/* ═══════════════════════════════════════════════════════════
   DESIGN SYSTEM — Typography, spacing, cards, animations, palette.
   Additive; does not override existing styles unless used by new components.
   ═══════════════════════════════════════════════════════════ */

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

:root {
    /* Typography */
    --ds-font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --ds-font-mono: 'Fira Code', 'Consolas', monospace;

    /* Spacing (8px grid) */
    --ds-space-1: 8px;
    --ds-space-2: 16px;
    --ds-space-3: 24px;
    --ds-space-4: 32px;
    --ds-space-5: 40px;
    --ds-space-6: 48px;
    --ds-space-8: 64px;
    --ds-space-10: 80px;

    /* Radius */
    --ds-radius-sm: 8px;
    --ds-radius: 12px;
    --ds-radius-lg: 16px;
    --ds-radius-xl: 24px;
    --ds-radius-full: 9999px;

    /* Colors — modern palette */
    --ds-primary: #4f46e5;
    --ds-primary-hover: #4338ca;
    --ds-primary-light: #e0e7ff;
    --ds-accent: #7c3aed;
    --ds-accent-pink: #db2777;
    --ds-success: #059669;
    --ds-warning: #d97706;
    --ds-error: #dc2626;
    --ds-text: #1e293b;
    --ds-text-muted: #64748b;
    --ds-text-subtle: #94a3b8;
    --ds-surface: #ffffff;
    --ds-surface-elevated: #f8fafc;
    --ds-border: #e2e8f0;
    --ds-border-light: #f1f5f9;

    /* Shadows */
    --ds-shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --ds-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08), 0 2px 4px -2px rgba(0, 0, 0, 0.06);
    --ds-shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.08), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
    --ds-shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.08), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
    --ds-shadow-glow: 0 0 40px rgba(79, 70, 229, 0.15);

    /* Transitions */
    --ds-transition-fast: 150ms ease;
    --ds-transition: 250ms ease;
    --ds-transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Base typography when design-system is in use */
.ds-root,
.ds-page {
    font-family: var(--ds-font-sans);
    color: var(--ds-text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.ds-heading-1 {
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    line-height: 1.2;
    color: var(--ds-text);
}

.ds-heading-2 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 700;
    letter-spacing: -0.01em;
    color: var(--ds-text);
}

.ds-heading-3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--ds-text);
}

.ds-body {
    font-size: 1rem;
    color: var(--ds-text-muted);
    line-height: 1.7;
}

.ds-body-sm {
    font-size: 0.875rem;
    color: var(--ds-text-muted);
}

/* Card */
.ds-card {
    background: var(--ds-surface);
    border-radius: var(--ds-radius-lg);
    border: 1px solid var(--ds-border);
    box-shadow: var(--ds-shadow);
    padding: var(--ds-space-4);
    transition: box-shadow var(--ds-transition), transform var(--ds-transition), border-color var(--ds-transition);
}

.ds-card:hover {
    box-shadow: var(--ds-shadow-md);
    border-color: var(--ds-border-light);
}

.ds-card-elevated {
    background: var(--ds-surface-elevated);
    box-shadow: var(--ds-shadow-md);
}

/* Buttons */
.ds-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--ds-space-1);
    font-family: var(--ds-font-sans);
    font-size: 0.9375rem;
    font-weight: 600;
    padding: 12px 24px;
    border-radius: var(--ds-radius);
    border: none;
    cursor: pointer;
    transition: background-color var(--ds-transition-fast), transform var(--ds-transition-fast), box-shadow var(--ds-transition-fast);
}

.ds-btn:active {
    transform: scale(0.98);
}

.ds-btn-primary {
    background: linear-gradient(135deg, var(--ds-primary), var(--ds-accent));
    color: #fff;
    box-shadow: 0 2px 8px rgba(79, 70, 229, 0.35);
}

.ds-btn-primary:hover {
    background: linear-gradient(135deg, var(--ds-primary-hover), #6d28d9);
    box-shadow: 0 4px 12px rgba(79, 70, 229, 0.4);
}

.ds-btn-secondary {
    background: var(--ds-surface);
    color: var(--ds-text);
    border: 1px solid var(--ds-border);
}

.ds-btn-secondary:hover {
    background: var(--ds-surface-elevated);
    border-color: var(--ds-primary-light);
    color: var(--ds-primary);
}

.ds-btn-ghost {
    background: transparent;
    color: var(--ds-text-muted);
}

.ds-btn-ghost:hover {
    background: var(--ds-surface-elevated);
    color: var(--ds-text);
}

/* Layout */
.ds-container {
    max-width: 1100px;
    margin: 0 auto;
    padding-left: var(--ds-space-3);
    padding-right: var(--ds-space-3);
}

.ds-section {
    padding-top: var(--ds-space-8);
    padding-bottom: var(--ds-space-8);
}

/* Animations */
@keyframes ds-fade-in {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes ds-scale-in {
    from { opacity: 0; transform: scale(0.96); }
    to { opacity: 1; transform: scale(1); }
}

.ds-animate-in {
    animation: ds-fade-in 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
}

.ds-animate-scale {
    animation: ds-scale-in 0.4s cubic-bezier(0.16, 1, 0.3, 1) both;
}

/* Responsive */
@media (max-width: 768px) {
    .ds-container {
        padding-left: var(--ds-space-2);
        padding-right: var(--ds-space-2);
    }
    .ds-section {
        padding-top: var(--ds-space-6);
        padding-bottom: var(--ds-space-6);
    }
}