:root {
    --primary: #4F46E5;
    --primary-hover: #4338ca;
    --secondary: #10B981;
    --bg-color: #F3F4F6;
    --text-color: #1F2937;
    --white: #ffffff;
    --gray-200: #E5E7EB;
    --gray-500: #6B7280;
    --danger: #EF4444;
}

body {
    font-family: 'Inter', sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--bg-color);
    color: var(--text-color);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    width: 100%;
    box-sizing: border-box;
}

.navbar {
    background-color: var(--white);
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    padding: 1rem 0;
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    align-items: center;
    margin: 0;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
}

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

.btn {
    padding: 0.5rem 1rem;
    border-radius: 0.375rem;
    font-weight: 500;
    cursor: pointer;
    text-decoration: none;
    transition: background-color 0.2s;
    display: inline-block;
    border: none;
    font-size: 1rem;
}

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

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

.btn-outline {
    border: 1px solid var(--gray-200);
    background: transparent;
}

.btn-outline:hover {
    border-color: var(--primary);
    color: var(--primary);
}

main {
    flex: 1;
    padding: 2rem 0;
}

.footer {
    background-color: var(--white);
    padding: 2rem 0;
    margin-top: auto;
    text-align: center;
    color: var(--gray-500);
}

/* Card Styles */
.card {
    background: var(--white);
    border-radius: 0.5rem;
    padding: 1.5rem;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    margin-bottom: 1.5rem;
}

.card h2 {
    margin-top: 0;
}

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

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.form-control {
    width: 100%;
    padding: 0.5rem;
    border: 1px solid var(--gray-200);
    border-radius: 0.375rem;
    font-family: inherit;
    box-sizing: border-box;
}

.form-control:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.2);
}

.alert {
    padding: 1rem;
    border-radius: 0.375rem;
    margin-bottom: 1rem;
}

.alert-danger {
    background-color: #FEF2F2;
    color: #B91C1C;
    border: 1px solid #FECACA;
}

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

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

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

.table th, .table td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid var(--gray-200);
}

.table th {
    background-color: #F9FAFB;
    font-weight: 600;
}

.kb-header {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 2rem;
}

.kb-subtitle {
    margin: 0.5rem 0 0;
    color: var(--gray-500);
}

.kb-tabs {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.kb-tab {
    border: 1px solid var(--gray-200);
    background: var(--white);
    color: var(--text-color);
    padding: 0.4rem 0.9rem;
    border-radius: 999px;
    font-weight: 500;
    cursor: pointer;
}

.kb-tab-active {
    background: var(--primary);
    border-color: var(--primary);
    color: var(--white);
}

.kb-layout {
    display: grid;
    grid-template-columns: minmax(240px, 320px) minmax(0, 1fr);
    gap: 1.5rem;
}

.kb-sidebar {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    height: fit-content;
}

.kb-sidebar-header {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.kb-sidebar-header h2 {
    margin: 0;
}

.kb-course-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.kb-course-item {
    border-radius: 0.75rem;
    border: 1px solid transparent;
}

.kb-course-item-active {
    background: #EEF2FF;
    border-color: #C7D2FE;
}

.kb-course-button {
    background: transparent;
    border: none;
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    padding: 0.75rem 1rem;
    text-align: left;
    cursor: pointer;
    font-weight: 600;
}

.kb-course-count {
    background: var(--white);
    border-radius: 999px;
    padding: 0.1rem 0.6rem;
    font-size: 0.85rem;
    color: var(--gray-500);
}

.kb-content {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.kb-content-header {
    display: flex;
    gap: 1.5rem;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: flex-start;
}

.kb-content-header h2 {
    margin: 0;
}

.kb-content-subtitle {
    margin: 0.5rem 0 0;
    color: var(--gray-500);
}

.kb-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.kb-tree {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    background: #F9FAFB;
    border-radius: 0.75rem;
    padding: 1rem;
}

.kb-tree-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 0.8rem;
    background: var(--white);
    border-radius: 0.6rem;
    border: 1px solid var(--gray-200);
}

.kb-tree-row-active {
    border-color: var(--primary);
    box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.15);
}

.kb-tree-main {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-weight: 500;
}

.kb-tree-icon {
    font-size: 1.1rem;
}

.kb-tree-meta {
    color: var(--gray-500);
    font-size: 0.85rem;
}

.kb-tree-children {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
    margin: 0.2rem 0 0.8rem 1.5rem;
}

.kb-detail {
    background: #EEF2FF;
    border-radius: 0.75rem;
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.kb-detail-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
}

.kb-detail-header h3 {
    margin: 0;
}

.kb-detail-tag {
    background: var(--white);
    border-radius: 999px;
    padding: 0.2rem 0.6rem;
    font-size: 0.8rem;
    color: var(--gray-500);
}

.kb-detail-title {
    margin: 0;
    font-weight: 600;
}

.kb-detail-text {
    margin: 0;
    color: var(--text-color);
}

.kb-detail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    font-size: 0.85rem;
    color: var(--gray-500);
}

@media (max-width: 900px) {
    .kb-layout {
        grid-template-columns: 1fr;
    }
}