body {
    font-family: courier, monospace;
    max-width: 980px;
    margin: 0 auto;
    padding: 0 16px 60px;
    line-height: 1.55;
    color: #222;
    background: #fff;
}

.top_link {
    float: right;
    margin-top: 12px;
}

header {
    text-align: center;
    padding-top: 30px;
    clear: both;
}

h1 {
    margin-bottom: 4px;
}

.subtitle {
    margin-top: 0;
    color: #666;
}

h2 {
    margin-top: 60px;
    border-bottom: 2px solid #ddd;
    padding-bottom: 6px;
}

h3 {
    margin-bottom: 6px;
}

.prose {
    max-width: 720px;
    margin-left: auto;
    margin-right: auto;
}

.contents {
    max-width: 720px;
    margin: 0 auto;
}

.contents ol {
    padding-left: 24px;
}

.contents a {
    color: #222;
}

/* ---- metaphor strip ---- */

.metaphor-box {
    background: #f4f4f4;
    border-left: 4px solid #bbb;
    padding: 12px 16px;
    margin: 24px 0;
}

.metaphor-title {
    margin: 0 0 8px;
    font-weight: bold;
}

.metaphors {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.metaphors button,
.tbtn {
    font-family: inherit;
    font-size: 0.85em;
    padding: 4px 10px;
    border: 1px solid #bbb;
    background: #fff;
    border-radius: 14px;
    cursor: pointer;
    color: #222;
}

.metaphors button:hover,
.tbtn:hover {
    border-color: #555;
}

.metaphors button.active,
.tbtn.active {
    background: #222;
    color: #fff;
    border-color: #222;
}

.metaphor-desc {
    margin: 10px 0 4px;
    min-height: 3.1em;
    color: #333;
}

.metaphor-note {
    margin: 6px 0 0;
    color: #666;
    font-size: 0.9em;
}

/* ---- timeline controls ---- */

.tl-controls {
    position: sticky;
    top: 0;
    z-index: 5;
    background: #fff;
    padding: 10px 0 8px;
    border-bottom: 1px solid #e6e6e6;
}

.thread-bar {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.tbtn {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    white-space: nowrap;
}

.tbtn .sw {
    display: inline-block;
    width: 14px;
    height: 3px;
    border-radius: 2px;
    background: var(--c, #888);
}

.tbtn.knots .sw {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    border: 2px solid #222;
    background: #fff;
    box-sizing: border-box;
}

.tbtn.active .sw {
    outline: 1px solid rgba(255, 255, 255, 0.6);
}

.tl-desc {
    margin: 8px 0 0;
    color: #444;
    font-size: 0.9em;
    min-height: 1.4em;
}

.tl-desc .count {
    color: #777;
}

.strand-heads {
    display: grid;
    grid-template-columns: 1fr 1fr;
    column-gap: 72px;
    margin: 22px 0 8px;
    text-align: center;
    font-weight: bold;
    color: #444;
}

.strand-heads span {
    font-weight: normal;
    font-size: 0.8em;
    color: #777;
}

.tl-foot {
    color: #777;
    font-size: 0.85em;
    text-align: center;
    margin-top: 16px;
}

/* ---- the timeline itself ---- */

.timeline {
    position: relative;
    display: grid;
    grid-template-columns: 1fr 1fr;
    column-gap: 72px;
    row-gap: 14px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: #e1e0d9;
    transform: translateX(-50%);
}

.threads {
    position: absolute;
    left: 0;
    top: 0;
    pointer-events: none;
    overflow: visible;
    z-index: 1;
}

.threads path {
    fill: none;
    stroke-width: 1.5;
    stroke-linecap: round;
    opacity: 0.38;
    transition: opacity 0.2s, stroke-width 0.2s;
}

.timeline.isolate .threads path {
    opacity: 0.05;
}

.timeline.isolate .threads path.active {
    opacity: 0.95;
    stroke-width: 2.5;
}

.threads path.hl {
    opacity: 0.95;
    stroke-width: 2.5;
}

.ev {
    position: relative;
    z-index: 2;
    border: 1px solid #d8d8d8;
    border-radius: 4px;
    padding: 10px 12px 9px;
    background: #fff;
    cursor: pointer;
    transition: opacity 0.2s, box-shadow 0.15s;
}

.ev:focus {
    outline: none;
    box-shadow: 0 0 0 2px #222;
}

.ev.hl {
    box-shadow: 0 0 0 2px #222;
}

.ev.side-cog {
    grid-column: 1;
    background: #faf7f2;
}

.ev.side-ai {
    grid-column: 2;
    background: #f3f6fa;
}

.ev.side-both {
    grid-column: 1 / 3;
    justify-self: center;
    width: min(100%, 560px);
    border: 2px solid #333;
    background: #fff;
}

.timeline.isolate .ev:not(.in) {
    opacity: 0.28;
}

.ev-year {
    position: absolute;
    top: 9px;
    width: 72px;
    text-align: center;
    font-weight: bold;
    color: #444;
    font-size: 0.9em;
    line-height: 1.3;
    /* a white halo keeps the year legible where it sits on the rails */
    text-shadow: 0 0 3px #fff, 0 0 3px #fff, 0 0 4px #fff, 0 0 5px #fff;
}

.side-cog .ev-year {
    left: 100%;
}

.side-ai .ev-year {
    right: 100%;
}

.side-both .ev-year {
    position: static;
    width: auto;
    display: block;
    text-align: center;
    margin-bottom: 4px;
}

.ev-tag {
    display: none;
    font-size: 0.72em;
    color: #777;
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.ev-title {
    margin: 0 0 6px;
    font-size: 1em;
    line-height: 1.35;
}

.ev-text {
    margin: 0;
    font-size: 0.9em;
}

.ev-more {
    display: none;
    margin: 8px 0 0;
    padding-top: 8px;
    border-top: 1px dashed #ccc;
    font-size: 0.9em;
    color: #333;
}

.ev.open .ev-more {
    display: block;
}

.ev-chips {
    margin-top: 8px;
    display: flex;
    flex-wrap: wrap;
    gap: 4px 12px;
    font-size: 0.75em;
    color: #555;
}

.chip::before {
    content: '';
    display: inline-block;
    width: 10px;
    height: 3px;
    border-radius: 2px;
    background: var(--c, #888);
    margin-right: 5px;
    vertical-align: middle;
}

.ev-hint {
    margin-top: 6px;
    font-size: 0.75em;
    color: #999;
}

.ev.open .ev-hint {
    display: none;
}

/* ---- patterns & meaning ---- */

.pattern {
    margin: 24px 0;
}

.pattern h3 {
    margin-bottom: 4px;
}

.pattern p {
    margin-top: 6px;
}

.trace {
    font-size: 0.9em;
}

.trace a {
    color: #222;
}

.claim {
    margin: 32px 0;
}

.claim h3 {
    margin-bottom: 4px;
}

.claim p {
    margin-top: 6px;
}

.challenge {
    background: #f4f4f4;
    border-left: 4px solid #bbb;
    padding: 10px 14px;
    margin: 12px 0 0;
    font-size: 0.95em;
}

.coda {
    border: 1px dashed #999;
    padding: 14px 16px;
    margin: 40px 0 10px;
    color: #333;
}

.coda-title {
    margin: 0 0 6px;
    font-weight: bold;
}

.coda p:last-child {
    margin-bottom: 0;
}

.reading {
    padding-left: 20px;
}

.reading li {
    margin-bottom: 8px;
    font-size: 0.95em;
}

footer {
    margin-top: 60px;
    text-align: center;
}

/* ---- narrow screens: one column, spine on the left ---- */

@media (max-width: 700px) {
    h2 {
        font-size: 1.2em;
    }

    .strand-heads {
        display: none;
    }

    .thread-bar {
        flex-wrap: nowrap;
        overflow-x: auto;
        padding-bottom: 4px;
        -webkit-overflow-scrolling: touch;
        /* fade the right edge so the row reads as scrollable */
        -webkit-mask-image: linear-gradient(to right, #000 calc(100% - 36px), transparent);
        mask-image: linear-gradient(to right, #000 calc(100% - 36px), transparent);
    }

    .timeline {
        grid-template-columns: 1fr;
        padding-left: 44px;
        row-gap: 12px;
    }

    .timeline::before {
        left: 22px;
        transform: none;
    }

    .ev.side-cog,
    .ev.side-ai,
    .ev.side-both {
        grid-column: 1;
        width: auto;
        justify-self: stretch;
    }

    .ev-year,
    .side-both .ev-year {
        position: static;
        display: inline;
        width: auto;
        text-align: left;
        margin: 0 8px 0 0;
    }

    .ev-tag {
        display: inline;
    }
}