/*
  DIVD Academy base styles and layout primitives (issue #13).
  Semantic HTML + minimal CSS; no framework.
*/

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

html {
  color-scheme: dark;
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top, rgba(245, 231, 22, 0.1), transparent 28%),
    linear-gradient(180deg, #0D0D0D 0%, var(--color-surface-0) 24%, var(--color-surface-0) 100%);
  color: var(--color-text-primary);
  font-family: var(--font-family-base);
  font-size: var(--font-size-body);
  line-height: var(--line-height-body);
}

::selection {
  background: rgba(245, 231, 22, 0.32);
  color: var(--color-text-primary);
}

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

/* Reflow at 320px and 200% text zoom without loss of content. */
html {
  overflow-x: hidden;
}

/* Skip link: visible on focus, first focusable element on every page. */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-sm);
  z-index: 1000;
  background: var(--color-accent);
  color: var(--color-text-on-accent);
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-md);
  font-weight: var(--font-weight-medium);
  text-decoration: none;
  transition: top var(--motion-duration-fast) var(--motion-ease);
}

.skip-link:focus-visible {
  top: var(--space-sm);
}

/* Visible focus states everywhere (WCAG 2.2 AA). */
:focus-visible {
  outline: var(--focus-ring-width) solid var(--focus-ring-color);
  outline-offset: var(--focus-ring-offset);
  border-radius: var(--radius-sm);
}

a {
  color: var(--color-text-link);
}

a:hover {
  color: var(--color-text-link-hover);
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-family-display);
  line-height: var(--line-height-heading);
  font-weight: var(--font-weight-bold);
  margin: 0 0 var(--space-sm);
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--font-size-h1);
  line-height: var(--line-height-tight);
}

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

h3 {
  font-size: var(--font-size-h3);
}

h4 {
  font-size: var(--font-size-h4);
}

p {
  margin: 0 0 var(--space-md);
  color: var(--color-text-secondary);
}

/* Layout primitives */
.container {
  width: 100%;
  max-width: var(--content-width-default);
  margin-inline: auto;
  padding-inline: var(--content-padding-inline);
}

.container--narrow {
  max-width: var(--content-width-narrow);
}

.container--wide {
  max-width: var(--content-width-wide);
}

.stack {
  display: flex;
  flex-direction: column;
}

.stack > * + * {
  margin-top: var(--space-md);
}

.cluster {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
}

.grid {
  display: grid;
  gap: var(--space-lg);
}

.grid--2 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 18rem), 1fr));
}

.grid--3 {
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 16rem), 1fr));
}

.section {
  padding-block: var(--space-2xl);
}

.section--tight {
  padding-block: var(--space-xl);
}

.eyebrow {
  display: inline-block;
  font-size: var(--font-size-eyebrow);
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: var(--space-sm);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Reduced-motion-safe scroll behaviour by default. */
html {
  scroll-behavior: smooth;
}