/*
 * ============================================
 * KHAN AI PROJECT MANAGER - DESIGN SYSTEM
 * ============================================
 *
 * Design Direction: Sophistication & Trust + Precision & Density
 *
 * This is a professional AI project management tool for power users.
 * The design language reflects: Intelligence, Trust, Precision, and Depth.
 *
 * Visual Identity:
 * - Cool slate foundations for professionalism and trust
 * - Cyan accent for AI/intelligence brand identity
 * - 4px grid for precise, crafted layouts
 * - Subtle depth with single shadows + borders
 * - Sharp border radius (4px, 6px, 8px) for technical precision
 *
 * Reference: Linear, Stripe, Vercel
 */

/* ==================== CSS RESET ==================== */

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

/* ==================== ROOT VARIABLES ==================== */

:root {
  /* ========== COLOR SYSTEM ========== */

  /* Primary - Cyan (AI, Intelligence, Data) */
  --color-primary-50: #ecfeff;
  --color-primary-100: #cffafe;
  --color-primary-200: #a5f3fc;
  --color-primary-300: #67e8f9;
  --color-primary-400: #22d3ee;
  --color-primary-500: #06b6d4;
  --color-primary-600: #0891b2;
  --color-primary-700: #0e7490;
  --color-primary-800: #155e75;
  --color-primary-900: #164e63;

  /* Neutral - Slate (Cool, Professional) */
  --color-slate-50: #f8fafc;
  --color-slate-100: #f1f5f9;
  --color-slate-200: #e2e8f0;
  --color-slate-300: #cbd5e1;
  --color-slate-400: #94a3b8;
  --color-slate-500: #64748b;
  --color-slate-600: #475569;
  --color-slate-700: #334155;
  --color-slate-800: #1e293b;
  --color-slate-900: #0f172a;
  --color-slate-950: #020617;

  /* Semantic Colors */
  --color-success: #10b981;
  --color-success-muted: rgba(16, 185, 129, 0.12);
  --color-warning: #f59e0b;
  --color-warning-muted: rgba(245, 158, 11, 0.12);
  --color-error: #ef4444;
  --color-error-muted: rgba(239, 68, 68, 0.12);
  --color-info: var(--color-primary-500);
  --color-info-muted: rgba(6, 182, 212, 0.12);

  /* ========== DARK MODE (Default) ========== */

  /* Backgrounds */
  --bg-base: #0c0f16;
  --bg-raised: #12151e;
  --bg-overlay: #181c27;
  --bg-elevated: #1e232f;

  /* Text - 4-level contrast hierarchy */
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #64748b;
  --text-faint: #475569;

  /* Borders */
  --border-default: rgba(255, 255, 255, 0.08);
  --border-subtle: rgba(255, 255, 255, 0.05);
  --border-strong: rgba(255, 255, 255, 0.12);

  /* Interactive states */
  --hover-bg: rgba(255, 255, 255, 0.04);
  --active-bg: rgba(255, 255, 255, 0.08);
  --focus-ring: rgba(6, 182, 212, 0.4);

  /* Shadows - Subtle single shadow approach */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.4);
  --shadow-xl: 0 8px 32px rgba(0, 0, 0, 0.5);

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

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  /* Font sizes - Precise scale */
  --text-xs: 0.6875rem;    /* 11px */
  --text-sm: 0.75rem;      /* 12px */
  --text-base: 0.8125rem;  /* 13px */
  --text-md: 0.875rem;     /* 14px */
  --text-lg: 1rem;         /* 16px */
  --text-xl: 1.125rem;     /* 18px */
  --text-2xl: 1.5rem;      /* 24px */
  --text-3xl: 2rem;        /* 32px */

  /* Line heights */
  --leading-none: 1;
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;

  /* Font weights */
  --font-normal: 400;
  --font-medium: 500;
  --font-semibold: 600;
  --font-bold: 700;

  /* Letter spacing */
  --tracking-tight: -0.02em;
  --tracking-normal: 0;
  --tracking-wide: 0.02em;
  --tracking-wider: 0.05em;

  /* ========== SPACING (4px Grid) ========== */

  --space-0: 0;
  --space-1: 0.25rem;   /* 4px - micro */
  --space-2: 0.5rem;    /* 8px - tight */
  --space-3: 0.75rem;   /* 12px - standard */
  --space-4: 1rem;      /* 16px - comfortable */
  --space-5: 1.25rem;   /* 20px */
  --space-6: 1.5rem;    /* 24px - generous */
  --space-8: 2rem;      /* 32px - major */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */

  /* ========== BORDER RADIUS (Sharp System) ========== */

  --radius-xs: 2px;
  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-xl: 12px;
  --radius-full: 9999px;

  /* ========== TRANSITIONS ========== */

  --ease-out: cubic-bezier(0.25, 1, 0.5, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);

  --duration-fast: 100ms;
  --duration-base: 150ms;
  --duration-slow: 200ms;
  --duration-slower: 300ms;

  --transition-fast: var(--duration-fast) var(--ease-out);
  --transition-base: var(--duration-base) var(--ease-out);
  --transition-slow: var(--duration-slow) var(--ease-out);

  /* ========== Z-INDEX ========== */

  --z-base: 0;
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-tooltip: 600;
  --z-khan: 1000;

  /* ========== LAYOUT ========== */

  --container-xs: 480px;
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1200px;
  --container-2xl: 1400px;

  --sidebar-width: 240px;
  --header-height: 56px;
}

/* ========== LIGHT MODE ========== */

[data-theme="light"] {
  /* Backgrounds */
  --bg-base: #fafafa;
  --bg-raised: #f5f5f5;
  --bg-overlay: #f1f5f9;
  --bg-elevated: #ffffff;

  /* Text */
  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --text-faint: #94a3b8;

  /* Borders */
  --border-default: rgba(0, 0, 0, 0.08);
  --border-subtle: rgba(0, 0, 0, 0.04);
  --border-strong: rgba(0, 0, 0, 0.12);

  /* Interactive states */
  --hover-bg: rgba(0, 0, 0, 0.03);
  --active-bg: rgba(0, 0, 0, 0.06);

  /* Shadows */
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 4px 16px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 8px 32px rgba(0, 0, 0, 0.12);
}

/* ========== BASE STYLES ========== */

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

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

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

/* Headings */
h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-semibold);
  letter-spacing: var(--tracking-tight);
  line-height: var(--leading-tight);
  color: var(--text-primary);
}

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

/* Text colors */
.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-muted { color: var(--text-muted); }
.text-faint { color: var(--text-faint); }

/* Accent colors */
.text-accent { color: var(--color-primary-500); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-error { color: var(--color-error); }

/* Font weights */
.font-normal { font-weight: var(--font-normal); }
.font-medium { font-weight: var(--font-medium); }
.font-semibold { font-weight: var(--font-semibold); }
.font-bold { font-weight: var(--font-bold); }

/* Font sizes */
.text-xs { font-size: var(--text-xs); }
.text-sm { font-size: var(--text-sm); }
.text-base { font-size: var(--text-base); }
.text-md { font-size: var(--text-md); }
.text-lg { font-size: var(--text-lg); }
.text-xl { font-size: var(--text-xl); }
.text-2xl { font-size: var(--text-2xl); }
.text-3xl { font-size: var(--text-3xl); }

/* Monospace for data */
.font-mono {
  font-family: var(--font-mono);
  font-feature-settings: 'tnum' 1;
}

/* Tabular numbers for alignment */
.tabular-nums {
  font-variant-numeric: tabular-nums;
}

/* Gradient text (Khan branding) */
.text-gradient {
  background: linear-gradient(135deg, var(--color-primary-400), var(--color-primary-600));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

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

.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding-left: var(--space-6);
  padding-right: var(--space-6);
}

.container-sm { max-width: var(--container-sm); }
.container-md { max-width: var(--container-md); }
.container-lg { max-width: var(--container-lg); }
.container-xl { max-width: var(--container-xl); }
.container-2xl { max-width: var(--container-2xl); }

/* Flexbox */
.flex { display: flex; }
.inline-flex { display: inline-flex; }
.flex-col { flex-direction: column; }
.flex-row { flex-direction: row; }
.flex-wrap { flex-wrap: wrap; }
.flex-1 { flex: 1 1 0%; }
.flex-shrink-0 { flex-shrink: 0; }

.items-start { align-items: flex-start; }
.items-center { align-items: center; }
.items-end { align-items: flex-end; }
.items-stretch { align-items: stretch; }
.items-baseline { align-items: baseline; }

.justify-start { justify-content: flex-start; }
.justify-center { justify-content: center; }
.justify-end { justify-content: flex-end; }
.justify-between { justify-content: space-between; }

/* Gap utilities */
.gap-1 { gap: var(--space-1); }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.gap-4 { gap: var(--space-4); }
.gap-5 { gap: var(--space-5); }
.gap-6 { gap: var(--space-6); }
.gap-8 { gap: var(--space-8); }

/* Grid */
.grid { display: grid; }
.grid-cols-1 { grid-template-columns: repeat(1, minmax(0, 1fr)); }
.grid-cols-2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid-cols-3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid-cols-4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* Spacing utilities */
.p-0 { padding: 0; }
.p-1 { padding: var(--space-1); }
.p-2 { padding: var(--space-2); }
.p-3 { padding: var(--space-3); }
.p-4 { padding: var(--space-4); }
.p-5 { padding: var(--space-5); }
.p-6 { padding: var(--space-6); }
.p-8 { padding: var(--space-8); }

.px-1 { padding-left: var(--space-1); padding-right: var(--space-1); }
.px-2 { padding-left: var(--space-2); padding-right: var(--space-2); }
.px-3 { padding-left: var(--space-3); padding-right: var(--space-3); }
.px-4 { padding-left: var(--space-4); padding-right: var(--space-4); }
.px-6 { padding-left: var(--space-6); padding-right: var(--space-6); }

.py-1 { padding-top: var(--space-1); padding-bottom: var(--space-1); }
.py-2 { padding-top: var(--space-2); padding-bottom: var(--space-2); }
.py-3 { padding-top: var(--space-3); padding-bottom: var(--space-3); }
.py-4 { padding-top: var(--space-4); padding-bottom: var(--space-4); }
.py-6 { padding-top: var(--space-6); padding-bottom: var(--space-6); }

.m-0 { margin: 0; }
.m-auto { margin: auto; }
.mx-auto { margin-left: auto; margin-right: auto; }

.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); }

.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); }

/* Dimensions */
.w-full { width: 100%; }
.h-full { height: 100%; }
.min-h-screen { min-height: 100vh; }

/* Text alignment */
.text-left { text-align: left; }
.text-center { text-align: center; }
.text-right { text-align: right; }

/* Visibility */
.hidden { display: none; }
.invisible { visibility: hidden; }

/* Position */
.relative { position: relative; }
.absolute { position: absolute; }
.fixed { position: fixed; }
.sticky { position: sticky; }

/* Overflow */
.overflow-hidden { overflow: hidden; }
.overflow-auto { overflow: auto; }
.overflow-x-auto { overflow-x: auto; }
.overflow-y-auto { overflow-y: auto; }

/* Cursor */
.cursor-pointer { cursor: pointer; }
.cursor-default { cursor: default; }

/* Selection */
.select-none { user-select: none; }

/* ========== FOCUS STYLES ========== */

:focus {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--color-primary-500);
  outline-offset: 2px;
}

/* ========== SCROLLBAR STYLING ========== */

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border-strong);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-faint);
}

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

@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slide-down {
  from {
    opacity: 0;
    transform: translateY(-8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.animate-fade-in {
  animation: fade-in var(--duration-slow) var(--ease-out);
}

.animate-slide-up {
  animation: slide-up var(--duration-slow) var(--ease-out);
}

.animate-pulse {
  animation: pulse 2s ease-in-out infinite;
}