/* ============================================
   ENHANCEMENTS — Stats, Back-to-Top, Card Tilt,
   Particle Canvas, Parallax Grid
   ============================================ */

/* ---- PARTICLE CANVAS ---- */
.particles-canvas {
    position: fixed;
    inset: 0;
    z-index: -1;
    pointer-events: none;
    opacity: 0.5;
    transition: opacity var(--transition-smooth);
}

[data-theme="dark"] .particles-canvas {
    opacity: 0.35;
}

@media (prefers-reduced-motion: reduce) {
    .particles-canvas {
        display: none;
    }
}

/* ---- STATS SECTION ---- */
.section--stats {
    padding: var(--space-2xl) 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-xl);
    max-width: 800px;
    margin: 0 auto;
}

.stat {
    text-align: center;
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    background: var(--bg-card);
    border: 1px solid var(--border-card);
    transition:
        transform var(--transition-smooth),
        box-shadow var(--transition-smooth),
        background-color var(--transition-smooth),
        border-color var(--transition-smooth);
}

.stat:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--border-hover);
}

.stat__number {
    font-family: var(--font-heading);
    font-size: clamp(2rem, 4vw, 2.75rem);
    font-weight: 800;
    background: linear-gradient(135deg, var(--purple-deep), var(--purple-glow));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.1;
}

.stat__suffix {
    font-family: var(--font-heading);
    font-size: clamp(1.5rem, 3vw, 2rem);
    font-weight: 700;
    background: linear-gradient(135deg, var(--purple-deep), var(--purple-glow));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat__label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-secondary);
    margin-top: var(--space-xs);
    transition: color var(--transition-smooth);
}

/* Stats responsive */
@media (max-width: 768px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-md);
    }
}

@media (max-width: 400px) {
    .stats-grid {
        grid-template-columns: 1fr 1fr;
        gap: var(--space-sm);
    }

    .stat {
        padding: var(--space-md);
    }
}

/* ---- BACK TO TOP BUTTON ---- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    z-index: 900;
    width: 46px;
    height: 46px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, var(--purple-deep), var(--purple-vivid));
    color: var(--text-on-purple);
    font-size: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 20px rgba(74, 45, 138, 0.35);
    opacity: 0;
    visibility: hidden;
    transform: translateY(16px);
    transition:
        opacity var(--transition-smooth),
        visibility var(--transition-smooth),
        transform var(--transition-smooth),
        box-shadow var(--transition-fast);
    cursor: pointer;
    border: none;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    box-shadow: 0 6px 28px rgba(74, 45, 138, 0.5);
    transform: translateY(-3px);
}

.back-to-top:active {
    transform: translateY(0);
}

@media (max-width: 480px) {
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 0.9rem;
    }
}

/* ---- CARD TILT (3D hover via JS) ---- */
.project-card {
    transform-style: preserve-3d;
    perspective: 1000px;
}

.project-card.tilt-active {
    transition: box-shadow var(--transition-smooth), border-color var(--transition-smooth);
}

.project-card__body {
    transform: translateZ(0);
    /* ensure child content stays crisp */
}

/* Inner glow on tilt */
.project-card.tilt-active::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius-lg);
    background: radial-gradient(circle at var(--mouse-x, 50%) var(--mouse-y, 50%),
            rgba(167, 139, 250, 0.08) 0%,
            transparent 60%);
    pointer-events: none;
    opacity: 0;
    transition: opacity var(--transition-fast);
}

.project-card.tilt-active:hover::after {
    opacity: 1;
}