/* Blog: the same sky as the home page, as a header band; the text sits on a calm reading surface. */
:root {
  --read-bg: #101b3a;
  --read-ink: #e7edfb;
  --read-muted: #a9b6d4;
  --read-line: rgba(190, 210, 255, 0.16);
  --read-panel: rgba(190, 210, 255, 0.06);
  --read-link: #9fd0ff;
  --band: radial-gradient(ellipse 60% 120% at 80% 0%, #1b3a80 0%, transparent 70%), linear-gradient(180deg, #0b1739, #101b3a);
  --stars: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='331' height='227'%3E%3Ccircle cx='107' cy='34' r='0.4' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='177' cy='83' r='0.4' fill='%23fff' fill-opacity='0.80'/%3E%3Ccircle cx='71' cy='20' r='0.8' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='30' cy='96' r='1.1' fill='%23fff' fill-opacity='0.32'/%3E%3Ccircle cx='74' cy='142' r='0.4' fill='%23fff' fill-opacity='0.60'/%3E%3Ccircle cx='131' cy='222' r='0.4' fill='%23fff' fill-opacity='0.58'/%3E%3Ccircle cx='44' cy='95' r='1.1' fill='%23fff' fill-opacity='0.32'/%3E%3Ccircle cx='102' cy='185' r='0.5' fill='%23fff' fill-opacity='0.31'/%3E%3Ccircle cx='189' cy='43' r='0.4' fill='%23fff' fill-opacity='0.58'/%3E%3Ccircle cx='21' cy='14' r='0.5' fill='%23fff' fill-opacity='0.55'/%3E%3Ccircle cx='176' cy='176' r='0.8' fill='%23fff' fill-opacity='0.60'/%3E%3Ccircle cx='150' cy='68' r='0.5' fill='%23fff' fill-opacity='0.67'/%3E%3Ccircle cx='81' cy='130' r='1.1' fill='%23fff' fill-opacity='0.55'/%3E%3Ccircle cx='114' cy='102' r='1.1' fill='%23fff' fill-opacity='0.84'/%3E%3Ccircle cx='39' cy='95' r='0.6' fill='%23fff' fill-opacity='0.34'/%3E%3Ccircle cx='162' cy='9' r='0.4' fill='%23fff' fill-opacity='0.71'/%3E%3Ccircle cx='190' cy='199' r='0.6' fill='%23fff' fill-opacity='0.45'/%3E%3Ccircle cx='116' cy='113' r='0.8' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='31' cy='61' r='0.4' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='232' cy='147' r='0.8' fill='%23fff' fill-opacity='0.42'/%3E%3Ccircle cx='128' cy='152' r='0.4' fill='%23fff' fill-opacity='0.81'/%3E%3Ccircle cx='118' cy='139' r='0.8' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='254' cy='29' r='0.5' fill='%23fff' fill-opacity='0.49'/%3E%3Ccircle cx='303' cy='113' r='0.5' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='182' cy='201' r='0.8' fill='%23fff' fill-opacity='0.77'/%3E%3Ccircle cx='92' cy='94' r='0.6' fill='%23fff' fill-opacity='0.66'/%3E%3Ccircle cx='126' cy='52' r='0.4' fill='%23fff' fill-opacity='0.36'/%3E%3Ccircle cx='77' cy='53' r='0.8' fill='%23fff' fill-opacity='0.75'/%3E%3Ccircle cx='60' cy='64' r='0.5' fill='%23fff' fill-opacity='0.50'/%3E%3Ccircle cx='122' cy='129' r='0.5' fill='%23fff' fill-opacity='0.66'/%3E%3Ccircle cx='171' cy='140' r='0.4' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='288' cy='216' r='1.1' fill='%23fff' fill-opacity='0.49'/%3E%3Ccircle cx='132' cy='24' r='0.8' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='22' cy='47' r='0.5' fill='%23fff' fill-opacity='0.32'/%3E%3Ccircle cx='199' cy='23' r='1.1' fill='%23fff' fill-opacity='0.34'/%3E%3Ccircle cx='34' cy='83' r='0.4' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='69' cy='85' r='0.6' fill='%23fff' fill-opacity='0.82'/%3E%3Ccircle cx='199' cy='108' r='0.4' fill='%23fff' fill-opacity='0.76'/%3E%3Ccircle cx='329' cy='106' r='0.8' fill='%23fff' fill-opacity='0.44'/%3E%3Ccircle cx='48' cy='170' r='0.6' fill='%23fff' fill-opacity='0.54'/%3E%3C/svg%3E"), url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='523' height='389'%3E%3Ccircle cx='237' cy='218' r='0.8' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='447' cy='74' r='1.1' fill='%23fff' fill-opacity='0.54'/%3E%3Ccircle cx='321' cy='72' r='0.8' fill='%23fff' fill-opacity='0.43'/%3E%3Ccircle cx='47' cy='315' r='0.4' fill='%23fff' fill-opacity='0.61'/%3E%3Ccircle cx='207' cy='176' r='1.1' fill='%23fff' fill-opacity='0.64'/%3E%3Ccircle cx='326' cy='324' r='0.4' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='99' cy='94' r='0.4' fill='%23fff' fill-opacity='0.72'/%3E%3Ccircle cx='171' cy='230' r='0.5' fill='%23fff' fill-opacity='0.56'/%3E%3Ccircle cx='335' cy='194' r='0.4' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='145' cy='388' r='0.4' fill='%23fff' fill-opacity='0.67'/%3E%3Ccircle cx='165' cy='89' r='0.6' fill='%23fff' fill-opacity='0.27'/%3E%3Ccircle cx='295' cy='42' r='0.4' fill='%23fff' fill-opacity='0.76'/%3E%3Ccircle cx='202' cy='373' r='0.4' fill='%23fff' fill-opacity='0.38'/%3E%3Ccircle cx='485' cy='20' r='0.8' fill='%23fff' fill-opacity='0.84'/%3E%3Ccircle cx='208' cy='28' r='0.5' fill='%23fff' fill-opacity='0.72'/%3E%3Ccircle cx='141' cy='34' r='0.6' fill='%23fff' fill-opacity='0.26'/%3E%3Ccircle cx='214' cy='359' r='0.5' fill='%23fff' fill-opacity='0.40'/%3E%3Ccircle cx='53' cy='23' r='0.8' fill='%23fff' fill-opacity='0.36'/%3E%3Ccircle cx='293' cy='174' r='0.5' fill='%23fff' fill-opacity='0.84'/%3E%3Ccircle cx='402' cy='163' r='0.8' fill='%23fff' fill-opacity='0.32'/%3E%3Ccircle cx='220' cy='83' r='0.6' fill='%23fff' fill-opacity='0.77'/%3E%3Ccircle cx='510' cy='231' r='0.4' fill='%23fff' fill-opacity='0.38'/%3E%3Ccircle cx='206' cy='332' r='1.1' fill='%23fff' fill-opacity='0.31'/%3E%3Ccircle cx='517' cy='83' r='0.6' fill='%23fff' fill-opacity='0.26'/%3E%3Ccircle cx='319' cy='323' r='0.8' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='47' cy='227' r='0.5' fill='%23fff' fill-opacity='0.26'/%3E%3Ccircle cx='193' cy='242' r='0.5' fill='%23fff' fill-opacity='0.83'/%3E%3Ccircle cx='253' cy='224' r='0.8' fill='%23fff' fill-opacity='0.36'/%3E%3Ccircle cx='81' cy='353' r='1.1' fill='%23fff' fill-opacity='0.40'/%3E%3Ccircle cx='99' cy='288' r='1.1' fill='%23fff' fill-opacity='0.37'/%3E%3Ccircle cx='497' cy='343' r='1.1' fill='%23fff' fill-opacity='0.30'/%3E%3Ccircle cx='25' cy='42' r='1.1' fill='%23fff' fill-opacity='0.83'/%3E%3Ccircle cx='125' cy='274' r='0.6' fill='%23fff' fill-opacity='0.50'/%3E%3Ccircle cx='473' cy='191' r='1.1' fill='%23fff' fill-opacity='0.36'/%3E%3Ccircle cx='377' cy='27' r='0.5' fill='%23fff' fill-opacity='0.54'/%3E%3Ccircle cx='342' cy='240' r='0.4' fill='%23fff' fill-opacity='0.42'/%3E%3Ccircle cx='480' cy='79' r='0.4' fill='%23fff' fill-opacity='0.29'/%3E%3Ccircle cx='215' cy='97' r='0.4' fill='%23fff' fill-opacity='0.36'/%3E%3Ccircle cx='193' cy='223' r='0.5' fill='%23fff' fill-opacity='0.31'/%3E%3Ccircle cx='72' 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fill-opacity='0.82'/%3E%3Ccircle cx='59' cy='303' r='0.8' fill='%23fff' fill-opacity='0.40'/%3E%3Ccircle cx='6' cy='117' r='1.1' fill='%23fff' fill-opacity='0.37'/%3E%3Ccircle cx='89' cy='352' r='0.8' fill='%23fff' fill-opacity='0.55'/%3E%3Ccircle cx='126' cy='157' r='0.6' fill='%23fff' fill-opacity='0.37'/%3E%3Ccircle cx='225' cy='314' r='0.5' fill='%23fff' fill-opacity='0.78'/%3E%3Ccircle cx='201' cy='227' r='0.6' fill='%23fff' fill-opacity='0.38'/%3E%3Ccircle cx='70' cy='136' r='0.4' fill='%23fff' fill-opacity='0.68'/%3E%3Ccircle cx='497' cy='108' r='0.5' fill='%23fff' fill-opacity='0.32'/%3E%3Ccircle cx='247' cy='360' r='0.8' fill='%23fff' fill-opacity='0.48'/%3E%3Ccircle cx='272' cy='261' r='1.1' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='39' cy='12' r='1.1' fill='%23fff' fill-opacity='0.27'/%3E%3Ccircle cx='371' cy='222' r='0.6' fill='%23fff' fill-opacity='0.64'/%3E%3Ccircle cx='295' cy='249' r='0.8' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='13' cy='323' r='0.5' fill='%23fff' fill-opacity='0.72'/%3E%3Ccircle cx='417' cy='383' r='0.4' fill='%23fff' fill-opacity='0.52'/%3E%3Ccircle cx='329' cy='255' r='0.6' fill='%23fff' fill-opacity='0.83'/%3E%3Ccircle cx='358' cy='78' r='0.8' fill='%23fff' fill-opacity='0.40'/%3E%3C/svg%3E");
  --paper: #fbfcfe;
  --paper-ink: #1b2130;
  --paper-line: #d2d6de;
}
:root[data-theme="day"] {
  --stars: none;
  --read-bg: #f7fbff;
  --read-ink: #0b1f3f;
  --read-muted: #3d5478;
  --read-line: rgba(11, 31, 63, 0.12);
  --read-panel: rgba(74, 168, 255, 0.08);
  --read-link: #0b5fd6;
  --band: radial-gradient(circle at 82% 10%, rgba(255, 250, 225, 0.9) 0, rgba(255, 255, 255, 0) 30%), linear-gradient(180deg, #5aaeff 0%, #9cd2ff 70%, #f7fbff 100%);
}
html, body { background: var(--read-bg); color: var(--read-ink); }

.band { position: relative; background: var(--band); padding-block: 4.5rem 3.5rem; }
.band::before { content: ""; position: absolute; inset: 0; background: var(--stars); background-position: 0 0, 137px 61px; -webkit-mask-image: linear-gradient(#000 50%, transparent); mask-image: linear-gradient(#000 50%, transparent); pointer-events: none; }
.band .wrap { position: relative; }
.band .wrap, .read { width: min(46rem, 100% - 2.5rem); margin-inline: auto; }
.band h1 { font-weight: 700; font-size: clamp(2.1rem, 5vw, 3.4rem); line-height: 1.08; letter-spacing: -0.035em; text-wrap: balance; }
.band .meta { margin-top: 1.1rem; color: var(--muted); }
:root[data-theme="day"] .band .meta { color: #1d3a63; }

/* Blog index */
.posts { list-style: none; margin-block: 2.5rem 1rem; display: grid; gap: 1rem; }
.posts a { display: block; padding: 1.6rem; border: 1px solid var(--read-line); border-radius: 14px; background: var(--read-panel); text-decoration: none; transition: border-color 0.3s var(--ease), transform 0.3s var(--ease); }
.posts a:hover { border-color: var(--line-strong); transform: translateY(-2px); }
.posts h2 { font-weight: 600; font-size: 1.25rem; line-height: 1.3; letter-spacing: -0.015em; }
.posts p { color: var(--read-muted); margin-top: 0.5rem; }
.posts .meta { display: block; color: var(--read-muted); margin-top: 0.9rem; font-size: 0.9375rem; }

/* Article */
.toc { border: 1px solid var(--read-line); background: var(--read-panel); border-radius: 12px; padding: 1.2rem 1.4rem; margin-block: 2.5rem; }
.toc b { font-weight: 600; }
.toc ol { margin: 0.6rem 0 0 1.3rem; color: var(--read-muted); }
.toc li { padding-block: 0.15rem; }
.toc a { text-decoration: none; }
.toc a:hover { color: var(--read-ink); text-decoration: underline; }
article { padding-bottom: 2rem; line-height: 1.72; }
article h2 { font-weight: 700; font-size: 1.75rem; line-height: 1.2; letter-spacing: -0.025em; margin: 4rem 0 1rem; padding-top: 2rem; border-top: 1px solid var(--read-line); scroll-margin-top: 4.5rem; text-wrap: balance; }
article h3 { font-weight: 600; font-size: 1.25rem; letter-spacing: -0.015em; margin: 2.5rem 0 0.75rem; }
article h4 { font-weight: 600; font-size: 1.05rem; margin: 2rem 0 0.6rem; }
article p, article ul, article ol { margin-bottom: 1.05rem; }
article ul, article ol { padding-left: 1.4rem; }
article li { margin-bottom: 0.35rem; }
article li::marker { color: var(--read-muted); }
article strong { font-weight: 600; }
article code { font-family: var(--mono); font-size: 0.86em; overflow-wrap: anywhere; background: var(--read-panel); border: 1px solid var(--read-line); border-radius: 5px; padding: 0.05em 0.35em; }
article a { color: var(--read-link); }
article pre { font-family: var(--mono); font-size: 0.8rem; line-height: 1.6; white-space: pre-wrap; overflow-wrap: anywhere; background: var(--read-panel); border: 1px solid var(--read-line); border-radius: 10px; padding: 0.85rem 1rem; margin: 0 0 1.25rem; }
#hector { scroll-margin-top: 4.5rem; }
blockquote { background: var(--read-panel); border: 1px solid var(--read-line); padding: 1.1rem 1.3rem; margin: 1.75rem 0; border-radius: 12px; }
blockquote p:last-child { margin-bottom: 0; }
.formula { font-family: var(--mono); font-size: 0.92rem; background: var(--read-panel); border: 1px solid var(--read-line); border-radius: 10px; padding: 0.85rem 1rem; overflow-x: auto; }

.table-wrap { overflow-x: auto; margin: 1.25rem 0 1.75rem; border: 1px solid var(--read-line); border-radius: 12px; }
table { border-collapse: collapse; width: 100%; font-size: 0.92rem; line-height: 1.5; }
th, td { text-align: left; vertical-align: top; padding: 0.65rem 0.85rem; border-bottom: 1px solid var(--read-line); }
thead th { font-weight: 600; color: var(--read-muted); background: var(--read-panel); }
tbody tr:last-child td { border-bottom: 0; }
td { min-width: 8rem; }

/* Diagrams: light cards in both themes, like the source document. */
.fig { margin: 2rem 0; background: var(--paper); color: var(--paper-ink); border: 1px solid var(--read-line); border-radius: 12px; padding: 0.75rem; }
.fig img { display: block; width: 100%; height: auto; }
.dia { padding: 1.25rem; font-size: 0.9375rem; line-height: 1.45; }
.dia-t { font-weight: 600; margin-bottom: 1rem; }
.box { border: 1px solid var(--paper-line); border-radius: 8px; padding: 0.6rem 0.8rem; background: #fff; }
.box b { display: block; font-weight: 600; }
.box span { color: #5a6070; }
.box.hl { border: 2px solid #0b5fd6; background: #e5eef9; }
.flow { display: flex; align-items: center; gap: 0.5rem; }
.flow > i { font-style: normal; color: #8e9bbb; }
.flow > .box { flex: 1; }
.flow.v { flex-direction: column; align-items: stretch; }
.flow.v > i { text-align: center; }
.col { display: grid; gap: 0.5rem; flex: 1.2; }
.grid3 .r { display: grid; grid-template-columns: 7.5rem 1fr 1fr; gap: 0.5rem; margin-bottom: 0.5rem; }
.grid3 .r > span { border: 1px solid var(--paper-line); border-radius: 8px; padding: 0.5rem 0.7rem; background: #fff; }
.grid3 .r > b { font-weight: 600; padding-top: 0.5rem; }
.grid3 .hd b { text-align: center; border: 1px solid var(--paper-line); border-radius: 8px; padding: 0.4rem; }
.grid3 .hd > span { border: 0; background: none; }
.dia span { overflow-wrap: anywhere; }
@media (max-width: 640px) {
  .flow { flex-direction: column; align-items: stretch; }
  .flow > i { text-align: center; }
  .flow:not(.v) > i svg { transform: rotate(90deg); }
  .grid3 .r { grid-template-columns: 1fr 1fr; }
  .grid3 .r:not(.hd) > b { grid-column: 1 / -1; }
  .grid3 .hd > span { display: none; }
}
.foot { margin-top: 3rem; }
.flow > i.arr { display: grid; place-items: center; }
.flow > i.arr svg { width: 0.9rem; height: 0.9rem; }
.flow.v > i.arr svg { transform: rotate(90deg); }

/* Synthesis: above the table of contents, its points in one framed list. */
.summary { margin-top: 2.5rem; line-height: 1.72; }
.summary h2 { font-weight: 700; font-size: 1.75rem; letter-spacing: -0.025em; margin-bottom: 1rem; }
.summary > p { margin-bottom: 1.05rem; }
.summary a { color: var(--read-link); }
.key { border: 1px solid var(--read-line); background: var(--read-panel); border-radius: 12px; padding: 1.4rem 1.6rem 0.4rem 1.4rem; margin-top: 1.5rem; }
.key > ul { list-style: none; padding: 0; }
.key > ul > li { margin-bottom: 1.1rem; }
.key > ul > li > strong { display: block; font-weight: 600; margin-bottom: 0.35rem; }
.key ul ul { padding-left: 1.25rem; }
.key ul ul li { margin-bottom: 0.35rem; }
.key ul ul li::marker { color: var(--read-muted); }
.key strong { font-weight: 600; }
.key > ul > li > strong { display: inline; }
.key > ul { list-style: disc; padding-left: 1.2rem; }
.key > ul > li::marker { color: var(--read-muted); }
.key { padding-bottom: 0.3rem; }

/* Topic tags at the end of a post, ready to reuse as hashtags. */
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 2.5rem; }
.tags span { font-family: var(--mono); font-size: 0.75rem; color: var(--read-muted); border: 1px solid var(--read-line); background: var(--read-panel); border-radius: 999px; padding: 0.25rem 0.7rem; }