/* DatadogStudy foundation
 * Owns reset, typography, form defaults, Japanese wrapping and accessibility.
 * It intentionally contains no viewport-width breakpoints; responsive geometry
 * belongs only to layout.css.
 */

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

html {
  max-width: 100%;
  scroll-padding-top: calc(var(--utility-height) + 20px);
  background: var(--bg);
}

body {
  min-width: 0;
  min-height: 100dvh;
  max-width: 100%;
  margin: 0;
  overflow-x: clip;
  background:
    radial-gradient(circle at 10% -8%, var(--canvas-ambient-a), transparent 34rem),
    radial-gradient(circle at 92% 8%, var(--canvas-ambient-b), transparent 30rem),
    radial-gradient(circle at 58% 108%, var(--canvas-ambient-c), transparent 34rem),
    var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP",
    "Hiragino Kaku Gothic ProN", "Yu Gothic UI", Meiryo, sans-serif;
  font-size: 17px;
  line-height: 1.72;
  letter-spacing: 0.005em;
  text-rendering: optimizeLegibility;
  -webkit-text-size-adjust: 100%;
}

@supports not (overflow: clip) {
  body {
    overflow-x: hidden;
  }
}

::selection {
  background: color-mix(in srgb, var(--accent) 22%, transparent);
}

h1,
h2,
h3,
h4,
h5,
p,
ul,
ol,
dl,
figure {
  margin-top: 0;
}

h1,
h2,
h3,
h4,
h5,
strong,
b {
  color: var(--text);
}

p,
li,
dt,
dd,
figcaption {
  text-wrap: pretty;
}

a {
  color: var(--accent);
  text-underline-offset: 0.18em;
}

button,
input,
select,
textarea {
  max-width: 100%;
  font: inherit;
}

button {
  color: inherit;
}

button:not(:disabled) {
  cursor: pointer;
}

button:disabled,
.btn:disabled {
  cursor: not-allowed;
  opacity: 0.5;
}

input[type="checkbox"],
input[type="radio"] {
  width: 18px;
  height: 18px;
  flex: 0 0 auto;
  margin-top: 3px;
  accent-color: var(--accent);
}

select,
input[type="number"],
textarea {
  min-height: var(--control-height);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  box-shadow: 0 1px 0 color-mix(in srgb, var(--text) 4%, transparent);
}

textarea {
  width: 100%;
  min-height: 180px;
  padding: 14px 15px;
  line-height: 1.65;
  resize: vertical;
}

code {
  padding: 0.1em 0.35em;
  border-radius: 5px;
  background: var(--surface-soft);
  font-family: "SFMono-Regular", "Cascadia Code", Consolas, monospace;
  font-size: 0.92em;
}

pre {
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

table {
  display: block;
  width: 100%;
  max-width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

img,
svg,
video,
canvas {
  max-width: 100%;
  height: auto;
}

[hidden] {
  display: none !important;
}

small,
.status-text {
  color: var(--muted);
}

:where(a, button, input, select, textarea, summary, [tabindex]):focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

:where(main, section, article, [id]) {
  scroll-margin-top: calc(var(--utility-height) + 16px);
}

/* Japanese line breaking */
:lang(ja) :where(
  p,
  li,
  dt,
  dd,
  figcaption,
  h1,
  h2,
  h3,
  h4,
  h5,
  .home-lead,
  .track-description,
  .chapter-summary,
  .resume-copy,
  .route-header,
  .focus-card,
  .concept,
  .stage-head,
  .stage-content,
  .detail-box,
  .feedback,
  .model-answer,
  .status-text
) {
  line-break: strict;
  word-break: normal;
  overflow-wrap: break-word;
}

:where(code, .official-reference, .resource a, .model-answer, .feedback, .scope-out) {
  overflow-wrap: anywhere;
  word-break: break-word;
}

/* Keyboard skip link */
.skip-link {
  position: fixed;
  inset-block-start: max(8px, env(safe-area-inset-top));
  inset-inline-start: max(8px, env(safe-area-inset-left));
  z-index: 10000;
  max-width: calc(100vw - 16px);
  padding: 10px 14px;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  background: var(--glass-fill-strong);
  color: var(--text);
  box-shadow: var(--glass-shadow-compact);
  font-weight: 700;
  text-decoration: none;
  backdrop-filter: blur(var(--glass-blur-compact)) saturate(var(--glass-saturation));
  -webkit-backdrop-filter: blur(var(--glass-blur-compact)) saturate(var(--glass-saturation));
  transform: translateY(-180%);
  transition: transform 120ms ease;
}

.skip-link:focus-visible {
  transform: translateY(0);
}

@media (pointer: coarse) {
  :where(
    button,
    .btn,
    .track-action,
    .chapter-step-nav a,
    .step-focus-nav a,
    .app-route-nav a,
    .site-footer a
  ) {
    min-block-size: 44px;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
  }

  .skip-link {
    transition: none;
  }
}