:root {
  --primary: #1877F2;
  --primary-dark: #145DBF;
  --primary-light: #E7F3FF;
  --white: #FFFFFF;
  --bg-light: #F5F7FA;
  --bg-secondary: #F8F9FA;
  --text-secondary: #65676B;
  --text-primary: #1C1E21;
  --border-color: #DADDE1;
  --border: #DADDE1;
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 12px 32px rgba(0, 0, 0, 0.15);
  --success: #42b72a;
  --success-light: #E8F5E9;
  --warning: #f59e0b;
  --warning-light: #FEF3C7;
  --error: #f02849;
  --error-light: #FEE2E2;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: all 0.15s ease;
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--bg-light);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   NAVBAR
   ============================================ */
.navbar {
  background-color: var(--white);
  border-bottom: 1px solid var(--border-color);
  box-shadow: var(--shadow-sm);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  background-color: rgba(255, 255, 255, 0.95);
}

.navbar-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 0;
  gap: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  text-decoration: none;
}

.brand-icon {
  font-size: 24px;
  color: var(--primary);
}

.brand-text {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 15px;
  font-weight: 500;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
}

.nav-link:hover {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
}

.nav-link.active {
  background-color: var(--primary-light);
  color: var(--primary);
  font-weight: 600;
}

.nav-link-danger:hover {
  background-color: var(--error-light);
  color: var(--error);
}

/* ============================================
   BUTTONS
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: 15px;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  font-family: inherit;
  line-height: 1.5;
  position: relative;
  overflow: hidden;
}

.btn:disabled {
  opacity: 0.6;
  cursor: not-allowed;
  pointer-events: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: var(--white);
  box-shadow: 0 2px 8px rgba(24, 119, 242, 0.3);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(24, 119, 242, 0.4);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
  box-shadow: 0 2px 6px rgba(24, 119, 242, 0.3);
}

.btn-block {
  width: 100%;
}

.btn-large {
  padding: 14px 28px;
  font-size: 16px;
}

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

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

.btn-link {
  background: none;
  border: none;
  color: var(--primary);
  cursor: pointer;
  font-size: 14px;
  padding: 0;
  text-decoration: underline;
  font-weight: 500;
  transition: var(--transition-fast);
}

.btn-link:hover {
  color: var(--primary-dark);
  text-decoration: none;
}

/* ============================================
   FORMS
   ============================================ */
.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
}

.form-group label {
  font-size: 14px;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 12px 16px;
  font-size: 15px;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--white);
  color: var(--text-primary);
  font-family: inherit;
  transition: var(--transition);
  outline: none;
}

.form-group input:hover,
.form-group textarea:hover,
.form-group select:hover {
  border-color: #B0B3B8;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 4px var(--primary-light);
}

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

.form-group textarea {
  resize: vertical;
  min-height: 100px;
}

.form-hint {
  font-size: 13px;
  color: var(--text-secondary);
  margin-top: -4px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.form-group-half {
  margin-bottom: 20px;
}

/* ============================================
   CARDS
   ============================================ */
.dashboard-card {
  background-color: var(--white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: var(--transition);
  border: 1px solid var(--border-color);
}

.dashboard-card:hover {
  box-shadow: var(--shadow-lg);
}

.dashboard-card-full {
  grid-column: 1 / -1;
}

.card-header {
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 0;
}

.card-body {
  padding: 24px;
}

/* ============================================
   ALERTS
   ============================================ */
.alert {
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: 14px;
  font-weight: 500;
  display: none;
  margin-top: 12px;
  animation: slideDown 0.3s ease;
}

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

.alert.success {
  background-color: var(--success-light);
  color: #2E7D32;
  border: 1px solid #A5D6A7;
}

.alert.error {
  background-color: var(--error-light);
  color: #C62828;
  border: 1px solid #EF9A9A;
}

.alert.info {
  background-color: var(--primary-light);
  color: var(--primary-dark);
  border: 1px solid #90CAF9;
}

/* ============================================
   AUTH PAGES
   ============================================ */
.auth-container {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - 60px);
  padding: 40px 20px;
}

.auth-card {
  width: 100%;
  max-width: 440px;
  background-color: var(--white);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-xl);
  padding: 40px;
  border: 1px solid var(--border-color);
  animation: fadeInUp 0.4s ease;
}

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

.auth-header {
  text-align: center;
  margin-bottom: 32px;
}

.auth-icon-wrapper {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  box-shadow: 0 4px 12px rgba(24, 119, 242, 0.3);
}

.auth-icon {
  font-size: 32px;
  color: white;
}

.auth-header h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.auth-subtitle {
  font-size: 15px;
  color: var(--text-secondary);
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.auth-footer {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin-top: 24px;
  font-size: 14px;
  color: var(--text-secondary);
}

.auth-link {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
  transition: var(--transition-fast);
}

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

/* ============================================
   MAIN CONTENT
   ============================================ */
.main-content {
  padding: 32px 0;
  min-height: calc(100vh - 60px);
}

.page-header {
  margin-bottom: 32px;
}

.page-title {
  font-size: 32px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-subtitle {
  font-size: 16px;
  color: var(--text-secondary);
}

.dashboard-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.stats-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 20px;
  margin-bottom: 32px;
}

.stat-card {
  background-color: var(--white);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--border-color);
  transition: var(--transition);
}

.stat-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

/* ============================================
   PAGES
   ============================================ */
.page {
  display: none;
}

.page.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

/* ============================================
   LOADING STATES
   ============================================ */
.loading-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 40px;
  color: var(--text-secondary);
  gap: 12px;
}

.loading-state i {
  font-size: 24px;
  margin-right: 0;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-center {
  text-align: center;
}

.mt-1 { margin-top: 8px; }
.mt-2 { margin-top: 16px; }
.mt-3 { margin-top: 24px; }
.mb-1 { margin-bottom: 8px; }
.mb-2 { margin-bottom: 16px; }
.mb-3 { margin-bottom: 24px; }

/* ============================================
   RESPONSIVE
   ============================================ */
@media (max-width: 768px) {
  .container {
    padding: 0 16px;
  }

  .auth-card {
    padding: 32px 24px;
  }

  .page-title {
    font-size: 24px;
  }

  .form-row {
    grid-template-columns: 1fr;
  }
  
  .dashboard-grid {
    grid-template-columns: 1fr;
  }
  
  .nav-links {
    gap: 4px;
  }
  
  .nav-link {
    padding: 8px 12px;
    font-size: 14px;
  }
  
  .nav-link span {
    display: none;
  }
}