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

:root {
  --primary-color: #4ec1b8;
  --primary-hover: #3aa89f;
  --error-color: #ef4444;
  --success-color: #10b981;
  --text-primary: #1a202c;
  --text-secondary: #4a5568;
  --bg-color: #f8f9fb;
  --card-bg: #ffffff;
  --border-color: #e5e7eb;
  --shadow: 0 1px 2px rgba(0,0,0,0.05);
  --shadow-lg: 0 4px 6px rgba(0,0,0,0.06);
}

.dark {
  --primary-color: #4ec1b8;
  --primary-hover: #7edcd5;
  --error-color: #f87171;
  --success-color: #34d399;
  --text-primary: #f3f4f6;
  --text-secondary: #d1d5db;
  --bg-color: #111827;
  --card-bg: #1f2937;
  --border-color: #374151;
  --shadow: 0 1px 2px rgba(0,0,0,0.15);
  --shadow-lg: 0 4px 6px rgba(0,0,0,0.2);
}

@media (prefers-color-scheme: dark) {
  :root:not(.light) {
    --primary-color: #4ec1b8;
    --primary-hover: #7edcd5;
    --error-color: #f87171;
    --success-color: #34d399;
    --text-primary: #f3f4f6;
    --text-secondary: #d1d5db;
    --bg-color: #111827;
    --card-bg: #1f2937;
    --border-color: #374151;
    --shadow: 0 1px 2px rgba(0,0,0,0.15);
    --shadow-lg: 0 4px 6px rgba(0,0,0,0.2);
  }
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.login-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  min-height: 100vh;
}

.login-card {
  background: var(--card-bg);
  border-radius: 0.75rem;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-lg);
  padding: 3rem;
  width: 100%;
  max-width: 400px;
}

.logo-container {
  text-align: center;
  margin-bottom: 2rem;
}

.logo {
  height: 40px;
  width: auto;
}

h1 {
  font-size: 1.75rem;
  font-weight: 600;
  text-align: center;
  margin-bottom: 0.5rem;
}

.subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

.alert {
  padding: 0.75rem 1rem;
  border-radius: 0.375rem;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.alert-error {
  background-color: #fef2f2;
  border: 1px solid #fecaca;
  color: #b91c1c;
}

.dark .alert-error {
  background-color: rgba(239, 68, 68, 0.15);
  border-color: rgba(239, 68, 68, 0.3);
  color: #fca5a5;
}

.alert-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.login-form {
  margin-bottom: 1.5rem;
}

.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
}

.form-input {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  background-color: var(--card-bg);
  color: var(--text-primary);
  transition: border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.form-input:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(78, 193, 184, 0.2);
}

.form-input::placeholder {
  color: var(--text-secondary);
  opacity: 0.6;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 500;
  border: none;
  border-radius: 0.375rem;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.15s ease-in-out;
  position: relative;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
  width: 100%;
}

.btn-primary:hover:not(:disabled) {
  background-color: var(--primary-hover);
}

.btn-secondary {
  background-color: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  width: 100%;
}

.btn-secondary:hover:not(:disabled) {
  background-color: var(--bg-color);
}

.btn:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

.loader {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-top: 2px solid var(--primary-color);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

.btn-primary .loader {
  border-color: rgba(255,255,255,0.3);
  border-top-color: white;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

.hidden {
  display: none !important;
}

.help-section {
  text-align: center;
  color: var(--text-secondary);
}

.help-section a {
  color: var(--primary-color);
  text-decoration: none;
}

.help-section a:hover {
  text-decoration: underline;
}

.footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Modal Styles */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal-content {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 0.75rem;
  padding: 2rem;
  max-width: 500px;
  width: 90%;
  max-height: 80vh;
  overflow-y: auto;
}

.modal-content h2 {
  margin-bottom: 1rem;
}

.modal-content p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

.practice-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.practice-item {
  padding: 1rem;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  cursor: pointer;
  transition: all 0.15s ease-in-out;
  background: var(--card-bg);
}

.practice-item:hover {
  border-color: var(--primary-color);
  box-shadow: var(--shadow);
}

.practice-name {
  font-weight: 500;
  margin-bottom: 0.25rem;
}

.practice-code {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

/* Error page styles */
.error-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 2rem;
}

.error-container h1 {
  font-size: 5rem;
  font-weight: 300;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.error-container p {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

/* Signup Styles */
.signup-card {
  max-width: 480px;
}

.signup-tabs {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 2rem;
  background-color: var(--bg-color);
  padding: 0.25rem;
  border-radius: 0.375rem;
}

.tab-button {
  flex: 1;
  padding: 0.75rem 1rem;
  background: transparent;
  border: none;
  border-radius: 0.25rem;
  cursor: pointer;
  font-weight: 500;
  color: var(--text-secondary);
  transition: all 0.15s ease-in-out;
}

.tab-button.active {
  background: var(--card-bg);
  color: var(--primary-color);
  box-shadow: var(--shadow);
}

.tab-button:hover:not(.active) {
  color: var(--text-primary);
}

.signup-form {
  margin-bottom: 1.5rem;
}

.form-help {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-top: 0.25rem;
}

.divider {
  position: relative;
  text-align: center;
  margin: 2rem 0;
}

.divider::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--border-color);
}

.divider span {
  position: relative;
  padding: 0 1rem;
  background: var(--card-bg);
  color: var(--text-secondary);
}

.btn-google {
  width: 100%;
  background: var(--card-bg);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  margin-bottom: 1.5rem;
}

.btn-google:hover {
  background: var(--bg-color);
  border-color: var(--text-secondary);
}

.google-icon {
  width: 20px;
  height: 20px;
}

.alert-success {
  background-color: #ecfdf5;
  border: 1px solid #a7f3d0;
  color: #065f46;
}

.dark .alert-success {
  background-color: rgba(16, 185, 129, 0.15);
  border-color: rgba(16, 185, 129, 0.3);
  color: #6ee7b7;
}

input[type="checkbox"] {
  margin-right: 0.5rem;
}

.form-group label {
  display: flex;
  align-items: flex-start;
  font-weight: normal;
  cursor: pointer;
}

.form-group label input[type="checkbox"] {
  margin-top: 0.25rem;
}

.btn-text {
  display: inline-block;
}

/* Passkey button */
.btn-passkey {
  width: 100%;
  background: var(--text-primary);
  color: var(--card-bg);
  margin-bottom: 1rem;
}

.btn-passkey:hover {
  opacity: 0.9;
}

.passkey-icon {
  width: 20px;
  height: 20px;
  fill: currentColor;
}

/* Theme toggle button */
.theme-toggle {
  position: fixed;
  bottom: 1.5rem;
  right: 1.5rem;
  width: 40px;
  height: 40px;
  border-radius: 0.5rem;
  border: 1px solid var(--border-color);
  background: var(--card-bg);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  box-shadow: var(--shadow);
}

.theme-toggle:hover {
  background: var(--bg-color);
  color: var(--text-primary);
}

/* Show sun in dark mode, moon in light mode */
.theme-icon-sun { display: none; }
.theme-icon-moon { display: block; }

.dark .theme-icon-sun { display: block; }
.dark .theme-icon-moon { display: none; }

/* Dark/light logo switching */
.logo-dark { display: none; }
.logo-light { display: inline; }

.dark .logo-dark { display: inline; }
.dark .logo-light { display: none; }

/* MFA Section Styles */
.mfa-section {
  padding: 1.5rem 0;
  border-top: 1px solid var(--border-color);
}

.mfa-section:first-child {
  border-top: none;
}

.mfa-section h2 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.mfa-section h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.mfa-section code {
  display: inline-block;
  padding: 0.125rem 0.375rem;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: 0.25rem;
  font-size: 0.875rem;
  word-break: break-all;
}

/* Responsive */
@media (max-width: 640px) {
  .login-card {
    padding: 1.5rem;
    max-width: 100%;
    border-radius: 0;
    border-left: none;
    border-right: none;
  }

  h1 {
    font-size: 1.5rem;
  }

  .signup-tabs {
    flex-direction: column;
  }

  .login-container {
    padding: 0;
    justify-content: flex-start;
    padding-top: 2rem;
  }
}

@media (min-width: 641px) and (max-width: 768px) {
  .login-card {
    max-width: 440px;
  }
}

@media (min-width: 1024px) {
  .login-card {
    max-width: 440px;
  }
}