@font-face {
  font-family: InterVariable; font-style: normal; font-weight: 100 900;
  font-display: block; /* <-- block, not swap */
  src: url('../font-files/InterVariable.woff2?v=4.0') format('woff2');
}
@font-face {
  font-family: InterVariable; font-style: italic; font-weight: 100 900;
  font-display: block; /* <-- block, not swap */
  src: url('../font-files/InterVariable-Italic.woff2?v=4.0') format('woff2');
}
@font-face {
  font-family: "jbmono";
  font-style: normal;
  font-weight: 100 800;
  font-display: swap;
  src: url("JetBrainsMono.woff2") format("woff2");
}
@font-face {
  font-family: "jbmono";
  font-style: italic;
  font-weight: 100 800;
  font-display: swap;
  src: url("JetBrainsMono-Italic.woff2") format("woff2");
}
@font-feature-values InterVariable {
  @styleset {
    alt-digits: 1;
    disambiguation: 2;
    round-quotes: 2;
  }
  @character-variant {
    cv01:  1; alt-one: 1;
    cv02:  2; alt-four: 2;
    cv03:  3; alt-six: 3;
    cv04:  4; alt-nine: 4;
    cv05:  5; l-tail: 5;
    cv06:  6; simple-u: 6;
    cv07:  7; alt-german-s: 7;
    cv08:  8; cap-i-serif: 8;
    cv09:  9; alt-three: 9;
    cv10: 10; cap-g-spur: 10;
    cv11: 11; simple-a: 11;
    cv12: 12; compact-f: 12;
    cv13: 13; compact-t: 13;
  }
}

:root {
  --font-size: 16px;
  --line-height: 1.5;

  --spacing: 2rem;
  --spacingv: 0.75rem; /* line-height / 2 = ((16*1.5)/2)/16 */
  --columnGap: 2rem;
  --line-width: 2px;
  --header-height: 48px;
  --row-padding: 4rem; /* .row */
  --row-padding-vertical: var(--row-padding);

  --background-color: #fff;
  --foreground-color: #000;
  --foreground-color-bright: #000;
  --foreground-color-5: rgba(0, 0, 0, 0.5);
  --foreground-color-1: rgba(0, 0, 0, 0.08);
  --underline-color: rgba(0, 0, 0, 0.3);
  --underline-color-bright: rgba(0, 0, 0, 0.6);
  --link-hover-color: var(--blue);
  --grid-color: #ccc; /* must be opaque */
  --unit-background-color: var(--foreground-color-1);
  --active-bgcolor: var(--yellow);

  --red:    color(display-p3 0.94 0.19 0.04);
  --hot-orange: color(display-p3 1 0.38 0.19);
  --yellow: color(display-p3 1 0.96 0.05);
  --warm-yellow: color(display-p3 1 0.83 0.2);
  --light-yellow: color(display-p3 1 1 0.7);
  --light-yellow2: color(display-p3 1 0.98 0.59);
  --blue:   rgb(3, 102, 230);
  --green:  rgb(38, 220, 78);
  --medium-green: rgb(119, 221, 134);

  --font-family: InterVariable;

  /* font-size needed at :root for rem to work as expected */
  font-family: var(--font-family), sans-serif;
  font-synthesis: none;
  font-size: var(--font-size);
  font-feature-settings: 'liga' 1, 'calt' 1; /* workaround for bug in Chrome */
}
@supports not (font-variation-settings: normal) { :root {
  --font-family: Inter;
}}
@supports not (color: color(display-p3 1 1 1)) { :root { /* sRGB colors */
  --red: #F03009;
  --yellow: #FFF310;
  --warm-yellow: #FFE310;
  --light-yellow: rgb(255, 255, 179);
  --light-yellow2: rgb(255, 250, 135);
}}
@media (prefers-color-scheme: dark) { :root {
  --background-color: #111;
  --foreground-color: #fafafa;
  --foreground-color-bright: #fff;
  --foreground-color-5: rgba(255, 255, 255, 0.5);
  --underline-color: rgba(255, 255, 255, 0.3);
  --underline-color-bright: rgba(255, 255, 255, 0.6);
  --link-hover-color: var(--light-yellow);
  --grid-color: #555; /* must be opaque */
  --unit-background-color: #333;
  --active-bgcolor: color(display-p3 0.57 0.44 0);
  font-weight: 400;
}}

/* narrow windows */
@media only screen and (max-width: 1391px) { /* window width <= 1391 */
  .only-huge-screen { display: none !important; }
}
@media only screen and (max-width: 719px) { /* window width <= 719 */
  :root { --row-padding: 2rem; }
  .only-large-screen { display: none !important; }
}
@media only screen and (max-width: 500px) { /* window width <= 500 */
  :root { --row-padding: 1rem; --row-padding-vertical: 2rem }
  .not-small-screen { display: none !important; }
}
/* wide windows */
@media only screen and (min-width: 720px) { /* window width >= 720 */
  .only-small-screen { display: none !important; }
}
@media only screen and (min-width: 1392px) { /* window width >= 1392 */
  :root { font-size: calc(100vw / 87); }
}

body {
  background-color: var(--background-color);
  color: var(--foreground-color);
  line-height: var(--line-height);
  -webkit-text-size-adjust: 100%;
  -ms-text-size-adjust: 100%;
  -webkit-overflow-scrolling: touch;
  scroll-behavior: smooth;
  margin: 0;
  padding: var(--header-height) 0 0 0;
}

* { scroll-padding-top: var(--header-height); }

header {
  position: sticky; top: 0; left: 0; right: 0;
  height: var(--header-height);
  overflow: hidden;
  z-index: 2;
  background: var(--background-color);
  display: flex;
  flex-direction: row;
  justify-content: center;
  align-items: stretch;
  padding: 0;
  font-size: 14px;
}
  header > div {
    width:100%;
    /*max-width: calc(1392px - 8rem);*/
    flex: 1 0 100%;
    display: flex;
    flex-direction: row;
    align-items: stretch;
  }
  header > div > * { padding: 0 var(--row-padding); }
  header .menu {
    flex: 1 0 auto;
    display: flex;
    flex-direction: row;
    justify-content: flex-end;
    align-items: center;
    gap: 2em;
  }
  header h4 {
    flex: 0 0 auto;
    margin: 0;
    display: flex;
    align-items: center;
  }
  header a { padding: 0; text-decoration: none }
  header a:hover { text-decoration: none; color:inherit }
  header a.active {
    background: var(--active-bgcolor);
    padding: 4px 8px;
    margin: -4px -8px;
    border-radius: 3px;
  }
  header .scroll-reveal {
    pointer-events: none;
    user-select: none;
    opacity: 0;
    transition: opacity 200ms ease-in-out;
  }
  header .scroll-reveal.visible {
    opacity: 1;
    pointer-events: all;
  }
@media only screen and (max-width: 500px) { /* window width <= 500 */
  header { position: fixed; }
  header .scroll-reveal { opacity: 1; pointer-events: all; }
  header .menu { gap: 8px }
  header .menu > * { flex: 1 1 auto }
}

footer { opacity: 0.4; }
footer:hover { opacity: 1; }

/* blocks */
div, p, pre, ol, ul, h1, h2, h3, h4, h5, h6 {
  margin: 0;
  padding: 0;
}
p, pre, ol, ul {
  margin-bottom: calc(var(--spacingv) * 2);
}

h1 {
  font-weight: 600;
  font-size: 4rem;
  letter-spacing: -0.01em;
  line-height: 1.0;
  margin-left: calc(3rem / -19);
  margin-bottom: calc(var(--spacingv) * 2);
  color: var(--foreground-color-bright);
}
h2 {
  font-weight: 600;
  font-size: 2rem;
  letter-spacing: -0.01em;
  line-height: calc(var(--spacingv) * 3);
  margin-bottom: calc(var(--spacingv) * 2);
}
h3 {
  font-weight: 600;
  font-size: 1.2rem;
  /*letter-spacing: -0.018em;*/
  /*line-height: calc(var(--spacingv) * 2);*/
  margin-bottom: calc(var(--spacingv) * 2);
}
h3 q {
  font-weight: 400;
  padding-left: 0.5em;
}
h4, h5, h6 {
  font-weight: 640;
  margin-bottom: calc(var(--spacingv) * 1);
}

h1 > a,
h2 > a,
h3 > a,
h4 > a {
  display: inline-block;
  color: inherit;
  text-decoration: none !important;
  text-shadow: none;
  background: none;
  outline:none;
}

/* add top margin to Hn when it follows another element */
* + h1 { margin-top: calc(var(--spacingv) * 6); }
* + h2 { margin-top: calc(var(--spacingv) * 4); }
* + h3 { margin-top: calc(var(--spacingv) * 3); }
* + h4 { margin-top: calc(var(--spacingv) * 2); }


a {
  text-decoration: underline;
  text-decoration-color: var(--underline-color);
  color: var(--foreground-color);
  word-break: break-word;
  word-wrap: break-word;
}
a.fat {
  font-weight:500;
  color: #333;
}
a:hover {
  color: var(--link-hover-color);
  text-decoration-color: var(--link-hover-color);
  text-decoration: underline;
}
a.plain, a.fat {
  background: none;
  text-shadow: none;
  text-decoration: none;
  cursor: pointer;
}
a[href^="#"]:hover {
  text-decoration-style: dashed;
}

code, pre, q, tt, r-feat, .feat {
  font-family: jbmono, Menlo, monospace;
  font-size: 92%;
  font-feature-settings: "calt" 0;
  line-height: inherit;
  font-weight: 440;
}
code, r-feat, .feat {
  padding: 0 .1em;
  white-space: pre;
}
pre {
  white-space: pre-wrap;
  line-break: loose;
  overflow-x: auto;
}
r-feat, .feat {
  padding: 0 .3em;
  /*margin: 0 .1em;*/
  border-radius: 0.3em;
  user-select: all;
  background: var(--unit-background-color);
}
a.feat:hover {
  text-decoration: none;
  background: var(--foreground-color);
  color:var(--background-color);
}
q {
  display: inline;
  white-space: pre-wrap;
}
q {
  display: inline;
}
q:before {
  content: "";
}
q:after {
  content: "";
}
kbd {
  -moz-font-feature-settings:    'liga' 1, 'calt' 1, 'kern' 1, 'case' 1;
  -ms-font-feature-settings:     'liga' 1, 'calt' 1, 'kern' 1, 'case' 1;
  -o-font-feature-settings:      'liga' 1, 'calt' 1, 'kern' 1, 'case' 1;
  -webkit-font-feature-settings: 'liga' 1, 'calt' 1, 'kern' 1, 'case' 1;
  font-feature-settings:         'liga' 1, 'calt' 1, 'kern' 1, 'case' 1;
  border: 1px solid rgba(0,0,0,0.18);
  border-radius: 3px;
  padding:0.1em 0.2em;
  margin:0 0.1em;
}
dem { /* de-emphasize */
  font-weight: 400;
  opacity: 0.7;
}
num, .num { /* number */
  letter-spacing:0.01em;
  white-space: nowrap;
  font-variant: tabular-nums slashed-zero;
  break-before: avoid;
}
em, i, .italic {
  font-style: italic;
}
small, .small {
  font-size: 1vw;
  letter-spacing: 0.012em;
}
@media only screen and (max-width: 1200px) {
  small, .small { font-size: 12px; }
}

hr {
  border: none;
  background: var(--foreground-color);
  /*width: 100%;*/
  height: var(--line-width);
  margin-top: calc(1em * var(--line-height));
  margin-bottom: calc(1em * var(--line-height));
}

ol, ul { padding-left:1.2rem; }

input, select { font: inherit }

.leading-trim {
  margin-top: -0.235em;
  line-height: 1.2;
}

.row {
  padding: var(--row-padding-vertical) var(--row-padding);
  display: flex;
  justify-content: center;
}
  .row > * {
    width:100%;
    max-width: calc(100vw - calc(var(--row-padding) * 2));
    flex: 1 0 100%;
  }
  .row .learn-more {
    margin-top: 2em;
    text-align: center;
    font-size: 11px;
    letter-spacing: 0.007em;
  }
  .row .learn-more a {
    color: rgba(0,0,0,0.4);
    text-decoration-color: rgba(0, 0, 0, 0);
  }
  .row .learn-more a:hover {
    color: inherit;
  }

.row.full-width {
  padding: 50px 0;
  justify-content: flex-start;
}
  .row.full-width > * {
    max-width: initial;
  }


/*
Feature helpers.

Note: font-variant-alternates:character-variant is not yet supported by
most browsers, which is why we use the "low leve" font-feature-settings
instead.
*/
.ff-none { font-feature-settings: 'kern' 1, 'calt' 0, 'liga' 0, 'ccmp' 0; -webkit-font-feature-settings: 'kern' 1, 'calt' 0, 'liga' 0, 'ccmp' 0; -ms-font-feature-settings: 'kern' 1, 'calt' 0, 'liga' 0, 'ccmp' 0; -moz-font-feature-settings: 'kern' 1, 'calt' 0, 'liga' 0, 'ccmp' 0; }

.ff-liga,
.ff-calt { font-feature-settings: 'liga' 1, 'calt' 1; -webkit-font-feature-settings: 'liga' 1, 'calt' 1; -ms-font-feature-settings: 'liga' 1, 'calt' 1; -moz-font-feature-settings: 'liga' 1, 'calt' 1; }
.ff-dlig { font-feature-settings: 'kern' 1, 'dlig' 1; -webkit-font-feature-settings: 'kern' 1, 'dlig' 1; -ms-font-feature-settings: 'kern' 1, 'dlig' 1; -moz-font-feature-settings: 'kern' 1, 'dlig' 1; }
.ff-numr { font-feature-settings: 'kern' 1, 'numr' 1; -webkit-font-feature-settings: 'kern' 1, 'numr' 1; -ms-font-feature-settings: 'kern' 1, 'numr' 1; -moz-font-feature-settings: 'kern' 1, 'numr' 1; }
.ff-dnom { font-feature-settings: 'kern' 1, 'dnom' 1; -webkit-font-feature-settings: 'kern' 1, 'dnom' 1; -ms-font-feature-settings: 'kern' 1, 'dnom' 1; -moz-font-feature-settings: 'kern' 1, 'dnom' 1; }
.ff-tnum { font-feature-settings: 'kern' 1, 'tnum' 1; -webkit-font-feature-settings: 'kern' 1, 'tnum' 1; -ms-font-feature-settings: 'kern' 1, 'tnum' 1; -moz-font-feature-settings: 'kern' 1, 'tnum' 1; }
.ff-case { font-feature-settings: 'kern' 1, 'case' 1; -webkit-font-feature-settings: 'kern' 1, 'case' 1; -ms-font-feature-settings: 'kern' 1, 'case' 1; -moz-font-feature-settings: 'kern' 1, 'case' 1; }
.ff-zero { font-feature-settings: 'kern' 1, 'zero' 1; -webkit-font-feature-settings: 'kern' 1, 'zero' 1; -ms-font-feature-settings: 'kern' 1, 'zero' 1; -moz-font-feature-settings: 'kern' 1, 'zero' 1; }
.ff-frac { font-feature-settings: 'kern' 1, 'frac' 1; -webkit-font-feature-settings: 'kern' 1, 'frac' 1; -ms-font-feature-settings: 'kern' 1, 'frac' 1; -moz-font-feature-settings: 'kern' 1, 'frac' 1; }
.ff-sups { font-feature-settings: 'kern' 1, 'sups' 1; -webkit-font-feature-settings: 'kern' 1, 'sups' 1; -ms-font-feature-settings: 'kern' 1, 'sups' 1; -moz-font-feature-settings: 'kern' 1, 'sups' 1; }
.ff-subs { font-feature-settings: 'kern' 1, 'subs' 1; -webkit-font-feature-settings: 'kern' 1, 'subs' 1; -ms-font-feature-settings: 'kern' 1, 'subs' 1; -moz-font-feature-settings: 'kern' 1, 'subs' 1; }
.ff-cpsp { font-feature-settings: 'kern' 1, 'cpsp' 1; -webkit-font-feature-settings: 'kern' 1, 'cpsp' 1; -ms-font-feature-settings: 'kern' 1, 'cpsp' 1; -moz-font-feature-settings: 'kern' 1, 'cpsp' 1; }
.ff-salt { font-feature-settings: 'kern' 1, 'salt' 1; -webkit-font-feature-settings: 'kern' 1, 'salt' 1; -ms-font-feature-settings: 'kern' 1, 'salt' 1; -moz-font-feature-settings: 'kern' 1, 'salt' 1; }
.ff-salt-zero { font-feature-settings: 'kern' 1, 'salt' 1, 'zero' 1; }
.ff-cv07-salt-zero { font-feature-settings: 'kern' 1, 'cv07' 1, 'salt' 1, 'zero' 1; }

.ff-ss01 { font-feature-settings: 'kern' 1, 'ss01' 1; -webkit-font-feature-settings: 'kern' 1, 'ss01' 1; -ms-font-feature-settings: 'kern' 1, 'ss01' 1; -moz-font-feature-settings: 'kern' 1, 'ss01' 1; }
.ff-ss02 { font-feature-settings: 'kern' 1, 'ss02' 1; -webkit-font-feature-settings: 'kern' 1, 'ss02' 1; -ms-font-feature-settings: 'kern' 1, 'ss02' 1; -moz-font-feature-settings: 'kern' 1, 'ss02' 1; }
.ff-ss03 { font-feature-settings: 'kern' 1, 'ss03' 1; -webkit-font-feature-settings: 'kern' 1, 'ss03' 1; -ms-font-feature-settings: 'kern' 1, 'ss03' 1; -moz-font-feature-settings: 'kern' 1, 'ss03' 1; }
.ff-cv01 { font-feature-settings: 'kern' 1, 'cv01' 1; -webkit-font-feature-settings: 'kern' 1, 'cv01' 1; -ms-font-feature-settings: 'kern' 1, 'cv01' 1; -moz-font-feature-settings: 'kern' 1, 'cv01' 1; }
.ff-cv02 { font-feature-settings: 'kern' 1, 'cv02' 1; -webkit-font-feature-settings: 'kern' 1, 'cv02' 1; -ms-font-feature-settings: 'kern' 1, 'cv02' 1; -moz-font-feature-settings: 'kern' 1, 'cv02' 1; }
.ff-cv03 { font-feature-settings: 'kern' 1, 'cv03' 1; -webkit-font-feature-settings: 'kern' 1, 'cv03' 1; -ms-font-feature-settings: 'kern' 1, 'cv03' 1; -moz-font-feature-settings: 'kern' 1, 'cv03' 1; }
.ff-cv04 { font-feature-settings: 'kern' 1, 'cv04' 1; -webkit-font-feature-settings: 'kern' 1, 'cv04' 1; -ms-font-feature-settings: 'kern' 1, 'cv04' 1; -moz-font-feature-settings: 'kern' 1, 'cv04' 1; }
.ff-cv05 { font-feature-settings: 'kern' 1, 'cv05' 1; -webkit-font-feature-settings: 'kern' 1, 'cv05' 1; -ms-font-feature-settings: 'kern' 1, 'cv05' 1; -moz-font-feature-settings: 'kern' 1, 'cv05' 1; }
.ff-cv06 { font-feature-settings: 'kern' 1, 'cv06' 1; -webkit-font-feature-settings: 'kern' 1, 'cv06' 1; -ms-font-feature-settings: 'kern' 1, 'cv06' 1; -moz-font-feature-settings: 'kern' 1, 'cv06' 1; }
.ff-cv07 { font-feature-settings: 'kern' 1, 'cv07' 1; -webkit-font-feature-settings: 'kern' 1, 'cv07' 1; -ms-font-feature-settings: 'kern' 1, 'cv07' 1; -moz-font-feature-settings: 'kern' 1, 'cv07' 1; }
.ff-cv08 { font-feature-settings: 'kern' 1, 'cv08' 1; -webkit-font-feature-settings: 'kern' 1, 'cv08' 1; -ms-font-feature-settings: 'kern' 1, 'cv08' 1; -moz-font-feature-settings: 'kern' 1, 'cv08' 1; }
.ff-cv09 { font-feature-settings: 'kern' 1, 'cv09' 1; -webkit-font-feature-settings: 'kern' 1, 'cv09' 1; -ms-font-feature-settings: 'kern' 1, 'cv09' 1; -moz-font-feature-settings: 'kern' 1, 'cv09' 1; }
.ff-cv10 { font-feature-settings: 'kern' 1, 'cv10' 1; -webkit-font-feature-settings: 'kern' 1, 'cv10' 1; -ms-font-feature-settings: 'kern' 1, 'cv10' 1; -moz-font-feature-settings: 'kern' 1, 'cv10' 1; }
.ff-cv11 { font-feature-settings: 'kern' 1, 'cv11' 1; -webkit-font-feature-settings: 'kern' 1, 'cv11' 1; -ms-font-feature-settings: 'kern' 1, 'cv11' 1; -moz-font-feature-settings: 'kern' 1, 'cv11' 1; }


.button, a.button {
  font: inherit;
  display: inline-block;
  padding: 0.25rem 0.8rem;
  margin: 0.5rem 0;
  border: none;
  border-radius: 6px;
  text-decoration: none;
  user-select: none;
  font-weight: 470;
  letter-spacing: 0.02em;
  background: var(--foreground-color);
  color: var(--background-color);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  flex: 0 1 auto;
}
.button:hover, a.button:hover {
  background: var(--link-hover-color);
}


#sponsor-button {
  display: inline-block;
  min-width: 1%;
  max-width: 100%;
  height: 2em;
  line-height: 2em;
  border-radius: 0.25em;
  border: 1px solid var(--underline-color);
  font-weight: 500; font-weight: 480;
  text-decoration: none;
  padding: 0 0.6em;
  user-select: none; -webkit-user-select: none;
}
#sponsor-button:hover {
  border-color: var(--foreground-color);
  color: inherit;
}
#sponsor-button span {
  display: flex;
  align-items: center;
  white-space: nowrap;
}
#sponsor-button span::before {
  content: "♥";
  color: var(--red);
  margin-right: 0.3em;
  font-size: 1.1em;
  line-height: 1em;
}


.cv01 { font-variant-alternates: character-variant(cv01); }
.cv02 { font-variant-alternates: character-variant(cv02); }
.cv03 { font-variant-alternates: character-variant(cv03); }
.cv04 { font-variant-alternates: character-variant(cv04); }
.cv05 { font-variant-alternates: character-variant(cv05); }
.cv06 { font-variant-alternates: character-variant(cv06); }
.cv07 { font-variant-alternates: character-variant(cv07); }
.cv08 { font-variant-alternates: character-variant(cv08); }
.cv09 { font-variant-alternates: character-variant(cv09); }
.cv10 { font-variant-alternates: character-variant(cv10); }
.cv11 { font-variant-alternates: character-variant(cv11); }
.cv12 { font-variant-alternates: character-variant(cv12); }
.cv13 { font-variant-alternates: character-variant(cv13); }
.zero { font-variant-numeric: slashed-zero; }


/* Raster grid subsystem (rsms.me/raster) */
r-grid {
  display: grid;
  --grid-tc: repeat(4, 1fr);
  grid-template-columns: var(--grid-tc);
  --grid-cs: 1; /* column start */
  --grid-ce: -1; /* column end */
  grid-column-gap: var(--columnGap);
  grid-row-gap: 0;
}

r-grid > r-cell.spacer {
  grid-column: 1 / -1;
  height: calc(var(--spacingv) * 6);
}
@media only screen and (max-width: 719px) {
  r-grid { grid-column-gap: 1rem; }
  r-cell.spacer { height: calc(var(--spacingv) * 3); }
}
r-grid > hr { grid-column: 1 / -1; width: 100% }


/* r-cell -- cell or column */
r-grid > r-cell { display: block; appearance: none; -webkit-appearance: none }

r-grid[columns="1"] { --grid-tc: repeat(1, 1fr) }
r-grid[columns="2"] { --grid-tc: repeat(2, 1fr) }
r-grid[columns="3"] { --grid-tc: repeat(3, 1fr) }
r-grid[columns="4"] { --grid-tc: repeat(4, 1fr) }
r-grid[columns="5"] { --grid-tc: repeat(5, 1fr) }
r-grid[columns="6"] { --grid-tc: repeat(6, 1fr) }
r-grid[columns="7"] { --grid-tc: repeat(7, 1fr) }
r-grid[columns="8"] { --grid-tc: repeat(8, 1fr) }

/* span=start... */
r-grid > r-cell[span^="1"] { --grid-cs: 1 }
r-grid > r-cell[span^="2"] { --grid-cs: 2 }
r-grid > r-cell[span^="3"] { --grid-cs: 3 }
r-grid > r-cell[span^="4"] { --grid-cs: 4 }
r-grid > r-cell[span^="5"] { --grid-cs: 5 }
r-grid > r-cell[span^="6"] { --grid-cs: 6 }
r-grid > r-cell[span^="7"] { --grid-cs: 7 }
r-grid > r-cell[span^="8"] { --grid-cs: 8 }

/* span=...+width, span=...-end */
r-grid > r-cell[span$="+1"], r-grid > r-cell[span="1"] { --grid-ce: 1 }
r-grid > r-cell[span$="+2"], r-grid > r-cell[span$="-1"], r-grid > r-cell[span="2"] { --grid-ce: 2 }
r-grid > r-cell[span$="+3"], r-grid > r-cell[span$="-2"], r-grid > r-cell[span="3"] { --grid-ce: 3 }
r-grid > r-cell[span$="+4"], r-grid > r-cell[span$="-3"], r-grid > r-cell[span="4"] { --grid-ce: 4 }
r-grid > r-cell[span$="+5"], r-grid > r-cell[span$="-4"], r-grid > r-cell[span="5"] { --grid-ce: 5 }
r-grid > r-cell[span$="+6"], r-grid > r-cell[span$="-5"], r-grid > r-cell[span="6"] { --grid-ce: 6 }
r-grid > r-cell[span$="+7"], r-grid > r-cell[span$="-6"], r-grid > r-cell[span="7"] { --grid-ce: 7 }
r-grid > r-cell[span$="+8"], r-grid > r-cell[span$="-7"], r-grid > r-cell[span="8"] { --grid-ce: 8 }
r-grid > r-cell[span$="-8"] { --grid-ce: 9 }

/* connect vars */
r-grid > r-cell[span] { grid-column-end: span var(--grid-ce) }
r-grid > r-cell[span*="+"], r-grid > r-cell[span*="-"], r-grid > r-cell[span*=".."] {
  grid-column-start: var(--grid-cs) }
r-grid > r-cell[span*="-"], r-grid > r-cell[span*=".."] {
  grid-column-end: var(--grid-ce) }
r-grid > r-cell[span="row"] { grid-column: 1 / -1 }

@media only screen and (max-width: 719px) {
  r-grid[columns-s="1"] { --grid-tc: repeat(1, 1fr) }
  r-grid[columns-s="2"] { --grid-tc: repeat(2, 1fr) }
  r-grid[columns-s="3"] { --grid-tc: repeat(3, 1fr) }
  r-grid[columns-s="4"] { --grid-tc: repeat(4, 1fr) }
  r-grid[columns-s="5"] { --grid-tc: repeat(5, 1fr) }
  r-grid[columns-s="6"] { --grid-tc: repeat(6, 1fr) }
  r-grid[columns-s="7"] { --grid-tc: repeat(7, 1fr) }
  r-grid[columns-s="8"] { --grid-tc: repeat(8, 1fr) }

  /* span-s=start... */
  r-grid > r-cell[span-s^="1"] { --grid-cs: 1 }
  r-grid > r-cell[span-s^="2"] { --grid-cs: 2 }
  r-grid > r-cell[span-s^="3"] { --grid-cs: 3 }
  r-grid > r-cell[span-s^="4"] { --grid-cs: 4 }
  r-grid > r-cell[span-s^="5"] { --grid-cs: 5 }
  r-grid > r-cell[span-s^="6"] { --grid-cs: 6 }
  r-grid > r-cell[span-s^="7"] { --grid-cs: 7 }
  r-grid > r-cell[span-s^="8"] { --grid-cs: 8 }

  /* span-s=...+width, span-s=...-end */
  r-grid > r-cell[span-s$="+1"], r-grid > r-cell[span-s="1"] { --grid-ce: 1 }
  r-grid > r-cell[span-s$="+2"], r-grid > r-cell[span-s$="-1"], r-grid > r-cell[span-s="2"] { --grid-ce: 2 }
  r-grid > r-cell[span-s$="+3"], r-grid > r-cell[span-s$="-2"], r-grid > r-cell[span-s="3"] { --grid-ce: 3 }
  r-grid > r-cell[span-s$="+4"], r-grid > r-cell[span-s$="-3"], r-grid > r-cell[span-s="4"] { --grid-ce: 4 }
  r-grid > r-cell[span-s$="+5"], r-grid > r-cell[span-s$="-4"], r-grid > r-cell[span-s="5"] { --grid-ce: 5 }
  r-grid > r-cell[span-s$="+6"], r-grid > r-cell[span-s$="-5"], r-grid > r-cell[span-s="6"] { --grid-ce: 6 }
  r-grid > r-cell[span-s$="+7"], r-grid > r-cell[span-s$="-6"], r-grid > r-cell[span-s="7"] { --grid-ce: 7 }
  r-grid > r-cell[span-s$="+8"], r-grid > r-cell[span-s$="-7"], r-grid > r-cell[span-s="8"] { --grid-ce: 8 }
  r-grid > r-cell[span-s$="-8"] { --grid-ce: 9 }

  /* connect vars */
  r-grid > r-cell[span-s] { grid-column-end: span var(--grid-ce) }
  r-grid > r-cell[span-s*="+"], r-grid > r-cell[span-s*="-"], r-grid > r-cell[span-s*=".."] {
    grid-column-start: var(--grid-cs) }
  r-grid > r-cell[span-s*="-"], r-grid > r-cell[span-s*=".."] {
    grid-column-end: var(--grid-ce) }
  r-grid > r-cell[span-s="row"] { grid-column: 1 / -1 }
}

/* for window width >= 1392 */
@media only screen and (min-width: 1392px) {
  r-grid[columns-l="1"] { --grid-tc: repeat(1, 1fr) }
  r-grid[columns-l="2"] { --grid-tc: repeat(2, 1fr) }
  r-grid[columns-l="3"] { --grid-tc: repeat(3, 1fr) }
  r-grid[columns-l="4"] { --grid-tc: repeat(4, 1fr) }
  r-grid[columns-l="5"] { --grid-tc: repeat(5, 1fr) }
  r-grid[columns-l="6"] { --grid-tc: repeat(6, 1fr) }
  r-grid[columns-l="7"] { --grid-tc: repeat(7, 1fr) }
  r-grid[columns-l="8"] { --grid-tc: repeat(8, 1fr) }

  /* span-l=start... */
  r-grid > r-cell[span-l^="1"] { --grid-cs: 1 }
  r-grid > r-cell[span-l^="2"] { --grid-cs: 2 }
  r-grid > r-cell[span-l^="3"] { --grid-cs: 3 }
  r-grid > r-cell[span-l^="4"] { --grid-cs: 4 }
  r-grid > r-cell[span-l^="5"] { --grid-cs: 5 }
  r-grid > r-cell[span-l^="6"] { --grid-cs: 6 }
  r-grid > r-cell[span-l^="7"] { --grid-cs: 7 }
  r-grid > r-cell[span-l^="8"] { --grid-cs: 8 }

  /* span-l=...+width, span-l=...-end */
  r-grid > r-cell[span-l$="+1"], r-grid > r-cell[span-l="1"] { --grid-ce: 1 }
  r-grid > r-cell[span-l$="+2"], r-grid > r-cell[span-l$="-1"], r-grid > r-cell[span-l="2"] { --grid-ce: 2 }
  r-grid > r-cell[span-l$="+3"], r-grid > r-cell[span-l$="-2"], r-grid > r-cell[span-l="3"] { --grid-ce: 3 }
  r-grid > r-cell[span-l$="+4"], r-grid > r-cell[span-l$="-3"], r-grid > r-cell[span-l="4"] { --grid-ce: 4 }
  r-grid > r-cell[span-l$="+5"], r-grid > r-cell[span-l$="-4"], r-grid > r-cell[span-l="5"] { --grid-ce: 5 }
  r-grid > r-cell[span-l$="+6"], r-grid > r-cell[span-l$="-5"], r-grid > r-cell[span-l="6"] { --grid-ce: 6 }
  r-grid > r-cell[span-l$="+7"], r-grid > r-cell[span-l$="-6"], r-grid > r-cell[span-l="7"] { --grid-ce: 7 }
  r-grid > r-cell[span-l$="+8"], r-grid > r-cell[span-l$="-7"], r-grid > r-cell[span-l="8"] { --grid-ce: 8 }
  r-grid > r-cell[span-l$="-8"] { --grid-ce: 9 }

  /* connect vars */
  r-grid > r-cell[span-l] { grid-column-end: span var(--grid-ce) }
  r-grid > r-cell[span-l*="+"], r-grid > r-cell[span-l*="-"], r-grid > r-cell[span-l*=".."] {
    grid-column-start: var(--grid-cs) }
  r-grid > r-cell[span-l*="-"], r-grid > r-cell[span-l*=".."] {
    grid-column-end: var(--grid-ce) }
  r-grid > r-cell[span-l="row"] { grid-column: 1 / -1 }
}

/* .debug can be added to a r-grid to visualize its effective cells */
r-grid.debug > * {
  --color: rgba(248,110,91 ,0.3);
  background-image:
    linear-gradient(to bottom, var(--color) 0%, var(--color) 100%);
}
r-grid.debug > :nth-child(6n+2) { --color: rgba(103,126,208,0.3) }
r-grid.debug > :nth-child(6n+3) { --color: rgba(224,174,72 ,0.3) }
r-grid.debug > :nth-child(6n+4) { --color: rgba(77, 214,115,0.3) }
r-grid.debug > :nth-child(6n+5) { --color: rgba(217,103,219,0.3) }
r-grid.debug > :nth-child(6n+6) { --color: rgba(94, 204,211,0.3) }
r-grid.debug > :nth-child(6n+7) { --color: rgba(248,110,91 ,0.3) }


[contenteditable] {
  outline:none;
}


:root.debug *:nth-child(4n) { outline:1px solid rgba(0,0,255,0.5); }
:root.debug *:nth-child(4n+1) { outline:1px solid rgba(0,255,255,0.5); }
:root.debug *:nth-child(4n+2) { outline:1px solid rgba(255,0,255,0.5); }
:root.debug *:nth-child(4n+3) { outline:1px solid rgba(255,0,0,0.5); }