/* Base element styles, typography roles, scrollbars and focus (SPEC §2.2–2.3). */
*, *::before, *::after { box-sizing: border-box; }

html, body, #root { height: 100%; }

html {
  font-family: var(--font-sans);
  font-size: var(--text-body);
  line-height: var(--leading-body);
  letter-spacing: var(--tracking-body);
  color: var(--text);
  background: var(--bg-canvas);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  font-feature-settings: "ss01" 0, "cv11" 1;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  overflow: hidden;
  background: var(--bg-canvas);
  color: var(--text);
}

:lang(zh), :lang(zh-CN) { letter-spacing: 0; }

h1, h2, h3, h4, p, ol, ul, figure, blockquote, pre { margin: 0; }
h1, h2, h3, h4 { font-weight: 600; text-wrap: balance; }
ol, ul { padding: 0; }
img, svg, video { display: block; max-width: 100%; }
svg { flex-shrink: 0; }
button, input, textarea, select { font: inherit; color: inherit; letter-spacing: inherit; }
button { cursor: pointer; background: none; border: 0; padding: 0; text-align: inherit; }
button:disabled { cursor: not-allowed; }
input, textarea { margin: 0; }
a { color: var(--accent-ink); text-decoration: none; text-underline-offset: 2px; }
a:hover { text-decoration: underline; }
code, kbd, pre, samp { font-family: var(--font-mono); font-size: .92em; }
::selection { background: var(--selection); }
[hidden] { display: none !important; }

/* Typography roles. */
.t-display { font-size: var(--text-display); line-height: var(--leading-display); font-weight: 600; letter-spacing: var(--tracking-display); }
.t-title-1 { font-size: var(--text-title-1); line-height: var(--leading-title-1); font-weight: 600; letter-spacing: var(--tracking-title-1); }
.t-title-2 { font-size: var(--text-title-2); line-height: var(--leading-title-2); font-weight: 600; letter-spacing: var(--tracking-title-2); }
.t-body { font-size: var(--text-body); line-height: var(--leading-body); }
.t-reading { font-size: var(--text-reading); line-height: var(--leading-reading); }
.t-control { font-size: var(--text-control); line-height: var(--leading-control); font-weight: 500; }
.t-caption { font-size: var(--text-caption); line-height: var(--leading-caption); }
.t-micro { font-size: var(--text-micro); line-height: var(--leading-micro); font-weight: 500; }
.t-label { font-size: var(--text-caption); line-height: var(--leading-caption); font-weight: 500; color: var(--text-3); }
.t-mono { font-family: var(--font-mono); }
.t-num { font-variant-numeric: tabular-nums; }
.t-2 { color: var(--text-2); }
.t-3 { color: var(--text-3); }
.truncate { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; min-width: 0; }
.sr-only {
  position: absolute !important; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
}

/* Focus: a visible ring for keyboard users on every interactive element. */
:focus { outline: none; }
:focus-visible {
  outline: 2px solid var(--border-focus);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}
input:focus-visible, textarea:focus-visible { outline-offset: 0; }

/* Thin scrollbars: 6px, thumb appears on hover. */
.scroll, .scroll-area {
  overflow: auto;
  scrollbar-width: thin;
  scrollbar-color: transparent transparent;
  overscroll-behavior: contain;
}
.scroll:hover, .scroll-area:hover, .scroll:focus-within, .scroll-area:focus-within { scrollbar-color: var(--scrollbar-thumb) transparent; }
.scroll::-webkit-scrollbar, .scroll-area::-webkit-scrollbar { width: 6px; height: 6px; }
.scroll::-webkit-scrollbar-track, .scroll-area::-webkit-scrollbar-track { background: transparent; }
.scroll::-webkit-scrollbar-thumb, .scroll-area::-webkit-scrollbar-thumb { background: transparent; border-radius: 6px; }
.scroll:hover::-webkit-scrollbar-thumb, .scroll-area:hover::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); }
.scroll::-webkit-scrollbar-corner, .scroll-area::-webkit-scrollbar-corner { background: transparent; }
* { scrollbar-width: thin; scrollbar-color: var(--scrollbar-thumb) transparent; }
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-thumb { background: var(--scrollbar-thumb); border-radius: 6px; }
::-webkit-scrollbar-track, ::-webkit-scrollbar-corner { background: transparent; }

/* Electron window chrome. */
.drag-region { -webkit-app-region: drag; app-region: drag; }
.drag-region button, .drag-region input, .drag-region a, .drag-region [role="button"], .drag-region .no-drag { -webkit-app-region: no-drag; app-region: no-drag; }

/* Boot screen shown until the workspace loads. */
.boot {
  height: 100%;
  display: grid;
  place-items: center;
  align-content: center;
  gap: var(--s-16);
  color: var(--text-3);
  background: var(--bg-canvas);
}
.boot-mark { width: 40px; height: 40px; color: var(--text); }
.boot-error { max-width: 420px; text-align: center; color: var(--danger); }