margin: var(--spacing-md) auto var(--spacing-lg);
  text-align: center;
}

/* ============================================
   SECTION BACKGROUNDS
   ============================================ */

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

.section-dark h2, .section-dark h3 {
  color: white;
}

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

.section-accent h2 {
  color: white;
}

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

/* ============================================
   UTILITIES
   ============================================ */

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

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

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

.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }

.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }

.p-sm { padding: var(--spacing-sm); }
.p-md { padding: var(--spacing-md); }
.p-lg { padding: var(--spacing-lg); }

.hidden {
  display: none;
}

.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;
}

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

@media (max-width: 768px) {
  .grid {
    grid-template-columns: repeat(1, 1fr);
  }
  
  .grid-col-6, .grid-col-4, .grid-col-8, .grid-col-12 {
    grid-column: span 1;
  }
  
  h1 {
    font-size: 2.5rem;
  }
  
  h2 {
    font-size: 1.75rem;
  }
  
  nav ul {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .footer-content {
    grid-template-columns: 1fr;
  }
  
  .hero h1 {
    font-size: 2.5rem;
  }
  
  .container {
    padding: 0 var(--spacing-md);
  }
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.75rem;
  }
  
  h2 {
    font-size: 1.25rem;
  }
  
  p {
    font-size: 0.95rem;
  }
  
  .logo {
    font-size: 1.25rem;
  }
  
  nav {
    display: none;
  }
}