:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --primary-light: #60a5fa;
    --secondary-color: #10b981;
    --secondary-dark: #059669;
    --secondary-light: #34d399;
    --danger-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;
    --success-color: #10b981;
    
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --text-muted: #9ca3af;
    --text-inverse: #ffffff;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --bg-dark: #111827;
    
    --border-color: #e5e7eb;
    --border-radius: 0.5rem;
    --border-radius-sm: 0.375rem;
    --border-radius-lg: 0.75rem;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    
    --sidebar-width: 260px;
    --navbar-height: 64px;
    
    --transition-fast: 150ms;
    --transition-base: 200ms;
    --transition-slow: 300ms;
}

[data-theme="dark"] {
    --primary-color: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    
    --text-primary: #f9fafb;
    --text-secondary: #d1d5db;
    --text-muted: #9ca3af;
    
    --bg-primary: #1f2937;
    --bg-secondary: #111827;
    --bg-tertiary: #374151;
    
    --border-color: #374151;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    margin-bottom: 1rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1rem;
}

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

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem 1rem;
    border: none;
    border-radius: var(--border-radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    line-height: 1.5;
    cursor: pointer;
    transition: all var(--transition-fast);
    white-space: nowrap;
    user-select: none;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

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

.btn-primary:hover:not(:disabled) {
    background-color: var(--primary-dark);
}

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

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

.btn-outline {
    background-color: transparent;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn-outline:hover:not(:disabled) {
    background-color: var(--primary-color);
    color: var(--text-inverse);
}

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

.btn-lg {
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
}

.btn-sm {
    padding: 0.375rem 0.75rem;
    font-size: 0.75rem;
}

.btn-icon {
    padding: 0.5rem;
    border-radius: 50%;
}

/* Forms */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-primary);
}

.form-control {
    width: 100%;
    padding: 0.625rem 0.875rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-size: 0.875rem;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-control:disabled {
    background-color: var(--bg-tertiary);
    cursor: not-allowed;
}

.form-control.is-invalid {
    border-color: var(--danger-color);
}

.form-text {
    display: block;
    margin-top: 0.25rem;
    font-size: 0.75rem;
    color: var(--text-muted);
}

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

select.form-control {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='%236b7280'%3E%3Cpath d='M7 10l5 5 5-5z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.5rem center;
    background-size: 1.5rem;
    padding-right: 2.5rem;
}

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

.checkbox-wrapper,
.radio-wrapper {
    display: flex;
    align-items: center;
    margin-bottom: 0.5rem;
}

.checkbox-wrapper input,
.radio-wrapper input {
    margin-right: 0.5rem;
}

/* Cards */
.card {
    background-color: var(--bg-primary);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.card-header {
    padding: 1.25rem;
    border-bottom: 1px solid var(--border-color);
}

.card-body {
    padding: 1.25rem;
}

.card-footer {
    padding: 1.25rem;
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
}

/* Grid System */
.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1rem;
}

.container-fluid {
    width: 100%;
    padding: 0 1rem;
}

.row {
    display: flex;
    flex-wrap: wrap;
    margin: 0 -0.5rem;
}

.col {
    flex: 1;
    padding: 0 0.5rem;
}

@media (min-width: 640px) {
    .col-sm-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
    .col-sm-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
    .col-sm-3 { flex: 0 0 25%; max-width: 25%; }
    .col-sm-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
    .col-sm-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
    .col-sm-6 { flex: 0 0 50%; max-width: 50%; }
    .col-sm-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
    .col-sm-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
    .col-sm-9 { flex: 0 0 75%; max-width: 75%; }
    .col-sm-10 { flex: 0 0 83.333333%; max-width: 83.333333%; }
    .col-sm-11 { flex: 0 0 91.666667%; max-width: 91.666667%; }
    .col-sm-12 { flex: 0 0 100%; max-width: 100%; }
}

@media (min-width: 768px) {
    .col-md-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
    .col-md-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
    .col-md-3 { flex: 0 0 25%; max-width: 25%; }
    .col-md-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
    .col-md-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
    .col-md-6 { flex: 0 0 50%; max-width: 50%; }
    .col-md-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
    .col-md-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
    .col-md-9 { flex: 0 0 75%; max-width: 75%; }
    .col-md-10 { flex: 0 0 83.333333%; max-width: 83.333333%; }
    .col-md-11 { flex: 0 0 91.666667%; max-width: 91.666667%; }
    .col-md-12 { flex: 0 0 100%; max-width: 100%; }
}

@media (min-width: 1024px) {
    .col-lg-1 { flex: 0 0 8.333333%; max-width: 8.333333%; }
    .col-lg-2 { flex: 0 0 16.666667%; max-width: 16.666667%; }
    .col-lg-3 { flex: 0 0 25%; max-width: 25%; }
    .col-lg-4 { flex: 0 0 33.333333%; max-width: 33.333333%; }
    .col-lg-5 { flex: 0 0 41.666667%; max-width: 41.666667%; }
    .col-lg-6 { flex: 0 0 50%; max-width: 50%; }
    .col-lg-7 { flex: 0 0 58.333333%; max-width: 58.333333%; }
    .col-lg-8 { flex: 0 0 66.666667%; max-width: 66.666667%; }
    .col-lg-9 { flex: 0 0 75%; max-width: 75%; }
    .col-lg-10 { flex: 0 0 83.333333%; max-width: 83.333333%; }
    .col-lg-11 { flex: 0 0 91.666667%; max-width: 91.666667%; }
    .col-lg-12 { flex: 0 0 100%; max-width: 100%; }
}

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

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

.bg-primary { background-color: var(--bg-primary); }
.bg-secondary { background-color: var(--bg-secondary); }
.bg-tertiary { background-color: var(--bg-tertiary); }

.d-none { display: none; }
.d-block { display: block; }
.d-flex { display: flex; }
.d-inline-flex { display: inline-flex; }

.align-items-start { align-items: flex-start; }
.align-items-center { align-items: center; }
.align-items-end { align-items: flex-end; }

.justify-content-start { justify-content: flex-start; }
.justify-content-center { justify-content: center; }
.justify-content-end { justify-content: flex-end; }
.justify-content-between { justify-content: space-between; }

.flex-column { flex-direction: column; }
.flex-row { flex-direction: row; }
.flex-wrap { flex-wrap: wrap; }

.gap-1 { gap: 0.25rem; }
.gap-2 { gap: 0.5rem; }
.gap-3 { gap: 0.75rem; }
.gap-4 { gap: 1rem; }

.m-0 { margin: 0; }
.m-1 { margin: 0.25rem; }
.m-2 { margin: 0.5rem; }
.m-3 { margin: 0.75rem; }
.m-4 { margin: 1rem; }
.m-5 { margin: 1.5rem; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 0.25rem; }
.mt-2 { margin-top: 0.5rem; }
.mt-3 { margin-top: 0.75rem; }
.mt-4 { margin-top: 1rem; }
.mt-5 { margin-top: 1.5rem; }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.25rem; }
.mb-2 { margin-bottom: 0.5rem; }
.mb-3 { margin-bottom: 0.75rem; }
.mb-4 { margin-bottom: 1rem; }
.mb-5 { margin-bottom: 1.5rem; }

.p-0 { padding: 0; }
.p-1 { padding: 0.25rem; }
.p-2 { padding: 0.5rem; }
.p-3 { padding: 0.75rem; }
.p-4 { padding: 1rem; }
.p-5 { padding: 1.5rem; }

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

/* Loading Spinner */
.spinner {
    display: inline-block;
    width: 2rem;
    height: 2rem;
    border: 3px solid var(--border-color);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.5rem;
    border-radius: var(--border-radius-sm);
    font-size: 0.75rem;
    font-weight: 500;
}

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

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

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

.badge-warning {
    background-color: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
}

/* Alerts */
.alert {
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius-sm);
    margin-bottom: 1rem;
}

.alert-success {
    background-color: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
    border-left: 4px solid var(--success-color);
}

.alert-danger {
    background-color: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
    border-left: 4px solid var(--danger-color);
}

.alert-warning {
    background-color: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
    border-left: 4px solid var(--warning-color);
}

.alert-info {
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--info-color);
    border-left: 4px solid var(--info-color);
}