/* Design System - Notion Style */
/* Simple, clean, minimal - mostly black and white */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* ===== CSS RESET ===== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ===== CSS VARIABLES ===== */
:root {
  /* Colors - Minimal Palette (Light Mode) */
  --text-primary: #111827;
  --text-secondary: #6B7280;
  --text-tertiary: #9CA3AF;

  --bg-primary: #FFFFFF;
  --bg-secondary: #F9FAFB;
  --bg-tertiary: #F3F4F6;

  --border-light: #E5E7EB;
  --border-medium: #D1D5DB;

  --accent: #111827;
  --accent-hover: #374151;

  /* Subtle category colors - Notion style */
  --color-polity: #DBEAFE;       /* Very light blue */
  --color-economy: #D1FAE5;      /* Very light green */
  --color-geography: #E0E7FF;    /* Very light indigo */
  --color-environment: #DCFCE7;  /* Very light emerald */
  --color-international: #FEF3C7; /* Very light amber */
  --color-defence: #FEE2E2;      /* Very light red */
  --color-culture: #FCE7F3;      /* Very light pink */
  --color-history: #F3E8FF;      /* Very light purple */
  --color-science: #CFFAFE;      /* Very light cyan */
  --color-social: #FFE4E6;       /* Very light rose */

  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;

  --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 */

  /* Spacing */
  --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 */

  /* Border Radius */
  --radius-sm: 0.25rem;  /* 4px */
  --radius-md: 0.375rem; /* 6px */
  --radius-lg: 0.5rem;   /* 8px */
  --radius-xl: 0.75rem;  /* 12px */

  /* Shadows - Subtle */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 2px 4px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 4px 8px rgba(0, 0, 0, 0.08);
  --shadow-xl: 0 8px 16px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-base: 0.2s ease;
  --transition-slow: 0.3s ease;
}

/* Dark Mode - Only color overrides */
.dark {
  --text-primary: #F9FAFB;
  --text-secondary: #D1D5DB;
  --text-tertiary: #9CA3AF;

  --bg-primary: #111827;
  --bg-secondary: #1F2937;
  --bg-tertiary: #374151;

  --border-light: #374151;
  --border-medium: #4B5563;

  --accent: #F9FAFB;
  --accent-hover: #E5E7EB;
}

/* ===== BASE STYLES ===== */
html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-secondary);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== TYPOGRAPHY ===== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  color: var(--text-primary);
  margin-bottom: var(--space-4);
}

h1 { font-size: var(--text-5xl); }
h2 { font-size: var(--text-3xl); }
h3 { font-size: var(--text-2xl); }
h4 { font-size: var(--text-xl); }
h5 { font-size: var(--text-lg); }
h6 { font-size: var(--text-base); }

p {
  margin-bottom: var(--space-4);
  line-height: 1.7;
}

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

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

/* ===== BUTTONS ===== */
.btn {
  display: inline-block;
  padding: var(--space-3) var(--space-6);
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 500;
  text-decoration: none;
  transition: all var(--transition-base);
  cursor: pointer;
  border: none;
  font-family: var(--font-family);
}

.btn-primary {
  background: #111827;
  color: white;
}

.btn-primary:hover {
  background: #374151;
  transform: translateY(-1px);
}

.dark .btn-primary {
  background: white;
  color: #111827;
}

.dark .btn-primary:hover {
  background: #F3F4F6;
}

.btn-secondary {
  background: var(--bg-primary);
  color: var(--text-primary);
  border: 1px solid var(--border-medium);
}

.btn-secondary:hover {
  background: var(--bg-secondary);
  border-color: var(--text-tertiary);
}

/* ===== CARDS ===== */
.card {
  background: white;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-lg);
  padding: var(--space-8);
  transition: all var(--transition-base);
}

.card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

/* ===== CONTAINERS ===== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

.container-narrow {
  max-width: 680px;
  margin: 0 auto;
  padding: 0 var(--space-6);
}

/* ===== UTILITY CLASSES ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }
.mt-12 { margin-top: var(--space-12); }
.mt-16 { margin-top: var(--space-16); }

.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }
.mb-12 { margin-bottom: var(--space-12); }
.mb-16 { margin-bottom: var(--space-16); }

.flex { display: flex; }
.flex-col { flex-direction: column; }
.items-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: var(--space-2); }
.gap-4 { gap: var(--space-4); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* ===== THEME TOGGLE BUTTON ===== */
.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: 6px;
  border: 1px solid var(--border-light);
  background: var(--bg-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  transition: all 0.2s ease;
}

.theme-toggle:hover {
  background: var(--bg-tertiary);
  border-color: var(--border-medium);
}

.theme-toggle:active {
  transform: scale(0.95);
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  :root {
    --text-5xl: 2rem;      /* 32px on mobile */
    --text-4xl: 1.75rem;   /* 28px on mobile */
    --text-3xl: 1.5rem;    /* 24px on mobile */
  }

  .container {
    padding: 0 var(--space-4);
  }
}