.random_img { display:none; }

:root {
  --bg: #f9fafb;
  --fg: #111827;
  --primary: #3b82f6;
  --accent: #f97316;
  --card: #ffffff;
  --border: #e5e7eb;
  --radius: 8px;
  --transition: 0.2s ease-out;
}
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  display: flex;
  flex-direction: column;
  height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--fg);
}

.container {
  display: grid;
  grid-template-columns: 240px 1fr;
  flex: 1;
  overflow: visible;
}
.sidebar {
  background: var(--card);
  border-right: 1px solid var(--border);
  overflow-y: auto;
}
.nav ul {
  list-style: none;
  padding: 0 1rem;
}
.nav li {
  margin-bottom: 0!important;
  padding: 0;
  font-size: 1rem;
}

.folder-button {
  display: flex;
  align-items: center;
  width: 100%;
  padding: 0.5rem 1rem;
  background: none;
  border: none;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--transition);
  position: relative;
}

.children {
  list-style: none;
  display: none;
}

.content {
  padding: 0 1.5rem 1.5rem;
  overflow-y: auto;
  background: var(--bg);
}

/* PDF は縦並びリスト */
.pdf-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin: 0 3rem 2rem;
}

/* その他ファイルはグリッド */
#fileGrid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px,1fr));
  gap: 1rem;
}

.file-card {
  position: relative;
  display: block;
  text-decoration: none;
  color: inherit;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform var(--transition), box-shadow var(--transition);
  cursor: pointer;
}
.file-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}

.file-card .label-pdf {
  position: absolute;
  top: 0.5rem;
  left: 0.5rem;
  padding: 0.25rem 0.5rem;
  background: var(--accent);
  color: #fff;
  font-size: 0.75rem;
  border-radius: 4px;
}

.file-card img {
  width: 100%;
  height: 140px;
  object-fit: cover;
}

.file-card .file-name {
  padding: 0.75rem;
  font-size: 0.95rem;
  font-weight: 1200;
  text-align: center;
}

.loader-item {
  display: flex;
  align-items: center;
  padding: 1rem;
  background: var(--card);
  border-radius: var(--radius);
  margin-bottom: 1rem;
  color: #555;
  font-size: 0.95rem;
}
.loader-item::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 14px;
  margin-right: 0.5rem;
  border: 2px solid #bbb;
  border-top-color: #333;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/*-------------------------------------------------------------------------
  年号ボタン
-------------------------------------------------------------------------*/
button[data-node-type="year"] {
  position: relative;
  padding: 0.5rem 0.75rem;
  background: var(--card);
  color: var(--primary);
  font-size: 1.125rem;
  font-weight: 600;
  border: 3px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
  border-image-source: linear-gradient(60deg, #3b82f6, #9333ea, #f97316);
  border-image-slice: 1;
}

@keyframes gradientShift {
  0%   { border-image-source: linear-gradient(60deg, #3b82f6, #9333ea, #f97316); }
  50%  { border-image-source: linear-gradient(60deg, #f97316, #3b82f6, #9333ea); }
  100% { border-image-source: linear-gradient(60deg, #9333ea, #f97316, #3b82f6); }
}

button[data-node-type="year"]:hover {
  transform: scale(0.95);
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  animation: gradientShift 3s linear infinite;
}

button[data-node-type="year"]::after {
  content: '+';
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%) rotate(0deg);
  width: 1.5rem;
  height: 1.5rem;
  background: var(--card);
  color: var(--primary);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition);
}

button[data-node-type="year"].open::after {
  content: '−';
  transform: translateY(-50%) rotate(180deg);
}

/*-------------------------------------------------------------------------
  月ボタン
-------------------------------------------------------------------------*/
button[data-node-type="month"] {
  display: flex;
  align-items: center;
  margin: 0.25rem 1rem;
  padding: 0.5rem 0.75rem;
  background: linear-gradient(120deg, #3b82f6, #f9cf16ff);
  color: #fff;
  font-size: 1rem;
  font-weight: 500;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: transform var(--transition), box-shadow var(--transition);
}

button[data-node-type="month"]:hover {
  transform: translateX(4px);
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

button[data-node-type="month"].open {
  background: linear-gradient(120deg, #9333ea, #3b82f6);
}

/*-------------------------------------------------------------------------
  子フォルダのスライドダウン開閉
-------------------------------------------------------------------------*/
.children {
  overflow: hidden;
  opacity: 0;
  transition: max-height var(--transition) ease, opacity var(--transition);
}

button[data-node-type="year"].open + .children {
  opacity: 1;
}

.children { display: none; }
.children.open { display: block; }

/*-------------------------------------------------------------------------
  サイドバー・フォルダリスト
-------------------------------------------------------------------------*/
#folderList {
  overflow: visible;
  position: relative;
  z-index: 0;
}

.folder-button {
  display: block;
  width: 100%;
  text-align: left;
  padding: 8px 12px;
  transition: transform 180ms cubic-bezier(.2,.9,.2,1), box-shadow 180ms, z-index 0ms;
  position: relative;
  background: transparent;
  border: none;
  cursor: pointer;
}

.folder-button.flyout {
  transform: translateX(-16px);
  z-index: 20;
  box-shadow: 0 8px 24px rgba(2,12,27,0.12);
  border-radius: 8px;
  font-weight: 600;
}

.folder-button.flyout::after {
  content: "";
  position: absolute;
  right: -8px;
  top: 50%;
  transform: translateY(-50%) rotate(45deg);
  width: 12px;
  height: 12px;
  background: #023dffff;
  box-shadow: 0 8px 24px rgba(2,12,27,0.12);
  border-radius: 2px;
  z-index: -1;
}

.folder-button[aria-current="true"] {
  outline: none;
}

/*-------------------------------------------------------------------------
  日付ヘッダー
-------------------------------------------------------------------------*/
.date-header {
  position: relative;
  margin: 0rem 1.5rem 1rem;
  padding: 0;
  font-size: 1.25rem;
  font-weight: 600;
  text-align: center;
  color: #fff;
  border-radius: var(--radius);
  background: linear-gradient(90deg, #3b82f6, #9333ea, #f9cf16ff);
  animation: pulse 4s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50%       { transform: scale(1.02); opacity: 0.85; }
}

/*-------------------------------------------------------------------------
  タブレット以下（1024px以下）
-------------------------------------------------------------------------*/
@media (max-width: 1024px) {
  .container {
    grid-template-columns: 200px 1fr;
  }
  .folder-button {
    padding: 10px;
    font-size: 0.95rem;
  }
  .file-card img { height: 160px; }
  .pdf-list { margin: 0 2rem 1.5rem; }
}

/*-------------------------------------------------------------------------
  モバイル（640px以下）
-------------------------------------------------------------------------*/
@media (max-width: 640px) {
  .container {
    grid-template-columns: 1fr;
  }
  .sidebar {
    position: fixed;
    left: 0;
    top: 45px;
    bottom: 0;
    width: 280px;
    max-width: 80%;
    transform: translateX(-110%);
    transition: transform var(--transition);
    z-index: 60;
    box-shadow: 0 12px 32px rgba(2,12,27,0.18);
    border-right: 1px solid var(--border);
  }
  .sidebar.open {
    transform: translateX(0);
  }
  .content {
    padding: 1rem;
  }

  .hamburger {
    position: fixed;
    left: -12px;
    top: 20%;
    width: 46px;
    height: 46px;
    border-radius: 10px;
    background: linear-gradient(180deg, rgba(255,255,255,0.98), var(--card));
    box-shadow: 0 8px 20px rgba(2,12,27,0.10);
    border: 1px solid var(--border);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    cursor: pointer;
    z-index: 74;
    transition: left 0.25s ease;
  }
  .hamburger:hover {
    transform: translateX(2px);
  }

  .hamburger .hb-inner {
    width: 25px;
    height: 14px;
    position: relative;
    display: inline-block;
  }

  .hamburger .hb-inner span {
    position: absolute;
    left: 5px;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), #7c3aed);
    border-radius: 2px;
    transition: transform 240ms cubic-bezier(.2,.9,.2,1), opacity 180ms, top 240ms;
  }

  .hamburger .hb-inner span:nth-child(1) { top: 0;  transform: translateY(0px) rotate(45deg); }
  .hamburger .hb-inner span:nth-child(2) { top: 6px; opacity: 0; }
  .hamburger .hb-inner span:nth-child(3) { top: 12px; transform: translateY(0) rotate(-45deg); }

  .hamburger[aria-expanded="true"] .hb-inner span:nth-child(1) {
    transform: translateY(0) rotate(-45deg);
  }
  .hamburger[aria-expanded="true"] .hb-inner span:nth-child(2) {
    opacity: 0;
    transform: scaleX(0.8);
  }
  .hamburger[aria-expanded="true"] .hb-inner span:nth-child(3) {
    transform: translateY(0px) rotate(45deg);
  }

  .hamburger:focus {
    outline: 3px solid rgba(59,130,246,0.18);
    outline-offset: 2px;
  }

  .hamburger.open {
    left: 270px;
  }

  .sidebar-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.32);
    opacity: 0;
    visibility: hidden;
    transition: opacity var(--transition);
    z-index: 70;
  }
  body.sidebar-open .sidebar-overlay {
    opacity: 1;
    visibility: visible;
  }

  .sidebar {
    z-index: 75;
  }

  #fileGrid {
    grid-template-columns: repeat(auto-fill, minmax(160px,1fr));
    gap: 0.75rem;
  }
  .file-card img { height: 120px; }

  button[data-node-type="year"] {
    padding: 0.5rem 0.75rem;
    font-size: 1rem;
  }

  .folder-button.flyout { transform: none; box-shadow: none; }
  .folder-button.flyout::after { display: none; }
}

/*-------------------------------------------------------------------------
  共通ユーティリティ
-------------------------------------------------------------------------*/
body.sidebar-open {
  overflow: hidden;
}

.folder-button,
button[data-node-type="month"],
button[data-node-type="year"] {
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.folder-button:focus,
.hamburger:focus {
  outline: 3px solid rgba(59,130,246,0.18);
  outline-offset: 2px;
}