what-new-in-chrome/public/html-in-canvas/styles.css

:root {
  color-scheme: light;
  --ink: #17202a;
  --muted: #5d6670;
  --panel: #f7f4ec;
  --canvas: #101820;
  --accent: #ffb000;
  --accent-strong: #e04f2f;
  --line: #263241;
  --ok: #1d7f4f;
  --warn: #9a5b00;
  font-family: "Avenir Next", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(90deg, rgba(23, 32, 42, 0.06) 1px, transparent 1px),
    linear-gradient(rgba(23, 32, 42, 0.05) 1px, transparent 1px),
    #fffaf0;
  background-size: 28px 28px;
}

button,
input {
  font: inherit;
}

code {
  border: 1px solid rgba(23, 32, 42, 0.16);
  border-radius: 4px;
  padding: 0.08rem 0.28rem;
  background: rgba(255, 255, 255, 0.74);
}

.page-shell {
  width: min(1120px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 44px 0 56px;
}

.intro {
  display: grid;
  gap: 12px;
  margin-bottom: 28px;
}

.eyebrow {
  margin: 0;
  color: var(--accent-strong);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin: 0;
}

h1 {
  max-width: 760px;
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(3rem, 6vw, 5.8rem);
  line-height: 0.92;
  letter-spacing: 0;
}

.lede {
  max-width: 760px;
  color: var(--muted);
  font-size: 1.06rem;
  line-height: 1.75;
}

.status-panel {
  width: fit-content;
  max-width: 100%;
  border: 1px solid rgba(23, 32, 42, 0.18);
  border-left: 6px solid var(--warn);
  border-radius: 6px;
  padding: 10px 14px;
  color: var(--warn);
  background: rgba(255, 255, 255, 0.72);
  font-weight: 700;
}

.status-panel[data-state="ok"] {
  border-left-color: var(--ok);
  color: var(--ok);
}

.status-panel[data-state="fail"] {
  border-left-color: var(--accent-strong);
  color: var(--accent-strong);
}

.demo-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.55fr) minmax(280px, 0.8fr);
  gap: 24px;
  align-items: stretch;
}

.canvas-stage {
  position: relative;
  display: grid;
  place-items: center;
  min-height: 480px;
  border: 1px solid rgba(23, 32, 42, 0.24);
  border-radius: 8px;
  padding: 22px;
  background:
    radial-gradient(circle at 24% 18%, rgba(255, 176, 0, 0.34), transparent 28%),
    linear-gradient(135deg, #1a2633 0%, #0d141b 100%);
  box-shadow: 0 24px 70px rgba(23, 32, 42, 0.18);
}

canvas {
  width: min(638px, 100%);
  height: auto;
  aspect-ratio: 638 / 318;
  border: 2px solid rgba(255, 176, 0, 0.9);
  border-radius: 6px;
  background: var(--canvas);
  box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.16);
}

.fallback-preview {
  display: none;
  position: absolute;
  inset: 42px;
  place-items: center;
  gap: 14px;
  border: 1px dashed rgba(255, 176, 0, 0.72);
  border-radius: 6px;
  padding: 22px;
  background: rgba(16, 24, 32, 0.9);
}

body[data-api="fallback"] .fallback-preview {
  display: grid;
}

body[data-api="fallback"] canvas {
  opacity: 0.34;
}

.fallback-label {
  color: #ffd27c;
  font-size: 0.86rem;
  font-weight: 800;
  text-align: center;
}

.control-panel {
  width: 578px;
  color: #101820;
}

.control-panel fieldset {
  display: grid;
  gap: 12px;
  margin: 0;
  border: 2px solid #17202a;
  border-radius: 6px;
  padding: 18px;
  background: #fffaf0;
}

.control-panel legend {
  padding: 0 8px;
  font-weight: 900;
}

.field-row,
.check-row {
  display: flex;
  gap: 10px;
  align-items: center;
}

.field-row {
  justify-content: space-between;
}

.field-row input[type="text"] {
  width: min(310px, 58%);
  border: 1px solid #17202a;
  border-radius: 4px;
  padding: 7px 9px;
  background: #ffffff;
}

.field-row input[type="range"] {
  width: min(300px, 58%);
  accent-color: var(--accent-strong);
}

.nested-fieldset {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.nested-fieldset legend {
  grid-column: 1 / -1;
}

.control-panel button {
  justify-self: end;
  border: 2px solid #17202a;
  border-radius: 4px;
  padding: 8px 18px;
  color: #17202a;
  background: var(--accent);
  font-weight: 900;
  cursor: pointer;
}

.preview-panel {
  width: min(578px, 100%);
}

.preview-panel input:disabled,
.preview-panel button:disabled {
  cursor: not-allowed;
  opacity: 0.72;
}

.notes {
  display: grid;
  align-content: start;
  gap: 14px;
  border-left: 4px solid var(--line);
  padding: 20px 0 20px 22px;
  color: var(--muted);
  line-height: 1.7;
}

.notes h2 {
  color: var(--ink);
  font-size: 1rem;
}

.notes ul {
  display: grid;
  gap: 8px;
  margin: 0;
  padding-left: 1.2rem;
}

@media (max-width: 820px) {
  .page-shell {
    width: min(100vw - 22px, 680px);
    padding-top: 28px;
  }

  h1 {
    font-size: 3.1rem;
  }

  .demo-grid {
    grid-template-columns: 1fr;
  }

  .canvas-stage {
    min-height: 360px;
    padding: 14px;
  }

  .fallback-preview {
    inset: 24px;
    padding: 14px;
  }

  .nested-fieldset {
    grid-template-columns: 1fr;
  }

  .notes {
    border-left: 0;
    border-top: 4px solid var(--line);
    padding: 18px 0 0;
  }
}