/* 中ページのタイトルを画面の上に残す帯(2026-11-04、たいちが4案から案2を選んだ)
   page-pin.js が .page-pin を足す。色は style.css の :root の変数から引く
   (濃い面の上の薄い線だけは、ページの見出し帯と同じく白の半透明で書く) */
:root {
  --page-pin-height: 44px;
}
.page-pin {
  position: fixed;
  /* ヘッダーの下線の下。page-pin.js もこの位置を出す線に使う */
  top: calc(var(--header-height) + 1px);
  left: 0;
  right: 0;
  z-index: 49; /* ヘッダー(50)とメニューの下 */
  /* 少し透かす(たいち 11/07)。後ろの文字が読みの邪魔をしないよう、ぼかしも入れる */
  background: color-mix(in srgb, var(--color-primary) 84%, transparent);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  color: var(--color-base);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(-100%);
  transition:
    opacity 0.3s var(--ease),
    transform 0.45s var(--ease);
}
.page-pin.is-shown {
  opacity: 1;
  pointer-events: auto;
  transform: none;
}
.page-pin-inner {
  display: flex;
  align-items: center;
  gap: 16px;
  width: min(100% - var(--gutter) * 2, var(--container));
  height: var(--page-pin-height);
  margin-inline: auto;
}
.page-pin-title {
  flex-shrink: 0;
  max-width: 50%;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.08em;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.page-pin-chapter {
  display: none;
  min-width: 0;
  font-size: 13px;
  color: var(--color-dark-text-sub);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.page-pin.has-chapter .page-pin-chapter {
  display: block;
}
/* タイトルが長くて切れる時は、章を隠してタイトルに幅を譲り、2行まで折り返す(page-pin.js が is-long を付ける) */
.page-pin.is-long .page-pin-inner {
  height: auto;
  min-height: var(--page-pin-height);
  padding-block: 4px;
}
.page-pin.is-long .page-pin-title {
  flex-shrink: 1;
  max-width: none;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 2;
  line-clamp: 2;
  white-space: normal;
  line-height: 1.45;
}
.page-pin.is-long.has-chapter .page-pin-chapter {
  display: none;
}
.page-pin-chapter::before {
  content: "";
  display: inline-block;
  width: 1px;
  height: 12px;
  margin-right: 16px;
  vertical-align: -1px;
  background: rgba(255, 255, 255, 0.35);
}
.page-pin-top {
  margin-left: auto;
  flex-shrink: 0;
  /* 楕円のボタン(たいち 11/07)。押せるのは帯全体のまま */
  padding: 5px 16px;
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: 999px;
  font-size: 12px;
  line-height: 1.4;
  letter-spacing: 0.08em;
  color: var(--color-base);
  transition:
    background-color 0.2s var(--ease),
    color 0.2s var(--ease);
}
@media (hover: hover) {
  .page-pin:hover .page-pin-top {
    background: var(--color-base);
    color: var(--color-primary);
  }
}
/* どこまで読んだかの線 */
.page-pin-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 2px;
  background: var(--color-base);
  transform: scaleX(0);
  transform-origin: left;
}

@media (max-width: 760px) {
  :root {
    --page-pin-height: 40px;
  }
  .page-pin-inner {
    gap: 12px;
  }
  .page-pin-title {
    max-width: 55%;
    font-size: 13.5px;
  }
  .page-pin-chapter {
    font-size: 11.5px;
  }
  .page-pin-chapter::before {
    margin-right: 12px;
  }
  .page-pin-top {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-pin {
    transition: none;
  }
}

@media print {
  .page-pin {
    display: none;
  }
}