/* ==========================================================================
   ChapterIA — Reset, tipografia base e utilitários
   ========================================================================== */

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

* {
  margin: 0;
  padding: 0;
}

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

body {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: var(--lh-base);
  color: var(--text-base);
  background-color: var(--bg-800);
  background-image:
    radial-gradient(1200px 600px at 15% -5%, rgba(24, 163, 183, 0.10), transparent 60%),
    radial-gradient(1000px 700px at 100% 10%, rgba(111, 113, 161, 0.10), transparent 55%),
    radial-gradient(900px 600px at 50% 120%, rgba(39, 230, 236, 0.06), transparent 60%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

button {
  font: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

h1, h2, h3, h4 {
  color: var(--text-strong);
  line-height: var(--lh-snug);
  font-weight: 600;
  letter-spacing: -0.01em;
}

::selection {
  background: var(--color-cyan);
  color: var(--bg-900);
}

/* -- Scrollbar ----------------------------------------------------------- */
::-webkit-scrollbar { width: 10px; }
::-webkit-scrollbar-track { background: var(--bg-900); }
::-webkit-scrollbar-thumb {
  background: var(--color-deep-blue);
  border-radius: var(--radius-pill);
  border: 2px solid var(--bg-900);
}
::-webkit-scrollbar-thumb:hover { background: var(--color-teal); }

/* ==========================================================================
   Layout helpers
   ========================================================================== */

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

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

.section {
  position: relative;
  padding-block: var(--section-pad);
}

.section--tight {
  padding-block: clamp(3rem, 6vw, 5rem);
}

/* ==========================================================================
   Tipografia utilitária
   ========================================================================== */

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: var(--fs-small);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-cyan);
}

.eyebrow::before {
  content: "";
  width: 28px;
  height: 1px;
  background: linear-gradient(90deg, var(--color-cyan), transparent);
}

.gradient-text {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  color: transparent;
}

.section-title {
  font-size: var(--fs-h1);
  max-width: 22ch;
}

.section-subtitle {
  font-size: var(--fs-h2);
  color: var(--text-base);
  font-weight: 400;
  line-height: var(--lh-snug);
  max-width: 58ch;
  margin-top: var(--space-3);
}

.lead {
  font-size: var(--fs-lead);
  color: var(--text-base);
  max-width: 62ch;
}

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

.section-head {
  margin-bottom: var(--space-6);
  max-width: 720px;
}

.section-head--center {
  margin-inline: auto;
  text-align: center;
}

.section-head--center .section-title,
.section-head--center .section-subtitle {
  margin-inline: auto;
}

/* ==========================================================================
   Botões
   ========================================================================== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.6rem;
  padding: 0.95rem 1.9rem;
  border-radius: var(--radius-pill);
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: 0.01em;
  transition: transform var(--t-fast), box-shadow var(--t-base),
              background var(--t-base), border-color var(--t-base);
  white-space: nowrap;
}

.btn:active { transform: translateY(1px); }

.btn--primary {
  background: var(--gradient-brand);
  color: #04141a;
  box-shadow: var(--glow-subtle);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--glow-cyan);
}

.btn--ghost {
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-strong);
  border: 1px solid var(--border-strong);
}

.btn--ghost:hover {
  border-color: var(--border-glow);
  background: rgba(39, 230, 236, 0.06);
}

.btn--lg {
  padding: 1.1rem 2.4rem;
  font-size: 1.05rem;
}

/* ==========================================================================
   Cards / superfícies
   ========================================================================== */

.card {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: var(--space-4);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  transition: transform var(--t-base), border-color var(--t-base),
              box-shadow var(--t-base);
}

.card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-md);
}

/* linha de brilho sutil no topo do card */
.card--glow::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-glow), transparent);
  opacity: 0;
  transition: opacity var(--t-base);
}

.card--glow:hover::before { opacity: 1; }

/* ==========================================================================
   Divisor geométrico
   ========================================================================== */

.divider-line {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, transparent, var(--border-strong), transparent);
}

/* ==========================================================================
   Animação reveal on scroll
   ========================================================================== */

.reveal {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity var(--t-slow), transform var(--t-slow);
  will-change: opacity, transform;
}

.reveal.is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  * { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}