/* ─── 1. Reset ─────────────────────────────────── */

/* 1. Use a more-intuitive box-sizing model */
*,
*::before,
*::after {
  box-sizing: border-box;
}

/* 2. Remove default margin */
*:not(dialog) {
  margin: 0;
}

/* 3. Enable keyword animations */
@media (prefers-reduced-motion: no-preference) {
  html {
    interpolate-size: allow-keywords;
  }
}

body {
  /* 4. Increase line-height */
  line-height: 1.5;
  /* 5. Improve text rendering */
  -webkit-font-smoothing: antialiased;
}

/* 6. Improve media defaults */
img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
}

/* 7. Inherit fonts for form controls */
input,
button,
textarea,
select {
  font: inherit;
}

/* 8. Avoid text overflows */
p,
h1,
h2,
h3,
h4,
h5,
h6 {
  overflow-wrap: break-word;
}

/* 9. Improve line wrapping */
p {
  text-wrap: pretty;
}
h1,
h2,
h3,
h4,
h5,
h6 {
  text-wrap: balance;
}

/*
  10. Create a root stacking context
*/
#root,
#__next {
  isolation: isolate;
}

/* ─── 2. Variáveis ──────────────────────────────── */

:root {
  --primary-color: #007bff;
  --success-color: #28a745;
  --danger-color: #dc3545;
  --warning-color: #ffc107;
  --info-color: #17a2b8;
  --gray-light: #f8f9fa;
  --gray-medium: #e9ecef;
  --gray-dark: #6c757d;
  --highlight-color: #6f42c1;
}

/* ─── 3. Base ───────────────────────────────────── */

body {
  font-family: system-ui, -apple-system, sans-serif;
  max-width: 800px;
  margin-inline: auto;
  padding: 2rem;
  background-color: #fff;
  color: #333;
}

header {
  border-bottom: 2px solid var(--gray-medium);
  margin-bottom: 2rem;
  padding-bottom: 1rem;
}

main section {
  margin-bottom: 3rem;
  padding: 1.5rem;
  border: 1px solid var(--gray-medium);
  border-radius: 8px;
}

main h2 {
  margin-bottom: 1.5rem;
  color: var(--gray-dark);
  border-left: 5px solid var(--primary-color);
  padding-left: 0.5rem;
}

ul, ol {
  margin-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
}

/* ─── 4. Layout ─────────────────────────────────── */

main {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* ─── 5. Componentes ────────────────────────────── */

/* Seção 1 — Seletores de atributo */
#sec-atributo a[href^="https"] {
  color: var(--success-color);
}

#sec-atributo a[href^="http"]:not([href^="https"])::after {
  content: " ⚠";
  color: var(--danger-color);
}

#sec-atributo a[href^="http"]:not([href^="https"]) {
  color: var(--danger-color);
}

#sec-atributo a[href$=".pdf"] {
  color: orange;
}

#sec-atributo a[href$=".pdf"]::after {
  content: " [PDF]";
}

#sec-atributo a[href^="#"] {
  color: var(--gray-dark);
  font-style: italic;
}

#sec-atributo a[target="_blank"]::after {
  content: " ↗";
}

/* Seção 2 — Pseudo-classes estruturais */
#sec-estrutural li:first-child {
  font-weight: bold;
}

#sec-estrutural li:last-child {
  color: var(--highlight-color);
}

#sec-estrutural li:nth-child(even) {
  background-color: var(--gray-light);
}

#sec-estrutural li:nth-child(odd) {
  background-color: var(--gray-medium);
}

#sec-estrutural li:nth-child(3) {
  border-left: 4px solid var(--primary-color);
  padding-left: 5px;
}

/* Seção 3 — Pseudo-classes de estado */
form {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

input:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

input:disabled {
  background-color: var(--gray-medium);
  cursor: not-allowed;
}

input:required {
  border-left: 3px solid var(--warning-color);
}

input:not([type="checkbox"]):valid {
  border-color: var(--success-color);
}

input:not([type="checkbox"]):invalid {
  border-color: var(--danger-color);
}

input[type="checkbox"]:checked + label {
  font-weight: bold;
}

button {
  padding: 0.5rem 1rem;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  width: fit-content;
}

button:hover {
  background-color: #0056b3;
}

/* Seção 4 — Pseudo-elementos */
.citacao {
  font-size: 1.25rem;
  margin-block: 1rem;
}

.citacao::before {
  content: "“";
  font-size: 2rem;
  color: var(--highlight-color);
  vertical-align: middle;
}

.citacao::after {
  content: "”";
  font-size: 2rem;
  color: var(--highlight-color);
  vertical-align: middle;
}

.obrigatorio::after {
  content: " *";
  color: var(--danger-color);
}

::selection {
  background-color: var(--highlight-color);
  color: white;
}

.input-custom::placeholder {
  color: var(--gray-dark);
  font-style: italic;
}

/* Seção 5 — Combinadores e :not() */
#sec-combinadores h3 + p {
  font-size: 1.15rem;
  color: var(--highlight-color);
}

#sec-combinadores li:not(.ativo) {
  opacity: 0.5;
}

#sec-combinadores li.ativo {
  font-weight: bold;
}

#sec-combinadores li.ativo::before {
  content: "✔ ";
}

/* ─── 6. Utilitários ────────────────────────────── */