:root {
  color-scheme: light;
  --ink: #152d3b;
  --muted: #526572;
  --accent: #08627b;
  --line: #d8e2e6;
  --navy: #080d14;
  --cyan: #61d9ee;
  font-family: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  color: var(--ink);
  background: #f6f8fa;
  line-height: 1.85;
}
* { box-sizing: border-box; }
body { margin: 0; }
a { color: var(--accent); text-underline-offset: .25em; }
a:focus-visible { outline: 3px solid var(--accent); outline-offset: 5px; }
.wrap { width: min(100% - 3rem, 70rem); margin-inline: auto; }
.skip-link { position: absolute; z-index: 2; top: .5rem; left: .5rem; padding: .5rem 1rem; background: white; transform: translateY(-200%); }
.skip-link:focus { transform: translateY(0); }
.site-header { display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; padding-block: 1.25rem; }
.brand { display: inline-flex; align-items: center; gap: .8rem; font-size: 1.15rem; font-weight: 800; color: var(--ink); text-decoration: none; white-space: nowrap; line-height: 1.5; }
.brand img { border-radius: 50%; flex: none; }
.brand small { display: block; color: var(--muted); font-weight: 400; font-size: .67rem; margin-top: .15rem; letter-spacing: .03em; }
nav { display: flex; flex-wrap: wrap; align-items: center; gap: .6rem 1.5rem; font-size: .85rem; }
nav a { color: var(--muted); }
.site-header nav a { text-decoration: none; }
.site-header nav a:hover { color: var(--accent); text-decoration: underline; }
.channel-nav { border: 1px solid var(--line); border-radius: 2rem; padding: .45rem 1rem; color: var(--ink); background: white; }
.channel-banner { height: 238px; overflow: hidden; border-radius: .8rem; background: var(--navy); }
.channel-banner img { width: 100%; height: 100%; display: block; object-fit: cover; object-position: center; }
.hero { display: grid; grid-template-columns: 1fr 1fr; gap: 3rem; align-items: center; padding-block: 3rem 3.5rem; }
.eyebrow, .number { color: var(--accent); font-weight: 700; font-size: .78rem; letter-spacing: .09em; }
h1 { font-size: clamp(2.35rem, 4.2vw, 3.6rem); line-height: 1.45; letter-spacing: .02em; margin: .8rem 0 0; }
.lead { font-size: 1rem; color: var(--muted); }
.hero-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 1.2rem; margin-top: 1.6rem; }
.button { display: inline-flex; align-items: center; justify-content: space-between; gap: 1.5rem; padding: .75rem 1.15rem; border: 1px solid var(--accent); border-radius: .35rem; text-decoration: none; font-size: .9rem; }
.button:hover { background: #e4f2f5; }
.button-primary { color: #fff; background: var(--ink); border-color: var(--ink); }
.button-primary:hover { background: #254b5b; color: white; }
.button-primary span { color: var(--cyan); }
.text-link { font-size: .85rem; }
.section { padding-block: 3rem; border-top: 1px solid var(--line); scroll-margin-top: 1rem; }
h2 { font-size: 1.5rem; margin: 0 0 1.75rem; }
h3 { font-size: 1.5rem; margin: .75rem 0; }
.section-intro { margin-top: -1rem; margin-bottom: 2rem; color: var(--muted); }
.topics { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 2rem; }
.topic { padding: 1rem 0; border-top: 2px solid #a1c6d0; }
.number { margin: 0; }
.topic p:last-child, .about p { color: var(--muted); }
.about { display: grid; grid-template-columns: 1fr 1.25fr; align-items: center; gap: 3rem; }
.channel-profile { display: flex; align-items: center; gap: 1.5rem; }
.channel-profile img { border-radius: 50%; }
.channel-profile h2 { margin: .2rem 0; }
.channel-profile .eyebrow { margin: 0; }
.about .button { margin-top: .6rem; }
.site-footer { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; padding-block: 2rem; border-top: 1px solid var(--line); font-size: .8rem; }
.site-footer > div { display: flex; flex-wrap: wrap; gap: 1.5rem; }
.footer-caption { color: var(--muted); }
.video-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1.5rem; }
.video-card { border: 1px solid var(--line); background: white; border-radius: .65rem; overflow: hidden; }
.video-card > a { display: grid; grid-template-columns: 140px minmax(0, 1fr); height: 100%; align-items: center; gap: 1.5rem; color: var(--ink); text-decoration: none; }
.video-card img { display: block; width: 100%; height: auto; }
.video-card > a > div { padding: 1.5rem 1.5rem 1.5rem 0; }
.video-card h3 { margin-top: .4rem; font-size: 1.25rem; line-height: 1.65; }
.video-card p:not(.eyebrow) { color: var(--muted); font-size: .85rem; }
.video-card .eyebrow { font-size: .68rem; margin: 0; }
.card-link { display: inline-block; margin-top: .35rem; color: var(--accent); font-size: .85rem; text-decoration: underline; text-underline-offset: .25em; }
.video-card a:hover { background: #f0f7f9; }
.video-card a:hover .card-link { text-decoration-thickness: 2px; }
.breadcrumb { font-size: .8rem; margin-block: 1.5rem; color: var(--muted); }
.video-article { border-top: 1px solid var(--line); }
.article-heading { max-width: 52rem; padding-block: 1.5rem 3rem; }
.article-heading h1 { font-size: clamp(2rem, 4.5vw, 3.3rem); }
.watch-section { display: grid; grid-template-columns: minmax(0, 360px) minmax(0, 1fr); gap: 4rem; align-items: center; padding-bottom: 3rem; }
.video-frame { width: 100%; height: auto; aspect-ratio: 9 / 16; border: 0; display: block; background: var(--navy); border-radius: .5rem; }
.video-external { text-align: center; font-size: .9rem; }
.video-pending { background: #e8f0f5; border: 1px solid var(--line); padding: 2rem; border-radius: .5rem; }
.takeaway { padding: 2rem; background: white; border-left: 3px solid var(--accent); border-radius: 0 .5rem .5rem 0; }
.takeaway h2 { font-size: 1.35rem; line-height: 1.9; }
.conditions { font-size: .9rem; color: var(--muted); border-top: 1px solid var(--line); padding-top: 1.25rem; }
.story-toc { display: block; padding: 1.25rem 1.5rem; background: #e8f0f5; border-radius: .5rem; margin-bottom: 2rem; }
.story-toc ol { padding-left: 1.4rem; margin: 0; }
.story-toc li { padding: .35rem 0; }
.story { padding: 0; margin: 0; list-style: none; }
.story-step { display: grid; grid-template-columns: 260px minmax(0, 1fr); gap: 3rem; align-items: center; padding: 2.5rem 0; border-top: 1px solid var(--line); scroll-margin-top: 1.5rem; }
.step-copy { grid-column: 2; grid-row: 1; max-width: 38rem; }
.step-copy h3 { font-size: clamp(1.25rem, 2.3vw, 1.65rem); }
.step-copy > p:last-child { color: var(--muted); }
.story-step figure { grid-column: 1; grid-row: 1; margin: 0; }
.story-step img { width: 100%; height: auto; display: block; border-radius: .4rem; }
.story-step figcaption { text-align: center; color: var(--muted); font-size: .75rem; margin-top: .5rem; }
.related > a { font-size: 1.1rem; }
@media (max-width: 62rem) {
  .video-list { grid-template-columns: 1fr; }
  .hero { gap: 1.5rem; }
  .hero-actions { align-items: flex-start; flex-direction: column; gap: 1rem; }
}
@media (max-width: 45rem) {
  .wrap { width: calc(100% - 2.5rem); }
  .site-header { align-items: flex-start; flex-direction: column; gap: 1rem; padding-block: 1rem; }
  .site-header nav { width: 100%; justify-content: space-between; gap: .5rem; font-size: .78rem; }
  .channel-nav { padding: .35rem .7rem; }
  .channel-banner { height: 160px; border-radius: .5rem; }
  .channel-banner img { width: 170%; max-width: none; margin-left: -35%; }
  .hero { grid-template-columns: 1fr; gap: .8rem; padding-block: 2rem 2.5rem; }
  .hero .eyebrow { font-size: .7rem; }
  .hero-intro .lead { font-size: .9rem; }
  .hero-actions { margin-top: 1.3rem; }
  .section { padding-block: 2.5rem; }
  .topics, .about { grid-template-columns: 1fr; gap: 1.5rem; }
  .channel-profile { gap: 1rem; }
  .channel-profile img { width: 72px; height: 72px; }
  .watch-section { grid-template-columns: 1fr; gap: 2rem; }
  .video-block { width: min(100%, 360px); margin-inline: auto; }
  .takeaway { padding: 1.5rem; }
  .story-step { grid-template-columns: 1fr; gap: 1.25rem; }
  .step-copy, .story-step figure { grid-column: 1; grid-row: auto; }
  .story-step figure { width: min(100%, 300px); margin-inline: auto; }
  .video-card > a { grid-template-columns: 100px minmax(0, 1fr); gap: 1rem; }
  .video-card > a > div { padding: 1rem 1rem 1rem 0; }
  .video-card h3 { font-size: 1.05rem; }
  .video-card p:not(.eyebrow) { display: none; }
  .card-link { font-size: .78rem; }
}

/* YouTube's favicon marks links to the channel and individual videos. */
a[href^="https://www.youtube.com/"]::before {
  content: "";
  display: inline-block;
  width: 16px;
  height: 16px;
  flex: 0 0 16px;
  margin-right: .4rem;
  vertical-align: -2px;
  background: url("./youtube-favicon.ico") center / contain no-repeat;
}
a.button[href^="https://www.youtube.com/"] { justify-content: flex-start; gap: .6rem; }
a.button[href^="https://www.youtube.com/"]::before { margin-right: 0; }