/* =====================================================
   SISTEMA DE DESIGN - VARIÁVEIS GLOBAIS
   ===================================================== */

:root {
  /* Cores Primárias */
  --color-primary: #2563eb;
  --color-primary-dark: #1e40af;
  --color-primary-light: #3b82f6;

  /* Cores de Estado */
  --color-success: #10b981;
  --color-error: #ef4444;
  --color-warning: #f59e0b;
  --color-info: #0ea5e9;

  /* Escala de Cinzas */
  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2937;
  --color-gray-900: #111827;

  /* Tipografia */
  --font-family-base: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;

  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;

  /* Espaçamento */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;

  /* Bordas */
  --radius-xs: 0.25rem;
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Sombras */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);

  /* Transições */
  --transition-fast: 150ms ease-in-out;
  --transition-base: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;

  /* Breakpoints (Mobile First) */
  --breakpoint-sm: 640px;
  --breakpoint-md: 768px;
  --breakpoint-lg: 1024px;
  --breakpoint-xl: 1280px;
}

/* =====================================================
   RESET E NORMALIZAÇÕES
   ===================================================== */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: 1.6;
  color: var(--color-gray-700);
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-dark) 100%);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md);
}

/* =====================================================
   COMPONENTES BASE
   ===================================================== */

/* Container Principal */
.box {
  background: white;
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-2xl);
  padding: var(--spacing-2xl);
  width: 100%;
  max-width: 420px;
  animation: slideUp var(--transition-slow);
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* =====================================================
   TIPOGRAFIA
   ===================================================== */

h1, h2, h3, h4, h5, h6 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
  color: var(--color-gray-900);
}

h2 {
  font-size: var(--font-size-2xl);
  text-align: center;
  margin-bottom: var(--spacing-xl);
  position: relative;
  padding-bottom: var(--spacing-lg);
}

h2::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--color-primary), transparent);
  border-radius: var(--radius-full);
}

/* =====================================================
   FORMULÁRIO
   ===================================================== */

form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

/* Input Base */
input[type="email"],
input[type="password"],
input[type="text"] {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-family: var(--font-family-base);
  border: 2px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  background: var(--color-gray-50);
  color: var(--color-gray-900);
  transition: all var(--transition-base);
  outline: none;
}

input[type="email"]:focus,
input[type="password"]:focus,
input[type="text"]:focus {
  background: white;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

input[type="email"]::placeholder,
input[type="password"]::placeholder,
input[type="text"]::placeholder {
  color: var(--color-gray-400);
}

/* Botão */
button[type="submit"] {
  padding: var(--spacing-md) var(--spacing-lg);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  border: none;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  cursor: pointer;
  transition: all var(--transition-base);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  box-shadow: var(--shadow-md);
  position: relative;
  overflow: hidden;
}

button[type="submit"]::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: rgba(255, 255, 255, 0.2);
  transition: left var(--transition-base);
}

button[type="submit"]:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

button[type="submit"]:hover::before {
  left: 100%;
}

button[type="submit"]:active {
  transform: translateY(0);
  box-shadow: var(--shadow-md);
}

button[type="submit"]:disabled {
  background: var(--color-gray-400);
  cursor: not-allowed;
  transform: none;
}

/* =====================================================
   MENSAGENS DE ERRO
   ===================================================== */

.erro {
  padding: var(--spacing-md) var(--spacing-lg);
  background: linear-gradient(135deg, rgba(239, 68, 68, 0.1), rgba(239, 68, 68, 0.05));
  border: 1px solid var(--color-error);
  border-left: 4px solid var(--color-error);
  border-radius: var(--radius-lg);
  color: var(--color-error);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-lg);
  animation: slideDown var(--transition-base);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.erro::before {
  content: '⚠️';
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

@keyframes slideDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* =====================================================
   SUCESSO (Para futuras mensagens de sucesso)
   ===================================================== */

.sucesso {
  padding: var(--spacing-md) var(--spacing-lg);
  background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(16, 185, 129, 0.05));
  border: 1px solid var(--color-success);
  border-left: 4px solid var(--color-success);
  border-radius: var(--radius-lg);
  color: var(--color-success);
  font-weight: var(--font-weight-medium);
  margin-bottom: var(--spacing-lg);
  animation: slideDown var(--transition-base);
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.sucesso::before {
  content: '✓';
  font-size: var(--font-size-lg);
  flex-shrink: 0;
}

/* =====================================================
   RESPONSIVIDADE - TABLET (768px+)
   ===================================================== */

@media (min-width: 768px) {
  :root {
    font-size: 18px;
  }

  .box {
    padding: var(--spacing-3xl);
    box-shadow: var(--shadow-2xl);
  }

  h2 {
    font-size: var(--font-size-3xl);
  }

  input[type="email"],
  input[type="password"],
  input[type="text"] {
    padding: var(--spacing-lg) var(--spacing-xl);
    font-size: var(--font-size-lg);
  }

  button[type="submit"] {
    padding: var(--spacing-lg) var(--spacing-xl);
    font-size: var(--font-size-lg);
  }
}

/* =====================================================
   RESPONSIVIDADE - DESKTOP (1024px+)
   ===================================================== */

@media (min-width: 1024px) {
  .box {
    max-width: 500px;
  }

  input[type="email"]:hover,
  input[type="password"]:hover,
  input[type="text"]:hover {
    border-color: var(--color-primary-light);
    background: var(--color-gray-50);
  }

  button[type="submit"] {
    letter-spacing: 1px;
  }
}

/* =====================================================
   MODO ESCURO (Opcional - Para navegadores que suportam)
   ===================================================== */

@media (prefers-color-scheme: dark) {
  body {
    background: linear-gradient(135deg, #1a237e 0%, #0d47a1 100%);
  }

  .box {
    background: var(--color-gray-900);
    box-shadow: var(--shadow-2xl);
  }

  h2 {
    color: white;
  }

  input[type="email"],
  input[type="password"],
  input[type="text"] {
    background: var(--color-gray-800);
    border-color: var(--color-gray-700);
    color: white;
  }

  input[type="email"]:focus,
  input[type="password"]:focus,
  input[type="text"]:focus {
    background: var(--color-gray-700);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
  }

  input[type="email"]::placeholder,
  input[type="password"]::placeholder,
  input[type="text"]::placeholder {
    color: var(--color-gray-500);
  }

  .erro {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.2), rgba(239, 68, 68, 0.1));
  }

  .sucesso {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.2), rgba(16, 185, 129, 0.1));
  }
}

/* =====================================================
   ACESSIBILIDADE
   ===================================================== */

/* Reduz movimento para usuários que preferem */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* Focus visível para teclado */
:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

/* =====================================================
   UTILITÁRIOS
   ===================================================== */

/* Esconder visualmente mas manter acessível */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Animação de carregamento (se precisar) */
@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.spinner {
  display: inline-block;
  width: 1em;
  height: 1em;
  border: 2px solid var(--color-primary);
  border-right-color: transparent;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}