body {
    background-repeat: repeat;
    margin: 2em;
    font-family: sans-serif;
    line-height: 1.6;
    color: #222;
    background-color: #f2f2f2;
}
@media (max-width: 767) {
  body {
    margin: 1em;
    background-color: #f2f2f2;
    background-image: none;
  }
  form { max-width: 100%; }
  table { width: 100%; }
  .form-row { display: block; }
  input, select {
    width: 100%;
    box-sizing: border-box;
  }
}
a {
    color: #0645ad;
    text-decoration: underline;
}
h2 {
    margin-top: 2em;
    border-bottom: 1px solid #ccc;
    padding-bottom: 0.3em;
}
h3 {
    margin-top: 1.5em;
    color: #333;
}
hr {
    margin: 2em 0;
}
.local a,
.see-also a,
.references a ,
.external-links a {
  text-decoration: none;
  border-bottom: 1px dotted #888;
}
.local a:hover,
.see-also a:hover,
.references a:hover,
.external-links a:hover {
  border-bottom-style: solid;
}
.title-block {
    text-align: center;
    margin: 3em auto;
    font-family: "hiragino kaku gothic pron", meiryo, "yu gothic", arial, sans-serif;
    color: #222;
}
.title-block h1 {
    font-size: 1.8em;
    font-weight: 600;
    margin: 0.2em 0;
    letter-spacing: 0.5px;
}
.title-block .subtitle {
    font-size: 1.2em;
    font-weight: 400;
    color: #555;
    margin: 0.4em 0 1.2em;
    font-style: italic;
}
.title-block .meta {
    font-size: 0.95em;
    color: #666;
    line-height: 1.5;
    margin-top: 0;
}
.title-block .author {
    font-variant: small-caps;
    letter-spacing: 0.8px;
}
.title {
  max-width: 42rem;
  line-height: 1.2;
  margin-bottom: 0.4em;
}
/* inline text math */
.inline-math {
  font-size: 1.2em;
  font-family: Times, serif;
}
img { border:0 }
img.inline-math {
  height: 1.2em;
  width: auto;
  vertical-align: -0.15em;
}
/* math / definition / important assumption block */
.math {
    margin: 1em 0;
    padding-left: 1em;
    border-left: 3px solid #ccc;
}
.formulas {
  font-size: 1.33em;
  font-family: Times, serif;
  margin-left: 40px;
}
.quote {
    margin: 1em 0;
    padding-left: 1em;
    border-left: 3px solid #ccc;
}
.note {
    font-size: 0.9em;
    color: #555;
    padding: 0.1em 0.5em;
    border-left: 3px solid #f90;
    background-color: #fef;
}
/* standalone images */
.illustration {
    display: block;
    margin: 24px auto;
    border-radius: 12px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.12);
    max-width: 100%;
    height: auto;
}
.image {
    display: block;
    margin: 24px auto;
    border-radius: 12px;
    max-width: 100%;
    height: auto;
}
.image-left   {
    display: block;
    margin: 24px 0; 
    border-radius: 12px;
    max-width: 100%;
    height: auto;
}
/* technical figures with caption */
.tech-figure {
    display: inline-block;
    max-width: 800px;
    margin: 0em 0 1em 2em;
}
.tech-figure img {
    height: auto;
    display: block;
}
.tech-figure figcaption {
    text-align: center;
    margin-top: 0.3em;
    font-size: 0.9em;
    color: #555;
    line-height: 1.4;
}
.table-wrap {
  overflow-x: auto;
}
.answer-head {
    font-size: 1.1em;
    font-weight: bold;
    margin-top: 0.5em;
}
@media (max-width: 768px) {
  .tech-figure {
    margin-left: 0;
  }
}
.site-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.2em 0.4em;
    margin-bottom: 0.8em;
}

.site-logo img { /* logo side  */
    display: block;
}

.column {
    margin: 1.2em 0 1.5em 0;
    padding: 0.8em 1.2em;
    border: 1px solid #b0b0b0;
    border-radius: 6px;
    background-color: #fafafa;
    box-shadow: 0 0 0 1px rgba(255,255,255,0.6) inset;
}
.column p {
    margin: 0.5em 0;
    line-height: 1.6;
}
.card {
    max-width: 1024px;
    margin:0 auto;
    background: #fff;
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 6px 20px rgba(30,40,60,0.08)
}
.tooltip {
  position: relative;
  cursor: help;
  border-bottom: 1px dotted #666;
}
.tooltip-text {
  position: absolute;
  visibility: hidden;
  bottom: calc(100% + 6px);
  left: 50%;
  transform: none;
  width: max-content;
  max-width: min(680px, calc(100vw - 20px));
  white-space: normal;
  background-color: #fffff8;
  color: #222222;
  border: 1px solid #ccc;
  padding: 6px 10px;
  border-radius: 4px;
  font-size: 12px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.25);
  z-index: 1;
  opacity: 0;
  transition: opacity 0.2s;
}
.tooltip:is(:hover, :focus-visible, :focus-within, :active) > .tooltip-text {
  visibility: visible;
  opacity: 1;
}
.tooltip-sakura .tooltip-text {
  background-color: #f6f0f3; /* Somei-Yoshino petal */
  color: #2a2a2a;
  border: 1px solid #d8d2f0; /* faint bluish edge reflection */
}
.tooltip-skyblue .tooltip-text {
  background-color: #eef6ff; /* spring haze sky */
  border: 1px solid #c9dbf2; /* #cfe0f5; */
  color: #1f2a36;
}
.tooltip-rich { text-align: center; }
.tooltip-rich img,
.tooltip-rich svg {
  display: block;
  margin: 6px auto 0;
  width: 220px;
  max-width: 100%;
  height: auto;
  border-radius: 3px;
}


/* JIS Z 9103 Safe colors. c.f. https://safetycolor.jp/shiteichi/ */
.safe-red    { color: #ff4b00; }  /* JIS Z 9103:2018 safe color; red -- for P-type color vision */
.safe-orange { color: #f6aa00; }  /* JIS Z 9103:2018 safe color; yellow red -- adjust hue to red */
.safe-yellow { color: #f2e700; }  /* JIS Z 9103:2018 safe color; yello -- for P and D-type color vision */
.safe-green  { color: #00b06b; }  /* JIS Z 9103:2018 safe color; green -- for P and D-type color vision */
.safe-blue   { color: #1971ff; }  /* JIS Z 9103:2018 safe color; blue -- for low vision */
.safe-purple { color: #990099; }  /* JIS Z 9103:2018 safe color; red purple -- for D-type color vision */
.b-rose      { color: #e36; } /* author emphasis / assertion */
.em-finetune { color: #7366ff; font-style: italic; } /* finetune corporate color */
.em-blue     { color: #36f; font-style: italic; } /* conceptual emphasis */
.misty-rose  { color: #eeddff; }
.snow-white  { color: #fdfeff; }
.dim-gray    { color: #999; }