:root {
  --bg: #eef2f4;
  --bg-deep: #d9e2e8;
  --ink: #1a242b;
  --muted: #5b6b76;
  --line: rgba(26, 36, 43, 0.12);
  --surface: rgba(255, 255, 255, 0.78);
  --brand: #0f6a6a;
  --brand-deep: #0b4f4f;
  --accent: #c47b2c;
  --danger: #8a2f2f;
  --shadow: 0 18px 50px rgba(26, 36, 43, 0.08);
  --radius: 18px;
  --font-sans: "IBM Plex Sans JP", "Hiragino Sans", sans-serif;
  --font-display: "Shippori Mincho", "Hiragino Mincho ProN", serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-sans);
  line-height: 1.75;
  background:
    radial-gradient(circle at 12% 12%, rgba(15, 106, 106, 0.16), transparent 34%),
    radial-gradient(circle at 88% 0%, rgba(196, 123, 44, 0.14), transparent 28%),
    linear-gradient(180deg, #f7fafb 0%, var(--bg) 42%, var(--bg-deep) 100%);
  min-height: 100vh;
}
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  opacity: 0.35;
  background-image:
    linear-gradient(rgba(26, 36, 43, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(26, 36, 43, 0.04) 1px, transparent 1px);
  background-size: 28px 28px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,.55), transparent 80%);
}
img { max-width: 100%; display: block; }
a { color: var(--brand-deep); text-decoration-thickness: 1px; text-underline-offset: 3px; }
a:hover { color: var(--accent); }
.skip {
  position: absolute;
  left: -999px;
  top: 0;
  background: #fff;
  padding: 8px 12px;
  z-index: 50;
}
.skip:focus { left: 12px; top: 12px; }
.shell {
  width: min(1080px, calc(100% - 2rem));
  margin-inline: auto;
}
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(14px);
  background: rgba(247, 250, 251, 0.86);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 0;
}
.brand {
  display: inline-flex;
  gap: 0.8rem;
  align-items: center;
  text-decoration: none;
  color: inherit;
  min-width: 0;
}
.brand-mark {
  width: 2.6rem;
  height: 2.6rem;
  display: grid;
  place-items: center;
  border-radius: 0.7rem;
  background: linear-gradient(145deg, var(--brand), var(--brand-deep));
  color: #f4fbfb;
  font-family: var(--font-display);
  font-weight: 700;
  box-shadow: var(--shadow);
}
.brand-text {
  display: grid;
  gap: 0.05rem;
  min-width: 0;
}
.brand-text strong {
  font-family: var(--font-display);
  font-size: 1.05rem;
  letter-spacing: 0.02em;
}
.brand-text small {
  color: var(--muted);
  font-size: 0.75rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem 1rem;
  align-items: center;
}
.site-nav a {
  text-decoration: none;
  color: var(--ink);
  font-size: 0.92rem;
  font-weight: 500;
}
.nav-toggle {
  display: none;
  border: 1px solid var(--line);
  background: var(--surface);
  border-radius: 999px;
  padding: 0.45rem 0.9rem;
}
.hero {
  position: relative;
  min-height: min(88vh, 760px);
  display: grid;
  align-items: end;
  overflow: hidden;
  isolation: isolate;
}
.hero-visual {
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(90deg, rgba(247,250,251,0.92) 0%, rgba(247,250,251,0.72) 42%, rgba(247,250,251,0.28) 100%),
    linear-gradient(180deg, transparent 40%, rgba(26,36,43,0.22)),
    radial-gradient(circle at 70% 40%, rgba(15,106,106,0.35), transparent 42%),
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 1200 800'%3E%3Crect width='1200' height='800' fill='%23d7e4ea'/%3E%3Crect x='620' y='220' width='420' height='280' rx='18' fill='%23f7fbfc' stroke='%230f6a6a' stroke-width='8'/%3E%3Crect x='660' y='280' width='120' height='16' rx='8' fill='%23c47b2c'/%3E%3Crect x='660' y='320' width='200' height='12' rx='6' fill='%239bb0bb'/%3E%3Crect x='160' y='430' width='360' height='24' rx='8' fill='%23b7c8d1'/%3E%3Crect x='160' y='470' width='520' height='90' rx='12' fill='%23eef5f8'/%3E%3C/svg%3E")
      center/cover no-repeat;
  transform: scale(1.02);
  animation: heroDrift 18s ease-in-out infinite alternate;
}
@keyframes heroDrift {
  from { transform: scale(1.02) translate3d(0,0,0); }
  to { transform: scale(1.06) translate3d(-1.2%, 1%, 0); }
}
.hero-inner {
  padding: clamp(4rem, 12vh, 7rem) 0 clamp(3rem, 8vh, 5rem);
  max-width: 42rem;
  animation: riseIn 0.9s ease both;
}
@keyframes riseIn {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: translateY(0); }
}
.hero-kicker {
  margin: 0 0 0.8rem;
  color: var(--brand-deep);
  font-weight: 600;
  letter-spacing: 0.08em;
  font-size: 0.85rem;
}
.hero-brand {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 7vw, 4.4rem);
  line-height: 1.15;
  letter-spacing: 0.02em;
}
.hero-lead {
  margin: 1rem 0 1.5rem;
  color: var(--muted);
  font-size: 1.05rem;
}
.hero-actions, .btn-row { display: flex; flex-wrap: wrap; gap: 0.75rem; }
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 0.75rem 1.2rem;
  border: 1px solid transparent;
  text-decoration: none;
  font-weight: 600;
  transition: transform 0.2s ease, background 0.2s ease, color 0.2s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary {
  background: linear-gradient(135deg, var(--brand), var(--brand-deep));
  color: #f4fbfb;
}
.btn-ghost {
  background: rgba(255,255,255,0.7);
  border-color: var(--line);
  color: var(--ink);
}
.btn-amazon {
  background: #222;
  color: #fff;
}
.section { padding: clamp(2.5rem, 6vw, 4.5rem) 0; }
.section-alt {
  background: rgba(255,255,255,0.45);
  border-block: 1px solid var(--line);
}
.section-head { margin-bottom: 1.4rem; max-width: 40rem; }
.section-head h2, h1, h2, h3 {
  font-family: var(--font-display);
  letter-spacing: 0.01em;
  line-height: 1.35;
}
.lead { color: var(--muted); font-size: 1.05rem; }
.entry-list, .category-list {
  display: grid;
  gap: 1rem;
}
.entry, .category-link, .product-block, .space-form, .space-result {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.15rem 1.2rem;
  box-shadow: var(--shadow);
}
.entry h3 { margin: 0.2rem 0 0.5rem; font-size: 1.15rem; }
.entry h3 a { text-decoration: none; color: inherit; }
.entry h3 a:hover { color: var(--brand); }
.eyebrow {
  margin: 0;
  color: var(--brand);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}
.meta, .muted { color: var(--muted); font-size: 0.92rem; }
.category-link {
  display: grid;
  gap: 0.35rem;
  text-decoration: none;
  color: inherit;
  transition: transform 0.2s ease;
}
.category-link:hover { transform: translateY(-2px); }
.split {
  display: grid;
  gap: 1.5rem;
}
.plain-list { padding-left: 1.1rem; }
.ad-notice, .source-note, .affiliate-standby {
  background: rgba(15, 106, 106, 0.08);
  border-left: 3px solid var(--brand);
  padding: 0.75rem 0.9rem;
  border-radius: 0 12px 12px 0;
}
.ad-notice--standby {
  background: rgba(196, 123, 44, 0.1);
  border-left-color: var(--accent);
}
.article-shell { max-width: 760px; }
.article-hero { margin-bottom: 1.5rem; }
.prose :is(h2, h3) { margin-top: 2rem; }
.prose table { width: 100%; border-collapse: collapse; font-size: 0.92rem; }
.prose th, .prose td, .compare-table th, .compare-table td {
  border: 1px solid var(--line);
  padding: 0.65rem 0.7rem;
  vertical-align: top;
  text-align: left;
}
.table-wrap { overflow-x: auto; }
.compare-table { width: 100%; border-collapse: collapse; background: rgba(255,255,255,0.7); }
.space-form {
  display: grid;
  gap: 0.9rem;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 1.2rem 0;
}
.space-form label { display: grid; gap: 0.35rem; font-weight: 600; }
.space-form input {
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.7rem 0.8rem;
  background: #fff;
}
.space-form button { grid-column: 1 / -1; justify-self: start; }
.space-result h2 { margin-top: 0; }
.site-footer {
  margin-top: 2rem;
  border-top: 1px solid var(--line);
  background: rgba(26, 36, 43, 0.94);
  color: #e8eef2;
}
.site-footer a { color: #b7e3e0; }
.footer-grid {
  display: grid;
  gap: 1.5rem;
  padding: 2.2rem 0 1rem;
}
.footer-brand {
  font-family: var(--font-display);
  font-size: 1.3rem;
  margin: 0 0 0.5rem;
}
.footer-label { font-weight: 700; margin-bottom: 0.4rem; }
.footer-links { list-style: none; padding: 0; margin: 0; display: grid; gap: 0.35rem; }
.footer-bottom {
  padding: 0 0 1.5rem;
  color: #9db0bb;
  font-size: 0.9rem;
}
.footer-copy { color: #c5d2d9; }

@media (min-width: 800px) {
  .entry-list, .category-list, .split, .footer-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .related-products {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
  }
}

@media (max-width: 820px) {
  .nav-toggle { display: inline-flex; }
  .site-nav {
    display: none;
    position: absolute;
    left: 1rem;
    right: 1rem;
    top: calc(100% + 0.4rem);
    background: rgba(255,255,255,0.96);
    border: 1px solid var(--line);
    border-radius: 16px;
    padding: 0.9rem 1rem;
    box-shadow: var(--shadow);
  }
  .site-nav.is-open { display: grid; }
  .space-form { grid-template-columns: 1fr; }
  .hero { min-height: 78vh; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}