/* Timeline Container */
.timeline-container {
    position: relative;
    max-width: 900px;
    padding: 4rem 0;
    margin: 2rem 0;
}

/* Vertical Timeline Line - runs through center column */
.timeline-line {
    position: absolute;
    left: 110px; /* left column (80px) + half center column (30px) */
    top: 0;
    bottom: 0;
    width: 2px;
    background: repeating-linear-gradient(
        to bottom,
        rgba(0, 0, 0, 0.1) 0px,
        rgba(0, 0, 0, 0.1) 6px,
        transparent 6px,
        transparent 10px
    );
    z-index: 1;
    pointer-events: none;
}


/* Timeline Item */
.timeline-item {
    position: relative;
    display: flex;
    flex-direction: row;
    align-items: start;
    margin-bottom: 4rem;
    padding-left: 0;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.3s ease-out, transform 0.3s ease-out;
    gap: 1rem;
}

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

/* Left Column - Year Tag */
.timeline-left {
    width: 80px;
    min-width: 80px;
    display: flex;
    justify-content: flex-end;
    align-items: center;
    margin-top: 0.4rem;
    margin-left: 0.45rem;
}

/* Circle Marker on Timeline Line */
.timeline-marker {
    position: absolute;
    left: 110px; /* Same as timeline line position (80px left + 30px center) */
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: #333;
    border: 2px solid #fff;
    transform: translateX(-50%) translateY(-50%);
    z-index: 2;
    transition: all 0.2s ease-out;
    box-sizing: border-box;
    /* Aligned with title center: content padding (1.5rem) + half title line-height (2rem * 1.2 / 2 = 1.2rem) = 2.7rem */
    margin-top: 1.25rem;
    margin-left: 0.06rem;
}


/* Timeline Content */
.timeline-content {
    flex: 1;
    max-width: 600px;
    padding: 0;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    margin-left: 3rem;
}

.timeline-title {
    font-family: "Henrietta Regular";
    font-size: 2rem;
    line-height: 1.2;
    margin: 0 0 0.5rem 0;
    color: #333;
    letter-spacing: -0.02em;
    /* Aligned center with marker/year at 2.7rem */
    /* Title center: padding-top (1.5rem) + half line-height (2rem * 1.2 / 2 = 1.2rem) = 2.7rem */
}

.timeline-meta {
    margin-top: 0.6rem;
    margin-bottom: 1rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    align-items: center;
}

/* Tag Styles */
.timeline-tag {
    display: inline-block;
    /* background: rgb(233, 233, 233); */
    padding: 0.2em 0.6em;
    margin: 0;
    border-radius: 999px;
    border: 1px solid #dedcd2;
    font-size: 0.85em;
    font-family: "FranklinGothicURW-Boo", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    color: #333;
    line-height: 1.4;
    transition: all 0.2s ease-out;
}

/* Year Tag on Timeline */
.timeline-tag-year {
    background: var(--very-light-yellow);
    font-weight: 600;
    white-space: nowrap;
    /* Naturally positioned in timeline-left column, aligned via flexbox */
}


.timeline-description {
    font-size: 1.4em;
    line-height: 1.5;
    color: #333;
    margin: 1rem 0;
    font-family: "FranklinGothicURW-Boo", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

.timeline-link {
    display: inline-block;
    margin-top: 1rem;
    font-size: 1.4em;
    color: #333;
    text-decoration: none;
    font-family: "FranklinGothicURW-Boo", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    position: relative;
    transition: color 0.2s ease;
    width: fit-content;
    align-self: flex-start;
}

.timeline-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--link-underline-color, #5452B7);
    transition: width 0.3s ease-out;
}

.timeline-link:hover {
    color: #000;
}

.timeline-link:hover::after {
    width: 100%;
}


/* Reduced motion support - disable all animations */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
    
    /* Ensure timeline items are visible immediately */
    .timeline-item {
        opacity: 1;
        transform: none;
    }
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .timeline-container {
        padding: 2rem 0;
        margin: 1rem 0;
    }
    
    .timeline-line {
        left: 60px; /* Adjusted for smaller column widths on mobile */
    }
    
    .timeline-item {
        margin-bottom: 3rem;
        gap: 0.75rem;
    }
    
    .timeline-left {
        width: 50px;
        min-width: 50px;
    }
    
    .timeline-marker {
        left: 60px; /* Adjusted for mobile: 50px left + 10px */
        width: 12px;
        height: 12px;
        top: calc(1rem + 0.96rem); /* content padding + half title line-height for mobile */
    }
    
    .timeline-content {
        max-width: 100%;
        padding: 0;
    }
    
    .timeline-title {
        font-size: 1.6rem;
        margin-top: 0;
    }
    
    .timeline-description {
        font-size: 1.2em;
    }
    
    .timeline-tag {
        font-size: 0.8em;
        padding: 0.15em 0.5em;
    }
    
    .timeline-link {
        font-size: 1.2em;
        min-height: 44px;
        display: inline-flex;
        align-items: center;
        padding: 0.5rem 0;
    }
}

@media (max-width: 480px) {
    .timeline-container {
        padding: 1.5rem 0;
    }
    
    .timeline-line {
        left: 45px; /* Adjusted for smaller column widths on very small screens */
    }
    
    .timeline-item {
        margin-bottom: 2.5rem;
        gap: 0.5rem;
    }
    
    .timeline-left {
        width: 40px;
        min-width: 40px;
    }
    
    .timeline-marker {
        left: 45px; /* Adjusted for very small screens: 40px left + 5px */
        width: 10px;
        height: 10px;
        top: calc(1rem + 0.84rem); /* content padding + half title line-height for small mobile */
    }
    
    .timeline-tag-year {
        font-size: 0.75em;
        padding: 0.15em 0.5em;
    }
    
    .timeline-content {
        padding: 0;
    }
    
    .timeline-title {
        font-size: 1.4rem;
        margin-top: 0;
    }
    
    .timeline-description {
        font-size: 1.1em;
    }
    
    .timeline-tag {
        font-size: 0.75em;
        padding: 0.1em 0.4em;
    }
    
    .timeline-link {
        min-height: 44px;
    }
}

/* Inline header row: date, title */
@media (max-width: 900px) {
    .timeline-line {
        display: none;
    }

    .timeline-item {
        display: grid;
        grid-template-columns: minmax(0, 1fr) auto;
        align-items: center;
        column-gap: 0.5rem;
        row-gap: 0.75rem;
        margin-bottom: 2.5rem;
    }

    .timeline-content {
        display: contents;
        margin-left: 0;
        max-width: none;
        width: auto;
        padding: 0;
    }

    .timeline-left {
        grid-column: 2;
        grid-row: 1;
        width: auto;
        min-width: 0;
        margin: 0;
        display: flex;
        align-items: center;
        justify-content: flex-end;
    }

    .timeline-left:empty {
        display: none;
    }

    .timeline-marker {
        display: none;
    }

    .timeline-title {
        grid-column: 1;
        grid-row: 1;
        margin: 0;
        font-size: clamp(1.35rem, 5vw, 1.75rem);
        line-height: 1.1;
        align-self: center;
        min-width: 0;
    }

    .timeline-item:not(:has(.timeline-left:not(:empty))) .timeline-title {
        grid-column: 1;
    }

    .timeline-tag {
        line-height: 1.2;
    }

    .timeline-tag-year {
        display: inline-flex;
        align-items: center;
    }

    .timeline-description,
    .timeline-meta,
    .timeline-link,
    .timeline-preview-card {
        grid-column: 1 / -1;
        width: 100%;
        max-width: 100%;
        min-width: 0;
    }
}

/* Preview card for experiment demos */
.timeline-preview-card {
    display: block;
    margin: 1rem 0 1.25rem;
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid rgba(255, 255, 255, 0.08);
    text-decoration: none;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
    cursor: pointer;
}

.timeline-preview-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 32px rgba(0, 0, 0, 0.5);
    border-color: rgba(255, 255, 255, 0.18);
}

.timeline-preview-card:active {
    transform: translateY(-1px);
}

.tpc-screenshot {
    display: block;
    width: 100%;
    height: auto;
}