:root {
  --bg: #ffffff;
  --bg-2: #f2f2f2;
  --bg-3: #e5e5e5;
  --text: #0f0f0f;
  --text-2: #606060;
  --accent: #1a56db;
  --accent-text: #ffffff;
  --danger: #c81e1e;
  --border: #e0e0e0;
  --radius: 12px;
  --header-h: 56px;
  --subject-0: #1d4ed8; --subject-0-bg: #dbeafe;  /* 商業簿記 */
  --subject-1: #047857; --subject-1-bg: #d1fae5;  /* 会計学 */
  --subject-2: #b45309; --subject-2-bg: #fef3c7;  /* 工業簿記 */
  --subject-3: #7e22ce; --subject-3-bg: #f3e8ff;  /* 原価計算 */
  --subject-4: #be123c; --subject-4-bg: #ffe4e6;
  --subject-5: #0e7490; --subject-5-bg: #cffafe;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f0f0f;
    --bg-2: #222222;
    --bg-3: #333333;
    --text: #f1f1f1;
    --text-2: #aaaaaa;
    --accent: #4f8ef7;
    --accent-text: #0f0f0f;
    --danger: #f05252;
    --border: #333333;
    --subject-0: #93c5fd; --subject-0-bg: #1e3a8a66;
    --subject-1: #6ee7b7; --subject-1-bg: #064e3b66;
    --subject-2: #fcd34d; --subject-2-bg: #78350f66;
    --subject-3: #d8b4fe; --subject-3-bg: #581c8766;
    --subject-4: #fda4af; --subject-4-bg: #88133766;
    --subject-5: #67e8f9; --subject-5-bg: #164e6366;
  }
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Hiragino Sans", "Yu Gothic UI", "Meiryo", system-ui, sans-serif;
  font-size: 14px;
  line-height: 1.5;
}
a { color: inherit; text-decoration: none; }
button, input, select, textarea { font: inherit; color: inherit; }
[hidden] { display: none !important; }

/* ---------- ヘッダー ---------- */
.header {
  position: sticky; top: 0; z-index: 10;
  height: var(--header-h);
  display: flex; align-items: center; gap: 16px;
  padding: 0 16px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
}
.logo { display: flex; align-items: center; gap: 8px; font-weight: 800; font-size: 24px; white-space: nowrap; letter-spacing: -0.02em; }
.logo-mark {
  display: grid; place-items: center;
  width: 38px; height: 27px; border-radius: 8px;
  background: var(--accent); color: var(--accent-text);
}
.logo-mark::after { content: ""; border-left: 11px solid currentColor; border-top: 7px solid transparent; border-bottom: 7px solid transparent; margin-left: 2px; }
.search { flex: 1; max-width: 560px; margin: 0 auto; display: flex; }
.search input {
  flex: 1; min-width: 0;
  padding: 8px 16px;
  border: 1px solid var(--border); border-right: none;
  border-radius: 20px 0 0 20px;
  background: var(--bg);
}
.search input:focus { outline: none; border-color: var(--accent); }
.search button {
  padding: 0 18px;
  border: 1px solid var(--border);
  border-radius: 0 20px 20px 0;
  background: var(--bg-2); cursor: pointer;
}
.header-right { display: flex; align-items: center; gap: 10px; white-space: nowrap; }
.user-chip { color: var(--text-2); font-size: 13px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  padding: 8px 16px;
  border: none; border-radius: 18px;
  background: var(--bg-2); cursor: pointer; font-weight: 600;
}
.btn:hover { background: var(--bg-3); }
.btn-primary { background: var(--accent); color: var(--accent-text); }
.btn-primary:hover { background: var(--accent); filter: brightness(1.1); }
.btn-danger { color: var(--danger); }
.btn:disabled { opacity: .5; cursor: default; }

/* ---------- 一覧 ---------- */
.main { padding: 16px 24px 48px; max-width: 1800px; margin: 0 auto; }
.filters { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; margin-bottom: 20px; }
.chips { display: flex; gap: 8px; overflow-x: auto; scrollbar-width: none; flex: 1; min-width: 0; }
.chip {
  padding: 6px 12px; border-radius: 8px; border: none;
  background: var(--bg-2); cursor: pointer; white-space: nowrap; font-weight: 500;
}
.chip.active { background: var(--text); color: var(--bg); }
.select {
  padding: 6px 10px; border-radius: 8px;
  border: 1px solid var(--border); background: var(--bg);
}

.grid {
  display: grid; gap: 32px 16px;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
}
.card { display: flex; flex-direction: column; gap: 10px; }
.thumb {
  position: relative; aspect-ratio: 16 / 9;
  border-radius: var(--radius); overflow: hidden;
  background: var(--bg-2);
}
.thumb img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform .2s; }
.card:hover .thumb img { transform: scale(1.03); }
.thumb .no-thumb { position: absolute; inset: 0; display: grid; place-items: center; color: var(--text-2); font-size: 13px; }
.duration {
  position: absolute; right: 8px; bottom: 8px;
  padding: 1px 5px; border-radius: 4px;
  background: rgba(0,0,0,.8); color: #fff; font-size: 12px; font-weight: 600;
}
.progress-bar { position: absolute; left: 0; bottom: 0; height: 4px; background: var(--danger); }
.card-title {
  font-weight: 600; font-size: 16px; line-height: 1.35;
  display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden;
}
.card-meta { color: var(--text-2); font-size: 13px; margin-top: 2px; }
.tag {
  display: inline-block; padding: 1px 8px; border-radius: 4px;
  background: var(--bg-2); color: var(--text-2); font-size: 12px; margin-right: 4px;
}
.empty { text-align: center; color: var(--text-2); padding: 80px 16px; }

.subj { font-weight: 700; }
.subj-0 { color: var(--subject-0); background: var(--subject-0-bg); }
.subj-1 { color: var(--subject-1); background: var(--subject-1-bg); }
.subj-2 { color: var(--subject-2); background: var(--subject-2-bg); }
.subj-3 { color: var(--subject-3); background: var(--subject-3-bg); }
.subj-4 { color: var(--subject-4); background: var(--subject-4-bg); }
.subj-5 { color: var(--subject-5); background: var(--subject-5-bg); }
.chip.subj { background: var(--bg-2); color: var(--text); }
.chip.subj.active { color: #fff; }
.chip.subj-0.active { background: var(--subject-0); }
.chip.subj-1.active { background: var(--subject-1); }
.chip.subj-2.active { background: var(--subject-2); }
.chip.subj-3.active { background: var(--subject-3); }
@media (prefers-color-scheme: dark) { .chip.subj.active { color: #0f0f0f; } }

/* ---------- ホームのセクション ---------- */
.section { margin-bottom: 36px; }
.section-head { display: flex; align-items: baseline; gap: 12px; margin: 0 0 12px; }
.section-head h2 { font-size: 20px; margin: 0; }
.grid-pl { display: grid; gap: 24px 16px; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); }

/* 再生リストのカード：後ろに重なった板で「まとまり」を表現 */
.stack { position: relative; padding-top: 8px; }
.stack::before, .stack::after {
  content: ""; position: absolute; left: 50%; transform: translateX(-50%);
  border-radius: var(--radius) var(--radius) 0 0; background: var(--bg-3);
}
.stack::before { top: 0; width: 84%; height: 8px; opacity: .5; }
.stack::after { top: 4px; width: 92%; height: 4px; }
.count-badge {
  position: absolute; right: 0; top: 0; bottom: 0; width: 38%;
  display: grid; place-items: center;
  background: rgba(0,0,0,.72); color: #fff; font-weight: 700; font-size: 14px;
}
.playlist-card .card-title { font-size: 15px; }

/* ---------- 再生リスト ---------- */
.pl-page { display: grid; grid-template-columns: 360px minmax(0, 1fr); gap: 24px; max-width: 1280px; margin: 0 auto; padding: 24px; align-items: start; }
.pl-hero {
  position: sticky; top: calc(var(--header-h) + 24px);
  padding: 20px; border-radius: 16px; background: var(--bg-2);
  display: grid; gap: 12px;
}
.pl-hero .thumb { border-radius: 10px; }
.pl-hero h1 { font-size: 22px; margin: 0; line-height: 1.3; }
.pl-hero .meter { background: var(--bg-3); }
.pl-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.pl-list { display: flex; flex-direction: column; }
.pl-group {
  font-weight: 700; font-size: 13px; color: var(--text-2);
  padding: 14px 8px 6px; border-bottom: 1px solid var(--border); margin-bottom: 4px;
}
.pl-row {
  display: grid; grid-template-columns: 28px 160px minmax(0, 1fr); gap: 10px; align-items: center;
  padding: 6px 8px; border-radius: 10px;
}
.pl-row:hover { background: var(--bg-2); }
.pl-row.current { background: var(--bg-3); }
.pl-row .thumb { border-radius: 8px; }
.pl-index { text-align: center; color: var(--text-2); font-size: 13px; }
.pl-row.current .pl-index { color: var(--accent); }
.pl-text { display: grid; gap: 2px; min-width: 0; }
.pl-pos { font-size: 12px; color: var(--text-2); font-weight: 600; }
.pl-title { font-weight: 600; overflow: hidden; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; }
.subject-tabs { display: flex; gap: 8px; flex-wrap: wrap; }

/* 再生ページ右側の再生リスト枠 */
.pl-panel { border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; margin-bottom: 16px; }
.pl-panel-head { padding: 12px 14px; background: var(--bg-2); display: grid; gap: 4px; }
.pl-panel-head a.title { font-weight: 700; font-size: 16px; }
.pl-panel-head label { display: flex; align-items: center; gap: 6px; font-size: 13px; color: var(--text-2); cursor: pointer; }
.pl-panel-body { max-height: 440px; overflow-y: auto; padding: 4px; }
.pl-panel .pl-row { grid-template-columns: 22px 100px minmax(0, 1fr); gap: 8px; padding: 4px 6px; }
.pl-panel .pl-title { font-size: 13px; }
.pl-panel .pl-group { padding: 10px 6px 4px; }
.pl-panel .duration { font-size: 11px; right: 4px; bottom: 4px; }
.breadcrumb { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; color: var(--text-2); font-size: 13px; margin-top: 12px; }
.breadcrumb a:hover { color: var(--accent); text-decoration: underline; }

/* ---------- アップロード（複数ファイル） ---------- */
.common-bar {
  display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)) auto; gap: 8px; align-items: end;
  padding: 12px; border-radius: var(--radius); background: var(--bg-2); margin-bottom: 12px;
}
.common-bar label { font-size: 12px; }
.common-bar .input { padding: 6px 8px; }
.queue { display: grid; gap: 10px; }
.q-item {
  display: grid; grid-template-columns: 200px minmax(0, 1fr) auto; gap: 14px; align-items: start;
  padding: 12px; border: 1px solid var(--border); border-radius: var(--radius);
}
.q-item.done { opacity: .6; }
.q-item.failed { border-color: var(--danger); }
.q-thumb { display: grid; gap: 4px; }
.q-thumb canvas { width: 100%; aspect-ratio: 16 / 9; border-radius: 8px; background: var(--bg-2); display: block; }
.q-thumb input[type=range] { width: 100%; }
.q-fields { display: grid; grid-template-columns: 1.1fr .7fr .8fr 1fr .7fr; gap: 8px; }
.q-fields .wide { grid-column: 1 / -1; }
.q-fields label { font-size: 12px; gap: 2px; }
.q-fields .input { padding: 6px 8px; }
.q-side { display: grid; gap: 6px; justify-items: end; min-width: 90px; }
.q-status { font-size: 12px; color: var(--text-2); text-align: right; }
.q-item .meter { grid-column: 1 / -1; }
.upload-footer { position: sticky; bottom: 0; display: flex; gap: 8px; justify-content: flex-end; align-items: center; padding: 12px 0; background: var(--bg); border-top: 1px solid var(--border); margin-top: 12px; }

/* ---------- 動画の管理 ---------- */
.m-filters { display: grid; grid-template-columns: 2fr repeat(4, minmax(0, 1fr)); gap: 8px; margin: 12px 0; }
.m-filters .input { padding: 8px 10px; }
.bulk-bar {
  position: sticky; top: calc(var(--header-h) + 8px); z-index: 5;
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
  padding: 10px 12px; margin-bottom: 8px; border-radius: var(--radius);
  background: var(--accent); color: var(--accent-text);
}
.bulk-bar .btn { background: var(--bg); color: var(--text); }
.bulk-bar .btn-danger { color: var(--danger); }
.m-list { display: flex; flex-direction: column; }
.m-group {
  display: flex; align-items: center; gap: 10px;
  padding: 16px 8px 8px; border-bottom: 1px solid var(--border); font-weight: 700;
}
.m-group a:hover { text-decoration: underline; }
.m-row {
  display: grid; grid-template-columns: 28px 128px minmax(0, 1fr) 88px auto; gap: 12px; align-items: center;
  padding: 8px; border-bottom: 1px solid var(--border);
}
.m-row:hover { background: var(--bg-2); }
.m-row.selected { background: var(--bg-3); }
.m-row.is-hidden .thumb, .m-row.is-hidden .m-main { opacity: .5; }
.m-row .thumb { border-radius: 8px; }
.m-main { display: grid; gap: 2px; min-width: 0; }
.m-check { display: grid; place-items: center; cursor: pointer; }
.m-check input { width: 18px; height: 18px; cursor: pointer; }
.status-toggle {
  border: none; border-radius: 14px; padding: 5px 0; cursor: pointer; font-weight: 700; font-size: 12px;
}
.status-toggle.on { background: var(--subject-1-bg); color: var(--subject-1); }
.status-toggle.off { background: var(--bg-3); color: var(--text-2); }
.status-toggle.on::before { content: "● "; }
.status-toggle.off::before { content: "○ "; }

/* 編集ダイアログ */
dialog.editor {
  width: min(920px, calc(100vw - 32px)); max-height: calc(100vh - 32px);
  padding: 20px; border: none; border-radius: 16px;
  background: var(--bg); color: var(--text); box-shadow: 0 20px 60px rgba(0,0,0,.35);
}
dialog.editor::backdrop { background: rgba(0,0,0,.5); }
.editor-head { display: flex; justify-content: space-between; align-items: center; }
.editor-head h2 { margin: 0; font-size: 18px; }
.editor-grid { display: grid; grid-template-columns: minmax(0, 1fr) 280px; gap: 20px; align-items: start; }
.editor .ed-current { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; border-radius: 8px; background: var(--bg-2); display: block; }
.editor-foot { display: flex; gap: 8px; align-items: center; }
.switch-row {
  display: flex !important; flex-direction: row; gap: 10px; align-items: flex-start;
  padding: 10px 12px; border-radius: 10px; background: var(--bg-2); cursor: pointer; font-weight: 400 !important;
}
.switch-row input { width: 18px; height: 18px; margin-top: 2px; flex-shrink: 0; }

/* 非公開の動画を教員が見ているときの表示 */
.hidden-banner {
  margin-top: 12px; padding: 10px 14px; border-radius: 10px;
  background: var(--subject-2-bg); color: var(--subject-2); font-weight: 600;
}

/* ---------- 再生ページ ---------- */
.watch { display: grid; grid-template-columns: minmax(0, 1fr) 400px; gap: 24px; max-width: 1760px; margin: 0 auto; padding: 24px; }
.player {
  width: 100%; aspect-ratio: 16 / 9; background: #000;
  border-radius: var(--radius); display: block;
}
.watch-title { font-size: 20px; font-weight: 700; margin: 12px 0 8px; }
.watch-bar { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px; }
.speed { display: flex; gap: 4px; align-items: center; color: var(--text-2); font-size: 13px; }
.speed button { padding: 4px 10px; border-radius: 14px; border: none; background: var(--bg-2); cursor: pointer; font-size: 13px; }
.speed button.active { background: var(--text); color: var(--bg); }
.desc {
  margin-top: 12px; padding: 12px; border-radius: var(--radius);
  background: var(--bg-2); white-space: pre-wrap; word-break: break-word;
}
.desc .stats { font-weight: 600; margin-bottom: 4px; }
.desc a { color: var(--accent); }
.desc a.ts { cursor: pointer; }
.related { display: flex; flex-direction: column; gap: 8px; }
.related .card { flex-direction: row; gap: 8px; }
.related .thumb { width: 168px; flex-shrink: 0; border-radius: 8px; }
.related .card-title { font-size: 14px; }
.related .card-meta { font-size: 12px; }
.related h3 { margin: 0 0 4px; font-size: 16px; }

/* ---------- フォーム ---------- */
.panel { max-width: 960px; margin: 24px auto; padding: 0 16px; }
.panel h1 { font-size: 22px; margin: 0 0 16px; }
.form { display: grid; gap: 14px; }
.form label { display: grid; gap: 4px; font-weight: 600; font-size: 13px; }
.form .hint { font-weight: 400; color: var(--text-2); font-size: 12px; }
.input {
  width: 100%; padding: 10px 12px;
  border: 1px solid var(--border); border-radius: 8px; background: var(--bg);
}
.input:focus { outline: 2px solid var(--accent); outline-offset: -1px; border-color: transparent; }
textarea.input { min-height: 140px; resize: vertical; }
.row2 { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.drop {
  display: grid; place-items: center; gap: 8px; text-align: center;
  padding: 48px 16px; border: 2px dashed var(--border); border-radius: var(--radius);
  color: var(--text-2); cursor: pointer;
}
.drop.drag { border-color: var(--accent); background: var(--bg-2); }
.upload-grid { display: grid; grid-template-columns: 1fr 320px; gap: 24px; align-items: start; }
.thumb-picker { display: grid; gap: 8px; }
.thumb-picker canvas { width: 100%; aspect-ratio: 16 / 9; border-radius: 8px; background: var(--bg-2); }
.meter { height: 8px; border-radius: 4px; background: var(--bg-2); overflow: hidden; }
.meter > div { height: 100%; width: 0; background: var(--accent); transition: width .2s; }
.error { color: var(--danger); font-size: 13px; }

/* ---------- ログイン ---------- */
.login-wrap { min-height: 100vh; display: grid; place-items: center; padding: 16px; }
.login-card {
  width: 100%; max-width: 380px; padding: 32px 28px;
  border: 1px solid var(--border); border-radius: 16px;
}
.login-card .logo { justify-content: center; font-size: 30px; margin-bottom: 24px; }
.tabs { display: grid; grid-template-columns: 1fr 1fr; background: var(--bg-2); border-radius: 10px; padding: 4px; margin-bottom: 20px; }
.tabs button { padding: 8px; border: none; border-radius: 8px; background: none; cursor: pointer; font-weight: 600; color: var(--text-2); }
.tabs button.active { background: var(--bg); color: var(--text); box-shadow: 0 1px 3px rgba(0,0,0,.15); }

/* ---------- レスポンシブ ---------- */
@media (max-width: 1000px) {
  .watch { grid-template-columns: 1fr; padding: 0 0 24px; }
  .watch > .primary > :not(.player) { margin-left: 16px; margin-right: 16px; }
  .player { border-radius: 0; }
  .watch > aside { padding: 0 16px; }
  .upload-grid { grid-template-columns: 1fr; }
  .pl-page { grid-template-columns: 1fr; padding: 16px; }
  .pl-hero { position: static; }
  .common-bar { grid-template-columns: 1fr 1fr; }
  .q-item { grid-template-columns: 1fr; }
  .q-thumb { max-width: 240px; }
  .q-side { justify-items: start; }
  .q-fields { grid-template-columns: 1fr 1fr; }
  .m-filters { grid-template-columns: 1fr 1fr; }
  .m-filters #f-q { grid-column: 1 / -1; }
  .editor-grid { grid-template-columns: 1fr; }
}
@media (max-width: 640px) {
  .header { gap: 8px; padding: 0 12px; }
  .logo-text, .user-chip { display: none; }
  .main { padding: 12px 16px 40px; }
  .grid { grid-template-columns: 1fr; }
  .row2 { grid-template-columns: 1fr; }
  .related .thumb { width: 140px; }
  .pl-row { grid-template-columns: 24px 120px minmax(0, 1fr); }
  .m-row { grid-template-columns: 24px 96px minmax(0, 1fr); }
  .m-row .status-toggle, .m-row [data-edit] { grid-column: span 1; }
  .m-row .status-toggle { grid-column: 2; padding: 5px 10px; }
  .m-row [data-edit] { grid-column: 3; justify-self: start; }
}