/*
 * base.css — Design tokens, reset e tipografia
 * Lavoisier — Laboratório Visual de Química
 * =====================================================================
 */

/* -----------------------------------------------------------------------
   Tokens de design
----------------------------------------------------------------------- */
:root {
  /* Paleta — tema escuro (padrão) */
  --bg-base:         #0d1117;
  --bg-surface:      #161b22;
  --bg-raised:       #1c2128;
  --bg-overlay:      #21262d;
  --border-subtle:   #21262d;
  --border-default:  #30363d;
  --border-strong:   #484f58;

  /* Texto */
  --text-primary:    #e6edf3;
  --text-secondary:  #8b949e;
  --text-muted:      #6e7681;
  --text-inverse:    #0d1117;

  /* Acentos temáticos */
  --accent-electron: #4fc3f7;   /* elétrons, ciência, azul */
  --accent-bond:     #ffd166;   /* ligações, amber */
  --accent-organic:  #6bcb77;   /* orgânica, verde */
  --accent-reaction: #ef476f;   /* reações, vermelho-rosa */
  --accent-energy:   #ffa726;   /* energia, laranja */
  --accent-neutral:  #b39ddb;   /* neutro, lilás */

  /* Estado */
  --state-correct:   #3fb950;
  --state-error:     #f85149;
  --state-hint:      #e3b341;
  --state-neutral:   #8b949e;

  /* Tipografia */
  --font-body:    "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --font-mono:    "Cascadia Code", "Fira Code", "Consolas", monospace;
  --font-display: "Segoe UI", "Helvetica Neue", Arial, sans-serif;

  /* Escala tipográfica — proporção 1.25 (Major Third) */
  --text-xs:   0.64rem;
  --text-sm:   0.8rem;
  --text-base: 1rem;
  --text-md:   1.25rem;
  --text-lg:   1.563rem;
  --text-xl:   1.953rem;
  --text-2xl:  2.441rem;
  --text-3xl:  3.052rem;

  /* Espaçamento */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-5:  1.25rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;

  /* Bordas */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Sombras */
  --shadow-sm:  0 1px 3px rgba(0,0,0,0.4);
  --shadow-md:  0 4px 12px rgba(0,0,0,0.5);
  --shadow-lg:  0 8px 24px rgba(0,0,0,0.6);
  --shadow-glow-electron: 0 0 12px rgba(79,195,247,0.35);
  --shadow-glow-bond:     0 0 12px rgba(255,209,102,0.35);
  --shadow-glow-organic:  0 0 12px rgba(107,203,119,0.35);

  /* Transições */
  --transition-fast:   120ms ease;
  --transition-normal: 200ms ease;
  --transition-slow:   350ms ease;

  /* Layout */
  --header-height: 56px;
  --sidebar-width: 260px;
  --content-max:   1100px;
  --module-max:    900px;

  /* Z-index */
  --z-base:    0;
  --z-raised:  10;
  --z-overlay: 100;
  --z-sidebar: 200;
  --z-toast:   300;
  --z-modal:   400;
}

/* -----------------------------------------------------------------------
   Alto contraste
----------------------------------------------------------------------- */
@media (prefers-contrast: more) {
  :root {
    --border-default: #6e7681;
    --text-secondary: #b1bac4;
    --bg-surface:     #0d1117;
  }
}

/* -----------------------------------------------------------------------
   Reset
----------------------------------------------------------------------- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  text-size-adjust: 100%;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-base);
  min-height: 100vh;
  overflow-x: hidden;
}

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

canvas {
  display: block;
  /* Sem max-width: canvas precisa de tamanho fixo para hit detection correta */
}

a {
  color: var(--accent-electron);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

ul, ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  line-height: 1.25;
  font-weight: 600;
  color: var(--text-primary);
}

code, pre, .mono {
  font-family: var(--font-mono);
}

/* -----------------------------------------------------------------------
   Acessibilidade — foco visível
----------------------------------------------------------------------- */
:focus-visible {
  outline: 2px solid var(--accent-electron);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 0;
  background: var(--accent-electron);
  color: var(--text-inverse);
  padding: var(--space-2) var(--space-4);
  z-index: var(--z-modal);
  border-radius: 0 0 var(--radius-md) 0;
  font-weight: 600;
  transition: top var(--transition-fast);
}

.skip-link:focus {
  top: 0;
}

/* -----------------------------------------------------------------------
   Barra de rolagem personalizada
----------------------------------------------------------------------- */
@supports selector(::-webkit-scrollbar) {
  ::-webkit-scrollbar { width: 6px; height: 6px; }
  ::-webkit-scrollbar-track { background: var(--bg-base); }
  ::-webkit-scrollbar-thumb {
    background: var(--border-strong);
    border-radius: var(--radius-full);
  }
  ::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }
}

/* -----------------------------------------------------------------------
   Animação de carregamento
----------------------------------------------------------------------- */
.loading-screen {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  gap: var(--space-6);
  color: var(--text-secondary);
  font-size: var(--text-sm);
  letter-spacing: 0.05em;
}

.loading-atom {
  position: relative;
  width: 64px;
  height: 64px;
}

.loading-nucleus {
  position: absolute;
  inset: 50%;
  transform: translate(-50%, -50%);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--accent-electron);
  box-shadow: var(--shadow-glow-electron);
}

.loading-orbit {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 1.5px solid rgba(79, 195, 247, 0.3);
}

.loading-orbit.orbit-1 { animation: spin 1.6s linear infinite; }
.loading-orbit.orbit-2 { animation: spin 2.4s linear infinite reverse; transform: rotate(60deg); }

.loading-electron {
  position: absolute;
  top: -4px;
  left: 50%;
  transform: translateX(-50%);
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent-electron);
  box-shadow: var(--shadow-glow-electron);
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* -----------------------------------------------------------------------
   Notação química inline
----------------------------------------------------------------------- */
sub { font-size: 0.75em; vertical-align: sub; }
sup { font-size: 0.75em; vertical-align: super; }

.chem-formula {
  font-family: var(--font-mono);
  font-size: 0.95em;
  color: var(--accent-electron);
}

.chem-ion {
  font-family: var(--font-mono);
  color: var(--accent-bond);
}