:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #a5b4fc;
    --bg: #f8fafc;
    --surface: #ffffff;
    --text: #1e293b;
    --text-muted: #64748b;
    --border: #e2e8f0;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --radius: 12px;
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

/* Login Page */
.login-container {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    padding: 20px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
}

.login-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 48px;
    width: 100%;
    max-width: 420px;
    box-shadow: var(--shadow-lg);
}

.login-card h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 8px;
    color: var(--text);
}

.login-card p {
    color: var(--text-muted);
    margin-bottom: 32px;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 6px;
    color: var(--text);
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    transition: border-color 0.2s, box-shadow 0.2s;
    outline: none;
}

.form-group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    text-decoration: none;
}

.btn-primary {
    background: var(--primary);
    color: white;
    width: 100%;
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

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

.btn-outline:hover {
    background: var(--bg);
}

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

.btn-sm {
    padding: 8px 16px;
    font-size: 13px;
}

.error-msg {
    background: #fef2f2;
    color: var(--danger);
    padding: 12px;
    border-radius: 8px;
    font-size: 14px;
    margin-bottom: 16px;
    display: none;
}

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

.sidebar {
    width: 280px;
    background: var(--surface);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}

.sidebar-header {
    padding: 20px;
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.sidebar-header h2 {
    font-size: 18px;
    font-weight: 600;
}

.sidebar-sessions {
    flex: 1;
    overflow-y: auto;
    padding: 12px;
}

.session-item {
    padding: 12px 16px;
    border-radius: 8px;
    cursor: pointer;
    margin-bottom: 4px;
    transition: background 0.15s;
}

.session-item:hover {
    background: var(--bg);
}

.session-item.active {
    background: #eef2ff;
    border: 1px solid var(--primary-light);
}

.session-item .session-title {
    font-size: 14px;
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.session-item .session-meta {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

.sidebar-footer {
    padding: 16px 20px;
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.user-info {
    font-size: 14px;
    font-weight: 500;
}

/* Main Chat Area */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.chat-header {
    padding: 16px 24px;
    border-bottom: 1px solid var(--border);
    background: var(--surface);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.chat-header h3 {
    font-size: 16px;
    font-weight: 600;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.message {
    display: flex;
    gap: 12px;
    max-width: 80%;
}

.message.user {
    align-self: flex-end;
    flex-direction: row-reverse;
}

.message-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 600;
    flex-shrink: 0;
}

.message.user .message-avatar {
    background: var(--primary);
    color: white;
}

.message.assistant .message-avatar {
    background: #10b981;
    color: white;
}

.message-bubble {
    padding: 12px 16px;
    border-radius: 12px;
    font-size: 14px;
    line-height: 1.6;
}

.message.user .message-bubble {
    background: var(--primary);
    color: white;
    border-bottom-right-radius: 4px;
}

.message.assistant .message-bubble {
    background: var(--surface);
    border: 1px solid var(--border);
    border-bottom-left-radius: 4px;
}

.chat-input-area {
    padding: 16px 24px;
    border-top: 1px solid var(--border);
    background: var(--surface);
}

.chat-input-wrapper {
    display: flex;
    gap: 12px;
    align-items: center;
}

.chat-input-wrapper input {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-size: 15px;
    outline: none;
    transition: border-color 0.2s;
}

.chat-input-wrapper input:focus {
    border-color: var(--primary);
}

.chat-input-wrapper button {
    padding: 12px 20px;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 15px;
    cursor: pointer;
    transition: background 0.2s;
}

.chat-input-wrapper button:hover {
    background: var(--primary-dark);
}

.chat-input-wrapper button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Admin Dashboard */
.admin-layout {
    min-height: 100vh;
}

.admin-header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 16px 32px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.admin-header h1 {
    font-size: 22px;
    font-weight: 700;
}

.admin-body {
    padding: 32px;
    max-width: 1400px;
    margin: 0 auto;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 20px;
    margin-bottom: 32px;
}

.stat-card {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
}

.stat-card .stat-label {
    font-size: 13px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    font-weight: 500;
}

.stat-card .stat-value {
    font-size: 32px;
    font-weight: 700;
    margin-top: 8px;
    color: var(--primary);
}

.data-card {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    margin-bottom: 24px;
    overflow: hidden;
}

.data-card-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--border);
    font-size: 16px;
    font-weight: 600;
}

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

.data-table th,
.data-table td {
    padding: 14px 24px;
    text-align: left;
    border-bottom: 1px solid var(--border);
    font-size: 14px;
}

.data-table th {
    background: var(--bg);
    font-weight: 600;
    color: var(--text-muted);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.data-table tr:hover td {
    background: #f8faff;
}

.data-table tr:last-child td {
    border-bottom: none;
}

.badge {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 500;
}

.badge-primary {
    background: #eef2ff;
    color: var(--primary);
}

.badge-success {
    background: #ecfdf5;
    color: var(--success);
}

.clickable-row {
    cursor: pointer;
}

/* Empty state */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--text-muted);
    padding: 40px;
}

.empty-state svg {
    width: 64px;
    height: 64px;
    margin-bottom: 16px;
    opacity: 0.5;
}

.empty-state p {
    font-size: 16px;
}

/* Loading */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 2px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Responsive */
@media (max-width: 768px) {
    .sidebar {
        display: none;
    }

    .admin-body {
        padding: 16px;
    }

    .stats-grid {
        grid-template-columns: 1fr;
    }

    .data-table {
        font-size: 12px;
    }

    .data-table th,
    .data-table td {
        padding: 10px 12px;
    }

    .login-card {
        padding: 32px 24px;
    }

    .chat-header {
        padding: 12px 16px;
    }

    .chat-messages {
        padding: 16px;
    }

    .chat-input-area {
        padding: 12px 16px;
    }

    .message {
        max-width: 95%;
    }
}