/* ============================================================================
   ENTERPRISE IT AUTHORITY - DESIGN SYSTEM (ENHANCED)
   Sophisticated, polished design for senior technology leaders
   ============================================================================ */

/* ----------------------------------------------------------------------------
   DESIGN TOKENS
   ---------------------------------------------------------------------------- */

:root {
  /* Typography Scale */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, 
               "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "Cascadia Code", "Source Code Pro", Menlo, 
               Consolas, monospace;

  /* Type Scale - Fluid responsive sizing */
  --text-xs: clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
  --text-sm: clamp(0.875rem, 0.825rem + 0.25vw, 1rem);
  --text-base: clamp(1.0625rem, 1rem + 0.3125vw, 1.125rem);
  --text-lg: clamp(1.125rem, 1.05rem + 0.375vw, 1.3125rem);
  --text-xl: clamp(1.3125rem, 1.2rem + 0.5625vw, 1.625rem);
  --text-2xl: clamp(1.625rem, 1.45rem + 0.875vw, 2rem);
  --text-3xl: clamp(2rem, 1.75rem + 1.25vw, 2.5rem);
  --text-4xl: clamp(2.5rem, 2.1rem + 2vw, 3.5rem);

  /* Line Heights */
  --leading-tight: 1.25;
  --leading-snug: 1.375;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  --leading-loose: 1.75;

  /* Enhanced Colour Palette */
  --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;

  /* Sophisticated blue accent with depth */
  --color-accent-50: #eff6ff;
  --color-accent-100: #dbeafe;
  --color-accent-200: #bfdbfe;
  --color-accent-500: #3b82f6;
  --color-accent-600: #2563eb;
  --color-accent-700: #1d4ed8;
  --color-accent-800: #1e40af;

  /* Semantic Colours */
  --color-text-primary: var(--color-slate-900);
  --color-text-secondary: var(--color-slate-600);
  --color-text-tertiary: var(--color-slate-500);
  --color-border: var(--color-slate-200);
  --color-border-subtle: var(--color-slate-100);
  --color-border-hover: var(--color-slate-300);
  --color-background: #ffffff;
  --color-background-subtle: var(--color-slate-50);
  --color-background-elevated: #ffffff;
  --color-link: var(--color-accent-600);
  --color-link-hover: var(--color-accent-700);

  /* Spacing Scale */
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  --space-5xl: 8rem;

  /* Layout Constraints */
  --width-prose: 68ch;
  --width-content: 1140px;
  --width-narrow: 820px;

  /* Enhanced Shadows - More depth */
  --shadow-xs: 0 1px 2px 0 rgb(0 0 0 / 0.03);
  --shadow-sm: 0 1px 3px 0 rgb(0 0 0 / 0.06), 0 1px 2px -1px rgb(0 0 0 / 0.06);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.08), 0 2px 4px -2px rgb(0 0 0 / 0.08);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.08), 0 4px 6px -4px rgb(0 0 0 / 0.08);
  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.08), 0 8px 10px -6px rgb(0 0 0 / 0.08);

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}


/* ----------------------------------------------------------------------------
   RESET & BASE
   ---------------------------------------------------------------------------- */

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

* {
  margin: 0;
  padding: 0;
}

html {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  /* Enable Inter's optical sizing and ligatures */
  font-feature-settings: 'salt' on, 'ss01' on, 'ss02' on, 'cv05' on, 'cv10' on;
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text-primary);
  background-color: var(--color-background);
  overflow-x: hidden;
}

/* Remove list styles on ul, ol elements with a list role */
ul[role='list'],
ol[role='list'] {
  list-style: none;
}


/* ----------------------------------------------------------------------------
   TYPOGRAPHY
   ---------------------------------------------------------------------------- */

h1, h2, h3, h4, h5, h6 {
  font-weight: 650;
  line-height: var(--leading-tight);
  letter-spacing: -0.025em;
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--text-4xl);
  font-weight: 700;
  margin-bottom: var(--space-lg);
  letter-spacing: -0.035em;
}

h2 {
  font-size: var(--text-3xl);
  margin-top: var(--space-3xl);
  margin-bottom: var(--space-lg);
  font-weight: 650;
}

h3 {
  font-size: var(--text-2xl);
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
  font-weight: 600;
}

h4 {
  font-size: var(--text-xl);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
  font-weight: 600;
}

p {
  margin-bottom: var(--space-lg);
  max-width: var(--width-prose);
}

/* Lead paragraphs */
.lead {
  font-size: var(--text-lg);
  line-height: var(--leading-relaxed);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xl);
  font-weight: 450;
}

/* Small text */
small, .text-sm {
  font-size: var(--text-sm);
}

/* Links with subtle underline animation */
a {
  color: var(--color-link);
  text-decoration: none;
  text-decoration-skip-ink: auto;
  transition: color var(--transition-fast);
  position: relative;
}

article a:not(.button) {
  background-image: linear-gradient(transparent calc(100% - 1px), var(--color-accent-500) 1px);
  background-repeat: no-repeat;
  background-size: 0% 100%;
  transition: background-size var(--transition-base);
}

article a:not(.button):hover {
  background-size: 100% 100%;
}

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

/* Emphasis */
strong {
  font-weight: 600;
  color: var(--color-text-primary);
}

em {
  font-style: italic;
}

/* Lists within prose */
article ul:not([role='list']),
article ol {
  margin-bottom: var(--space-lg);
  padding-left: var(--space-xl);
}

article li {
  margin-bottom: var(--space-sm);
  line-height: var(--leading-relaxed);
}

article ul:not([role='list']) li {
  list-style-type: disc;
  padding-left: var(--space-xs);
}

article ul:not([role='list']) li::marker {
  color: var(--color-slate-400);
}

article ol li {
  list-style-type: decimal;
  padding-left: var(--space-xs);
}

/* Code */
code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background-color: var(--color-slate-100);
  padding: 0.2em 0.4em;
  border-radius: var(--radius-sm);
  color: var(--color-slate-800);
  border: 1px solid var(--color-slate-200);
}

pre {
  margin-bottom: var(--space-lg);
  padding: var(--space-lg);
  background-color: var(--color-slate-50);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow-x: auto;
  line-height: var(--leading-normal);
}

pre code {
  background: none;
  padding: 0;
  border: none;
}

/* Blockquotes - more distinctive */
blockquote {
  margin: var(--space-2xl) 0;
  padding: var(--space-lg) var(--space-xl);
  border-left: 4px solid var(--color-accent-500);
  background: linear-gradient(to right, var(--color-accent-50), transparent);
  color: var(--color-text-secondary);
  font-style: italic;
  line-height: var(--leading-relaxed);
  border-radius: var(--radius-md);
  font-size: var(--text-lg);
}

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

blockquote p:last-child {
  margin-bottom: 0;
}

/* Horizontal rule */
hr {
  margin: var(--space-3xl) 0;
  border: none;
  border-top: 1px solid var(--color-border);
}


/* ----------------------------------------------------------------------------
   LAYOUT UTILITIES
   ---------------------------------------------------------------------------- */

.container {
  max-width: var(--width-content);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-lg);
  padding-right: var(--space-lg);
}

.container-narrow {
  max-width: var(--width-narrow);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-lg);
  padding-right: var(--space-lg);
}

.prose {
  max-width: var(--width-prose);
}

/* Vertical rhythm */
.stack > * + * {
  margin-top: var(--stack-space, var(--space-lg));
}

.stack-sm { --stack-space: var(--space-sm); }
.stack-md { --stack-space: var(--space-md); }
.stack-lg { --stack-space: var(--space-lg); }
.stack-xl { --stack-space: var(--space-xl); }
.stack-2xl { --stack-space: var(--space-2xl); }


/* ----------------------------------------------------------------------------
   COMPONENTS
   ---------------------------------------------------------------------------- */

/* Callout blocks - enhanced with icons */
.callout {
  margin: var(--space-2xl) 0;
  padding: var(--space-lg) var(--space-xl);
  background-color: var(--color-slate-50);
  border-left: 3px solid var(--color-slate-400);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.callout--info {
  background: linear-gradient(to right, var(--color-accent-50), var(--color-background));
  border-color: var(--color-accent-500);
}

.callout--warning {
  background: linear-gradient(to right, #fef3c7, var(--color-background));
  border-color: #f59e0b;
}

.callout--insight {
  background: linear-gradient(to right, #f0fdf4, var(--color-background));
  border-color: #10b981;
}

.callout p:last-child {
  margin-bottom: 0;
}

/* Tables - refined borders and hover */
table {
  width: 100%;
  margin: var(--space-2xl) 0;
  border-collapse: collapse;
  font-size: var(--text-sm);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

thead {
  background: linear-gradient(to bottom, var(--color-slate-50), var(--color-slate-100));
  border-bottom: 2px solid var(--color-border);
}

th {
  padding: var(--space-md) var(--space-lg);
  text-align: left;
  font-weight: 600;
  color: var(--color-text-primary);
  font-size: var(--text-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

td {
  padding: var(--space-md) var(--space-lg);
  border-bottom: 1px solid var(--color-border-subtle);
  transition: background-color var(--transition-fast);
}

tbody tr:hover {
  background-color: var(--color-slate-50);
}

tbody tr:last-child td {
  border-bottom: none;
}

/* Buttons - refined with subtle depth */
.button {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-sm) var(--space-lg);
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text-primary);
  background-color: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-base);
  cursor: pointer;
  box-shadow: var(--shadow-xs);
}

.button:hover {
  border-color: var(--color-slate-400);
  background-color: var(--color-slate-50);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.button--primary {
  background: linear-gradient(to bottom, var(--color-slate-900), var(--color-slate-950));
  color: white;
  border-color: var(--color-slate-900);
  box-shadow: var(--shadow-md);
}

.button--primary:hover {
  background: linear-gradient(to bottom, var(--color-slate-800), var(--color-slate-900));
  border-color: var(--color-slate-800);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}


/* ----------------------------------------------------------------------------
   UTILITIES
   ---------------------------------------------------------------------------- */

.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;
}

.text-secondary {
  color: var(--color-text-secondary);
}

.text-tertiary {
  color: var(--color-text-tertiary);
}


/* ----------------------------------------------------------------------------
   RESPONSIVE
   ---------------------------------------------------------------------------- */

@media (max-width: 768px) {
  :root {
    --space-3xl: 3rem;
    --space-4xl: 4rem;
  }

  h2 {
    margin-top: var(--space-2xl);
  }

  .container,
  .container-narrow {
    padding-left: var(--space-md);
    padding-right: var(--space-md);
  }

  table {
    font-size: var(--text-xs);
  }

  th, td {
    padding: var(--space-sm);
  }
}


/* ----------------------------------------------------------------------------
   MICRO-ANIMATIONS & POLISH
   ---------------------------------------------------------------------------- */

/* Smooth fade-in for page loads */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

main {
  animation: fadeIn 0.5s ease-out;
}

/* Focus visible for accessibility */
:focus-visible {
  outline: 2px solid var(--color-accent-500);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Selection styling */
::selection {
  background-color: var(--color-accent-200);
  color: var(--color-slate-900);
}

/* Improved list markers */
article ul:not([role='list']) li::marker {
  font-size: 0.75em;
}

/* Subtle text gradient for large headings (optional enhancement) */
h1 {
  background: linear-gradient(to bottom, var(--color-slate-900), var(--color-slate-700));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

@supports not (background-clip: text) {
  h1 {
    color: var(--color-slate-900);
  }
}