/* Design System & Variables */
:root {
  --bg: #f9fafb;
  --card-bg: #ffffff;
  --text: #1f2937;
  --text-secondary: #6b7280;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --primary-light: #dbeafe;
  --secondary: #10b981;
  --secondary-hover: #059669;
  --danger: #ef4444;
  --danger-hover: #dc2626;
  --warning: #f59e0b;
  --sidebar-bg: #1e293b;
  --sidebar-text: #f1f5f9;
  --sidebar-hover: #334155;
  --border: #e5e7eb;
  --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.05);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
  --icon: #3b82f6;
  --radius: 8px;
  --radius-lg: 12px;
  --transition: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="dark"] {
  --bg: #0f172a;
  --card-bg: #1e293b;
  --text: #f1f5f9;
  --text-secondary: #cbd5e1;
  --primary: #60a5fa;
  --primary-hover: #3b82f6;
  --primary-light: #1e3a8a;
  --secondary: #10b981;
  --sidebar-bg: #0f172a;
  --sidebar-text: #cbd5e1;
  --sidebar-hover: #1e293b;
  --border: #334155;
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.4);
  --icon: #60a5fa;
}

/* Accessibility & Focus States */
.cta:focus, button:focus, input:focus, select:focus {
  outline: 2px solid var(--primary);
  outline-offset: 2px;
  box-shadow: 0 0 0 3px var(--primary-light);
}

/* Messages & Alerts */
.error {
  color: var(--danger);
  background: rgba(239, 68, 68, 0.08);
  border: 1px solid rgba(239, 68, 68, 0.3);
  border-radius: var(--radius);
  padding: 12px 16px;
  margin: 12px 0;
  font-size: 0.95em;
  line-height: 1.5;
}

.success {
  color: var(--secondary);
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.3);
  border-radius: var(--radius);
  padding: 12px 16px;
  margin: 12px 0;
  font-size: 0.95em;
  line-height: 1.5;
}

.warning {
  color: var(--warning);
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.3);
  border-radius: var(--radius);
  padding: 12px 16px;
  margin: 12px 0;
}

button[disabled], .cta[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
}
/* Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
  font-size: 16px;
  line-height: 1.6;
  min-height: 100vh;
  transition: background-color var(--transition), color var(--transition);
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 1rem;
  color: var(--text);
}

h1 { font-size: 2rem; }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.25rem; }
h4 { font-size: 1.1rem; }

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

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

p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

/* Layout */
.layout {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  background: var(--sidebar-bg);
  color: var(--sidebar-text);
  width: 260px;
  min-height: 100vh;
  padding: 32px 20px;
  display: flex;
  flex-direction: column;
  box-shadow: var(--shadow);
}

.logo {
  font-size: 1.5em;
  font-weight: 700;
  margin-bottom: 32px;
  letter-spacing: -0.5px;
  background: linear-gradient(135deg, var(--primary), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.sidebar nav {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: auto;
}

.sidebar nav a {
  color: var(--sidebar-text);
  text-decoration: none;
  padding: 10px 12px;
  border-radius: var(--radius);
  transition: all var(--transition);
  font-weight: 500;
  font-size: 0.95em;
}

.sidebar nav a:hover {
  background: var(--sidebar-hover);
  color: var(--primary);
}

.sidebar nav a.active {
  background: rgba(59, 130, 246, 0.15);
  color: var(--primary);
  font-weight: 600;
}

.logout-btn {
  margin-top: auto;
  border-top: 1px solid var(--sidebar-hover);
  padding-top: 16px;
}

main {
  flex: 1;
  padding: 40px;
  display: flex;
  flex-direction: column;
  background: var(--bg);
}

/* Cards */
.card {
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 32px;
  margin-bottom: 24px;
  border: 1px solid var(--border);
  transition: all var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  border-color: var(--primary);
}

.card.hero {
  text-align: left;
}

.card.center {
  text-align: center;
  max-width: 420px;
  margin: auto;
}

/* Forms */
.form-group {
  margin-bottom: 20px;
  display: flex;
  flex-direction: column;
}

.form-group label {
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 0.95em;
  color: var(--text);
}

input, textarea, select {
  font-family: inherit;
  font-size: 1em;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  padding: 10px 14px;
  background: var(--card-bg);
  color: var(--text);
  transition: all var(--transition);
  width: 100%;
}

input:hover, textarea:hover, select:hover {
  border-color: var(--primary);
}

input:focus, textarea:focus, select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

input::placeholder {
  color: var(--text-secondary);
}

/* Buttons & CTAs */
.cta, button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--primary);
  color: #fff;
  padding: 11px 24px;
  border-radius: var(--radius);
  font-weight: 600;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: all var(--transition);
  font-size: 0.95em;
}

.cta:hover, button:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: var(--shadow-lg);
}

.cta.secondary, button.secondary {
  background: var(--border);
  color: var(--text);
}

.cta.secondary:hover, button.secondary:hover {
  background: var(--text-secondary);
  color: #fff;
}

.cta.danger, button.danger {
  background: var(--danger);
}

.cta.danger:hover, button.danger:hover {
  background: var(--danger-hover);
}

button[disabled], .cta[disabled] {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* Tables */
.table-wrapper {
  background: var(--card-bg);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
}

thead {
  background: linear-gradient(135deg, var(--primary), var(--primary-hover));
  color: #fff;
}

th {
  padding: 16px;
  text-align: left;
  font-weight: 600;
  font-size: 0.9em;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
}

tbody tr {
  transition: background-color var(--transition);
}

tbody tr:hover {
  background: rgba(59, 130, 246, 0.05);
}

tbody tr:last-child td {
  border-bottom: none;
}

/* Badges & Tags */
.badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.85em;
  font-weight: 600;
  background: rgba(59, 130, 246, 0.1);
  color: var(--primary);
}

.badge-success {
  background: rgba(16, 185, 129, 0.1);
  color: var(--secondary);
}

.badge-danger {
  background: rgba(239, 68, 68, 0.1);
  color: var(--danger);
}

/* Grid & Flex */
.grid {
  display: grid;
  gap: 24px;
}

.grid-2 {
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

.grid-4 {
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

.flex {
  display: flex;
  gap: 16px;
  align-items: center;
}

.flex-col {
  flex-direction: column;
}

.flex-between {
  justify-content: space-between;
}

.flex-center {
  justify-content: center;
}

/* Stat Cards */
.stat-card {
  background: var(--card-bg);
  padding: 24px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: all var(--transition);
}

.stat-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.stat-card h3 {
  color: var(--text-secondary);
  font-size: 0.85em;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 12px;
}

.stat-card .value {
  font-size: 2.2em;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 8px;
}

.stat-card p {
  margin: 0;
  font-size: 0.9em;
}

/* Responsive */
@media (max-width: 1024px) {
  main {
    padding: 24px;
  }

  .card {
    padding: 24px;
  }
}

@media (max-width: 768px) {
  .layout {
    flex-direction: column;
  }

  .sidebar {
    width: 100%;
    min-height: auto;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    gap: 16px;
    box-shadow: var(--shadow);
  }

  .sidebar nav {
    flex-direction: row;
    gap: 8px;
    margin-bottom: 0;
    order: 2;
  }

  .logo {
    margin-bottom: 0;
    font-size: 1.2em;
    order: 1;
  }

  .logout-btn {
    margin-top: 0;
    border-top: none;
    border-left: 1px solid var(--sidebar-hover);
    padding-top: 0;
    padding-left: 16px;
    order: 3;
  }

  main {
    padding: 16px;
  }

  .card {
    padding: 20px;
  }

  h1 { font-size: 1.5rem; }
  h2 { font-size: 1.25rem; }
}

@media (max-width: 480px) {
  .sidebar {
    flex-direction: column;
    gap: 12px;
    padding: 12px;
  }

  .sidebar nav {
    flex-direction: column;
    width: 100%;
  }

  .sidebar nav a {
    padding: 8px 10px;
    font-size: 0.9em;
  }

  .logo {
    width: 100%;
    text-align: center;
    font-size: 1em;
  }

  .logout-btn {
    width: 100%;
    border-top: 1px solid var(--sidebar-hover);
    border-left: none;
    padding-top: 12px;
    padding-left: 0;
  }

  main {
    padding: 12px;
  }

  .card {
    padding: 16px;
  }

  input, textarea, select {
    padding: 9px 12px;
    font-size: 16px;
  }

  .cta, button {
    padding: 10px 20px;
    font-size: 0.9em;
    width: 100%;
  }

  table {
    font-size: 0.9em;
  }

  th, td {
    padding: 10px 8px;
  }
}