/* ========== 1. Tokens & reveal baseline ========== */
.ab-container {
    --ab-radius: 20px;
    --ab-radius-sm: 14px;
    --ab-accent: #3B82F6;
    --ab-ink: #0F172A;
    --ab-ink-2: #334155;
    --ab-mute: #64748B;
    --ab-line: #E2E8F0;
    --ab-bg: #FFFFFF;
    --ab-tint: #F8FAFC;
    --ab-ease: cubic-bezier(0.16, 1, 0.3, 1);
    width: 100%;
    max-width: 1080px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: clamp(2.5rem, 5vw, 4rem);
    padding: 2rem 0;
}

.ab-reveal {
    opacity: 0;
    transform: translateY(28px);
    transition: opacity 0.9s var(--ab-ease), transform 0.9s var(--ab-ease);
}

.ab-reveal.ab-in {
    opacity: 1;
    transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
    .ab-reveal { opacity: 1; transform: none; transition: none; }
}

/* ========== 2. Section header ========== */
.ab-section {
    display: block;
}

.ab-section-head {
    margin-bottom: 1.75rem;
}

.ab-section-tag {
    display: inline-block;
    font-size: 0.72rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--ab-accent);
    margin-bottom: 0.85rem;
}

.ab-section-h2 {
    font-size: clamp(1.5rem, 2.6vw, 2rem);
    font-weight: 700;
    color: var(--ab-ink);
    letter-spacing: -0.01em;
    margin: 0;
}

/* ========== 3. Timeline ========== */
.ab-timeline {
    list-style: none;
    margin: 0;
    padding: 0;
    position: relative;
}

.ab-timeline::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 88px;
    width: 1px;
    background: linear-gradient(180deg, transparent 0%, var(--ab-line) 8%, var(--ab-line) 92%, transparent 100%);
}

.ab-timeline-item {
    position: relative;
    padding: 0 0 1.75rem 130px;
    transition: transform 0.5s var(--ab-ease), opacity 0.5s var(--ab-ease);
}

.ab-timeline-item::before {
    content: "";
    position: absolute;
    top: 0.5rem;
    left: 84px;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--ab-bg);
    border: 2px solid var(--ab-accent);
    transition: transform 0.35s var(--ab-ease), background 0.35s var(--ab-ease);
}

.ab-timeline-item:hover::before {
    transform: scale(1.4);
    background: var(--ab-accent);
}

.ab-timeline-year {
    position: absolute;
    top: 0.1rem;
    left: 0;
    width: 70px;
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--ab-accent);
    font-variant-numeric: tabular-nums;
    letter-spacing: 0.05em;
}

.ab-timeline-item h4 {
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--ab-ink);
    margin: 0 0 0.25rem;
}

.ab-timeline-item p {
    font-size: 0.88rem;
    line-height: 1.6;
    color: var(--ab-mute);
    margin: 0;
    max-width: 540px;
}

/* ========== 4. Responsive ========== */
@media (max-width: 600px) {
    .ab-timeline::before { left: 18px; }
    .ab-timeline-item { padding: 0 0 1.5rem 50px; }
    .ab-timeline-item::before { left: 14px; }
    .ab-timeline-year { position: static; margin-bottom: 0.25rem; }
}