:root {
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-card: rgba(255,255,255,0.03);
    --bg-card-hover: rgba(255,255,255,0.06);
    --border: rgba(255,255,255,0.06);
    --border-accent: rgba(99,180,255,0.2);
    --text-primary: #f0f0f5;
    --text-secondary: rgba(240,240,245,0.6);
    --text-muted: rgba(240,240,245,0.45);
    --accent: #63b4ff;
    --accent-2: #a78bfa;
    --accent-3: #34d399;
    --accent-warm: #f59e0b;
    --gradient-1: linear-gradient(135deg, #63b4ff 0%, #a78bfa 100%);
    --gradient-2: linear-gradient(135deg, #34d399 0%, #63b4ff 100%);
    --gradient-3: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
    --radius: 16px;
    --radius-sm: 10px;
    --radius-xs: 6px;
}

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

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    overflow-x: hidden;
}

/* --- SVG ICON SYSTEM --- */
.icon-svg {
    width: 22px;
    height: 22px;
    stroke: currentColor;
    fill: none;
    stroke-width: 1.5;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.icon-svg-sm {
    width: 18px;
    height: 18px;
}

.icon-svg-lg {
    width: 28px;
    height: 28px;
}

/* --- BUTTONS --- */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.8rem 1.8rem;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
    font-family: inherit;
}

.btn-primary {
    background: var(--gradient-1);
    color: #0a0a0f;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(99,180,255,0.25);
}

.btn-secondary {
    background: rgba(255,255,255,0.05);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: rgba(255,255,255,0.08);
    border-color: rgba(255,255,255,0.12);
}

/* --- ICON DARK (for gradient bg buttons) --- */
.icon-dark { stroke: var(--bg-primary); }

/* --- SKIP LINK & SR-ONLY --- */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}

.sr-only:focus {
    position: fixed;
    top: 8px;
    left: 8px;
    width: auto;
    height: auto;
    padding: 0.75rem 1.5rem;
    margin: 0;
    overflow: visible;
    clip: auto;
    white-space: normal;
    background: var(--accent);
    color: #0a0a0f;
    font-weight: 600;
    font-size: 0.88rem;
    border-radius: var(--radius-xs);
    z-index: 9999;
}

.hidden { display: none !important; }

/* --- FOCUS STYLES --- */
.btn:focus-visible, .course-close:focus-visible,
.format-toggle button:focus-visible, .nav-hamburger:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* --- HOVER ONLY ON POINTER DEVICES --- */
@media (hover: none) {
    .btn-primary:hover,
    .btn-secondary:hover,
    .context-card:hover,
    .objective-item:hover,
    .question-card:hover,
    .scenario-card:hover,
    .material-item:hover,
    .diff-card:hover,
    .tl-card:hover,
    .stat-card:hover,
    .compare-card:hover,
    .feature-card:hover,
    .flow-step:hover,
    .meter-item:hover,
    .resource-link:hover {
        transform: none;
        box-shadow: none;
    }
}

/* --- REDUCED MOTION --- */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    .hero-bg .orb { animation: none; opacity: 0.1; }
    .hero-badge .dot { animation: none; opacity: 0.6; }
    html { scroll-behavior: auto; }
    .reveal { opacity: 1; transform: none; }
    .timeline-item { opacity: 1; transform: none; }
}