/* ========================================
   Teacher's Pet — Shared Utilities
   Scroll animations, transitions, patterns
   ======================================== */

/* Scroll-triggered fade-in */
.animate-on-scroll {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s cubic-bezier(0.16, 1, 0.3, 1),
                transform 0.6s cubic-bezier(0.16, 1, 0.3, 1);
}

.animate-on-scroll.in-view {
    opacity: 1;
    transform: translateY(0);
}

/* Staggered children */
.animate-on-scroll.in-view > *:nth-child(1) { transition-delay: 0ms; }
.animate-on-scroll.in-view > *:nth-child(2) { transition-delay: 80ms; }
.animate-on-scroll.in-view > *:nth-child(3) { transition-delay: 160ms; }
.animate-on-scroll.in-view > *:nth-child(4) { transition-delay: 240ms; }

/* Gradient text utility */
.text-gradient {
    background: linear-gradient(135deg, var(--krishna-indigo), var(--krishna-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.text-gradient-gold {
    background: linear-gradient(135deg, var(--divine-gold), var(--coral-vermillion));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Fluid typography presets */
.heading-xl {
    font-size: clamp(2.5rem, 2rem + 4vw, 4.5rem);
    font-weight: 700;
    letter-spacing: -0.04em;
    line-height: 1.05;
}

.heading-lg {
    font-size: clamp(2rem, 1.5rem + 3vw, 3.5rem);
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
}

.heading-md {
    font-size: clamp(1.5rem, 1.25rem + 1.5vw, 2.25rem);
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
}

/* Glass panel utility */
.glass-panel {
    background: rgba(255, 255, 255, 0.06);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(255, 255, 255, 0.08);
    border-radius: var(--radius-lg);
}

/* Pill button */
.btn-pill {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: 9999px;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    border: none;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.btn-pill-primary {
    background: linear-gradient(135deg, var(--krishna-indigo), var(--krishna-light));
    color: white;
    box-shadow: 0 4px 16px rgba(76, 29, 149, 0.3);
}

.btn-pill-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(76, 29, 149, 0.4);
}

.btn-pill-gold {
    background: linear-gradient(135deg, var(--divine-gold), #c9a030);
    color: var(--warm-charcoal);
    box-shadow: 0 4px 16px rgba(212, 175, 55, 0.3);
}

.btn-pill-gold:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(212, 175, 55, 0.4);
}

/* Arrow slide on hover */
.btn-pill .btn-arrow {
    display: inline-block;
    transition: transform 0.3s ease;
}

.btn-pill:hover .btn-arrow {
    transform: translateX(4px);
}

/* Visually hidden (for screen readers) */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}