/* 小學數學網頁管理器 — blocky utilitarian admin style */
* { box-sizing: border-box; margin: 0; padding: 0; }
:root {
  --bg: #f4f4f4;
  --panel: #fff;
  --line: #111;
  --accent: #1a4fa0;
  --muted: #666;
  --good: #1a7a1a;
  --bad: #b00;
}
html { font-family: -apple-system, "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", sans-serif; }
body { background: var(--bg); color: #111; font-size: 15px; line-height: 1.5; }
a { color: var(--accent); }
button, .btn { font-family: inherit; font-size: 14px; background: var(--line); color: #fff; border: 0; padding: 8px 14px; cursor: pointer; }
button:hover, .btn:hover { background: var(--accent); }
button.danger { background: var(--bad); }
button.danger:hover { background: #800; }
input[type=text], input[type=password], input[type=file] { font-family: inherit; font-size: 15px; border: 2px solid var(--line); padding: 7px 9px; width: 100%; }
.topbar { background: var(--line); color: #fff; padding: 10px 16px; display: flex; justify-content: space-between; align-items: center; }
.topbar h1 { font-size: 16px; font-weight: 700; }
.topbar form { display: inline; }
.topbar button { background: #333; }
.wrap { max-width: 1100px; margin: 0 auto; padding: 16px; }
.panel { background: var(--panel); border: 2px solid var(--line); margin-bottom: 16px; }
.panel > h2 { background: var(--line); color: #fff; padding: 8px 12px; font-size: 15px; }
.panel-body { padding: 12px; }
.login-box { max-width: 360px; margin: 40px auto; }
.label { display: block; font-weight: 700; margin: 10px 0 4px; }
.tree { list-style: none; }
.tree-cat { font-weight: 700; margin: 10px 0 4px; padding: 6px 10px; background: #d9d9d9; border-left: 6px solid var(--line); }
.tree-class { margin: 0 0 12px; }
.tree-class-head { font-weight: 700; padding: 8px 10px; background: #eaeaea; display: flex; justify-content: space-between; align-items: center; border: 2px solid var(--line); border-bottom: 0; }
.tree-class-head .meta { font-size: 12px; font-weight: 400; }
.tree-pages { list-style: none; border: 2px solid var(--line); }
.tree-page { display: flex; align-items: center; gap: 10px; padding: 8px 10px; border-top: 1px solid #ccc; }
.tree-page:first-child { border-top: 0; }
.tree-page.current { background: #e3f0e3; font-weight: 700; }
.tree-page .title { flex: 1; }
.tree-page .title small { color: var(--muted); font-weight: 400; display: block; font-size: 12px; }
.preview-frame { border: 1px solid var(--line); width: 180px; height: 110px; pointer-events: none; background: #fff; }
.empty-page { padding: 8px 10px; color: var(--muted); border: 2px solid var(--line); border-top: 0; }
.tag { display: inline-block; font-size: 11px; padding: 1px 6px; background: var(--line); color: #fff; }
.tag.good { background: var(--good); }
.tag.muted { background: var(--muted); }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.muted { color: var(--muted); font-size: 13px; }
.err { color: var(--bad); font-weight: 700; }
.upload-row { display: flex; gap: 8px; align-items: center; padding: 8px 10px; background: #f0f0f0; border: 2px solid var(--line); border-top: 0; }
.upload-row input[type=file] { width: auto; flex: 1; }
.qr-img { border: 2px solid var(--line); background: #fff; }
.flash { padding: 8px 12px; margin-bottom: 12px; border: 2px solid; font-weight: 700; }
.flash.ok { border-color: var(--good); color: var(--good); background: #eef7ee; }
.flash.bad { border-color: var(--bad); color: var(--bad); background: #fdeeee; }