/* ==========================================
   1. DESKTOP / BASE STYLES
   ========================================== */
.timeline-container {
    overflow-x: auto;
}

.timeline-content {
    min-width: 850px;
}

.timeline-ruler {
    display: flex;
    justify-content: space-between;
    border-bottom: 2px solid var(--bs-primary, #06A3DA);
    position: relative;
    padding-bottom: 8px;
}

.ruler-year {
    position: relative;
    font-weight: 700;
    font-size: 16px;
    flex: 1;
    text-align: center;
}

.ruler-year::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 10px;
    background-color: var(--bs-primary, #06A3DA);
}

.timeline-ticks {
    display: flex;
    justify-content: space-between;
    height: 12px;
    margin-top: 2px;
    margin-bottom: 20px;
    border-bottom: 1px solid #dee2e6;
}

.tick-line {
    width: 1px;
    height: 6px;
    background-color: #adb5bd;
}

.timeline-grid {
    display: flex;
    justify-content: space-between;
    position: relative;
}

.timeline-column {
    flex: 1;
    border-right: 1px dashed #dee2e6;
    padding: 0 10px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    min-height: 460px;
}

.timeline-column:last-child {
    border-right: none;
}

.milestone-card {
    background: #ffffff;
    padding: 10px;
    border: 1px solid #e9ecef;
    border-radius: 5px;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
}

.milestone-year {
    font-size: 15px;
    font-weight: 700;
}

.milestone-text {
    font-size: 13px;
    color: #6c757d;
    line-height: 1.4;
    margin-bottom: 0;
}

.spacer-top {
    margin-top: 50px;
}


/* ==========================================
   2. MOBILE RESPONSIVE STYLES (<= 768px)
   ========================================== */
@media (max-width: 768px) {
    .timeline-content {
        min-width: 100% !important;
    }

    .timeline-ruler, 
    .timeline-ticks {
        display: none !important;
    }

    .timeline-grid {
        flex-direction: column;
        gap: 25px;
    }

    .timeline-column {
        border-right: none !important;
        border-left: 3px solid var(--bs-primary, #06A3DA);
        padding-left: 20px;
        padding-right: 0;
        min-height: auto !important;
    }

    .spacer-top {
        margin-top: 0 !important;
    }
    
    .milestone-card {
        margin-bottom: 15px;
    }
}