.timeline.vertical {
    position: relative;
    margin-top: 3rem;
    padding-left: 2rem;
}

.timeline.vertical::before {
    content: '';
    position: absolute;
    left: 20px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(var(--accent-blue), var(--accent-purple));
}

.timeline-card {
    margin-bottom: 2rem;
    padding: 1.5rem 1.5rem 1.5rem 3rem;
    background: var(--glass);
    border: var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    position: relative;
    transform: translateX(-20px);
    opacity: 0.6;
    transition: transform 0.6s ease, opacity 0.6s ease;
}

.timeline-card::before {
    content: attr(data-year);
    position: absolute;
    left: -2.6rem;
    top: 1.2rem;
    writing-mode: vertical-rl;
    transform: rotate(180deg);
    letter-spacing: 0.1em;
    font-size: 0.75rem;
    color: var(--muted);
}

.timeline-card::after {
    content: '';
    position: absolute;
    left: 9px;
    top: 1.4rem;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--accent-mint);
    box-shadow: 0 0 15px rgba(110, 231, 183, 0.6);
}

.timeline-card ul {
    margin-top: 1rem;
    display: grid;
    gap: 0.5rem;
}

.timeline-card.active {
    transform: translateX(0);
    opacity: 1;
}