/* ==========================================================================
   Material Academy — Base
   Reset, element defaults, layout primitives. Mobile-first throughout:
   plain rules are the small-screen case, min-width queries layer up.
   Requires tokens.css.
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink-900);
  font-family: var(--font-sans);
  font-size: var(--text-md);
  line-height: var(--leading-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---------- Headings -------------------------------------------------- */
h1, h2, h3, h4, h5, h6 {
  margin: 0 0 var(--space-4);
  font-family: var(--font-serif);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-snug);
  letter-spacing: var(--tracking-tight);
  color: var(--brand-800);
  text-wrap: balance;          /* stops orphaned words on headings */
}
h1 { font-size: var(--text-3xl); line-height: var(--leading-tight); }
h2 { font-size: var(--text-2xl); }
h3 { font-size: var(--text-xl); }
h4 { font-size: var(--text-lg); }
h5 { font-size: var(--text-base); }
h6 {
  font-size: var(--text-sm);
  font-family: var(--font-sans);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wide);
  color: var(--ink-600);
}

@media (min-width: 48rem) {
  h1 { font-size: var(--text-4xl); }
  h2 { font-size: var(--text-3xl); }
  h3 { font-size: var(--text-2xl); }
}

p { margin: 0 0 var(--space-4); max-width: var(--measure); text-wrap: pretty; }

/* ---------- Links ------------------------------------------------------ */
a {
  color: var(--brand-700);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
  transition: color var(--transition);
}
a:hover { color: var(--brand-900); }

/* ---------- Focus ------------------------------------------------------
   Visible on every interactive element. :focus-visible so a mouse click
   does not leave a ring behind, but keyboard users always see one.       */
:focus-visible {
  outline: var(--focus-ring-width) solid var(--focus-ring-color);
  outline-offset: var(--focus-ring-offset);
  border-radius: var(--radius-sm);
}

/* ---------- Media ------------------------------------------------------ */
img, picture, video, canvas, svg { display: block; max-width: 100%; height: auto; }

/* ---------- Forms inherit type ----------------------------------------- */
input, button, textarea, select { font: inherit; color: inherit; }

/* ---------- Rules ------------------------------------------------------ */
hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: var(--space-8) 0;
}

/* ---------- Lists ------------------------------------------------------ */
ul, ol { margin: 0 0 var(--space-4); padding-inline-start: var(--space-5); }
li { margin-bottom: var(--space-2); }

/* ---------- Skip link --------------------------------------------------
   First focusable element on the page; invisible until focused.          */
.skip-link {
  position: absolute;
  left: var(--space-4);
  top: calc(-1 * var(--space-12));
  z-index: var(--z-dialog);
  padding: var(--space-3) var(--space-4);
  background: var(--brand-800);
  color: #fff;
  border-radius: var(--radius);
  text-decoration: none;
  transition: top var(--transition);
}
.skip-link:focus { top: var(--space-4); color: #fff; }

/* ---------- Layout ----------------------------------------------------- */
.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
@media (min-width: 64rem) {
  .container { padding-inline: var(--gutter-lg); }
}

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

/* Vertical rhythm between page sections. Sections must breathe. */
.section        { padding-block: var(--space-9); }
.section--tight { padding-block: var(--space-7); }
.section--loose { padding-block: var(--space-10); }
@media (min-width: 48rem) {
  .section        { padding-block: var(--space-11); }
  .section--tight { padding-block: var(--space-9); }
  .section--loose { padding-block: var(--space-12); }
}

/* 12-column grid. Mobile-first: one column until there is room. */
.grid {
  display: grid;
  gap: var(--space-5);
  grid-template-columns: repeat(1, minmax(0, 1fr));
}
@media (min-width: 40rem) { .grid { grid-template-columns: repeat(6, minmax(0, 1fr)); gap: var(--space-6); } }
@media (min-width: 64rem) { .grid { grid-template-columns: repeat(var(--grid-columns), minmax(0, 1fr)); } }

/* Column spans only apply once the grid actually has columns. */
@media (min-width: 40rem) {
  .col-3, .col-4, .col-6 { grid-column: span 3; }
  .col-8, .col-9, .col-12 { grid-column: span 6; }
}
@media (min-width: 64rem) {
  .col-3  { grid-column: span 3; }
  .col-4  { grid-column: span 4; }
  .col-6  { grid-column: span 6; }
  .col-8  { grid-column: span 8; }
  .col-9  { grid-column: span 9; }
  .col-12 { grid-column: span 12; }
}

.stack > * + * { margin-top: var(--space-4); }
.cluster { display: flex; flex-wrap: wrap; gap: var(--space-3); align-items: center; }

/* ---------- Small helpers ---------------------------------------------- */
.eyebrow {
  font-family: var(--font-sans);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  color: var(--ink-600);
  margin-bottom: var(--space-3);
}
.lede { font-size: var(--text-lg); color: var(--ink-700); }
.muted { color: var(--ink-600); }
.text-sm { font-size: var(--text-sm); }

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