/* ========================================================================
   TIMELINE - Universal Timeline Styles
   Alternating card layout, vertical centre line, pulsing nodes, scroll reveal.
   Two inline CSS custom properties are used for data-driven colour:
     --card-color  (per event, from category)
     --era-color   (per era section)
   No other inline styles. Honors prefers-reduced-motion.
   ======================================================================== */

/* ===== PAGE LAYOUT ===== */

.timeline-page {
    max-width: 1100px;
    margin: 0 auto;
    padding: var(--spacing-lg) var(--spacing-md);
}

.timeline-page__header {
    text-align: center;
    margin-bottom: var(--spacing-xxl);
}

.timeline-page__title {
    font-family: var(--font-heading);
    font-size: var(--font-size-h1);
    color: var(--accent-warm);
    margin-bottom: var(--spacing-sm);
}

.timeline-page__subtitle {
    color: var(--text-on-dark-secondary);
    font-size: var(--font-size-lg);
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
}

/* ===== CTA BLOCKS ===== */

.timeline-page__cta,
.timeline-page__footer-cta {
    background: var(--surface-base);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    margin: var(--spacing-lg) auto;
    max-width: 600px;
    text-align: center;
}

.timeline-page__cta p,
.timeline-page__footer-cta p {
    color: var(--text-on-dark-secondary);
    margin-bottom: var(--spacing-md);
}

.timeline-page__cta strong,
.timeline-page__footer-cta strong {
    color: var(--accent-warm);
}

.timeline-page__cta--progress {
    border-color: var(--accent-warm-transparent);
}

.timeline-page__footer-cta {
    margin-top: var(--spacing-xxl);
}

.timeline-page__footer-cta h2 {
    font-family: var(--font-heading);
    color: var(--text-on-dark);
    margin-bottom: var(--spacing-sm);
}

/* ===== LEGEND ===== */

.timeline-legend {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-xxl);
    padding: var(--spacing-md);
    background: var(--surface-base);
    border-radius: var(--radius-md);
}

.timeline-legend__item {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-xs);
    color: var(--text-on-dark-secondary);
    white-space: nowrap;
}

.timeline-legend__dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    flex-shrink: 0;
}

/* ===== TIMELINE STRUCTURE ===== */

.timeline {
    position: relative;
}

.timeline-empty {
    text-align: center;
    padding: var(--spacing-xxl);
    color: var(--text-on-dark-secondary);
    font-style: italic;
}

/* ===== ERA SECTIONS ===== */

.timeline__era {
    position: relative;
    padding: var(--spacing-xl) 0 var(--spacing-xxl);
}

/* Subtle era-coloured wash band */
.timeline__era::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--era-color, transparent);
    opacity: 0.04;
    pointer-events: none;
    z-index: 0;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.timeline__era-header {
    position: sticky;
    top: 0;
    z-index: 10;
    text-align: center;
    padding: var(--spacing-md) 0 var(--spacing-lg);
    pointer-events: none;
}

.timeline__era-pill {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 20px;
    font-family: var(--font-heading);
    font-size: var(--font-size-xs);
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--era-color, var(--accent-warm));
    border: 1px solid var(--era-color, var(--accent-warm));
    background: rgba(6, 11, 24, 0.85);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    pointer-events: auto;
}

/* ===== EVENTS CONTAINER + VERTICAL LINE ===== */

.timeline__era-events {
    position: relative;
    z-index: 1;
    padding: var(--spacing-md) 0;
}

.timeline__era-events::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    transform: translateX(-1px);
    background: linear-gradient(
        to bottom,
        transparent 0%,
        var(--era-color, var(--accent-warm)) 8%,
        var(--era-color, var(--accent-warm)) 92%,
        transparent 100%
    );
    z-index: 1;
}

/* ===== TIMELINE EVENT (alternating row) ===== */

.timeline-event {
    display: grid;
    grid-template-columns: 1fr 48px 1fr;
    align-items: center;
    margin-bottom: var(--spacing-xxl);
    position: relative;
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.timeline-event.is-visible {
    opacity: 1;
    transform: translateY(0);
}

.timeline-event__node {
    grid-column: 2;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    z-index: 5;
}

.timeline-event--left .timeline-event__card {
    grid-column: 1;
    margin-right: var(--spacing-md);
    text-align: right;
    border-right: 3px solid var(--card-color, var(--accent-warm));
}

.timeline-event--right .timeline-event__card {
    grid-column: 3;
    margin-left: var(--spacing-md);
    text-align: left;
    border-left: 3px solid var(--card-color, var(--accent-warm));
}

/* ===== NODE / DOT ===== */

.timeline-event__dot {
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--bg-base);
    border: 2px solid var(--card-color, var(--accent-warm));
    position: relative;
    z-index: 2;
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.timeline-event__dot::after {
    content: '';
    position: absolute;
    inset: -7px;
    border-radius: 50%;
    border: 1px solid var(--card-color, var(--accent-warm));
    opacity: 0;
    animation: timeline-pulse 3s ease infinite;
    pointer-events: none;
}

.timeline-event:hover .timeline-event__dot {
    transform: scale(1.4);
    box-shadow: 0 0 16px var(--card-color, var(--accent-warm));
}

@keyframes timeline-pulse {
    0%   { transform: scale(0.5); opacity: 0.6; }
    100% { transform: scale(1.8); opacity: 0; }
}

/* ===== TIMELINE CARDS ===== */

.timeline-event__card {
    background: var(--surface-base);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    transition: background var(--transition-normal), box-shadow var(--transition-normal), transform var(--transition-normal);
}

.timeline-event__card:hover {
    background: var(--surface-light);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.timeline-card__date {
    font-family: var(--font-heading);
    font-size: var(--font-size-xs);
    color: var(--card-color, var(--accent-warm));
    margin-bottom: var(--spacing-xs);
    letter-spacing: 0.05em;
}

.timeline-card__sfut {
    color: var(--accent-warm);
    font-weight: 500;
}

.timeline-card__title {
    font-family: var(--font-heading);
    font-size: var(--font-size-lg);
    color: var(--text-on-dark);
    margin: 0 0 var(--spacing-xs);
}

.timeline-card__subtitle {
    color: var(--text-on-dark-secondary);
    font-size: var(--font-size-sm);
    margin: 0 0 var(--spacing-md);
    font-style: italic;
}

.timeline-card__image {
    margin-bottom: var(--spacing-md);
    border-radius: var(--radius-sm);
    overflow: hidden;
}

.timeline-card__image img {
    width: 100%;
    height: auto;
    display: block;
}

.timeline-card__body {
    color: var(--text-on-dark-accent);
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

/* ===== DETAIL BLOCKS (gated content) ===== */

.timeline-card__detail {
    margin-top: var(--spacing-md);
    padding-top: var(--spacing-md);
    border-top: 1px solid var(--border-light);
}

/* Right-aligned cards keep details left-aligned for readability */
.timeline-event--left .timeline-card__detail,
.timeline-event--left .timeline-card__body {
    text-align: right;
}

.timeline-card__detail--unlocked {
    color: var(--text-on-dark-accent);
    font-size: var(--font-size-sm);
    line-height: 1.6;
}

.timeline-card__detail--just-unlocked {
    animation: timeline-reveal 0.6s ease-out;
}

@keyframes timeline-reveal {
    from { opacity: 0; transform: translateY(-8px); }
    to   { opacity: 1; transform: translateY(0); }
}

.timeline-card__detail--locked,
.timeline-card__detail--gated {
    text-align: center;
    padding: var(--spacing-md);
}

.timeline-unlock-btn {
    background: var(--surface-light);
    border: 1px dashed var(--accent-warm-transparent);
    border-radius: var(--radius-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    color: var(--accent-warm);
    cursor: pointer;
    font-size: var(--font-size-sm);
    transition: background var(--transition-fast), border-color var(--transition-fast);
}

.timeline-unlock-btn:hover {
    background: var(--surface-lighter);
    border-color: var(--accent-warm);
}

.timeline-unlock-btn__icon {
    font-size: var(--font-size-md);
}

.timeline-card__gate-msg {
    color: var(--text-on-dark-secondary);
    font-size: var(--font-size-sm);
    font-style: italic;
}

.timeline-card__detail--progress summary {
    color: var(--accent-warm);
    font-size: var(--font-size-sm);
    cursor: pointer;
    padding: var(--spacing-xs) 0;
}

.timeline-card__detail--progress summary:hover {
    color: var(--accent-warm-bright);
}

.timeline-card__detail-content {
    color: var(--text-on-dark-accent);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    padding-top: var(--spacing-sm);
}

/* ===== RESPONSIVE — collapse to single column ===== */

@media (max-width: 768px) {
    .timeline-page {
        padding: var(--spacing-md) var(--spacing-sm);
    }

    .timeline-page__title {
        font-size: var(--font-size-h2);
    }

    .timeline-event {
        grid-template-columns: 36px 1fr;
        margin-bottom: var(--spacing-xl);
    }

    .timeline-event__node {
        grid-column: 1;
    }

    .timeline-event--left .timeline-event__card,
    .timeline-event--right .timeline-event__card {
        grid-column: 2;
        margin-left: var(--spacing-md);
        margin-right: 0;
        text-align: left;
        border-left: 3px solid var(--card-color, var(--accent-warm));
        border-right: 1px solid var(--border);
    }

    .timeline-event--left .timeline-card__detail,
    .timeline-event--left .timeline-card__body {
        text-align: left;
    }

    .timeline__era-events::before {
        left: 18px;
        transform: none;
    }

    .timeline-legend {
        gap: var(--spacing-sm);
        padding: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    .timeline-event {
        grid-template-columns: 28px 1fr;
    }

    .timeline__era-events::before {
        left: 14px;
    }

    .timeline-event__card {
        padding: var(--spacing-md);
    }
}

/* ===== REDUCED MOTION ===== */

@media (prefers-reduced-motion: reduce) {
    .timeline-event {
        opacity: 1;
        transform: none;
        transition: none;
    }
    .timeline-event__dot::after {
        animation: none;
    }
    .timeline-event__card,
    .timeline-event:hover .timeline-event__dot {
        transition: none;
    }
}