/* ============================================================
   DesmosGraph.com - Modern Design System
   Mobile-first, accessible, fast, dark/light theme
   ============================================================ */

:root {
  --color-bg: #ffffff;
  --color-bg-soft: #f7f8fb;
  --color-bg-elev: #ffffff;
  --color-border: #e6e8ee;
  --color-border-strong: #cfd3dd;
  --color-text: #0f172a;
  --color-text-soft: #475569;
  --color-text-mute: #64748b;
  --color-primary: #4f46e5;
  --color-primary-hover: #4338ca;
  --color-primary-soft: #eef2ff;
  --color-accent: #06b6d4;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-pink: #ec4899;
  --color-violet: #8b5cf6;

  --shadow-sm: 0 1px 2px rgba(15,23,42,.06);
  --shadow-md: 0 4px 16px rgba(15,23,42,.08);
  --shadow-lg: 0 12px 32px rgba(15,23,42,.12);

  --radius-sm: 8px;
  --radius: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;

  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;

  --header-h: 64px;
  --container: 1200px;

  --t-fast: 120ms cubic-bezier(.4,0,.2,1);
  --t-base: 200ms cubic-bezier(.4,0,.2,1);
}

[data-theme="dark"] {
  --color-bg: #0b1020;
  --color-bg-soft: #0f1530;
  --color-bg-elev: #131a36;
  --color-border: #1f274a;
  --color-border-strong: #2a3460;
  --color-text: #e6e8f2;
  --color-text-soft: #b0b6cd;
  --color-text-mute: #8a91ad;
  --color-primary: #818cf8;
  --color-primary-hover: #a5b4fc;
  --color-primary-soft: #1c2350;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.4);
  --shadow-md: 0 4px 16px rgba(0,0,0,.45);
  --shadow-lg: 0 12px 32px rgba(0,0,0,.55);
}

/* Reset */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background var(--t-base), color var(--t-base);
}
img, svg, canvas { max-width: 100%; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: color var(--t-fast); }
a:hover { color: var(--color-primary-hover); text-decoration: underline; }

h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-3) 0;
  line-height: 1.25;
  font-weight: 700;
  letter-spacing: -.01em;
}
h1 { font-size: clamp(28px, 5vw, 44px); }
h2 { font-size: clamp(22px, 3.5vw, 32px); }
h3 { font-size: clamp(18px, 2.5vw, 22px); }

p { margin: 0 0 var(--space-4) 0; color: var(--color-text-soft); }

ul, ol { padding-left: 1.25rem; }
li { margin: var(--space-1) 0; color: var(--color-text-soft); }

code, pre, kbd { font-family: var(--font-mono); }
code {
  background: var(--color-bg-soft);
  padding: 2px 6px;
  border-radius: 6px;
  font-size: .92em;
  border: 1px solid var(--color-border);
}
pre {
  background: var(--color-bg-soft);
  padding: var(--space-4);
  border-radius: var(--radius);
  overflow-x: auto;
  border: 1px solid var(--color-border);
}

hr {
  border: 0;
  border-top: 1px solid var(--color-border);
  margin: var(--space-6) 0;
}

/* Layout */
.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--space-4);
}

.section { padding: var(--space-7) 0; }
.section-tight { padding: var(--space-6) 0; }

@media (min-width: 768px) {
  .section { padding: var(--space-8) 0; }
  .container { padding: 0 var(--space-5); }
}

/* Header / Nav */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--color-bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--color-border);
  height: var(--header-h);
  display: flex;
  align-items: center;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
}
.brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-weight: 800;
  font-size: 18px;
  color: var(--color-text);
  text-decoration: none;
  letter-spacing: -.01em;
}
.brand:hover { color: var(--color-text); text-decoration: none; }
.brand-mark {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  display: grid;
  place-items: center;
  color: #fff;
  font-weight: 800;
  font-size: 16px;
  box-shadow: var(--shadow-sm);
}

.nav { display: none; }
.nav-list {
  list-style: none;
  display: flex;
  gap: var(--space-5);
  margin: 0;
  padding: 0;
  align-items: center;
}
.nav-list a {
  color: var(--color-text-soft);
  font-weight: 500;
  padding: 6px 0;
  position: relative;
}
.nav-list a:hover { color: var(--color-text); text-decoration: none; }
.nav-list a.active { color: var(--color-primary); }

@media (min-width: 880px) {
  .nav { display: block; }
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}
.theme-toggle, .menu-toggle {
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  cursor: pointer;
  color: var(--color-text);
  transition: background var(--t-fast), border-color var(--t-fast);
}
.theme-toggle:hover, .menu-toggle:hover {
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
}
@media (min-width: 880px) {
  .menu-toggle { display: none; }
}

/* Mobile menu */
.mobile-menu {
  position: fixed;
  inset: var(--header-h) 0 0 0;
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  padding: var(--space-5);
  z-index: 49;
  transform: translateY(-100%);
  opacity: 0;
  pointer-events: none;
  transition: transform var(--t-base), opacity var(--t-base);
  overflow-y: auto;
}
.mobile-menu.open { transform: translateY(0); opacity: 1; pointer-events: auto; }
.mobile-menu ul { list-style: none; margin: 0; padding: 0; }
.mobile-menu li a {
  display: block;
  padding: var(--space-3) var(--space-2);
  color: var(--color-text);
  border-radius: var(--radius-sm);
  font-weight: 500;
}
.mobile-menu li a:hover {
  background: var(--color-bg-soft);
  text-decoration: none;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 10px 18px;
  border-radius: 10px;
  border: 1px solid transparent;
  font-weight: 600;
  cursor: pointer;
  font-size: 15px;
  transition: transform var(--t-fast), background var(--t-fast), border-color var(--t-fast), box-shadow var(--t-fast);
  font-family: var(--font-sans);
  text-decoration: none;
  line-height: 1.2;
}
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: var(--color-primary);
  color: #fff;
  box-shadow: 0 6px 16px color-mix(in srgb, var(--color-primary) 35%, transparent);
}
.btn-primary:hover {
  background: var(--color-primary-hover);
  color: #fff;
  text-decoration: none;
  box-shadow: 0 10px 24px color-mix(in srgb, var(--color-primary) 45%, transparent);
}
.btn-ghost {
  background: var(--color-bg-soft);
  color: var(--color-text);
  border-color: var(--color-border);
}
.btn-ghost:hover {
  background: var(--color-primary-soft);
  border-color: var(--color-primary);
  color: var(--color-text);
  text-decoration: none;
}
.btn-sm { padding: 7px 12px; font-size: 13px; border-radius: 8px; }
.btn-lg { padding: 14px 24px; font-size: 16px; border-radius: 12px; }
.btn-icon { padding: 8px; width: 38px; height: 38px; }

/* Hero */
.hero {
  position: relative;
  padding: var(--space-7) 0 var(--space-6);
  background:
    radial-gradient(900px 400px at 12% 0%, color-mix(in srgb, var(--color-primary) 12%, transparent), transparent 60%),
    radial-gradient(900px 400px at 90% 0%, color-mix(in srgb, var(--color-accent) 12%, transparent), transparent 60%);
  overflow: hidden;
}
.hero h1 {
  font-size: clamp(34px, 6vw, 56px);
  background: linear-gradient(135deg, var(--color-text), color-mix(in srgb, var(--color-primary) 70%, var(--color-text)));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero p.lead {
  font-size: clamp(16px, 2vw, 19px);
  color: var(--color-text-soft);
  max-width: 700px;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-3);
  margin-top: var(--space-5);
}
.hero-stats {
  display: flex;
  gap: var(--space-6);
  margin-top: var(--space-6);
  flex-wrap: wrap;
}
.hero-stats .stat strong {
  display: block;
  font-size: 22px;
  color: var(--color-text);
}
.hero-stats .stat span {
  font-size: 13px;
  color: var(--color-text-mute);
}

/* Cards / Grid */
.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-4);
}
@media (min-width: 640px) { .grid-2 { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 880px) {
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }
}

.card {
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-5);
  transition: transform var(--t-fast), box-shadow var(--t-fast), border-color var(--t-fast);
}
.card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-border-strong);
}
.card .icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: grid;
  place-items: center;
  background: var(--color-primary-soft);
  color: var(--color-primary);
  margin-bottom: var(--space-3);
  font-size: 20px;
}
.card h3 { margin-bottom: var(--space-2); }
.card p { margin: 0; font-size: 14.5px; }

.feature-card {
  display: block;
  text-decoration: none;
  color: inherit;
}
.feature-card:hover { text-decoration: none; color: inherit; }

/* Eyebrow */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--color-primary);
  background: var(--color-primary-soft);
  padding: 6px 10px;
  border-radius: 999px;
  margin-bottom: var(--space-3);
}

/* Calculator Layout */
.calc-shell {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  height: calc(100vh - var(--header-h));
  min-height: 600px;
}
@media (min-width: 880px) {
  .calc-shell { grid-template-columns: 380px 1fr; }
}

.calc-sidebar {
  background: var(--color-bg-elev);
  border-right: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
  overflow: hidden;
  max-height: 50vh;
}
@media (min-width: 880px) {
  .calc-sidebar { max-height: none; }
}

.calc-toolbar {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-3);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg-soft);
  flex-wrap: wrap;
}
.calc-toolbar .btn { padding: 7px 12px; font-size: 13px; }
.calc-toolbar .btn.calc-toggle.active {
  background: var(--color-primary);
  color: #fff;
  border-color: var(--color-primary);
}
.calc-toolbar .btn.calc-toggle.active:hover { background: var(--color-primary-hover, var(--color-primary)); }

.expr-list {
  flex: 1;
  overflow-y: auto;
  padding: var(--space-2);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.expr-item {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 10px;
  display: grid;
  grid-template-columns: 6px 1fr auto;
  gap: var(--space-2);
  align-items: center;
}
.expr-item:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-primary) 25%, transparent);
}
.expr-color {
  width: 6px;
  height: 100%;
  min-height: 36px;
  border-radius: 3px;
  cursor: pointer;
}
.expr-input {
  border: none;
  outline: none;
  background: transparent;
  font-family: var(--font-mono);
  font-size: 15px;
  color: var(--color-text);
  width: 100%;
  padding: 6px 4px;
}
.expr-actions {
  display: flex;
  gap: 4px;
  align-items: center;
}
.expr-actions button {
  background: transparent;
  border: none;
  width: 28px;
  height: 28px;
  border-radius: 6px;
  cursor: pointer;
  color: var(--color-text-mute);
  display: grid;
  place-items: center;
}
.expr-actions button:hover {
  background: var(--color-bg-soft);
  color: var(--color-text);
}
.expr-error {
  grid-column: 2 / -1;
  font-size: 12px;
  color: var(--color-danger);
  padding: 0 4px 4px;
}
.expr-meta {
  grid-column: 2 / -1;
  font-size: 12px;
  color: var(--color-text-mute);
  padding: 0 4px 4px;
}

.slider-row {
  grid-column: 2 / -1;
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 4px 4px 6px;
}
.slider-row label { font-family: var(--font-mono); font-size: 13px; color: var(--color-text-soft); }
.slider-row input[type=range] { flex: 1; }
.slider-row input[type=number] { width: 70px; padding: 4px 6px; border: 1px solid var(--color-border); border-radius: 6px; font-family: var(--font-mono); font-size: 12px; background: var(--color-bg); color: var(--color-text); }

input[type=range] {
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  background: var(--color-border-strong);
  border-radius: 4px;
  outline: none;
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  border: 2px solid #fff;
  box-shadow: 0 1px 4px rgba(0,0,0,.2);
}
input[type=range]::-moz-range-thumb {
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  border: 2px solid #fff;
}

.calc-stage {
  position: relative;
  background: var(--color-bg);
  overflow: hidden;
}
#plot-canvas { width: 100%; height: 100%; display: block; cursor: crosshair; touch-action: none; }
.calc-overlay {
  position: absolute;
  top: 12px;
  right: 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  z-index: 5;
}
.calc-overlay button {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  color: var(--color-text);
  cursor: pointer;
  display: grid;
  place-items: center;
  box-shadow: var(--shadow-sm);
}
.calc-overlay button:hover { border-color: var(--color-primary); color: var(--color-primary); }

.coord-readout {
  position: absolute;
  bottom: 10px;
  left: 10px;
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 6px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-text-soft);
  pointer-events: none;
  box-shadow: var(--shadow-sm);
}

/* Examples / Library */
.example-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: var(--space-3);
}
.example-card {
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-3);
  cursor: pointer;
  transition: all var(--t-fast);
  text-decoration: none;
  color: inherit;
  display: block;
}
.example-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  text-decoration: none;
  color: inherit;
}
.example-card h4 { font-size: 15px; margin-bottom: 4px; }
.example-card code {
  display: block;
  background: var(--color-bg-soft);
  padding: 6px 8px;
  border-radius: 6px;
  font-size: 12px;
  color: var(--color-primary);
  border: 1px solid var(--color-border);
  word-break: break-all;
}

/* Footer */
.site-footer {
  background: var(--color-bg-soft);
  border-top: 1px solid var(--color-border);
  padding: var(--space-7) 0 var(--space-5);
  margin-top: var(--space-8);
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-5);
  margin-bottom: var(--space-5);
}
@media (min-width: 720px) { .footer-grid { grid-template-columns: 2fr 1fr 1fr 1fr; } }
.footer-grid h4 { font-size: 14px; text-transform: uppercase; letter-spacing: .05em; color: var(--color-text-mute); }
.footer-grid ul { list-style: none; padding: 0; margin: 0; }
.footer-grid li { margin-bottom: 6px; }
.footer-grid a { color: var(--color-text-soft); }
.footer-grid a:hover { color: var(--color-primary); text-decoration: none; }
.footer-bottom {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-4);
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: var(--space-3);
  font-size: 13px;
  color: var(--color-text-mute);
}
.disclaimer {
  font-size: 12.5px;
  color: var(--color-text-mute);
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 8px 12px;
  margin-top: var(--space-4);
  line-height: 1.5;
}

/* Article / Blog */
.article {
  max-width: 760px;
  margin: 0 auto;
  padding: var(--space-6) var(--space-4);
}
.article h1 { margin-bottom: var(--space-2); }
.article .meta { color: var(--color-text-mute); font-size: 14px; margin-bottom: var(--space-5); }
.article h2 { margin-top: var(--space-6); }
.article h3 { margin-top: var(--space-5); }
.article img { border-radius: var(--radius); margin: var(--space-4) 0; }
.article blockquote {
  border-left: 4px solid var(--color-primary);
  background: var(--color-bg-soft);
  padding: var(--space-3) var(--space-4);
  margin: var(--space-4) 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  color: var(--color-text-soft);
}

.toc {
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-4);
  margin: var(--space-4) 0;
}
.toc h4 { margin: 0 0 var(--space-2) 0; font-size: 14px; text-transform: uppercase; letter-spacing: .05em; color: var(--color-text-mute); }
.toc ul { margin: 0; padding-left: 1.1em; }

.faq-item {
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  margin-bottom: var(--space-2);
  overflow: hidden;
}
.faq-item summary {
  padding: var(--space-3) var(--space-4);
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; font-size: 20px; color: var(--color-primary); transition: transform var(--t-fast); }
.faq-item[open] summary::after { content: "−"; }
.faq-item .faq-body { padding: 0 var(--space-4) var(--space-4); color: var(--color-text-soft); }

/* Breadcrumbs */
.breadcrumbs {
  font-size: 13px;
  color: var(--color-text-mute);
  margin-bottom: var(--space-3);
  display: flex;
  align-items: center;
  gap: 6px;
  flex-wrap: wrap;
}
.breadcrumbs a { color: var(--color-text-soft); }
.breadcrumbs a:hover { color: var(--color-primary); text-decoration: none; }
.breadcrumbs span.sep { color: var(--color-border-strong); }

/* Forms */
.form-row { display: flex; flex-direction: column; gap: 6px; margin-bottom: var(--space-3); }
.form-row label { font-weight: 600; font-size: 14px; }
.form-row input, .form-row textarea, .form-row select {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: 10px;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 15px;
  transition: border-color var(--t-fast), box-shadow var(--t-fast);
}
.form-row input:focus, .form-row textarea:focus, .form-row select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--color-primary) 25%, transparent);
}
.form-row textarea { min-height: 140px; resize: vertical; }

/* Tooltip / Toast */
.toast {
  position: fixed;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--color-text);
  color: var(--color-bg);
  padding: 10px 18px;
  border-radius: 10px;
  font-size: 14px;
  font-weight: 500;
  box-shadow: var(--shadow-lg);
  z-index: 1000;
  transition: transform var(--t-base);
  pointer-events: none;
}
.toast.show { transform: translateX(-50%) translateY(0); }

/* Modal */
.modal-backdrop {
  position: fixed;
  inset: 0;
  background: rgba(15, 23, 42, .55);
  z-index: 100;
  display: none;
  align-items: center;
  justify-content: center;
  padding: var(--space-4);
}
.modal-backdrop.open { display: flex; }
.modal {
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  max-width: 540px;
  width: 100%;
  padding: var(--space-5);
  max-height: 85vh;
  overflow-y: auto;
}
.modal h3 { margin-top: 0; }
.modal-actions { display: flex; justify-content: flex-end; gap: var(--space-2); margin-top: var(--space-4); }
.modal table.content { width: 100%; border-collapse: collapse; margin-top: var(--space-3); font-family: var(--font-mono); font-size: 13px; }
.modal table.content th, .modal table.content td { padding: 6px 10px; border-bottom: 1px solid var(--color-border); text-align: right; }
.modal table.content th { color: var(--color-text-mute); font-weight: 600; text-align: right; background: var(--color-bg-soft); }
.modal .grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-3); }

/* Example grid inside modals */
.example-grid { display: grid; gap: var(--space-2); grid-template-columns: 1fr; max-height: 60vh; overflow-y: auto; }
@media (min-width: 540px) { .example-grid { grid-template-columns: 1fr 1fr; } }
.example-card {
  display: block;
  padding: 10px 12px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  text-decoration: none;
  color: var(--color-text);
  transition: border-color var(--t-fast), transform var(--t-fast);
}
.example-card:hover { border-color: var(--color-primary); transform: translateY(-1px); }
.example-card h4 { margin: 0 0 4px 0; font-size: 14px; font-weight: 600; }
.example-card code { font-size: 12px; color: var(--color-text-mute); word-break: break-all; }

/* Utility */
.text-center { text-align: center; }
.muted { color: var(--color-text-mute); }
.flex { display: flex; }
.gap-2 { gap: var(--space-2); }
.gap-3 { gap: var(--space-3); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }
.mt-5 { margin-top: var(--space-5); }
.mt-6 { margin-top: var(--space-6); }
.mb-0 { margin-bottom: 0; }

.tag {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--color-bg-soft);
  border: 1px solid var(--color-border);
  font-size: 12px;
  color: var(--color-text-soft);
  font-weight: 500;
}
.tag.primary { background: var(--color-primary-soft); border-color: color-mix(in srgb, var(--color-primary) 30%, transparent); color: var(--color-primary); }
.tag.success { background: color-mix(in srgb, var(--color-success) 12%, transparent); color: var(--color-success); border-color: color-mix(in srgb, var(--color-success) 30%, transparent); }

/* Skip link */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-primary);
  color: #fff;
  padding: 10px 16px;
  z-index: 1000;
  border-radius: 0 0 8px 0;
}
.skip-link:focus { left: 0; }

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
  }
}

/* Print */
@media print {
  .site-header, .site-footer, .calc-toolbar, .calc-overlay, .mobile-menu { display: none !important; }
  body { background: #fff; color: #000; }
}

/* Loader */
.spinner {
  width: 16px;
  height: 16px;
  border: 2px solid var(--color-border-strong);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* Tables for content pages */
table.content {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-4) 0;
  font-size: 14px;
}
table.content th, table.content td {
  text-align: left;
  padding: 10px 12px;
  border-bottom: 1px solid var(--color-border);
}
table.content th { background: var(--color-bg-soft); font-weight: 700; }
table.content tr:hover { background: var(--color-bg-soft); }

/* Cookie banner */
.cookie-banner {
  position: fixed;
  bottom: 16px;
  left: 16px;
  right: 16px;
  background: var(--color-bg-elev);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--space-4);
  box-shadow: var(--shadow-lg);
  z-index: 60;
  display: none;
  gap: var(--space-3);
  flex-direction: column;
}
.cookie-banner.show { display: flex; }
@media (min-width: 720px) {
  .cookie-banner {
    flex-direction: row;
    align-items: center;
    max-width: 720px;
    left: 50%;
    transform: translateX(-50%);
  }
}
.cookie-banner p { margin: 0; font-size: 14px; }
.cookie-banner .actions { display: flex; gap: var(--space-2); flex-shrink: 0; }