/* Base Styles */
:root {
  /* Color System */
  --color-primary: #0A84FF;
  --color-primary-light: #5AC8FA;
  --color-primary-dark: #007AFF;
  
  --color-secondary: #8E8E93;
  --color-secondary-light: #AEAEB2;
  --color-secondary-dark: #636366;
  
  --color-accent: #5856D6;
  
  --color-success: #30D158;
  --color-warning: #FF9F0A;
  --color-error: #FF453A;
  
  --color-background: #F2F2F7;
  --color-card: #FFFFFF;
  --color-text: #1C1C1E;
  --color-text-secondary: #6C6C70;
  
  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  
  /* Spacing (8px system) */
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-5: 40px;
  --space-6: 48px;
  
  /* Borders */
  --border-radius-sm: 8px;
  --border-radius-md: 12px;
  --border-radius-lg: 16px;
  
  /* Shadows */
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.12);
  --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.15);
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
  :root {
    --color-background: #1C1C1E;
    --color-card: #2C2C2E;
    --color-text: #FFFFFF;
    --color-text-secondary: #AEAEB2;
  }
}

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

body {
  font-family: var(--font-family);
  line-height: 1.5;
  color: var(--color-text);
  background-color: var(--color-background);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 0.3s ease;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  margin-bottom: var(--space-2);
  font-weight: 600;
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.5rem;
}

h3 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--space-2);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--color-primary-dark);
}

/* Layout */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-2);
}

.row {
  display: flex;
  flex-wrap: wrap;
  margin: 0 calc(var(--space-2) * -1);
}

.col {
  flex: 1 1 0;
  padding: 0 var(--space-2);
}

/* Grid System */
.col-1 { flex: 0 0 8.333%; max-width: 8.333%; }
.col-2 { flex: 0 0 16.667%; max-width: 16.667%; }
.col-3 { flex: 0 0 25%; max-width: 25%; }
.col-4 { flex: 0 0 33.333%; max-width: 33.333%; }
.col-5 { flex: 0 0 41.667%; max-width: 41.667%; }
.col-6 { flex: 0 0 50%; max-width: 50%; }
.col-7 { flex: 0 0 58.333%; max-width: 58.333%; }
.col-8 { flex: 0 0 66.667%; max-width: 66.667%; }
.col-9 { flex: 0 0 75%; max-width: 75%; }
.col-10 { flex: 0 0 83.333%; max-width: 83.333%; }
.col-11 { flex: 0 0 91.667%; max-width: 91.667%; }
.col-12 { flex: 0 0 100%; max-width: 100%; }

/* Responsive Breakpoints */
@media (max-width: 768px) {
  .col-md-12 { flex: 0 0 100%; max-width: 100%; }
  .col-md-6 { flex: 0 0 50%; max-width: 50%; }
  .col-md-4 { flex: 0 0 33.333%; max-width: 33.333%; }
  .col-md-3 { flex: 0 0 25%; max-width: 25%; }
}

@media (max-width: 576px) {
  .col-sm-12 { flex: 0 0 100%; max-width: 100%; }
  .col-sm-6 { flex: 0 0 50%; max-width: 50%; }
}

/* Components */
.card {
  background-color: var(--color-card);
  border-radius: var(--border-radius-md);
  padding: var(--space-3);
  margin-bottom: var(--space-3);
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

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

.btn {
  display: inline-block;
  background-color: var(--color-primary);
  color: white;
  padding: var(--space-1) var(--space-3);
  border-radius: var(--border-radius-sm);
  border: none;
  cursor: pointer;
  font-weight: 500;
  text-align: center;
  transition: background-color 0.2s ease, transform 0.1s ease;
}

.btn:hover {
  background-color: var(--color-primary-dark);
}

.btn:active {
  transform: scale(0.98);
}

.btn-secondary {
  background-color: var(--color-secondary);
}

.btn-secondary:hover {
  background-color: var(--color-secondary-dark);
}

.btn-success {
  background-color: var(--color-success);
}

.btn-success:hover {
  background-color: var(--color-success);
  filter: brightness(0.9);
}

.btn-warning {
  background-color: var(--color-warning);
}

.btn-warning:hover {
  background-color: var(--color-warning);
  filter: brightness(0.9);
}

.btn-danger {
  background-color: var(--color-error);
}

.btn-danger:hover {
  background-color: var(--color-error);
  filter: brightness(0.9);
}

.btn-lg {
  padding: var(--space-2) var(--space-4);
  font-size: 1.1rem;
}

.btn-sm {
  padding: 6px var(--space-2);
  font-size: 0.9rem;
}

.form-group {
  margin-bottom: var(--space-3);
}

.form-label {
  display: block;
  margin-bottom: var(--space-1);
  font-weight: 500;
}

.form-control {
  width: 100%;
  padding: var(--space-1) var(--space-2);
  border: 1px solid var(--color-secondary-light);
  border-radius: var(--border-radius-sm);
  background-color: var(--color-card);
  color: var(--color-text);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-control:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(10, 132, 255, 0.1);
  outline: none;
}

.form-select {
  width: 100%;
  padding: var(--space-1) var(--space-2);
  border: 1px solid var(--color-secondary-light);
  border-radius: var(--border-radius-sm);
  background-color: var(--color-card);
  color: var(--color-text);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%238E8E93' d='M6 8.825l-4.44-4.41L2.438 3.54 6 7.075l3.562-3.536 0.878 0.874L6 8.825z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-2) center;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.form-select:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(10, 132, 255, 0.1);
  outline: none;
}

/* Badge */
.badge {
  display: inline-block;
  padding: 0.25em 0.6em;
  font-size: 0.75rem;
  font-weight: 600;
  border-radius: 20px;
  text-align: center;
  white-space: nowrap;
  vertical-align: middle;
}

.badge-primary {
  background-color: var(--color-primary-light);
  color: white;
}

.badge-success {
  background-color: var(--color-success);
  color: white;
}

.badge-warning {
  background-color: var(--color-warning);
  color: white;
}

.badge-danger {
  background-color: var(--color-error);
  color: white;
}

.badge-secondary {
  background-color: var(--color-secondary-light);
  color: var(--color-text);
}

/* Alert */
.alert {
  padding: var(--space-2);
  margin-bottom: var(--space-3);
  border-radius: var(--border-radius-sm);
  font-weight: 500;
}

.alert-success {
  background-color: rgba(48, 209, 88, 0.15);
  color: var(--color-success);
}

.alert-warning {
  background-color: rgba(255, 159, 10, 0.15);
  color: var(--color-warning);
}

.alert-danger {
  background-color: rgba(255, 69, 58, 0.15);
  color: var(--color-error);
}

.alert-info {
  background-color: rgba(10, 132, 255, 0.15);
  color: var(--color-primary);
}

/* Header & Navigation */
.header {
  background-color: var(--color-card);
  box-shadow: var(--shadow-sm);
  padding: var(--space-2) 0;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
}

.nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-brand {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--color-text);
}

.nav-links {
  display: flex;
  list-style: none;
}

.nav-item {
  margin-left: var(--space-3);
}

.nav-link {
  color: var(--color-text);
  font-weight: 500;
  padding: var(--space-1);
  transition: color 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

/* Main Content */
.main-content {
  padding-top: 80px;
  padding-bottom: var(--space-4);
  min-height: calc(100vh - 70px);
}

/* Footer */
.footer {
  background-color: var(--color-card);
  padding: var(--space-3) 0;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: 0.9rem;
}

/* Utilities */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }

.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-secondary); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-danger { color: var(--color-error); }
.text-muted { color: var(--color-text-secondary); }

.bg-primary { background-color: var(--color-primary); }
.bg-secondary { background-color: var(--color-secondary); }
.bg-success { background-color: var(--color-success); }
.bg-warning { background-color: var(--color-warning); }
.bg-danger { background-color: var(--color-error); }

.mb-1 { margin-bottom: var(--space-1); }
.mb-2 { margin-bottom: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.mb-4 { margin-bottom: var(--space-4); }

.mt-1 { margin-top: var(--space-1); }
.mt-2 { margin-top: var(--space-2); }
.mt-3 { margin-top: var(--space-3); }
.mt-4 { margin-top: var(--space-4); }

.p-1 { padding: var(--space-1); }
.p-2 { padding: var(--space-2); }
.p-3 { padding: var(--space-3); }
.p-4 { padding: var(--space-4); }

.d-flex { display: flex; }
.flex-column { flex-direction: column; }
.justify-content-between { justify-content: space-between; }
.justify-content-center { justify-content: center; }
.align-items-center { align-items: center; }
.flex-wrap { flex-wrap: wrap; }

.w-100 { width: 100%; }
.h-100 { height: 100%; }

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

.fade-in {
  animation: fadeIn 0.3s ease-in-out;
}

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

.slide-in-up {
  animation: slideInUp 0.3s ease-out;
}

/* Loader */
.loader-container {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  width: 100%;
}

.loader {
  width: 40px;
  height: 40px;
  border: 4px solid rgba(0, 0, 0, 0.1);
  border-radius: 50%;
  border-top-color: var(--color-primary);
  animation: spin 1s linear infinite;
}

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

/* Modal */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  display: flex;
  justify-content: center;
  align-items: center;
  z-index: 1100;
  backdrop-filter: blur(2px);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
}

.modal-overlay.active {
  opacity: 1;
  visibility: visible;
}

.modal {
  background-color: var(--color-card);
  border-radius: var(--border-radius-lg);
  padding: var(--space-3);
  width: 90%;
  max-width: 500px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: var(--shadow-lg);
  transform: translateY(20px);
  opacity: 0;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.modal-overlay.active .modal {
  transform: translateY(0);
  opacity: 1;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-3);
}

.modal-title {
  margin: 0;
  font-size: 1.5rem;
}

.modal-close {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-text-secondary);
}

.modal-body {
  margin-bottom: var(--space-3);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: var(--space-2);
}