/* 词形变化规则页 */
.f-body { background: var(--bg); }

.f-head {
  background:
    radial-gradient(1200px 320px at 12% -60%, #e8f0ff 0%, rgba(232, 240, 255, 0) 60%),
    var(--card);
  border-bottom: 1px solid var(--line);
  padding: 18px 0 22px;
}
.f-topbar {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}
.f-back {
  color: var(--ink-2);
  font-size: 13px;
  text-decoration: none;
}
.f-back:hover { color: var(--accent); }
.f-head h1 {
  margin: 6px 0 4px;
  font-size: clamp(24px, 4vw, 34px);
  letter-spacing: -.02em;
}
.f-sub { margin: 0 0 14px; color: var(--ink-2); font-size: 14px; }
.f-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}
.f-jump a {
  font-size: 12.5px;
  color: var(--ink-2);
  text-decoration: none;
  border: 1px solid var(--line);
  background: var(--card);
  border-radius: 999px;
  padding: 5px 12px;
}
.f-jump a:hover { border-color: var(--accent); color: var(--accent); }

.f-main { padding: 26px 20px 40px; }
.f-section { margin-bottom: 40px; scroll-margin-top: 16px; }
.f-section h2 {
  font-size: 21px;
  margin: 0 0 6px;
  letter-spacing: -.01em;
}
.f-section h2::before {
  content: "";
  display: inline-block;
  width: 4px;
  height: 16px;
  border-radius: 2px;
  background: var(--accent);
  margin-right: 9px;
  vertical-align: -2px;
}
.f-desc { margin: 0 0 14px; color: var(--ink-2); font-size: 13.5px; }
.f-h3 {
  font-size: 15.5px;
  margin: 22px 0 10px;
  color: var(--ink);
}
.f-note {
  margin: 14px 0 0;
  padding: 10px 14px;
  background: var(--accent-soft);
  border-radius: 10px;
  font-size: 12.5px;
  color: var(--ink-2);
}
.f-note a { color: var(--accent); }

.f-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 12px;
}
.f-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow);
}
.f-card h3 { margin: 0 0 6px; font-size: 14.5px; }
.f-card p { margin: 0; font-size: 13px; color: var(--ink-2); line-height: 1.7; }
.f-eg {
  margin-top: 8px !important;
  font-size: 12.5px !important;
  color: var(--ink) !important;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.f-table-wrap { overflow-x: auto; }
.f-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  font-size: 13px;
  margin-bottom: 4px;
}
.f-table th,
.f-table td {
  text-align: left;
  padding: 9px 12px;
  border-bottom: 1px solid var(--line-2);
  vertical-align: top;
}
.f-table th {
  background: #f7f9fc;
  font-weight: 600;
  color: var(--ink-2);
  font-size: 12px;
  white-space: nowrap;
}
.f-table tr:last-child td { border-bottom: 0; }
.f-table td:first-child { color: var(--ink); }
.f-table b { color: var(--accent); font-weight: 600; }
.f-verb-table td { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; }
.f-verb-table td.f-m { font-family: inherit; color: var(--ink-2); }
.f-table-3 td:nth-child(2) { color: var(--accent); font-weight: 600; }

.f-search {
  width: 100%;
  max-width: 420px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--card);
  font-size: 14px;
  color: var(--ink);
  outline: none;
}
.f-search:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.f-groups { margin-top: 16px; display: grid; gap: 18px; }
.f-group {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  box-shadow: var(--shadow);
}
.f-group-title {
  margin: 0 0 4px;
  font-size: 14.5px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.f-group-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 999px;
  padding: 1px 8px;
}
.f-group-hint { margin: 0 0 10px; font-size: 12.5px; color: var(--ink-3); }
.f-group .f-table { border: 0; }

.f-o-cols {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 12px;
  margin: 4px 0 10px;
}
.f-o-col {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 12px 14px;
}
.f-o-title { margin: 0 0 8px; font-size: 13px; color: var(--ink); }
.f-o-title b { color: var(--accent); }
.f-o-hint { margin: 8px 0 0; font-size: 11.5px; color: var(--ink-3); }
.f-chips { display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 6px; }
.f-chip {
  font-size: 12.5px;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--card);
  border: 1px solid var(--line);
  color: var(--ink-2);
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.f-maker {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  align-items: center;
}
.f-maker .f-search { max-width: 360px; }
.f-btn {
  border: 0;
  background: var(--accent);
  color: #fff;
  border-radius: 999px;
  padding: 10px 22px;
  font-size: 14px;
  cursor: pointer;
}
.f-btn:hover { filter: brightness(1.05); }

.f-mk-out { margin-top: 16px; }
.f-mk-head {
  margin: 0 0 10px;
  font-size: 18px;
  font-weight: 700;
}
.f-mk-tag {
  font-size: 12px;
  font-weight: 500;
  color: var(--warn);
  background: #fff7ed;
  border-radius: 999px;
  padding: 2px 9px;
  vertical-align: 3px;
}
.f-mk-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 10px;
}
.f-mk-card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
}
.f-mk-label { display: block; font-size: 11.5px; color: var(--ink-3); }
.f-mk-form {
  display: block;
  font-size: 19px;
  margin: 3px 0 4px;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  word-break: break-word;
}
.f-mk-rule { font-size: 11.5px; color: var(--ink-2); }

.f-empty { color: var(--ink-3); font-size: 13px; }

.f-foot {
  border-top: 1px solid var(--line);
  background: var(--card);
  padding: 18px 0 26px;
  font-size: 12px;
  color: var(--ink-3);
}
.f-foot p { margin: 0 0 4px; }
.f-foot a { color: var(--ink-2); }

@media (max-width: 640px) {
  .f-main { padding: 18px 14px 32px; }
  .f-section { margin-bottom: 32px; }
  .f-table th, .f-table td { padding: 8px 9px; font-size: 12.5px; }
  .f-search { max-width: none; font-size: 16px; }
  .f-maker .f-search { max-width: none; }
  .f-btn { width: 100%; }
  .f-section h2 { font-size: 19px; }
}