/* JLPT N4 Kanji — grouped by radical
   Dark, polished study-reference theme. */

:root {
  --bg: #0f1218;
  --bg-soft: #151a23;
  --card: #1b212d;
  --card-hover: #202837;
  --border: #2a3342;
  --text: #e6eaf2;
  --text-dim: #9aa5b5;
  --text-faint: #6b7686;
  --accent: #e63946;
  --accent-soft: rgba(230, 57, 70, 0.14);
  --jp: #e8b04b;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.35);
  --radius: 16px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 90px;
}

body {
  margin: 0;
  background: radial-gradient(1200px 600px at 50% -10%, #1a2130 0%, var(--bg) 55%) fixed;
  color: var(--text);
  font-family: "Hiragino Kaku Gothic ProN", "Hiragino Sans", "Noto Sans JP", "Yu Gothic", system-ui, -apple-system, "Segoe UI", sans-serif;
  line-height: 1.55;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  padding: 18px 20px 14px;
  background: rgba(15, 18, 24, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
  text-align: center;
}

.site-header h1 {
  margin: 0;
  font-size: clamp(1.5rem, 3.2vw, 2.1rem);
  letter-spacing: 0.06em;
}

.site-header h1 .jp {
  color: var(--jp);
  font-weight: 700;
}

.subtitle {
  margin: 6px 0 12px;
  color: var(--text-dim);
  font-size: 0.95rem;
}

.progress-wrap {
  max-width: 340px;
  height: 4px;
  margin: 0 auto 6px;
  border-radius: 999px;
  background: var(--border);
  overflow: hidden;
}

.progress-bar {
  width: 0;
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--jp));
  border-radius: 999px;
  transition: width 0.6s ease;
}

.progress-label {
  margin: 0;
  color: var(--text-faint);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
}

/* ---------- Quick nav chips ---------- */
.quick-nav {
  position: sticky;
  top: 96px;
  z-index: 15;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  padding: 12px 16px;
  background: linear-gradient(180deg, rgba(15, 18, 24, 0.92), rgba(15, 18, 24, 0.55));
}

.nav-chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 12px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--card);
  color: var(--text-dim);
  text-decoration: none;
  font-size: 0.8rem;
  transition: border-color 0.2s, color 0.2s, background 0.2s, transform 0.2s;
}

.nav-chip:hover {
  color: var(--text);
  border-color: var(--text-faint);
  transform: translateY(-1px);
}

.nav-chip.active {
  background: var(--accent-soft);
  border-color: var(--accent);
  color: var(--text);
}

.nav-chip span {
  font-weight: 600;
}

/* ---------- Layout ---------- */
.content {
  max-width: 1180px;
  margin: 0 auto;
  padding: 26px 20px 60px;
}

.kanji-group {
  margin: 0 0 56px;
  scroll-margin-top: 170px;
}

.kanji-group h2 {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 0 0 4px;
  font-size: clamp(1.25rem, 2.4vw, 1.55rem);
  letter-spacing: 0.04em;
}

.kanji-group h2 .radical {
  display: inline-grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: linear-gradient(145deg, var(--accent), #b32734);
  color: #fff;
  font-size: 1.5rem;
  box-shadow: var(--shadow);
}

.group-note {
  margin: 0 0 18px 56px;
  color: var(--text-faint);
  font-size: 0.88rem;
}

/* ---------- Cards ---------- */
.kanji-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 14px;
}

.card {
  background: linear-gradient(180deg, var(--card), var(--bg-soft));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: transform 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.card:hover {
  transform: translateY(-3px);
  border-color: var(--text-faint);
  background: var(--card-hover);
}

.card-main {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 6px;
}

.card-kanji {
  font-size: 2rem;
  line-height: 1;
  color: var(--jp);
  font-weight: 700;
}

.card-mean {
  color: var(--text);
  font-size: 0.86rem;
  font-weight: 600;
  text-align: right;
}

.card-read {
  margin: 0;
  color: var(--text-dim);
  font-size: 0.84rem;
}

.card-read b {
  color: var(--text-faint);
  font-weight: 600;
}

.card-ex {
  margin: 4px 0 0;
  padding-top: 8px;
  border-top: 1px dashed var(--border);
  color: var(--jp);
  font-size: 0.86rem;
  letter-spacing: 0.04em;
}

/* ---------- Group extra (weekday strip) ---------- */
.group-extra {
  margin: 18px 0 0;
  padding: 16px 18px;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.extra-title {
  margin: 0 0 10px;
  color: var(--text-dim);
  font-size: 0.85rem;
}

.weekday-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.weekday-row span {
  padding: 4px 12px;
  border-radius: 8px;
  background: var(--card);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.92rem;
}

.extra-sub {
  margin: 12px 0 0;
  color: var(--text-faint);
  font-size: 0.82rem;
}

/* ---------- Footer ---------- */
.site-footer {
  padding: 22px 20px 40px;
  border-top: 1px solid var(--border);
  text-align: center;
}

.site-footer p {
  margin: 0;
  color: var(--text-faint);
  font-size: 0.82rem;
}

.site-footer a {
  color: var(--text-dim);
  text-decoration: underline dotted;
}

.site-footer a:hover {
  color: var(--accent);
}

/* ---------- Small screens ---------- */
@media (max-width: 640px) {
  .quick-nav {
    top: 110px;
  }
  .kanji-group {
    scroll-margin-top: 190px;
  }
  .group-note {
    margin-left: 0;
  }
  .kanji-grid {
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 10px;
  }
  .card-kanji {
    font-size: 1.7rem;
  }
}