style.css

:root {
  --primary-color: #667eea;
  --primary-dark: #5a6fd8;
  --secondary-color: #764ba2;
  --text-primary: #2d3748;
  --text-secondary: #718096;
  --bg-primary: #ffffff;
  --bg-secondary: #f7fafc;
  --bg-sidebar: #f8f9fa;
  --border-color: #e2e8f0;
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
}

[data-theme="dark"] {
  --primary-color: #667eea;
  --primary-dark: #5a6fd8;
  --secondary-color: #764ba2;
  --text-primary: #f7fafc;
  --text-secondary: #cbd5e0;
  --bg-primary: #1a202c;
  --bg-secondary: #2d3748;
  --bg-sidebar: #2d3748;
  --border-color: #4a5568;
  --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.3), 0 1px 2px 0 rgba(0, 0, 0, 0.2);
}

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

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  transition: all 0.3s ease;
}

.dashboard-container {
  display: flex;
  min-height: 100vh;
}

/* Sidebar Styles */
.sidebar {
  width: 260px;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border-color);
  transition: all 0.3s ease;
  position: fixed;
  height: 100vh;
  z-index: 1000;
}

.sidebar-header {
  padding: 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
  color: var(--primary-color);
  font-size: 1.5rem;
  font-weight: 700;
}

.sidebar-nav {
  padding: 1rem 0;
}

.nav-item {
  display: flex;
  align-items: center;
  padding: 0.75rem 1.5rem;
  color: var(--text-secondary);
  text-decoration: none;
  transition: all 0.2s ease;
  border-left: 3px solid transparent;
}

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

.nav-item.active {
  background: var(--bg-secondary);
  color: var(--primary-color);
  border-left-color: var(--primary-color);
}

.nav-item i {
  margin-right: 0.75rem;
  width: 20px;
  text-align: center;
}

/* Main Content */
.main-content {
  flex: 1;
  margin-left: 260px;
  transition: all 0.3s ease;
}

/* Header Styles */
.header {
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  box-shadow: var(--shadow);
}

.header-left h1 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 1rem;
}

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 0.5rem;
  border-radius: 0.375rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

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

/* Content Area */
.content {
  padding: 2rem;
}

.page {
  display: none;
}

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

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

/* Card Styles */
.card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  padding: 1.5rem;
  box-shadow: var(--shadow);
  margin-bottom: 1.5rem;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.card-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* Table Styles */
.table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-primary);
}

.table th,
.table td {
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 1px solid var(--border-color);
}

.table th {
  background: var(--bg-secondary);
  font-weight: 600;
  color: var(--text-primary);
}

.table tr:hover {
  background: var(--bg-secondary);
}

/* Responsive */
@media (max-width: 768px) {
  .sidebar {
    width: 70px;
  }
  
  .sidebar-header h2,
  .nav-item span {
    display: none;
  }
  
  .main-content {
    margin-left: 70px;
  }
  
  .nav-item {
    padding: 0.75rem;
    justify-content: center;
  }
  
  .nav-item i {
    margin-right: 0;
  }
  
  .header {
    padding: 1rem;
  }
  
  .content {
    padding: 1rem;
  }
}

/* Stats Grid */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.stat-card {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.stat-value {
  font-size: 2rem;
  font-weight: 700;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.stat-label {
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Form Styles */
.form-group {
  margin-bottom: 1rem;
}

.form-label {
  display: block;
  margin-bottom: 0.5rem;
  color: var(--text-primary);
  font-weight: 500;
}

.form-control {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  background: var(--bg-primary);
  color: var(--text-primary);
  transition: all 0.2s ease;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.btn {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: 0.375rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s ease;
}

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

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

/* Settings Grid */
.settings-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.setting-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border-color);
}

.setting-item:last-child {
  border-bottom: none;
}

.toggle-switch {
  position: relative;
  display: inline-block;
  width: 50px;
  height: 24px;
}

.toggle-switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--border-color);
  transition: .4s;
  border-radius: 24px;
}

.toggle-slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 4px;
  bottom: 4px;
  background-color: white;
  transition: .4s;
  border-radius: 50%;
}

input:checked + .toggle-slider {
  background-color: var(--primary-color);
}

input:checked + .toggle-slider:before {
  transform: translateX(26px);
}