/* UI Design System - Aesthetic Focus */
:root {
  /* Brand Colors */
  --brand-primary: #6366f1;
  --brand-primary-light: #a5b4fc;
  --brand-primary-dark: #4338ca;
  --brand-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --brand-gradient-alt: linear-gradient(135deg, #ffecd2 0%, #fcb69f 100%);

  /* Visual Palette */
  --color-white: #ffffff;
  --color-black: #000000;
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;

  --color-success: #10b981;
  --color-success-light: #a7f3d0;
  --color-error: #ef4444;
  --color-error-light: #fecaca;
  --color-warning: #f59e0b;
  --color-info: #3b82f6;

  /* Typography Scale */
  --font-display: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'SF Mono', Monaco, monospace;

  /* Visual Hierarchy */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;

  /* Visual Spacing */
  --space-px: 1px;
  --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;

  /* Visual Effects */
  --radius-none: 0;
  --radius-sm: 0.375rem;
  --radius-base: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;

  /* Shadows & Depth */
  --shadow-soft: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
  --shadow-medium: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-large: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-extra-large: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);

  /* Visual Animations */
  --ease-in: cubic-bezier(0.4, 0, 1, 1);
  --ease-out: cubic-bezier(0, 0, 0.2, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
  --ease-spring: cubic-bezier(0.68, -0.55, 0.265, 1.55);

  --duration-fast: 150ms;
  --duration-normal: 200ms;
  --duration-slow: 300ms;
  --duration-slower: 500ms;
}

/* Global Reset & Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-gray-800);
  background: var(--brand-gradient);
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
}

/* Animated Background */
body::before {
  content: '';
  position: fixed;
  top: -50%;
  left: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(circle, rgba(255,255,255,0.1) 1px, transparent 1px);
  background-size: 50px 50px;
  animation: backgroundMove 20s linear infinite;
  z-index: -1;
}

@keyframes backgroundMove {
  0% { transform: translate(0, 0); }
  100% { transform: translate(50px, 50px); }
}

/* Header - Premium Look */
header {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid rgba(255, 255, 255, 0.2);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  transition: all var(--duration-normal) var(--ease-out);
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--space-4) var(--space-6);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  text-decoration: none;
  font-family: var(--font-display);
  font-size: var(--text-2xl);
  font-weight: 800;
  color: var(--brand-primary);
  transition: all var(--duration-normal) var(--ease-spring);
  position: relative;
}

.logo::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--brand-gradient);
  transition: width var(--duration-normal) var(--ease-out);
}

.logo:hover::after {
  width: 100%;
}

.logo:hover {
  transform: translateY(-1px);
}

.logo-image {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-full);
  object-fit: cover;
  border: 2px solid transparent;
  background: var(--brand-gradient);
  padding: 2px;
  transition: all var(--duration-normal) var(--ease-spring);
}

.logo:hover .logo-image {
  transform: rotate(5deg) scale(1.05);
  box-shadow: var(--shadow-glow);
}

/* Main Content - Visual Focus */
.main-content {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: calc(80px + var(--space-16)) var(--space-6) var(--space-16);
  position: relative;
}

.signup-container {
  background: var(--color-white);
  border-radius: var(--radius-2xl);
  box-shadow: var(--shadow-extra-large);
  width: 100%;
  max-width: 480px;
  padding: var(--space-10);
  position: relative;
  border: 1px solid rgba(255, 255, 255, 0.2);
  animation: slideUp 0.6s var(--ease-out);
}

.signup-container::before {
  content: '';
  position: absolute;
  top: -1px;
  left: -1px;
  right: -1px;
  height: 3px;
  background: var(--brand-gradient);
  border-radius: var(--radius-2xl) var(--radius-2xl) 0 0;
}

@keyframes slideUp {
  0% {
    opacity: 0;
    transform: translateY(40px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Header Section - Visual Impact */
.signup-header {
  text-align: center;
  margin-bottom: var(--space-10);
}

.signup-header h1 {
  font-family: var(--font-display);
  font-size: var(--text-4xl);
  font-weight: 900;
  color: var(--color-gray-900);
  margin-bottom: var(--space-3);
  letter-spacing: -0.025em;
  background: var(--brand-gradient);
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  animation: fadeInDown 0.6s var(--ease-out) 0.2s both;
}

.signup-header p {
  color: var(--color-gray-700);
  font-size: var(--text-lg);
  font-weight: 400;
  animation: fadeInDown 0.6s var(--ease-out) 0.4s both;
}

@keyframes fadeInDown {
  0% {
    opacity: 0;
    transform: translateY(-20px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Form Elements - Premium Styling */
.form-group {
  margin-bottom: var(--space-6);
  animation: fadeInUp 0.5s var(--ease-out) both;
}

.form-group:nth-child(1) { animation-delay: 0.1s; }
.form-group:nth-child(2) { animation-delay: 0.15s; }
.form-group:nth-child(3) { animation-delay: 0.2s; }
.form-group:nth-child(4) { animation-delay: 0.25s; }
.form-group:nth-child(5) { animation-delay: 0.3s; }

@keyframes fadeInUp {
  0% {
    opacity: 0;
    transform: translateY(20px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}

.form-row .form-group {
  margin-bottom: 0;
}

label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-gray-800);
  margin-bottom: var(--space-2);
  letter-spacing: 0.025em;
}

/* Premium Input Styling */
input[type="text"],
input[type="email"],
input[type="tel"],
input[type="password"],
select {
  width: 100%;
  padding: var(--space-4);
  border: 2px solid var(--color-gray-200);
  border-radius: var(--radius-lg);
  font-size: var(--text-base);
  font-family: inherit;
  background: var(--color-white);
  color: var(--color-gray-900);
  transition: all var(--duration-normal) var(--ease-out);
  position: relative;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="tel"]:focus,
input[type="password"]:focus,
select:focus {
  outline: none;
  border-color: var(--brand-primary);
  box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
  transform: translateY(-2px);
}

input::placeholder {
  color: var(--color-gray-300);
  font-weight: 400;
}

/* Validation States - Visual Feedback */
input.valid,
select.valid {
  border-color: var(--color-success);
  background: linear-gradient(135deg, var(--color-white), #f0fdf4);
}

input.invalid,
select.invalid {
  border-color: var(--color-error);
  background: linear-gradient(135deg, var(--color-white), #fef2f2);
  animation: shake 0.4s var(--ease-in-out);
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}

.validation-message {
  font-size: var(--text-sm);
  font-weight: 600;
  margin-top: var(--space-2);
  display: flex;
  align-items: center;
  gap: var(--space-2);
  transition: all var(--duration-fast) var(--ease-out);
}

.validation-message.success {
  color: var(--color-success);
}

.validation-message.success::before {
  content: '✓';
  display: flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  background: var(--color-success);
  color: white;
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 700;
}

.validation-message.error {
  color: var(--color-error);
}

.validation-message.error::before {
  content: '!';
  display: flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  background: var(--color-error);
  color: white;
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 700;
}

/* Select Styling - Custom Design */
select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='1.5' d='m6 8 4 4 4-4'/%3e%3c/svg%3e");
  background-position: right var(--space-3) center;
  background-repeat: no-repeat;
  background-size: 1.25rem 1.25rem;
  padding-right: var(--space-12);
  cursor: pointer;
}

/* Checkbox Groups - Premium Design */
.checkbox-group {
  display: flex;
  align-items: flex-start;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
  padding: var(--space-5);
  background: linear-gradient(135deg, var(--color-gray-50), var(--color-white));
  border: 2px solid var(--color-gray-100);
  border-radius: var(--radius-xl);
  transition: all var(--duration-normal) var(--ease-out);
  position: relative;
  overflow: hidden;
}

.checkbox-group::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(99, 102, 241, 0.05), transparent);
  transition: left var(--duration-slower);
}

.checkbox-group:hover::before {
  left: 100%;
}

.checkbox-group:hover {
  border-color: var(--brand-primary);
  box-shadow: 0 0 0 1px var(--brand-primary);
}

.checkbox-group input[type="checkbox"] {
  width: 20px;
  height: 20px;
  margin-top: 2px;
  accent-color: var(--brand-primary);
  cursor: pointer;
}

.checkbox-group label {
  margin: 0;
  font-size: var(--text-sm);
  font-weight: 400;
  color: var(--color-gray-700);
  line-height: 1.5;
  cursor: pointer;
}

.checkbox-group a {
  color: var(--brand-primary);
  text-decoration: none;
  font-weight: 600;
  border-bottom: 1px solid transparent;
  transition: all var(--duration-fast) var(--ease-out);
}

.checkbox-group a:hover {
  border-bottom-color: var(--brand-primary);
  color: var(--brand-primary-dark);
}

/* Button - Hero Element */
.btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-5) var(--space-8);
  border: none;
  border-radius: var(--radius-xl);
  font-size: var(--text-lg);
  font-weight: 700;
  font-family: inherit;
  cursor: pointer;
  transition: all var(--duration-normal) var(--ease-spring);
  position: relative;
  overflow: hidden;
  margin: var(--space-8) 0 var(--space-6);
}

.btn-primary {
  background: var(--brand-gradient);
  color: var(--color-white);
  box-shadow: var(--shadow-large);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.btn-primary::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
  transition: left var(--duration-slower);
}

.btn-primary:hover::before {
  left: 100%;
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-3px);
  box-shadow: var(--shadow-extra-large);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(-1px);
  transition-duration: var(--duration-fast);
}

.btn-primary:disabled {
  background: var(--color-gray-300);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* Loading Spinner - Elegant Animation */
.loading-spinner {
  display: none;
  width: 20px;
  height: 20px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top: 2px solid white;
  border-radius: var(--radius-full);
  animation: spin 1s linear infinite;
}

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

/* Messages - Visual Priority */
.error-message,
.success-message {
  padding: var(--space-4) var(--space-5);
  border-radius: var(--radius-lg);
  margin-bottom: var(--space-6);
  font-size: var(--text-sm);
  font-weight: 600;
  display: none;
  border-left: 4px solid;
  position: relative;
  overflow: hidden;
}

.error-message {
  background: linear-gradient(135deg, var(--color-error-light), #fef2f2);
  color: var(--color-error);
  border-color: var(--color-error);
}

/* Styles pour les liens dans les messages d'erreur - Responsive */
.error-message a {
  color: #1a73e8;
  text-decoration: none !important;
  font-weight: 700;
  padding: 6px 12px;
  margin: 0 2px;
  border-radius: 6px;
  background: rgba(26, 115, 232, 0.1);
  transition: all 0.2s ease;
  display: inline-block;
  border: 1px solid rgba(26, 115, 232, 0.2);
}

.error-message a:hover,
.error-message a:focus {
  background: rgba(26, 115, 232, 0.15);
  text-decoration: none !important;
  transform: translateY(-1px);
  box-shadow: 0 2px 4px rgba(26, 115, 232, 0.2);
}

.error-message a:active {
  transform: translateY(0);
  box-shadow: 0 1px 2px rgba(26, 115, 232, 0.2);
}

/* Responsive mobile - liens empilés */
@media (max-width: 480px) {
  .error-message a {
    display: block;
    margin: 4px 0;
    text-align: center;
    width: 100%;
    padding: 10px 16px;
    font-size: 14px;
  }

  .error-message {
    text-align: center;
    padding: var(--space-4);
  }
}

.success-message {
  background: linear-gradient(135deg, var(--color-success-light), #f0fdf4);
  color: var(--color-success);
  border-color: var(--color-success);
}

/* Login Link - Subtle Elegance */
.login-link {
  text-align: center;
  margin-top: var(--space-8);
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-gray-200);
  position: relative;
}

.login-link::before {
  content: '';
  position: absolute;
  top: -1px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 2px;
  background: var(--brand-gradient);
  border-radius: var(--radius-full);
}

.login-link p {
  font-size: var(--text-sm);
  color: var(--color-gray-700);
}

.login-link a {
  color: var(--brand-primary);
  text-decoration: none;
  font-weight: 600;
  position: relative;
  transition: color var(--duration-fast) var(--ease-out);
}

.login-link a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--brand-gradient);
  transition: width var(--duration-normal) var(--ease-out);
}

.login-link a:hover::after {
  width: 100%;
}

/* Footer - Clean Finish */
footer {
  background: linear-gradient(135deg, var(--color-gray-800), var(--color-gray-900));
  color: var(--color-gray-300);
  text-align: center;
  padding: var(--space-8);
  border-top: 1px solid var(--color-gray-700);
}

.footer-container p {
  font-size: var(--text-sm);
  opacity: 0.8;
}

/* Responsive Design */
@media (max-width: 768px) {
  .main-content {
    padding: calc(80px + var(--space-8)) var(--space-4) var(--space-8);
  }

  .signup-container {
    padding: var(--space-8);
    margin: 0 var(--space-2);
  }

  .signup-header h1 {
    font-size: var(--text-3xl);
  }

  .signup-header p {
    font-size: var(--text-base);
  }

  .form-row {
    grid-template-columns: 1fr;
    gap: 0;
  }

  .form-row .form-group {
    margin-bottom: var(--space-6);
  }

  .btn {
    padding: var(--space-4) var(--space-6);
    font-size: var(--text-base);
  }
}

@media (max-width: 480px) {
  .signup-container {
    padding: var(--space-6);
  }

  input[type="text"],
  input[type="email"],
  input[type="tel"],
  input[type="password"],
  select {
    font-size: 16px; /* Prevent zoom on iOS */
  }
}

.close-btn {
  position: fixed;
  top: 20px;
  right: 20px;
  width: 45px;
  height: 45px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  color: var(--brand-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 20px;
  font-weight: bold;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
  z-index: 1001;
}

.close-btn:hover {
  background: #dc3545;
  color: white;
  border-color: #dc3545;
  transform: scale(1.1) rotate(90deg);
}

.password-input-wrapper {
  position: relative;
}

.password-input-wrapper input[type="password"],
.password-input-wrapper input[type="text"] {
  padding-right: 48px;
}

.toggle-password-btn {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-gray-300, #9ca3af);
  transition: color 0.2s;
  border-radius: 4px;
}

.toggle-password-btn:hover {
  color: var(--color-gray-600, #4b5563);
}

.toggle-password-btn svg {
  width: 18px;
  height: 18px;
  display: block;
  pointer-events: none;
}