/* ========================================
   CSS Variables – PolyGrid Slate Palette
   ======================================== */
:root {
  --color-primary: #1E3A8A;
  --color-secondary: #0F766E;
  --color-accent: #F97316;
  --color-bg: #F8FAFC;
  --color-surface: #FFFFFF;
  --color-text: #0B1220;
  --color-muted: #475569;
  --color-border: #CBD5E1;
  --radius-1: 2px;
  --shadow-1: 0 1px 3px rgba(11, 18, 32, 0.08);
  --space-1: 1rem;
  --space-2: 2rem;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "Courier New", Courier, monospace;
  --transition-speed: 0.2s;
}

/* ========================================
   Reset and Base Styles
   ======================================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

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

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

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

/* ========================================
   Typography – Swiss Style
   ======================================== */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  text-align: left;
}

h1 {
  font-size: 2rem;
  margin-top: 0;
  margin-bottom: 1.5rem;
  color: var(--color-primary);
}

h2 {
  font-size: 1.5rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
  color: var(--color-primary);
}

h3 {
  font-size: 1.25rem;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
  color: var(--color-secondary);
}

p {
  margin-bottom: 1rem;
}

a {
  color: var(--color-primary);
  text-decoration: underline;
  transition: color var(--transition-speed) ease;
}

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

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

ul, ol {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
}

li {
  margin-bottom: 0.5rem;
}

dl {
  margin-bottom: 1rem;
}

dt {
  font-weight: 700;
  margin-top: 0.5rem;
}

dd {
  margin-left: 1.5rem;
  margin-bottom: 0.5rem;
}

/* ========================================
   Layout – Mobile-First Grid
   ======================================== */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-1);
}

@media (min-width: 768px) {
  .container {
    padding: 0 var(--space-2);
  }
}

/* ========================================
   Header and Navigation
   ======================================== */
header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-1) 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-1);
}

header .container {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.75rem;
}

@media (min-width: 768px) {
  header .container {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

.site-name {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-primary);
}

nav {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
}

nav a {
  text-decoration: none;
  font-weight: 500;
  color: var(--color-text);
  transition: color var(--transition-speed) ease;
}

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

nav a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* ========================================
   Main Content
   ======================================== */
main {
  padding: var(--space-2) 0;
  min-height: 60vh;
}

article {
  background-color: var(--color-surface);
  padding: var(--space-2);
  border-radius: var(--radius-1);
  box-shadow: var(--shadow-1);
}

@media (min-width: 768px) {
  article {
    padding: 3rem;
  }
}

section {
  margin-bottom: 2rem;
}

section:last-child {
  margin-bottom: 0;
}

/* ========================================
   Breadcrumbs
   ======================================== */
.breadcrumbs {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin-bottom: 1.5rem;
}

.breadcrumbs a {
  color: var(--color-muted);
  text-decoration: none;
}

.breadcrumbs a:hover {
  color: var(--color-accent);
  text-decoration: underline;
}

/* ========================================
   Aside (Callout Box)
   ======================================== */
aside {
  background-color: var(--color-bg);
  border-left: 4px solid var(--color-secondary);
  padding: var(--space-1);
  margin: 1.5rem 0;
  border-radius: var(--radius-1);
}

aside h3 {
  margin-top: 0;
  font-size: 1.125rem;
}

/* ========================================
   Blockquote (Accent Callout)
   ======================================== */
blockquote {
  background-color: #FFF7ED;
  border-left: 4px solid var(--color-accent);
  padding: var(--space-1);
  margin: 1.5rem 0;
  border-radius: var(--radius-1);
  font-style: normal;
}

blockquote p {
  margin-bottom: 0;
}

/* ========================================
   Tables – Responsive with Sticky Header
   ======================================== */
.table-container {
  overflow-x: auto;
  margin: 1.5rem 0;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-1);
}

table {
  width: 100%;
  border-collapse: collapse;
  background-color: var(--color-surface);
  font-size: 0.9375rem;
}

caption {
  font-weight: 700;
  text-align: left;
  padding: 0.75rem 1rem;
  background-color: var(--color-bg);
  border-bottom: 2px solid var(--color-border);
  color: var(--color-primary);
}

thead {
  background-color: var(--color-primary);
  color: var(--color-surface);
}

@media (min-width: 1024px) {
  thead {
    position: sticky;
    top: 0;
    z-index: 10;
  }
}

th, td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

th {
  font-weight: 600;
  text-transform: uppercase;
  font-size: 0.875rem;
  letter-spacing: 0.025em;
}

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

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

/* ========================================
   Details/Summary Accordion
   ======================================== */
details {
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-1);
  margin-bottom: 1rem;
  padding: 0;
  transition: box-shadow var(--transition-speed) ease;
}

details:hover {
  box-shadow: var(--shadow-1);
}

details[open] {
  border-color: var(--color-primary);
}

summary {
  font-weight: 600;
  padding: 1rem;
  cursor: pointer;
  user-select: none;
  list-style: none;
  color: var(--color-primary);
  transition: background-color var(--transition-speed) ease;
}

summary::-webkit-details-marker {
  display: none;
}

summary::before {
  content: "▸ ";
  display: inline-block;
  margin-right: 0.5rem;
  transition: transform var(--transition-speed) ease;
}

details[open] summary::before {
  transform: rotate(90deg);
}

summary:hover {
  background-color: var(--color-bg);
}

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

details p {
  padding: 0 1rem 1rem 1rem;
  margin-bottom: 0;
}

/* ========================================
   Footer
   ======================================== */
footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-2) 0;
  margin-top: var(--space-2);
  text-align: center;
  color: var(--color-muted);
  font-size: 0.875rem;
}

footer p {
  margin-bottom: 0;
}

/* ========================================
   Responsive Breakpoints
   ======================================== */
@media (min-width: 768px) {
  h1 {
    font-size: 2.5rem;
  }
  h2 {
    font-size: 1.75rem;
  }
  h3 {
    font-size: 1.375rem;
  }
}

@media (min-width: 1024px) {
  .container {
    max-width: 1200px;
  }
  article {
    padding: 4rem;
  }
}

/* ========================================
   Utility Classes
   ======================================== */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ========================================
   Focus Styles for Accessibility
   ======================================== */
*:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

button:focus-visible,
a:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}