/* ========================================
   AutoLearn AI - Design System (TradingAI Theme)
   ======================================== */

/* Import Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Outfit:wght@500;600;700;800;900&display=swap');

/* ========================================
   CSS Variables (Design Tokens)
   ======================================== */

:root {
    /* TradingAI Palette (Dark Mode Native) */
    --color-bg: #0b1120; /* Deep Navy text-slate-900 like */
    --color-bg-secondary: #1e293b; /* Slate-800 for cards */
    --color-bg-tertiary: #334155; /* Slate-700 */
    
    --color-primary: #3b82f6; /* Blue-500 */
    --color-primary-light: #60a5fa;
    --color-primary-dark: #2563eb;
    
    --color-accent: #0ea5e9; /* Sky-500 */
    --color-success: #10b981; /* Emerald-500 */
    --color-warning: #f59e0b; /* Amber-500 */
    --color-error: #ef4444; /* Red-500 */
    
    --color-text: #f1f5f9; /* Slate-100 */
    --color-text-secondary: #94a3b8; /* Slate-400 */
    --color-text-tertiary: #64748b; /* Slate-500 */
    
    --color-border: #334155; /* Slate-700 */
    --color-border-light: #475569;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%);
    --gradient-accent: linear-gradient(135deg, #0ea5e9 0%, #3b82f6 100%);
    --gradient-glow: radial-gradient(circle at center, rgba(59, 130, 246, 0.15) 0%, transparent 70%);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 20px rgba(59, 130, 246, 0.4);
    
    /* Typography */
    --font-sans: 'Inter', system-ui, -apple-system, sans-serif;
    --font-display: 'Outfit', var(--font-sans);
    
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    
    /* Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-full: 9999px;
    
    /* Animations */
    --transition-base: 200ms ease-in-out;
}

/* Light Mode Overrides (Optional - but strictly TradingAI is dark) */
[data-theme="light"] {
    --color-bg: #f8fafc;
    --color-bg-secondary: #ffffff;
    --color-bg-tertiary: #f1f5f9;
    --color-text: #0f172a;
    --color-text-secondary: #475569;
    --color-border: #cbd5e1;
}

/* ========================================
   Base Styles
   ======================================== */

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

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

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

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    color: white; /* Always white for contrast in dark theme */
    line-height: 1.2;
    margin-bottom: var(--space-4);
}

h1 { font-size: var(--font-size-5xl); font-weight: 800; letter-spacing: -0.02em; }
h2 { font-size: var(--font-size-4xl); font-weight: 700; letter-spacing: -0.01em; }
h3 { font-size: var(--font-size-2xl); font-weight: 700; }

a { color: var(--color-primary-light); text-decoration: none; transition: var(--transition-base); }
a:hover { color: var(--color-primary); }

/* ========================================
   Components
   ======================================== */

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-3) var(--space-6);
    border-radius: var(--radius-lg);
    font-weight: 600;
    transition: var(--transition-base);
    cursor: pointer;
    border: none;
    font-size: var(--font-size-sm);
    letter-spacing: 0.02em;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: 0 0 15px rgba(59, 130, 246, 0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 25px rgba(59, 130, 246, 0.6);
}

.btn-secondary {
    background: var(--color-bg-tertiary);
    color: white;
    border: 1px solid var(--color-border);
}

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

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

.btn-outline:hover {
    background: rgba(59, 130, 246, 0.1);
    color: white;
}

.btn-lg { padding: var(--space-4) var(--space-8); font-size: var(--font-size-base); }
.btn-sm { padding: var(--space-2) var(--space-4); font-size: var(--font-size-xs); }

/* Cards */
.card {
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-6);
    transition: var(--transition-base);
}

.card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}

.feature-icon {
    width: 50px;
    height: 50px;
    background: rgba(59, 130, 246, 0.1);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: var(--space-4);
    color: var(--color-primary-light);
    border: 1px solid rgba(59, 130, 246, 0.2);
}

/* Pricing Cards */
.pricing-card.popular {
    background: linear-gradient(180deg, var(--color-bg-secondary) 0%, rgba(37, 99, 235, 0.1) 100%);
    border-color: var(--color-primary);
    box-shadow: 0 0 30px rgba(59, 130, 246, 0.15);
}

.price {
    font-size: 3rem;
    font-weight: 800;
    color: white;
    margin: var(--space-4) 0;
}

.price-currency {
    color: var(--color-primary);
    font-size: 1.5rem;
    vertical-align: super;
}

.popular-badge {
    background: var(--color-primary);
    color: white;
    padding: 4px 12px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 700;
    position: absolute;
    top: -12px;
    right: 20px;
    box-shadow: 0 4px 10px rgba(59, 130, 246, 0.4);
}

/* ========================================
   Layout & Sections
   ======================================== */

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--space-6);
}

nav {
    border-bottom: 1px solid var(--color-border);
    background: rgba(11, 17, 32, 0.8);
    backdrop-filter: blur(12px);
    position: fixed;
    width: 100%;
    z-index: 100;
    top: 0;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.logo {
    font-family: var(--font-display);
    font-weight: 800;
    font-size: 1.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links { display: flex; gap: var(--space-8); align-items: center; }
.nav-links a { font-weight: 500; font-size: 0.95rem; color: var(--color-text-secondary); }
.nav-links a:hover { color: white; }
.nav-links .btn { color: white !important; }

/* Hero */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: radial-gradient(circle at 50% 0%, rgba(37, 99, 235, 0.15), transparent 60%);
    padding-top: 80px;
}

.hero h1 {
    font-size: 4.5rem;
    margin-bottom: var(--space-6);
}

.text-gradient {
    background: linear-gradient(to right, #60a5fa, #3b82f6, #0ea5e9);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* Grids */
.features-grid, .pricing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--space-6);
    margin-top: var(--space-12);
}

/* Footer */
footer {
    border-top: 1px solid var(--color-border);
    margin-top: var(--space-20);
    padding: var(--space-12) 0;
    background: var(--color-bg);
}

/* Utilities */
.text-center { text-align: center; }
.fade-in { animation: fadeIn 0.8s ease-out forwards; opacity: 0; transform: translateY(20px); }
@keyframes fadeIn { to { opacity: 1; transform: translateY(0); } }

/* Responsive */
@media(max-width: 768px) {
    .hero h1 { font-size: 3rem; }
    .features-grid, .pricing-grid { grid-template-columns: 1fr; }
    .nav-links { display: none; } /* Mobile menu simplified/hidden for this demo */
}