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

:root {
  /* Corporate Colors */
  --primary: #6366f1;
  --primary-dark: #4f46e5;
  --primary-light: #818cf8;
  --secondary: #8b5cf6;
  --accent: #06b6d4;
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;

  /* Light Theme */
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-tertiary: #94a3b8;
  --border: #e2e8f0;
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(255, 255, 255, 0.3);
  --shadow: rgba(0, 0, 0, 0.1);

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

  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
}

[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-tertiary: #64748b;
  --border: #334155;
  --glass-bg: rgba(30, 41, 59, 0.7);
  --glass-border: rgba(255, 255, 255, 0.1);
  --shadow: rgba(0, 0, 0, 0.3);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-lg);
  transition: background 0.3s ease;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  position: relative;
  overflow-x: hidden;
}

body::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: url("https://images.unsplash.com/photo-1557683316-973673baf926?w=1920&q=80") center / cover;
  opacity: 0.1;
  z-index: 0;
}

.auth-container {
  width: 100%;
  max-width: 440px;
  position: relative;
  z-index: 1;
  animation: fadeInUp 0.6s ease;
}

@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.theme-toggle {
  position: absolute;
  top: -60px;
  right: 0;
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px var(--shadow);
}

.theme-toggle:hover {
  background: var(--primary);
  color: white;
  transform: scale(1.1) rotate(15deg);
}

.auth-card {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: 0 20px 60px var(--shadow);
}

.auth-header {
  text-align: center;
  margin-bottom: var(--spacing-xl);
}

.logo {
  width: 72px;
  height: 72px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto var(--spacing-lg);
  font-size: 2rem;
  color: white;
  box-shadow: 0 8px 24px rgba(99, 102, 241, 0.3);
  animation: logoFloat 3s ease-in-out infinite;
}

@keyframes logoFloat {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

.auth-header h1 {
  font-size: 1.875rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--spacing-xs);
}

.auth-header p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

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

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.form-group label {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.form-group label i {
  color: var(--primary);
  font-size: 1rem;
}

.form-group input,
.form-group select {
  background: var(--bg-secondary);
  border: 2px solid var(--border);
  border-radius: var(--radius-md);
  padding: 0.875rem var(--spacing-md);
  color: var(--text-primary);
  font-size: 0.9375rem;
  outline: none;
  transition: all 0.3s ease;
  font-family: inherit;
}

.form-group input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.form-group input::placeholder {
  color: var(--text-tertiary);
}

.password-input {
  position: relative;
  display: flex;
  align-items: center;
}

.password-input input {
  flex: 1;
  padding-right: 3rem;
}

.toggle-password {
  position: absolute;
  right: 0;
  background: none;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  padding: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.toggle-password:hover {
  color: var(--primary);
}

.password-strength {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
  margin-top: var(--spacing-xs);
}

.strength-bar {
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  overflow: hidden;
}

.strength-fill {
  height: 100%;
  width: 0%;
  background: var(--error);
  transition: all 0.3s ease;
}

.strength-fill.weak {
  width: 33%;
  background: var(--error);
}

.strength-fill.medium {
  width: 66%;
  background: var(--warning);
}

.strength-fill.strong {
  width: 100%;
  background: var(--success);
}

.strength-text {
  font-size: 0.75rem;
  color: var(--text-tertiary);
}

.form-options {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-md);
  flex-wrap: wrap;
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  cursor: pointer;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.checkbox-label input[type="checkbox"] {
  width: 18px;
  height: 18px;
  cursor: pointer;
  accent-color: var(--primary);
}

.checkbox-label a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
}

.checkbox-label a:hover {
  text-decoration: underline;
}

.forgot-link {
  font-size: 0.875rem;
  color: var(--primary);
  text-decoration: none;
  font-weight: 500;
  transition: all 0.2s ease;
}

.forgot-link:hover {
  color: var(--primary-dark);
  text-decoration: underline;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 100%);
  color: white;
  border: none;
  padding: 1rem var(--spacing-lg);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(99, 102, 241, 0.4);
}

.btn-primary:active {
  transform: translateY(0);
}

.divider {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  margin: var(--spacing-md) 0;
}

.divider::before,
.divider::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
}

.divider span {
  font-size: 0.875rem;
  color: var(--text-tertiary);
  white-space: nowrap;
}

.social-login {
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
}

.social-btn {
  background: var(--bg-secondary);
  border: 2px solid var(--border);
  color: var(--text-primary);
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  transition: all 0.3s ease;
}

.social-btn:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--shadow);
}

.auth-footer {
  text-align: center;
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border);
}

.auth-footer p {
  font-size: 0.9375rem;
  color: var(--text-secondary);
}

.auth-footer a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
  transition: all 0.2s ease;
}

.auth-footer a:hover {
  color: var(--primary-dark);
  text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 480px) {
  body {
    padding: var(--spacing-md);
  }

  .auth-card {
    padding: var(--spacing-lg);
  }

  .auth-header h1 {
    font-size: 1.5rem;
  }

  .logo {
    width: 64px;
    height: 64px;
    font-size: 1.75rem;
  }

  .form-options {
    flex-direction: column;
    align-items: flex-start;
  }

  .social-login {
    gap: var(--spacing-sm);
  }

  .social-btn {
    flex: 1;
    width: auto;
  }
}

/* Loading State */
.btn-primary.loading {
  pointer-events: none;
  opacity: 0.7;
}

.btn-primary.loading span {
  opacity: 0;
}

.btn-primary.loading::after {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  border: 2px solid white;
  border-top-color: transparent;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}

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

/* Error State */
.form-group.error input {
  border-color: var(--error);
}

.form-group.error .error-message {
  display: block;
}

.error-message {
  display: none;
  font-size: 0.8125rem;
  color: var(--error);
  margin-top: var(--spacing-xs);
}

/* Success State */
.form-group.success input {
  border-color: var(--success);
}