:root {
  --paper: #f2f3ef;
  --panel: #e7e9e3;
  --ink: #1c2230;
  --muted: #586070;
  --lapis: #2c4a8a;
  --gilt: #9a7724;
  --rule: #d3d6da;
  --focus: #2c4a8a;
  --warn: #a12d2d;
  --serif: "Libre Caslon Text", "Iowan Old Style", Georgia, serif;
  --display: "Libre Caslon Display", "Libre Caslon Text", Georgia, serif;
  --sans: "Public Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #12161e; --panel: #1a2029; --ink: #e4e6ea; --muted: #9aa2b0;
    --lapis: #93abe6; --gilt: #d6b25e; --rule: #2b3241; --focus: #93abe6; --warn: #f19191; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #12161e; --panel: #1a2029; --ink: #e4e6ea; --muted: #9aa2b0;
  --lapis: #93abe6; --gilt: #d6b25e; --rule: #2b3241; --focus: #93abe6; --warn: #f19191; color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 400 1rem/1.55 var(--sans); }
.wrap { max-width: 72rem; margin: 0 auto; padding: 0 1rem; }
a { color: var(--lapis); }
:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.skip { position: absolute; left: -999px; top: 0; background: var(--ink); color: var(--paper); padding: .5rem 1rem; }
.skip:focus { left: 1rem; z-index: 10; }

/* masthead */
.masthead { padding: 3rem 0 1.5rem; }
.masthead h1 { font: 400 clamp(2.6rem, 7vw, 4.75rem)/1 var(--display); margin: 0; letter-spacing: -0.01em; }
.lede { font: 400 1.125rem/1.6 var(--serif); color: var(--muted); max-width: 38rem; margin: 1rem 0 0; }

/* controls */
.controls { position: sticky; top: 0; z-index: 5; background: var(--paper); border-bottom: 1px solid var(--rule); padding: .75rem 0; }
.controls label { display: block; font-size: .8125rem; font-weight: 500; color: var(--muted); margin-bottom: .2rem; }
.search input { width: 100%; font: 400 1.0625rem var(--sans); padding: .6rem .75rem; border: 1px solid var(--rule); border-radius: 6px; background: var(--panel); color: var(--ink); }
.filters { display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: .5rem .75rem; margin-top: .6rem; }
.filters select { width: 100%; font: 400 .9375rem var(--sans); padding: .4rem .5rem; border: 1px solid var(--rule); border-radius: 6px; background: var(--paper); color: var(--ink); }
.bar { display: flex; flex-wrap: wrap; justify-content: space-between; align-items: center; gap: .5rem; margin-top: .6rem; }
#count { margin: 0; font-size: .9375rem; color: var(--muted); }
#count strong { color: var(--ink); font-weight: 600; }
.actions { display: flex; gap: .4rem; flex-wrap: wrap; }
.actions button { font: 500 .875rem var(--sans); padding: .35rem .7rem; border: 1px solid var(--rule); border-radius: 6px; background: transparent; color: var(--ink); cursor: pointer; }
.actions button:hover { border-color: var(--lapis); color: var(--lapis); }
@media (max-width: 860px) { .filters { grid-template-columns: repeat(3, minmax(0, 1fr)); } }
@media (max-width: 520px) {
  .filters { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .controls { position: static; }
}

/* layout with era rail */
.layout { display: grid; grid-template-columns: 11rem minmax(0, 1fr); gap: 2rem; padding-top: 1.5rem; padding-bottom: 3rem; }
.rail { position: sticky; top: 13.5rem; align-self: start; max-height: calc(100vh - 15rem); overflow: auto; }
.layout.no-rail { grid-template-columns: minmax(0, 1fr); }
.rail[hidden] { display: none; }
.rail a { display: grid; grid-template-columns: 1fr auto; align-items: center; gap: .25rem .5rem; padding: .3rem 0; text-decoration: none; color: var(--ink); font-size: .875rem; }
.rail a:hover .rn { color: var(--lapis); }
.rail .rc { font-size: .75rem; color: var(--muted); font-variant-numeric: tabular-nums; }
.rail .rb { grid-column: 1 / -1; height: 3px; background: var(--gilt); border-radius: 2px; opacity: .8; }
.rail a.empty { color: var(--muted); opacity: .5; pointer-events: none; }
@media (max-width: 860px) { .layout { grid-template-columns: minmax(0, 1fr); } .rail { display: none; } }

/* groups */
details > summary { list-style: none; cursor: pointer; }
details > summary::-webkit-details-marker { display: none; }
.age { margin: 0 0 2.25rem; scroll-margin-top: 14rem; }
.age > summary { display: flex; align-items: baseline; gap: 1rem; flex-wrap: wrap; border-bottom: 2px solid var(--gilt); padding-bottom: .4rem; }
.age > summary h2 { font: 400 clamp(2rem, 5vw, 3.25rem)/1.05 var(--display); margin: 0; font-variant-numeric: lining-nums; }
.age > summary .meta { color: var(--muted); font-size: .875rem; }
.age > summary .tw, .author > summary .tw { margin-left: auto; color: var(--muted); font-size: .8125rem; }
.age:not([open]) > summary .tw::after, .author:not([open]) > summary .tw::after { content: "Show"; }
.age[open] > summary .tw::after, .author[open] > summary .tw::after { content: "Hide"; }

.author { border-bottom: 1px solid var(--rule); }
.author > summary { display: flex; align-items: baseline; gap: .75rem; flex-wrap: wrap; padding: .85rem 0 .5rem; }
.author > summary h3 { font: 700 1.1875rem/1.3 var(--serif); margin: 0; }
.author > summary .life { font: 400 .9375rem var(--serif); color: var(--muted); font-variant-numeric: oldstyle-nums; }
.author > summary:hover h3 { color: var(--lapis); }
.author.anon > summary h3 { font-weight: 400; font-style: italic; }

/* books: year | title and details | four tools in fixed places */
.books { list-style: none; margin: 0 0 .9rem; padding: 0; }
.book { display: grid; grid-template-columns: 6.5rem minmax(0, 1fr) auto; column-gap: 1rem; row-gap: .15rem; padding: .55rem 0; border-top: 1px solid transparent; }
.book + .book { border-top-color: color-mix(in srgb, var(--rule) 55%, transparent); }
.book .yr { grid-column: 1; grid-row: 1; font: 400 .9375rem/1.5 var(--serif); color: var(--muted); text-align: right; font-variant-numeric: oldstyle-nums; padding-top: .1rem; }
.book .yr .nodate { opacity: .6; font-style: italic; }
.book .tt { grid-column: 2; grid-row: 1; font: 400 1.0625rem/1.45 var(--serif); min-width: 0; }
.book .tt .sub { color: var(--muted); }
.book .by { font: 400 .9375rem var(--serif); color: var(--muted); }
.book .det { grid-column: 2; grid-row: 2; display: flex; flex-wrap: wrap; align-items: center; gap: .3rem .8rem; font-size: .8125rem; color: var(--muted); min-width: 0; }
.book .det .lv { color: var(--ink); border: 1px solid var(--rule); border-radius: 4px; padding: 0 .35rem; }
.book .det .core { color: var(--lapis); font-weight: 600; }
.book .tools { grid-column: 3; grid-row: 1 / span 2; display: grid; grid-template-columns: repeat(5, 3.6rem); gap: .2rem; align-self: start; }
.tool { display: flex; flex-direction: column; align-items: center; gap: .1rem; padding: .25rem 0 .2rem; border: 1px solid transparent; border-radius: 6px;
  background: none; color: var(--lapis); font: 500 .6875rem/1.1 var(--sans); text-decoration: none; cursor: pointer; }
.tool svg { width: 1.15rem; height: 1.15rem; fill: none; stroke: currentColor; stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
button.tool:hover, a.tool:hover, .tool[aria-expanded="true"] { background: var(--panel); border-color: var(--rule); }
.tool.off { color: var(--muted); opacity: .38; cursor: default; }
@media (max-width: 640px) {
  .book { grid-template-columns: 3.75rem minmax(0, 1fr); column-gap: .65rem; }
  .book .yr { font-size: .8125rem; }
  .book .tools { grid-column: 2; grid-row: 3; grid-template-columns: repeat(5, 3.3rem); margin-top: .15rem; }
}

/* popover */
.pop { position: fixed; z-index: 20; width: min(24rem, calc(100vw - 16px)); max-height: min(60vh, 28rem); overflow: auto; padding: .8rem .95rem .85rem;
  background: var(--paper); color: var(--ink); border: 1px solid var(--rule); border-radius: 8px; box-shadow: 0 10px 30px -12px rgba(15, 20, 35, .35);
  font: 400 .9375rem/1.5 var(--serif); }
.pop-h { margin: 0 1.6rem .4rem 0; font: 600 .75rem/1.3 var(--sans); color: var(--muted); display: flex; flex-direction: column; gap: .1rem; }
.pop-h span { font: italic 400 1rem/1.3 var(--serif); color: var(--ink); }
.pop p { margin: 0; }
.pop ul { margin: 0; padding-left: 1.1rem; }
.pop ul.buy { list-style: none; padding: 0; display: grid; gap: .3rem; }
.pop ul.buy a { display: flex; flex-direction: column; padding: .45rem .6rem; border: 1px solid var(--rule); border-radius: 6px; text-decoration: none; color: var(--ink); font: 400 .8125rem/1.35 var(--sans); }
.pop ul.buy a strong { color: var(--lapis); font-weight: 600; font-size: .875rem; }
.pop ul.buy a:hover { border-color: var(--lapis); }
.pop-f { margin-top: .6rem !important; font: 400 .75rem/1.4 var(--sans); color: var(--muted); }
.pop-x { position: absolute; top: .4rem; right: .45rem; width: 1.8rem; height: 1.8rem; border: 0; border-radius: 6px; background: none; color: var(--muted); font-size: 1.25rem; line-height: 1; cursor: pointer; }
.pop-x:hover { background: var(--panel); color: var(--ink); }
.disclosure:empty { display: none; }
.flat-head { font: 400 1.75rem var(--display); border-bottom: 2px solid var(--gilt); margin: 0 0 .5rem; padding-bottom: .3rem; }
.empty-state { padding: 3rem 0; font: 400 1.125rem var(--serif); color: var(--muted); }
.empty-state button { font: 500 1rem var(--sans); margin-top: .75rem; padding: .45rem .9rem; border: 1px solid var(--lapis); color: var(--lapis); background: none; border-radius: 6px; cursor: pointer; }

/* footer */
.foot { border-top: 1px solid var(--rule); padding: 1.5rem 0 3rem; color: var(--muted); font-size: .875rem; }
.foot ul { padding-left: 1.1rem; }
.foot summary { cursor: pointer; color: var(--lapis); }
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; } }

/* list abbreviations with a tooltip on hover, keyboard focus or tap */
.book .det .ls { display: inline-flex; flex-wrap: wrap; gap: .3rem; }
.book .det .ls abbr { position: relative; text-decoration: none; font-size: .75rem; font-weight: 500; letter-spacing: .03em; color: var(--lapis); border: 1px solid var(--rule); border-radius: 3px; padding: 0 .3rem; cursor: help; }
.book .det .ls abbr:hover, .book .det .ls abbr:focus-visible { border-color: var(--lapis); }
.book .det .ls abbr::after { content: attr(data-tip); position: absolute; left: 0; bottom: calc(100% + 6px); z-index: 4; width: max-content; max-width: 16rem; white-space: normal; padding: .35rem .5rem; border-radius: 4px; background: var(--ink); color: var(--paper); font-weight: 400; letter-spacing: 0; line-height: 1.35; display: none; pointer-events: none; }
.book .det .ls abbr:hover::after, .book .det .ls abbr:focus::after { display: block; }

/* recommendation */
.tool.rec-yes { color: var(--lapis); }
.tool.rec-no { color: var(--warn); }
.pop.pop-small { width: auto; max-width: min(18rem, calc(100vw - 16px)); padding: .5rem .75rem; }
.pop-rec { font: 600 .875rem/1.35 var(--sans); }
.pop-rec.rec-yes { color: var(--lapis); }
.pop-rec.rec-no { color: var(--warn); }