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

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: var(--leading-normal);
}

main {
  flex: 1 0 auto;
}

h1, h2 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  margin: 0 0 var(--space-4);
  color: var(--color-text);
}

h3, h4 {
  font-family: var(--font-sans);
  font-weight: 600;
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  margin: 0 0 var(--space-4);
  color: var(--color-text);
}

h1 { font-size: clamp(2.125rem, 3.1vw, 2.75rem); }
h2 { font-size: clamp(1.625rem, 2.6vw, 2.0625rem); }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.0625rem; }

p {
  margin: 0 0 var(--space-4);
  color: var(--color-text);
}

.lede {
  font-size: 1.1875rem;
  line-height: var(--leading-relaxed);
  color: var(--color-text-muted);
}

a {
  color: var(--color-positive-strong);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
  transition: color var(--transition-base);
}

a:hover {
  color: var(--color-accent-strong);
}

code, kbd, .mono {
  font-family: var(--font-mono);
  font-size: 0.875em;
}

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

ul, ol {
  padding-left: var(--space-5);
}

button {
  font-family: inherit;
}

/* Foco visível */
:focus-visible {
  outline: 3px solid var(--color-focus);
  outline-offset: 2px;
}

/* Skip link */
.skip-link {
  position: absolute;
  left: var(--space-3);
  top: -3rem;
  background: var(--color-bg-inverse);
  color: var(--color-text-inverse);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-sm);
  z-index: 1000;
  transition: top 0.15s ease;
}

.skip-link:focus {
  top: var(--space-3);
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

/* Layout base */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: 20px;
}

@media (min-width: 761px) {
  .container { padding-inline: 24px; }
}

@media (min-width: 1024px) {
  .container { padding-inline: 32px; }
}

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

.messages-wrap {
  padding-top: var(--space-5);
}

.grid {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 640px) {
  .grid--2 { grid-template-columns: repeat(2, 1fr); }
}

@media (min-width: 960px) {
  .grid--3 { grid-template-columns: repeat(3, 1fr); }
}

.stack {
  display: flex;
  flex-direction: column;
  gap: var(--space-4);
}

.section {
  padding-block: var(--space-6);
}

.section--tight {
  padding-block: var(--space-5);
}

.section--inverse {
  background: var(--color-bg-inverse);
  color: var(--color-text-inverse);
}

.section--inverse h1,
.section--inverse h2,
.section--inverse h3,
.section--inverse p {
  color: var(--color-text-inverse);
}

.section--surface {
  background: var(--color-bg-surface);
  border-block: var(--border-width-hairline) solid var(--color-border);
}

.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;
}