:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-primary-light: #dbeafe;
    --color-success: #059669;
    --color-error: #dc2626;
    --color-warning: #d97706;
    --color-text: #111827;
    --color-text-secondary: #6b7280;
    --color-text-muted: #9ca3af;
    --color-bg: #ffffff;
    --color-bg-secondary: #f9fafb;
    --color-bg-tertiary: #f3f4f6;
    --color-border: #e5e7eb;
    --color-border-light: #f3f4f6;
    --font-stack: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    --radius: 8px;
    --radius-sm: 4px;
    --radius-lg: 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 rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
    --max-width: 1200px;
}

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

body {
    font-family: var(--font-stack);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

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

/* Header */
.site-header {
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 16px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 22px;
    font-weight: 700;
    color: var(--color-primary);
    letter-spacing: -0.5px;
}

.nav-links { display: flex; align-items: center; gap: 24px; }
.nav-links a { color: var(--color-text-secondary); font-size: 15px; font-weight: 500; }
.nav-links a:hover { color: var(--color-text); }

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}
.mobile-menu-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--color-text);
    border-radius: 1px;
}

/* Buttons */
.btn, .btn-primary, .btn-outline, .btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 10px 20px;
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all 0.15s;
    text-decoration: none;
}

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

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

.btn-secondary {
    background: var(--color-bg-tertiary);
    color: var(--color-text);
}
.btn-secondary:hover { background: var(--color-border); }

.btn-text {
    background: none;
    border: none;
    color: var(--color-text-secondary);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    padding: 0;
}
.btn-text:hover { color: var(--color-text); }

.btn-lg { padding: 14px 28px; font-size: 16px; }
.btn-sm { padding: 6px 14px; font-size: 13px; }
.btn-full { width: 100%; }

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

/* Alerts */
.alert {
    padding: 12px 16px;
    border-radius: var(--radius);
    margin: 16px auto;
    max-width: var(--max-width);
    font-size: 14px;
}
.alert-error { background: #fef2f2; color: var(--color-error); border: 1px solid #fecaca; }
.alert-success { background: #f0fdf4; color: var(--color-success); border: 1px solid #bbf7d0; }
.alert-warning { background: #fffbeb; color: var(--color-warning); border: 1px solid #fde68a; }

/* Forms */
.form-group { margin-bottom: 20px; }
.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 6px;
}
.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    font-size: 15px;
    font-family: var(--font-stack);
    color: var(--color-text);
    background: var(--color-bg);
    transition: border-color 0.15s;
}
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}
.form-group .help-text {
    font-size: 13px;
    color: var(--color-text-muted);
    margin-top: 4px;
}

/* Cards */
.card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow);
}
.card-header { margin-bottom: 16px; }
.card-header h3 { font-size: 18px; font-weight: 600; }

/* Main content */
.main-content { min-height: calc(100vh - 64px - 200px); }

/* Container */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 16px;
}

/* Hero section */
.hero {
    padding: 80px 16px;
    text-align: center;
    background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-secondary) 100%);
}
.hero h1 {
    font-size: 48px;
    font-weight: 800;
    letter-spacing: -1px;
    line-height: 1.15;
    margin-bottom: 20px;
    color: var(--color-text);
}
.hero .subtitle {
    font-size: 20px;
    color: var(--color-text-secondary);
    max-width: 640px;
    margin: 0 auto 32px;
    line-height: 1.5;
}
.hero-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* Section */
.section {
    padding: 64px 16px;
    max-width: var(--max-width);
    margin: 0 auto;
}
.section-header {
    text-align: center;
    margin-bottom: 48px;
}
.section-header h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 12px;
}
.section-header p {
    font-size: 18px;
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* Grid */
.grid { display: grid; gap: 24px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }

/* Feature cards */
.feature-card {
    padding: 32px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    transition: box-shadow 0.15s;
}
.feature-card:hover { box-shadow: var(--shadow-lg); }
.feature-card .icon {
    width: 48px;
    height: 48px;
    border-radius: var(--radius);
    background: var(--color-primary-light);
    color: var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 16px;
}
.feature-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 8px; }
.feature-card p { font-size: 15px; color: var(--color-text-secondary); line-height: 1.5; }

/* Pricing */
.pricing-card {
    padding: 32px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background: var(--color-bg);
    text-align: center;
}
.pricing-card.featured {
    border-color: var(--color-primary);
    box-shadow: 0 0 0 1px var(--color-primary);
    position: relative;
}
.pricing-card.featured::before {
    content: 'Most Popular';
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-primary);
    color: #fff;
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}
.pricing-card .plan-name { font-size: 20px; font-weight: 600; margin-bottom: 8px; }
.pricing-card .price { font-size: 40px; font-weight: 800; margin-bottom: 4px; }
.pricing-card .price span { font-size: 16px; font-weight: 400; color: var(--color-text-secondary); }
.pricing-card .price-period { font-size: 14px; color: var(--color-text-muted); margin-bottom: 24px; }
.pricing-card ul { list-style: none; text-align: left; margin-bottom: 24px; }
.pricing-card li {
    padding: 8px 0;
    font-size: 14px;
    color: var(--color-text-secondary);
    border-bottom: 1px solid var(--color-border-light);
}
.pricing-card li::before { content: '\2713'; color: var(--color-success); margin-right: 8px; font-weight: 700; }

/* Table */
.table-wrapper { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 14px; }
th, td { padding: 12px 16px; text-align: left; border-bottom: 1px solid var(--color-border); }
th { font-weight: 600; background: var(--color-bg-secondary); }
tr:hover { background: var(--color-bg-secondary); }

/* Badge */
.badge {
    display: inline-flex;
    padding: 2px 10px;
    border-radius: 20px;
    font-size: 12px;
    font-weight: 600;
}
.badge-success { background: #d1fae5; color: #065f46; }
.badge-warning { background: #fef3c7; color: #92400e; }
.badge-error { background: #fee2e2; color: #991b1b; }
.badge-info { background: var(--color-primary-light); color: var(--color-primary-dark); }

/* Footer */
.site-footer {
    background: var(--color-bg-secondary);
    border-top: 1px solid var(--color-border);
    padding: 48px 16px 24px;
}
.footer-container { max-width: var(--max-width); margin: 0 auto; }
.footer-brand { margin-bottom: 24px; }
.footer-brand p { color: var(--color-text-secondary); font-size: 14px; margin-top: 4px; }
.footer-links { display: flex; gap: 48px; margin-bottom: 32px; }
.footer-links h4 { font-size: 14px; font-weight: 600; margin-bottom: 12px; }
.footer-links a { display: block; color: var(--color-text-secondary); font-size: 14px; margin-bottom: 8px; }
.footer-bottom { border-top: 1px solid var(--color-border); padding-top: 16px; }
.footer-bottom p { font-size: 13px; color: var(--color-text-muted); }

/* Dashboard layout */
.dashboard-layout { display: flex; min-height: calc(100vh - 64px); }
.sidebar {
    width: 240px;
    background: var(--color-bg-secondary);
    border-right: 1px solid var(--color-border);
    padding: 24px 16px;
    flex-shrink: 0;
}
.sidebar-nav a {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 10px 12px;
    border-radius: var(--radius);
    color: var(--color-text-secondary);
    font-size: 14px;
    font-weight: 500;
    margin-bottom: 2px;
}
.sidebar-nav a:hover, .sidebar-nav a.active {
    background: var(--color-primary-light);
    color: var(--color-primary);
}
.dashboard-content {
    flex: 1;
    padding: 32px;
    max-width: calc(var(--max-width) - 240px);
}
.dashboard-header {
    margin-bottom: 32px;
}
.dashboard-header h1 { font-size: 28px; font-weight: 700; }
.dashboard-header p { color: var(--color-text-secondary); margin-top: 4px; }

/* Stats grid */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin-bottom: 32px; }
.stat-card { padding: 20px; border: 1px solid var(--color-border); border-radius: var(--radius-lg); background: var(--color-bg); }
.stat-card .stat-label { font-size: 13px; color: var(--color-text-muted); font-weight: 500; }
.stat-card .stat-value { font-size: 28px; font-weight: 700; margin-top: 4px; }

/* Score display */
.score-circle {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    border: 4px solid var(--color-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 700;
    color: var(--color-primary);
}

/* Chat interface */
.chat-container {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    height: calc(100vh - 200px);
}
.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
}
.chat-bubble {
    max-width: 75%;
    padding: 14px 18px;
    border-radius: 16px;
    margin-bottom: 12px;
    font-size: 15px;
    line-height: 1.5;
}
.chat-bubble.assistant {
    background: var(--color-bg-tertiary);
    border-bottom-left-radius: 4px;
    margin-right: auto;
}
.chat-bubble.user {
    background: var(--color-primary);
    color: #fff;
    border-bottom-right-radius: 4px;
    margin-left: auto;
}
.chat-input-area {
    padding: 16px 24px;
    border-top: 1px solid var(--color-border);
    display: flex;
    gap: 12px;
    align-items: center;
}
.chat-input-area input {
    flex: 1;
    padding: 12px 16px;
    border: 1px solid var(--color-border);
    border-radius: 24px;
    font-size: 15px;
    font-family: var(--font-stack);
}
.chat-input-area input:focus {
    outline: none;
    border-color: var(--color-primary);
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-menu-toggle { display: flex; }
    .nav-links.open {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--color-bg);
        padding: 16px;
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow-lg);
    }
    .hero h1 { font-size: 32px; }
    .hero .subtitle { font-size: 17px; }
    .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
    .footer-links { flex-direction: column; gap: 24px; }
    .dashboard-layout { flex-direction: column; }
    .sidebar { width: 100%; border-right: none; border-bottom: 1px solid var(--color-border); padding: 12px 16px; }
    .sidebar-nav { display: flex; overflow-x: auto; gap: 4px; }
    .dashboard-content { padding: 16px; max-width: 100%; }
    .hero { padding: 48px 16px; }
    .section { padding: 40px 16px; }
}