:root {
  /* Colors */
  --bg-primary: #0a0a0f;
  --bg-secondary: #13131a;
  --bg-tertiary: #1a1a24;
  --bg-elevated: #20202e;
  
  --text-primary: #ffffff;
  --text-secondary: #a0a0b8;
  --text-tertiary: #6b6b85;
  
  --accent-primary: #6366f1;
  --accent-secondary: #8b5cf6;
  --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
  
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  
  --border-color: rgba(255, 255, 255, 0.1);
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 0.75rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  
  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  
  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.4);
  --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

body {
  font-family: var(--font-family);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
}

/* App Container */
.app-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--spacing-lg);
}

/* Header */
.app-header {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-lg) var(--spacing-xl);
  margin-bottom: var(--spacing-xl);
  box-shadow: var(--shadow-md);
}

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

.logo {
  font-size: 1.75rem;
  font-weight: 700;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.logo-icon {
  font-size: 2rem;
  filter: drop-shadow(0 0 10px rgba(99, 102, 241, 0.5));
}

.header-stats {
  display: flex;
  gap: var(--spacing-xl);
}

.stat {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-primary);
}

/* Main Content */
.main-content {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-md);
  min-height: 600px;
}

/* Tabs */
.tabs {
  display: flex;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: var(--spacing-md);
}

.tab {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1rem;
  font-weight: 500;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all 0.3s ease;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  position: relative;
}

.tab:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.tab.active {
  background: var(--accent-gradient);
  color: white;
  box-shadow: var(--shadow-glow);
}

.tab-icon {
  font-size: 1.25rem;
}

.badge {
  background: rgba(255, 255, 255, 0.2);
  padding: 0.125rem 0.5rem;
  border-radius: 1rem;
  font-size: 0.75rem;
  font-weight: 600;
}

/* Views */
.view {
  display: none;
  animation: fadeIn 0.3s ease;
}

.view.active {
  display: block;
}

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

.view-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: var(--spacing-sm);
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.view-description {
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xl);
}

/* Compose Form */
.compose-container {
  max-width: 800px;
}

.compose-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-weight: 600;
  color: var(--text-primary);
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.form-group textarea,
.form-group input {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: 1rem;
  transition: all 0.3s ease;
  resize: vertical;
}

.form-group textarea:focus,
.form-group input:focus {
  outline: none;
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.input-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.875rem;
}

.char-count {
  color: var(--text-tertiary);
}

.encoding-status {
  font-weight: 500;
}

.encoding-status.success {
  color: var(--success);
}

.encoding-status.warning {
  color: var(--warning);
}

.encoding-status.error {
  color: var(--error);
}

/* Buttons */
.btn {
  background: var(--accent-gradient);
  color: white;
  border: none;
  padding: var(--spacing-md) var(--spacing-xl);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s ease;
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
  box-shadow: var(--shadow-sm);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

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

.btn-secondary {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background: var(--bg-tertiary);
  box-shadow: var(--shadow-sm);
}

.btn-icon {
  font-size: 1.25rem;
}

/* Messages */
.messages-container {
  max-width: 900px;
}

.view-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-xl);
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.messages-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.message-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  cursor: pointer;
  transition: all 0.3s ease;
}

.message-card:hover {
  background: var(--bg-tertiary);
  border-color: var(--accent-primary);
  transform: translateX(4px);
}

.message-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-sm);
}

.message-sender {
  font-weight: 600;
  color: var(--text-primary);
}

.message-date {
  font-size: 0.875rem;
  color: var(--text-tertiary);
}

.message-preview {
  color: var(--text-secondary);
  font-size: 0.875rem;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.empty-state {
  text-align: center;
  padding: var(--spacing-2xl);
  color: var(--text-tertiary);
}

.empty-icon {
  font-size: 4rem;
  display: block;
  margin-bottom: var(--spacing-md);
  opacity: 0.5;
}

.empty-hint {
  font-size: 0.875rem;
  margin-top: var(--spacing-sm);
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(10px);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  animation: fadeIn 0.3s ease;
}

.modal.active {
  display: flex;
}

.modal-content {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-xl);
  max-width: 600px;
  width: 90%;
  max-height: 80vh;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  animation: slideUp 0.3s ease;
}

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

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-lg) var(--spacing-xl);
  border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
  font-size: 1.25rem;
  font-weight: 600;
}

.modal-close {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 2rem;
  cursor: pointer;
  transition: color 0.3s ease;
  line-height: 1;
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: var(--spacing-xl);
  max-height: 50vh;
  overflow-y: auto;
}

.message-meta {
  display: flex;
  gap: var(--spacing-xl);
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
}

.meta-item {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.meta-label {
  font-size: 0.75rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.meta-value {
  font-weight: 600;
  color: var(--text-primary);
}

.message-content {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  color: var(--text-primary);
  line-height: 1.8;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.modal-footer {
  display: flex;
  gap: var(--spacing-md);
  padding: var(--spacing-lg) var(--spacing-xl);
  border-top: 1px solid var(--border-color);
}

/* Responsive */
@media (max-width: 768px) {
  .app-container {
    padding: var(--spacing-md);
  }
  
  .header-content {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .header-stats {
    width: 100%;
    justify-content: space-between;
  }
  
  .tabs {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
  }
  
  .tab {
    white-space: nowrap;
  }
  
  .view-header {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .modal-content {
    width: 95%;
  }
  
  .modal-footer {
    flex-direction: column;
  }
  
  .modal-footer .btn {
    width: 100%;
  }
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--bg-elevated);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-primary);
}


/* Authentication Pages */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%);
    padding: 2rem;
}

.auth-card {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 16px;
    padding: 3rem;
    max-width: 400px;
    width: 100%;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.auth-card h1 {
    text-align: center;
    margin-bottom: 0.5rem;
    font-size: 2rem;
}

.auth-subtitle {
    text-align: center;
    color: rgba(255, 255, 255, 0.7);
    margin-bottom: 2rem;
    font-size: 0.9rem;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.auth-link {
    text-align: center;
    margin-top: 1rem;
    font-size: 0.9rem;
    color: rgba(255, 255, 255, 0.7);
}

.auth-link a {
    color: #4a90e2;
    text-decoration: none;
    font-weight: 500;
}

.auth-link a:hover {
    text-decoration: underline;
}

.error-message {
    background: rgba(239, 68, 68, 0.1);
    border: 1px solid rgba(239, 68, 68, 0.3);
    color: #ef4444;
    padding: 0.75rem;
    border-radius: 8px;
    margin-top: 1rem;
    font-size: 0.9rem;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.user-name {
    font-weight: 600;
    color: var(--text-primary);
}

.btn-logout {
    background: rgba(239, 68, 68, 0.1);
    color: #ef4444;
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.btn-logout:hover {
    background: rgba(239, 68, 68, 0.2);
    border-color: #ef4444;
}