/* ═══════════════════════════════════════════════════
   ZIGZAG TIMELINE  —  single source of truth
   ═══════════════════════════════════════════════════ */

/* Wrapper */
.timeline-center {
    position: relative;
    max-width: 1000px;
    margin: 40px auto;
    padding: 20px 0 60px;
    overflow: visible;
}

/* ── Vertical center line ── */
.timeline-center::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    transform: translateX(-50%);
    width: 3px;
    background: linear-gradient(to bottom,
            transparent 0%,
            var(--electric-blue) 8%,
            var(--neon-violet) 50%,
            var(--electric-blue) 92%,
            transparent 100%);
    /*
     * THREE PARALLEL LINES via box-shadow:
     * - Center line  : the element itself at 50%
     * - Left track   : box-shadow offset -12px  (electric blue) — tight rail
     * - Right track  : box-shadow offset +12px  (neon violet)  — tight rail
     */
    box-shadow:
        -12px 0 0 0 rgba(0, 243, 255, 0.5),
        12px 0 0 0 rgba(138, 43, 226, 0.5),
        0 0 10px var(--electric-blue),
        0 0 24px rgba(138, 43, 226, 0.6);
    animation: tlPulse 2.5s ease-in-out infinite alternate;
    z-index: 0;
}

@keyframes tlPulse {
    0% {
        box-shadow:
            -12px 0 0 0 rgba(0, 243, 255, 0.25),
            12px 0 0 0 rgba(138, 43, 226, 0.25),
            0 0 6px var(--electric-blue),
            0 0 14px rgba(138, 43, 226, 0.4);
        opacity: 0.8;
    }

    100% {
        box-shadow:
            -12px 0 0 0 rgba(0, 243, 255, 0.75),
            12px 0 0 0 rgba(138, 43, 226, 0.75),
            0 0 18px var(--electric-blue),
            0 0 36px rgba(138, 43, 226, 0.8);
        opacity: 1;
    }
}

/* Clearfix so the container wraps floated children */
.timeline-center::after {
    content: '';
    display: table;
    clear: both;
}

/* ── Each card ── */
.timeline-item {
    position: relative;
    width: calc(50% - 110px);
    /* 50% minus gap to center line — wider breathing room */
    margin-bottom: 50px;
    padding: 26px 24px;
    z-index: 1;
    overflow: visible !important;
    box-sizing: border-box;
}

/* LEFT cards float left */
.timeline-item.left {
    float: left;
    clear: left;
    text-align: left;
}

/* RIGHT cards float right — staggered DOWN so cards zigzag vertically */
.timeline-item.right {
    float: right;
    clear: right;
    text-align: left;
    margin-top: 130px;
    /* ← stagger: right card drops below left card */
}

/* ── Horizontal connector line ── */
.timeline-item::after {
    content: '';
    position: absolute;
    top: 34px;
    /* vertically centred on the dot */
    height: 2px;
    width: 110px;
    /* spans the wider gap to the center line */
    background: linear-gradient(to right, var(--electric-blue), var(--neon-violet));
    opacity: 0.7;
    z-index: 1;
    transition: opacity 0.3s, box-shadow 0.3s;
}

/* connector for LEFT card goes RIGHT toward center line */
.timeline-item.left::after {
    right: -110px;
}

/* connector for RIGHT card goes LEFT toward center line */
.timeline-item.right::after {
    left: -110px;
    background: linear-gradient(to left, var(--electric-blue), var(--neon-violet));
}

.timeline-item:hover::after {
    opacity: 1;
    box-shadow: 0 0 10px var(--neon-green), 0 0 20px var(--neon-green);
}

/* ── Dot that sits exactly on the center line ── */
/*
   Card width = calc(50% - 110px)
   → right edge of left card is at [calc(50% - 110px)] from container left
   → distance to 50% center = 110px
   Dot is 20px wide → half = 10px
   → right: -(110px + 10px) = -120px places dot CENTER at 50%   ✓
   Same logic for right cards with left: -120px
*/
.tl-dot {
    position: absolute;
    top: 24px;
    /* (34px connector top) - (10px half dot) = 24px */
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--bg-void);
    border: 3px solid var(--electric-blue);
    box-shadow: 0 0 12px var(--electric-blue);
    z-index: 3;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.timeline-item.left .tl-dot {
    right: -120px;
}

.timeline-item.right .tl-dot {
    left: -120px;
}

.timeline-item:hover .tl-dot {
    transform: scale(1.4);
    box-shadow: 0 0 20px currentColor, 0 0 40px currentColor;
}

/* ════════════════════════════════════════════
   TIMELINE FLIP CARD  —  inner mechanism
   The outer .timeline-item handles layout/float.
   The flip lives entirely inside .tl-flip-wrapper.
   ════════════════════════════════════════════ */

/* Perspective host — fills the timeline-item */
.tl-flip-wrapper {
    perspective: 1200px;
    width: 100%;
}

/* Rotating container */
.tl-card-inner {
    position: relative;
    width: 100%;
    transform-style: preserve-3d;
    transition: transform 0.75s cubic-bezier(0.4, 0.2, 0.2, 1);
}

/* Flipped state (toggled via JS onclick) */
.tl-card-inner.is-flipped {
    transform: rotateY(180deg);
}

/* Shared face styles */
.tl-front,
.tl-back {
    width: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    border-radius: 16px;
    padding: 26px 24px;
    box-sizing: border-box;
}

/* Front face — visible by default */
/* inherits glass-plate styles */

/* Back face — rotated 180° so it starts hidden */
.tl-back {
    position: absolute;
    top: 0;
    left: 0;
    transform: rotateY(180deg);
    background: rgba(8, 3, 20, 0.92);
    border: 2px solid var(--glass-border);
    display: flex;
    flex-direction: column;
    gap: 14px;
}

/* Image box on back face */
.tl-back-img {
    width: 100%;
    height: 150px;
    border-radius: 10px;
    overflow: hidden;
    border: 2px solid var(--electric-blue);
    flex-shrink: 0;
}

.tl-back-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.85;
    transition: opacity 0.3s;
}

.tl-back-img img:hover {
    opacity: 1;
}

/* Subtle flip-hint label */
.tl-flip-hint {
    display: flex;
    align-items: center;
    gap: 6px;
    font-family: 'Orbitron', sans-serif;
    font-size: 0.65rem;
    color: var(--text-secondary);
    opacity: 0.55;
    letter-spacing: 1px;
    text-transform: uppercase;
    margin-top: auto;
    transition: opacity 0.3s;
}

.tl-front:hover .tl-flip-hint,
.tl-back:hover .tl-flip-hint {
    opacity: 1;
    color: var(--neon-green);
}

/* Give each timeline-item a min-height so the absolute back face doesn't collapse it */
.timeline-item {
    min-height: 200px;
}

.chronology-data-block {
    margin-bottom: 40px;
}

.block-timestamp {
    font-family: 'Orbitron', sans-serif;
    color: var(--neon-green);
    font-weight: 800;
    font-size: 1.1rem;
    margin-bottom: 12px;
    letter-spacing: 2px;
}

.chronology-data-block h3 {
    font-family: 'Orbitron', sans-serif;
    font-size: 1.5rem;
    margin-bottom: 6px;
}

.chronology-data-block h4 {
    color: var(--electric-blue);
    font-weight: 500;
    margin-bottom: 16px;
}