:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --success: #16a34a;
  --danger: #dc2626;
  --bg: #f6f8fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --radius: 10px;
}
* { box-sizing: border-box; }
body { margin: 0; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; background: var(--bg); color: var(--text); line-height: 1.55; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: 1080px; margin: 0 auto; padding: 0 16px; }
.site-header { background: var(--card); border-bottom: 1px solid var(--border); position: sticky; top: 0; z-index: 10; }
.header-inner { display: flex; align-items: center; gap: 18px; padding: 10px 16px; flex-wrap: wrap; }
.logo { font-size: 20px; font-weight: 800; color: var(--text); display: flex; align-items: center; gap: 8px; }
.logo:hover { text-decoration: none; }
.logo-mark { background: var(--primary); color: #fff; border-radius: 6px; padding: 2px 7px; font-size: 13px; }
.search-form { flex: 1; display: flex; min-width: 220px; }
.search-input { flex: 1; border: 1px solid var(--border); border-radius: 8px 0 0 8px; padding: 8px 12px; font-size: 15px; outline: none; }
.search-form .btn { border-radius: 0 8px 8px 0; }
.nav-links { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.nav-user { font-weight: 600; }
main { padding: 24px 16px 48px; min-height: 70vh; }
.btn { display: inline-block; border: 1px solid transparent; border-radius: 8px; padding: 8px 16px; font-size: 14px; cursor: pointer; text-align: center; }
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline { background: transparent; border-color: var(--primary); color: var(--primary); }
.btn-success { background: var(--success); color: #fff; font-weight: 700; letter-spacing: .3px; }
.btn-danger { background: var(--danger); color: #fff; }
.btn-lg { padding: 12px 26px; font-size: 16px; }
.btn-block { width: 100%; }
.linklike { background: none; border: none; color: var(--muted); cursor: pointer; font-size: 14px; padding: 0; }
.inline-form { display: inline; }
.hero { text-align: center; padding: 26px 0 10px; }
.hero h1 { margin: 0 0 6px; font-size: 30px; }
.hero p { color: var(--muted); margin: 0 0 16px; }
.hero-actions { display: flex; gap: 12px; justify-content: center; }
.tabs { display: flex; gap: 8px; margin: 18px 0; border-bottom: 2px solid var(--border); }
.tab { padding: 8px 14px; color: var(--muted); border-bottom: 2px solid transparent; margin-bottom: -2px; }
.tab.active { color: var(--primary); border-color: var(--primary); font-weight: 600; }
.doc-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 18px; }
.doc-card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; transition: box-shadow .15s; }
.doc-card:hover { box-shadow: 0 4px 14px rgba(0,0,0,.08); }
.doc-thumb img { width: 100%; aspect-ratio: 1; object-fit: cover; display: block; background: #eef2f7; }
.doc-title { font-size: 14px; margin: 8px 10px 2px; line-height: 1.35; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.doc-title a { color: var(--text); }
.doc-meta { font-size: 12px; color: var(--muted); margin: 0 10px 10px; }
.section-title { font-size: 20px; margin: 28px 0 12px; }
.page-title { font-size: 24px; margin: 8px 0 14px; }
.muted { color: var(--muted); font-size: 13px; }
.empty { color: var(--muted); padding: 18px 0; }
.breadcrumb { font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.doc-page { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 22px; }
.doc-page h1 { margin: 0 0 4px; font-size: 24px; }
.doc-sub { color: var(--muted); margin: 0 0 16px; font-size: 14px; }
.doc-actions { display: flex; gap: 14px; align-items: center; flex-wrap: wrap; margin-bottom: 16px; }
.viewer-frame iframe { width: 100%; height: 820px; border: 1px solid var(--border); border-radius: var(--radius); background: #fff; }
.share-box, .report-box { border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 16px; margin: 16px 0; }
.share-box summary, .report-box summary { cursor: pointer; font-weight: 600; }
.share-row { display: flex; gap: 10px; margin: 10px 0; flex-wrap: wrap; }
.doc-desc h3, .comments h3 { font-size: 18px; margin: 22px 0 8px; }
.comment { border-bottom: 1px solid var(--border); padding: 10px 0; }
.comment-head { display: flex; gap: 10px; align-items: baseline; }
.comment-body { white-space: pre-wrap; }
#comment-form textarea { margin-bottom: 8px; }
.form-msg { margin-left: 10px; font-size: 13px; }
.form-field { margin-bottom: 14px; }
.form-label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 4px; }
.form-input { width: 100%; border: 1px solid var(--border); border-radius: 8px; padding: 9px 12px; font-size: 14px; font-family: inherit; }
textarea.form-input { resize: vertical; }
.form-checkbox { display: flex; gap: 8px; align-items: flex-start; font-size: 13px; margin: 12px 0; }
.auth-box { max-width: 420px; margin: 30px auto; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 26px; }
.auth-alt { font-size: 14px; color: var(--muted); }
.alert { padding: 10px 14px; border-radius: 8px; }
.alert-error { background: #fee2e2; color: #991b1b; }
.upload-box { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; max-width: 640px; }
.upload-hint { color: var(--muted); font-size: 13px; }
.progress-track { height: 10px; background: var(--border); border-radius: 6px; overflow: hidden; margin: 14px 0 6px; }
.progress-bar { height: 100%; width: 0; background: var(--primary); transition: width .2s; }
.upload-status { font-size: 13px; color: var(--muted); min-height: 18px; }
#thumb-preview img { max-width: 220px; border: 1px solid var(--border); border-radius: 8px; margin: 10px 0; }
.tag-cloud { display: flex; flex-wrap: wrap; gap: 10px; }
.tag { background: var(--card); border: 1px solid var(--border); border-radius: 999px; padding: 6px 14px; font-size: 14px; color: var(--text); }
.tag:hover { border-color: var(--primary); color: var(--primary); text-decoration: none; }
.rank-list { list-style: none; padding: 0; }
.rank-row { background: var(--card); border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin-bottom: 8px; display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.rank-row a { flex: 1; min-width: 200px; font-weight: 600; color: var(--text); }
.rank { width: 26px; height: 26px; background: var(--primary); color: #fff; border-radius: 50%; display: inline-flex; align-items: center; justify-content: center; font-size: 13px; }
.pager { display: flex; gap: 14px; align-items: center; justify-content: center; margin: 22px 0; }
.pager-info { color: var(--muted); font-size: 14px; }
.center-box { max-width: 560px; margin: 40px auto; text-align: center; }
.site-footer { border-top: 1px solid var(--border); background: var(--card); padding: 22px 0; margin-top: 30px; }
.footer-links { display: flex; gap: 18px; justify-content: center; margin-bottom: 6px; flex-wrap: wrap; }
.footer-links a { color: var(--muted); font-size: 14px; }
.copyright { text-align: center; color: var(--muted); font-size: 13px; margin: 0; }
.admin-table { width: 100%; border-collapse: collapse; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); font-size: 14px; }
.admin-table th, .admin-table td { border-bottom: 1px solid var(--border); padding: 10px 12px; text-align: left; vertical-align: top; }
.admin-actions form { display: inline-block; margin-right: 6px; }
.embed-top { background: var(--primary); color: #fff; font-size: 12px; padding: 4px 10px; text-decoration: none; display: block; }
.embed-top:hover { color: #fff; }
@media (max-width: 720px) {
  .header-inner { gap: 10px; }
  .search-form { order: 3; flex-basis: 100%; }
  .viewer-frame iframe { height: 560px; }
}