:root {
  --bg: #fff9ee;
  --surface: #ffffff;
  --ink: #2d2a3e;
  --muted: #6a6578;
  --line: #2d2a3e;
  --accent: #e2474b;
  --sky: #2f6fe4;
  --sky-soft: #e4efff;
  --mint: #23946b;
  --mint-soft: #e2f5ec;
  --sun: #ffc93c;
  --sun-soft: #fff3cf;
  --radius: 18px;
  --shadow: 4px 4px 0 var(--line);
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Zen Maru Gothic", "Hiragino Maru Gothic ProN", "Hiragino Sans", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.95;
  letter-spacing: 0.02em;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--sky); }

.pr-bar {
  background: var(--ink);
  color: #fff;
  font-size: 12px;
  text-align: center;
  padding: 5px 16px;
  letter-spacing: 0.05em;
}

.wrap { max-width: 780px; margin: 0 auto; padding: 0 16px; }

/* ---------- header / footer */
header.site { background: var(--surface); border-bottom: 3px solid var(--line); }
header.site .wrap {
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 6px 16px; padding-top: 10px; padding-bottom: 10px;
}
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--ink); }
.logo img { width: 44px; height: 44px; }
.logo b { font-size: 17px; line-height: 1.3; }
.logo small { display: block; font-size: 11px; color: var(--muted); font-weight: 500; }
nav a { font-size: 14px; color: var(--ink); text-decoration: none; margin-left: 14px; font-weight: 700; }
nav a:first-child { margin-left: 0; }
nav a:hover { color: var(--accent); }

footer { margin-top: 64px; border-top: 3px solid var(--line); background: var(--surface); padding: 28px 0 36px; font-size: 13px; color: var(--muted); }
footer a { color: var(--muted); margin-right: 16px; }

/* ---------- top page */
.hero {
  display: grid; grid-template-columns: 1fr 200px; gap: 16px; align-items: center;
  padding: 36px 0 12px;
}
.hero h1 { font-size: 30px; line-height: 1.45; margin: 0 0 10px; }
.hero h1 em { font-style: normal; background: linear-gradient(transparent 62%, var(--sun) 62%); }
.hero p { margin: 0; color: var(--muted); }
@media (max-width: 600px) {
  .hero { grid-template-columns: 1fr; }
  .hero img { width: 150px; margin: 0 auto; order: -1; }
  .hero h1 { font-size: 25px; }
}

.section-title { font-size: 20px; margin: 40px 0 16px; display: flex; align-items: center; gap: 10px; }
.section-title::before { content: ""; width: 14px; height: 14px; background: var(--accent); border: 3px solid var(--line); border-radius: 4px; }

.cards { display: grid; gap: 20px; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); }
.card {
  background: var(--surface); border: 3px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); overflow: hidden; text-decoration: none; color: var(--ink);
  transition: transform .12s, box-shadow .12s; display: flex; flex-direction: column;
}
.card:hover { transform: translate(-2px, -2px); box-shadow: 6px 6px 0 var(--line); }
.card img { aspect-ratio: 1200 / 630; object-fit: cover; border-bottom: 3px solid var(--line); }
.card .body { padding: 12px 16px 16px; }
.card .tag { font-size: 12px; font-weight: 700; color: var(--accent); }
.card h2 { font-size: 17px; line-height: 1.5; margin: 2px 0 0; padding: 0; background: none; border: 0; box-shadow: none; }

.promise {
  background: var(--surface); border: 3px solid var(--line); border-radius: var(--radius);
  padding: 18px 22px; box-shadow: var(--shadow);
}
.promise ul { margin: 6px 0 0; padding-left: 1.2em; }

/* ---------- article */
article { padding-top: 28px; }
.crumb { font-size: 13px; color: var(--muted); }
.crumb a { color: var(--muted); }
article h1 { font-size: 27px; line-height: 1.5; margin: 6px 0 14px; }
@media (max-width: 600px) { article h1 { font-size: 23px; } }
.eyecatch { border: 3px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); overflow: hidden; margin: 0 0 24px; }
article h2 {
  font-size: 22px; line-height: 1.5; margin: 52px 0 16px; padding: 10px 16px;
  background: var(--surface); border: 3px solid var(--line); border-radius: 14px; box-shadow: var(--shadow);
}
article h2 .num { color: var(--accent); margin-right: 6px; }
article h3 { font-size: 18px; margin: 32px 0 8px; }
article p { margin: 0 0 1.1em; }
.big { font-size: 1.15em; font-weight: 700; }
mark { background: linear-gradient(transparent 60%, var(--sun) 60%); color: inherit; padding: 0 2px; }

figure { margin: 22px 0; }
figure img { border: 3px solid var(--line); border-radius: 14px; }
figcaption { font-size: 13px; color: var(--muted); text-align: center; margin-top: 6px; }

.box { border: 3px solid var(--line); border-radius: var(--radius); padding: 16px 20px; margin: 24px 0; background: var(--surface); }
.box > :last-child { margin-bottom: 0; }
.box-title { display: inline-block; font-weight: 700; font-size: 15px; background: var(--ink); color: #fff; border-radius: 999px; padding: 2px 14px; margin-bottom: 10px; }

.answer { background: var(--sun-soft); }
.answer ol { margin: 0; padding-left: 1.4em; font-weight: 700; }

.hakase { display: grid; grid-template-columns: 64px 1fr; gap: 12px; align-items: start; margin: 22px 0; }
.hakase img { width: 64px; height: 64px; }
.hakase .say {
  position: relative; background: var(--surface); border: 3px solid var(--line); border-radius: 16px; padding: 10px 16px;
}
.hakase .say::before {
  content: ""; position: absolute; left: -12px; top: 18px; border: 9px solid transparent; border-right-color: var(--line); border-left: 0;
}
.hakase .say p:last-child { margin-bottom: 0; }

.experiment { background: var(--mint-soft); }
.experiment h3 { margin-top: 12px; }
.experiment ol, .experiment ul { padding-left: 1.4em; }
.caution { background: #fff; border: 2px dashed var(--accent); border-radius: 12px; padding: 10px 14px; font-size: 15px; margin-top: 12px; }

.quiz { background: var(--sky-soft); }
.quiz .q { font-weight: 700; margin: 12px 0 4px; }
details { background: #fff; border: 2px solid var(--line); border-radius: 12px; padding: 8px 14px; margin: 6px 0 14px; }
summary { cursor: pointer; font-weight: 700; color: var(--sky); }
details[open] summary { margin-bottom: 6px; }

.parents { background: #f6f3fb; }
.parents p, .parents li { font-size: 15.5px; }
.formula { font-family: "Times New Roman", serif; font-size: 20px; text-align: center; margin: 8px 0 14px; }

.pr { border-color: var(--sun); background: #fffdf6; }
.pr-label { font-size: 12px; color: var(--muted); }
.products { display: grid; gap: 12px; margin-top: 12px; }
.product { border: 2px solid var(--line); border-radius: 14px; padding: 12px 16px; background: #fff; }
.product b { display: block; }
.product p { font-size: 14.5px; margin: 4px 0 10px; color: var(--muted); }
.btn {
  display: inline-block; background: var(--accent); color: #fff; font-weight: 700; text-decoration: none;
  border: 3px solid var(--line); border-radius: 999px; padding: 6px 18px; font-size: 14px; box-shadow: 3px 3px 0 var(--line);
}
.btn:hover { transform: translate(-1px, -1px); }

.video { background: var(--ink); color: #fff; text-align: center; }
.video .frame { aspect-ratio: 9 / 16; max-width: 320px; margin: 0 auto; border-radius: 14px; overflow: hidden; background: #000; }
.video .frame img, .video .frame iframe { width: 100%; height: 100%; object-fit: cover; border: 0; }
.video p { font-size: 14px; margin: 10px 0 0; }

.next { display: grid; gap: 14px; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }

table { border-collapse: collapse; width: 100%; font-size: 15px; background: #fff; }
th, td { border: 2px solid var(--line); padding: 8px 10px; text-align: left; vertical-align: top; }
th { background: var(--sun-soft); }
.table-wrap { overflow-x: auto; }

.next-title { font-size: 20px; font-weight: 700; margin: 44px 0 14px; }