/* Reset, typography, focus ring, accessibility helpers. No colour literals here. */

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

html {
  font-size: var(--sg-font-size-base);
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  accent-color: var(--sg-color-accent);
  scroll-padding-top: var(--sg-space-4);
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--sg-color-bg);
  color: var(--sg-color-text);
  font-family: var(--sg-font-family);
  font-size: 1rem;
  line-height: var(--sg-line-height);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body.is-modal-open {
  overflow: hidden;
}

h1,
h2,
h3,
h4,
p,
ol,
ul,
dl,
dd,
figure,
fieldset {
  margin: 0;
}

h1,
h2,
h3,
h4 {
  line-height: 1.25;
  font-weight: 650;
}

h1 {
  font-size: var(--sg-font-size-xl);
}

h2 {
  font-size: var(--sg-font-size-lg);
}

h3 {
  font-size: 1rem;
}

ol,
ul {
  padding: 0;
  list-style: none;
}

fieldset {
  min-width: 0;
  padding: 0;
  border: 0;
}

a {
  color: var(--sg-color-accent);
  text-underline-offset: 0.15em;
}

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

code,
kbd,
pre,
samp {
  font-family: var(--sg-font-mono);
  font-size: 0.9em;
}

img,
svg,
canvas {
  display: block;
  max-width: 100%;
}

hr {
  height: 1px;
  margin: var(--sg-space-4) 0;
  border: 0;
  background: var(--sg-color-divider);
}

[hidden] {
  display: none !important;
}

/* ---- Form controls: inherit the typography, appearance is added in components.css ---- */
button,
input,
select,
textarea {
  margin: 0;
  color: inherit;
  font: inherit;
  letter-spacing: inherit;
}

button {
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

button:disabled,
input:disabled,
select:disabled,
textarea:disabled {
  cursor: not-allowed;
}

textarea {
  resize: vertical;
}

summary {
  cursor: pointer;
}

/* ---- Focus ring: 3px outline, >= 3:1 against every surface, never removed ---- */
:focus-visible {
  outline: var(--sg-focus-width) solid var(--sg-color-focus);
  outline-offset: var(--sg-focus-offset);
}

:focus:not(:focus-visible) {
  outline: none;
}

/* Programmatic focus targets (skip link, dialogs) do not need a ring around the whole region. */
[tabindex="-1"]:focus {
  outline: none;
}

::selection {
  background: var(--sg-color-accent);
  color: var(--sg-color-accent-text);
}

/* ---- Accessibility helpers ---- */
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: var(--sg-space-2);
  left: var(--sg-space-2);
  z-index: calc(var(--sg-z-toast) + 10);
  padding: var(--sg-space-2) var(--sg-space-4);
  border: 2px solid var(--sg-color-focus);
  border-radius: var(--sg-radius-2);
  background: var(--sg-color-surface);
  color: var(--sg-color-text);
  font-weight: 650;
  text-decoration: none;
  box-shadow: var(--sg-shadow-2);
  transform: translateY(-300%);
}

.skip-link:focus,
.skip-link:focus-visible {
  transform: none;
}

/* ---- Small typographic utilities ---- */
.text-muted {
  color: var(--sg-color-text-muted);
}

.mono {
  font-family: var(--sg-font-mono);
}

/* ---- Reduced motion: system preference or Settings switch (data-motion="off") ---- */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-delay: 0ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    transition-delay: 0ms !important;
    scroll-behavior: auto !important;
  }
}

:root[data-motion="off"] *,
:root[data-motion="off"] *::before,
:root[data-motion="off"] *::after {
  animation-duration: 0.01ms !important;
  animation-delay: 0ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.01ms !important;
  transition-delay: 0ms !important;
  scroll-behavior: auto !important;
}

/* ---- Smooth theme switching: colours only, and never under reduced motion ----
   js/ui/theme.js of each app adds .is-theming to <html> for a moment around a change of theme. */
@media (prefers-reduced-motion: no-preference) {
  :root.is-theming:not([data-motion="off"]),
  :root.is-theming:not([data-motion="off"]) *,
  :root.is-theming:not([data-motion="off"]) *::before,
  :root.is-theming:not([data-motion="off"]) *::after {
    transition:
      background-color var(--sg-motion-base) ease,
      color var(--sg-motion-base) ease,
      border-color var(--sg-motion-base) ease,
      fill var(--sg-motion-base) ease,
      stroke var(--sg-motion-base) ease,
      outline-color var(--sg-motion-base) ease !important;
  }
}

/* ---- Forced colours (Windows high contrast): the system palette wins, shapes keep the meaning ---- */
@media (forced-colors: active) {
  :focus-visible {
    outline: var(--sg-focus-width) solid Highlight;
  }

  .skip-link {
    border-color: CanvasText;
  }
}