/* ==========================================================================
   Global Variables & Reset
   ========================================================================== */
:root {
  --primary-color: #6366f1;
  --primary-hover: #4f46e5;
  --primary-gradient: linear-gradient(135deg, #6366f1 0%, #a855f7 100%);
  --secondary-gradient: linear-gradient(135deg, #a855f7 0%, #ec4899 100%);
  
  --bg-gradient: linear-gradient(135deg, #0f172a 0%, #1e1b4b 50%, #0f172a 100%);
  --card-bg: rgba(255, 255, 255, 0.96);
  --text-main: #0f172a;
  --text-muted: #64748b;
  --border-color: #e2e8f0;
  --input-bg: #f8fafc;
  --input-focus-border: #6366f1;
  --error-color: #ef4444;
  --success-color: #22c55e;
  
  --shadow-lg: 0 20px 40px -15px rgba(0, 0, 0, 0.3);
  --shadow-input: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  
  --transition-speed: 0.6s;
  --transition-ease: cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-gradient);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 20px;
  overflow-x: hidden;
  color: var(--text-main);
  position: relative;
}

/* Background Decorative Elements */
.background-decor {
  position: absolute;
  width: 100%;
  height: 100%;
  overflow: hidden;
  z-index: 0;
  pointer-events: none;
}

.circle {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.4;
}

.circle-1 {
  width: 400px;
  height: 400px;
  background: #6366f1;
  top: -100px;
  left: -100px;
}

.circle-2 {
  width: 450px;
  height: 450px;
  background: #a855f7;
  bottom: -150px;
  right: -100px;
}

/* ==========================================================================
   Main Container
   ========================================================================== */
.container {
  background-color: var(--card-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  position: relative;
  overflow: hidden;
  width: 920px;
  max-width: 100%;
  min-height: 680px;
  z-index: 1;
  backdrop-filter: blur(10px);
  border: 1px solid rgba(255, 255, 255, 0.1);
  display: flex;
}

/* Custom Scrollbar for form containers */
.form-container::-webkit-scrollbar {
  width: 5px;
}
.form-container::-webkit-scrollbar-track {
  background: transparent;
}
.form-container::-webkit-scrollbar-thumb {
  background: #cbd5e1;
  border-radius: 10px;
}
.form-container::-webkit-scrollbar-thumb:hover {
  background: #94a3b8;
}

/* ==========================================================================
   Form Components
   ========================================================================== */
.form-container {
  position: absolute;
  top: 0;
  height: 100%;
  transition: all var(--transition-speed) ease-in-out;
  padding: 32px 40px;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: #cbd5e1 transparent;
}

.sign-in-container {
  left: 0;
  width: 50%;
  z-index: 2;
  pointer-events: auto;
}

.sign-up-container {
  left: 0;
  width: 50%;
  opacity: 0;
  z-index: 1;
  pointer-events: none;
}

/* Active Sliding State */
.container.right-panel-active .sign-in-container {
  transform: translateX(100%);
  opacity: 0;
  pointer-events: none;
}

.container.right-panel-active .sign-up-container {
  transform: translateX(100%);
  opacity: 1;
  z-index: 5;
  pointer-events: auto;
  animation: show var(--transition-speed);
}

@keyframes show {
  0%, 49.99% {
    opacity: 0;
    z-index: 1;
  }
  50%, 100% {
    opacity: 1;
    z-index: 5;
  }
}

form {
  display: flex;
  flex-direction: column;
  min-height: 100%;
  justify-content: center;
  margin: auto 0;
}

.form-header {
  margin-bottom: 16px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--primary-color);
  font-weight: 700;
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.form-header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-main);
  margin-bottom: 4px;
  letter-spacing: -0.02em;
}

.form-header p {
  color: var(--text-muted);
  font-size: 0.8125rem;
}

/* Social Buttons */
.social-container {
  display: flex;
  gap: 10px;
  margin-bottom: 14px;
}

.social-btn {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 14px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: #ffffff;
  color: var(--text-main);
  font-size: 0.8125rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

.social-btn:hover {
  background-color: var(--input-bg);
  border-color: #cbd5e1;
  transform: translateY(-1px);
}

/* Divider */
.divider {
  display: flex;
  align-items: center;
  margin-bottom: 14px;
  color: var(--text-muted);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

.divider span {
  padding: 0 10px;
}

/* Input Fields */
.input-group {
  margin-bottom: 12px;
  display: flex;
  flex-direction: column;
}

.input-group label {
  font-size: 0.78125rem;
  font-weight: 600;
  color: var(--text-main);
  margin-bottom: 4px;
}

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

.input-icon {
  position: absolute;
  left: 12px;
  color: var(--text-muted);
  pointer-events: none;
  transition: color 0.2s ease;
}

.input-wrapper input {
  width: 100%;
  padding: 10px 12px 10px 40px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--input-bg);
  font-size: 0.84375rem;
  font-family: inherit;
  color: var(--text-main);
  transition: all 0.2s ease;
  outline: none;
}

.input-wrapper input:focus {
  border-color: var(--input-focus-border);
  background-color: #ffffff;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.15);
}

.input-wrapper input:focus + .input-icon,
.input-wrapper input:focus ~ .input-icon {
  color: var(--primary-color);
}

.toggle-password {
  position: absolute;
  right: 10px;
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 4px;
  border-radius: 4px;
  transition: color 0.2s ease;
}

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

.hidden {
  display: none !important;
}

/* Error Messages */
.error-msg {
  font-size: 0.72rem;
  color: var(--error-color);
  margin-top: 2px;
  min-height: 14px;
  display: block;
}

.input-group.invalid input {
  border-color: var(--error-color);
  background-color: #fef2f2;
}

.input-group.invalid input:focus {
  box-shadow: 0 0 0 3px rgba(239, 68, 68, 0.15);
}

/* Options Row (Checkbox & Forgot Link) */
.options-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 14px;
}

.terms-row {
  flex-direction: column;
  align-items: flex-start;
}

/* Custom Checkbox */
.checkbox-container {
  display: flex;
  align-items: center;
  position: relative;
  padding-left: 24px;
  cursor: pointer;
  font-size: 0.78125rem;
  user-select: none;
  color: var(--text-muted);
}

.checkbox-container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

.checkmark {
  position: absolute;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  height: 16px;
  width: 16px;
  background-color: var(--input-bg);
  border: 1px solid var(--border-color);
  border-radius: 4px;
  transition: all 0.2s ease;
}

.checkbox-container:hover input ~ .checkmark {
  border-color: var(--primary-color);
}

.checkbox-container input:checked ~ .checkmark {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
}

.checkmark::after {
  content: "";
  position: absolute;
  display: none;
  left: 5px;
  top: 1.5px;
  width: 4px;
  height: 8px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.checkbox-container input:checked ~ .checkmark::after {
  display: block;
}

/* Links & Buttons */
.link {
  color: var(--primary-color);
  text-decoration: none;
  font-size: 0.78125rem;
  font-weight: 500;
  transition: color 0.2s ease;
}

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

.link-btn {
  background: none;
  border: none;
  color: var(--primary-color);
  font-weight: 600;
  cursor: pointer;
  font-size: inherit;
  padding: 0;
}

.link-btn:hover {
  text-decoration: underline;
}

.btn {
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  padding: 10px 20px;
  font-size: 0.84375rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: all 0.2s ease;
  width: 100%;
}

.btn-primary {
  background: var(--primary-gradient);
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
  margin-top: 4px;
}

.btn-primary:hover {
  opacity: 0.95;
  transform: translateY(-1px);
  box-shadow: 0 6px 16px rgba(99, 102, 241, 0.4);
}

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

.btn-outline {
  background-color: transparent;
  border-color: #ffffff;
  color: #ffffff;
  width: auto;
  min-width: 130px;
}

.btn-outline:hover {
  background-color: #ffffff;
  color: var(--primary-color);
}

.mobile-switch-text {
  display: none;
  text-align: center;
  margin-top: 14px;
  font-size: 0.8125rem;
  color: var(--text-muted);
}

/* ==========================================================================
   Overlay Container (Sliding Banner for Desktop)
   ========================================================================== */
.overlay-container {
  position: absolute;
  top: 0;
  left: 50%;
  width: 50%;
  height: 100%;
  overflow: hidden;
  transition: transform var(--transition-speed) ease-in-out;
  z-index: 100;
}

.container.right-panel-active .overlay-container {
  transform: translateX(-100%);
}

.overlay {
  background: var(--primary-gradient);
  color: #ffffff;
  position: relative;
  left: -100%;
  height: 100%;
  width: 200%;
  transform: translateX(0);
  transition: transform var(--transition-speed) ease-in-out;
}

.container.right-panel-active .overlay {
  transform: translateX(50%);
}

.overlay-panel {
  position: absolute;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  padding: 0 40px;
  text-align: center;
  top: 0;
  height: 100%;
  width: 50%;
  transform: translateX(0);
  transition: transform var(--transition-speed) ease-in-out;
}

.overlay-left {
  transform: translateX(-20%);
}

.container.right-panel-active .overlay-left {
  transform: translateX(0);
}

.overlay-right {
  right: 0;
  transform: translateX(0);
}

.container.right-panel-active .overlay-right {
  transform: translateX(20%);
}

.overlay-panel h2 {
  font-size: 1.85rem;
  font-weight: 700;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.overlay-panel p {
  font-size: 0.875rem;
  line-height: 1.6;
  margin-bottom: 24px;
  opacity: 0.9;
  max-width: 300px;
}

/* ==========================================================================
   Responsive Design
   ========================================================================== */
@media (max-width: 840px) {
  body {
    padding: 12px;
    align-items: flex-start;
  }

  .container {
    width: 100%;
    max-width: 480px;
    min-height: auto;
    border-radius: var(--radius-md);
    display: block;
    overflow: visible;
  }

  .overlay-container {
    display: none;
  }

  .form-container {
    position: relative;
    width: 100%;
    height: auto;
    max-height: none;
    padding: 28px 20px;
    overflow-y: visible;
  }

  .sign-in-container {
    display: block;
    width: 100%;
    opacity: 1;
    pointer-events: auto;
    transform: none;
  }

  .sign-up-container {
    display: none;
    width: 100%;
    opacity: 1;
    pointer-events: auto;
    transform: none;
  }

  .container.right-panel-active .sign-in-container {
    display: none;
    transform: none;
  }

  .container.right-panel-active .sign-up-container {
    display: block;
    transform: none;
    opacity: 1;
    animation: fadeIn 0.3s ease-in-out;
  }

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

  .mobile-switch-text {
    display: block;
  }
}