:root {
  color-scheme: light;
  --ink: #17201a;
  --muted: #59685f;
  --paper: #fbf4e6;
  --panel: rgba(255, 251, 241, 0.86);
  --panel-strong: #fffaf0;
  --line: #d9c9aa;
  --cedar: #24483a;
  --cedar-2: #35624f;
  --persimmon: #d95d39;
  --gold: #e1ad3d;
  --aqua: #8ac6bd;
  --shadow: 0 24px 80px rgba(50, 41, 20, 0.18);
}

body {
  min-width: 320px;
  min-height: 100vh;
  background:
    radial-gradient(circle at 12% 8%, rgba(225, 173, 61, 0.42), transparent 28rem),
    radial-gradient(circle at 86% 20%, rgba(138, 198, 189, 0.45), transparent 24rem),
    linear-gradient(135deg, #fbf4e6 0%, #f2dfbc 55%, #d7e4d4 100%);
}

body::before {
  position: fixed;
  inset: 0;
  z-index: -1;
  content: "";
  background-image:
    linear-gradient(rgba(36, 72, 58, 0.055) 1px, transparent 1px),
    linear-gradient(90deg, rgba(36, 72, 58, 0.055) 1px, transparent 1px);
  background-size: 34px 34px;
  mask-image: linear-gradient(to bottom, black, transparent 90%);
}

main {
  width: min(1180px, calc(100% - 32px));
  padding: 24px 0 28px;
}

.site-nav {
  gap: 6px;
  margin-bottom: 14px;
  padding: 8px;
  border: 1px solid rgba(36, 72, 58, 0.16);
  border-radius: 999px;
  background: var(--panel);
  box-shadow: 0 12px 30px rgba(50, 41, 20, 0.1);
  backdrop-filter: blur(18px);
}

.site-nav a {
  min-height: 44px;
  border-radius: 999px;
  background: transparent;
  color: var(--cedar);
  padding: 10px 16px;
  font-weight: 900;
}

.site-nav a:hover {
  transform: translateY(-1px);
  background: rgba(36, 72, 58, 0.12);
  color: var(--cedar);
}

.site-nav a[aria-current="page"] {
  background: var(--persimmon);
  color: #fffaf0;
  box-shadow: 0 8px 18px rgba(217, 93, 57, 0.25);
}

.grade-page-hero,
.card,
.faq,
.worksheet,
footer {
  border: 1px solid rgba(36, 72, 58, 0.16);
  background: var(--panel);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.grade-page-hero {
  position: relative;
  overflow: hidden;
  margin-bottom: 14px;
  padding: clamp(18px, 3vw, 30px);
  border-radius: 28px;
}

.grade-page-hero::after {
  position: absolute;
  right: clamp(12px, 3vw, 34px);
  bottom: -30px;
  content: "学年";
  color: rgba(217, 93, 57, 0.09);
  font-size: clamp(4.5rem, 12vw, 8rem);
  font-weight: 900;
  line-height: 0.8;
  letter-spacing: -0.16em;
}

.grade-page-hero > * { position: relative; z-index: 1; }
.eyebrow { margin: 0 0 12px; font-weight: 800; letter-spacing: 0.14em; }
h1, h2 { margin: 0; letter-spacing: -0.05em; }
h1 { max-width: 760px; font-size: clamp(2.3rem, 5vw, 4rem); line-height: 0.92; }
h2 { color: var(--cedar); font-size: clamp(1.35rem, 3vw, 2rem); }
.lead { max-width: 640px; color: var(--cedar); font-size: clamp(0.98rem, 1.8vw, 1.16rem); font-weight: 700; }
.grade-page-hero > p:not(.eyebrow):not(.lead) { max-width: 720px; color: var(--muted); }

.actions, .grade-nav { gap: 8px; }
.button {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  border: 1px solid rgba(36, 72, 58, 0.16);
  background: rgba(255, 251, 241, 0.62);
  padding: 10px 16px;
  box-shadow: none;
  transition: transform 160ms ease, background 160ms ease, color 160ms ease, box-shadow 160ms ease;
}
.button.primary { background: var(--persimmon); color: #fffaf0; box-shadow: 0 8px 18px rgba(217, 93, 57, 0.25); }
.button:hover { transform: translateY(-1px); background: rgba(36, 72, 58, 0.12); color: var(--cedar); }
.button.primary:hover { background: var(--persimmon); color: #fffaf0; }

.card { margin-top: 14px; border-radius: 28px; padding: 22px; }
.grade-grid { grid-template-columns: repeat(auto-fill, minmax(132px, 1fr)); gap: 10px; margin-top: 18px; }
.kanji-card {
  min-height: 128px;
  border: 1px solid rgba(36, 72, 58, 0.16);
  border-radius: 18px;
  background: rgba(255, 251, 241, 0.72);
  padding: 16px;
  box-shadow: none;
  transition: transform 160ms ease, background 160ms ease, box-shadow 160ms ease;
}
.kanji-card:hover { transform: translateY(-3px); background: var(--panel-strong); box-shadow: 0 14px 26px rgba(50, 41, 20, 0.16); }
.kanji { font-size: 2.2rem; }
.reading { color: var(--persimmon); }
.meaning { color: var(--muted); }

@media (max-width: 760px) {
  main { width: min(100% - 20px, 1180px); padding-top: 10px; }
  .site-nav { gap: 4px; padding: 6px; }
  .site-nav a { flex: 1 1 calc(50% - 4px); justify-content: center; padding-inline: 10px; }
  .grade-page-hero, .card, .faq, .worksheet, footer { border-radius: 22px; }
  .grade-page-hero, .card { padding: 20px; }
  .grade-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}