:root {
  --bg: #0d1117; --panel: #161b22; --panel2: #1c2330; --border: #2d3644;
  --text: #e6edf3; --muted: #8b949e; --accent: #3fb950; --accent2: #58a6ff;
  --easy: #3fb950; --medium: #d29922; --hard: #f85149; --purple: #d2a8ff;
  --radius: 10px;
}
* { box-sizing: border-box; }
html, body { margin: 0; background: var(--bg); color: var(--text);
  font: 15px/1.5 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
a { color: var(--accent2); text-decoration: none; }
a:hover { text-decoration: underline; }
code { font-family: ui-monospace, "JetBrains Mono", Menlo, monospace; background: var(--panel2);
  padding: 1px 6px; border-radius: 4px; word-break: break-all; }
h1 { margin: 0 0 16px; font-size: 1.7rem; }
h2 { margin: 0 0 12px; font-size: 1.2rem; }

.topbar { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px;
  padding: 12px 24px; background: var(--panel); border-bottom: 1px solid var(--border); }
.brand { font-weight: 800; font-size: 1.3rem; color: var(--text); letter-spacing: .04em; }
.brand small { font-weight: 400; color: var(--muted); font-size: .8rem; letter-spacing: 0; margin-left: 6px; }
.brand .flag { color: var(--accent); }
.topbar nav { display: flex; gap: 18px; align-items: center; flex-wrap: wrap; }
.topbar nav a { color: var(--text); }
.admin-link { color: var(--medium) !important; }
.announcement { background: #1f2d1f; border-bottom: 1px solid #2e4a2e; padding: 10px 24px; }

main { max-width: 1100px; margin: 0 auto; padding: 24px 16px 48px; }
footer { text-align: center; color: var(--muted); font-size: .85rem; padding: 24px; }

.card { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 20px 24px; margin-bottom: 20px; }
.card.narrow { max-width: 420px; margin: 40px auto; }
.card.medium { max-width: 680px; margin: 24px auto; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.warn { color: var(--medium); }
.ok { color: var(--accent); }
.bad { color: var(--hard); }

form label { display: block; margin-bottom: 14px; color: var(--muted); font-size: .9rem; }
input, select, textarea { display: block; width: 100%; margin-top: 4px; padding: 9px 11px; font: inherit;
  color: var(--text); background: var(--bg); border: 1px solid var(--border); border-radius: 6px; }
input:focus, select:focus, textarea:focus { outline: 2px solid var(--accent2); outline-offset: -1px; }
input[type=checkbox], input[type=radio] { display: inline; width: auto; margin: 0 6px 0 0; }
label.check { color: var(--text); display: flex; align-items: center; }
form.inline { display: inline; }
.btn { display: inline-block; padding: 9px 18px; border: 0; border-radius: 6px; cursor: pointer; font: inherit;
  font-weight: 600; background: var(--accent); color: #04110a; }
.btn:hover { filter: brightness(1.1); text-decoration: none; }
.btn-danger { background: var(--hard); color: #fff; }
.linkish { background: none; border: 0; padding: 0; color: var(--accent2); font: inherit; cursor: pointer; }
.linkish:hover { text-decoration: underline; }
.danger { color: var(--hard); }
.danger-zone { border-color: #5a2a2a; }

.grid-form { display: grid; grid-template-columns: 1fr 1fr; gap: 0 18px; }
.grid-form .span2, .grid-form textarea { grid-column: span 2; }
.grid-form .btn { justify-self: start; }
.checks { display: flex; gap: 22px; flex-wrap: wrap; margin-bottom: 14px; }
.row-form { display: flex; gap: 12px; align-items: center; }
.row-form input { margin: 0; }
@media (max-width: 640px) { .grid-form { grid-template-columns: 1fr; } .grid-form .span2 { grid-column: span 1; } }

.flash { padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; border: 1px solid; }
.flash-success { background: #12261a; border-color: #2e6b3f; }
.flash-error { background: #2a1416; border-color: #7a2d33; }
.flash-info { background: #121f2e; border-color: #2b4d75; }

.question { border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 18px; margin: 0 0 16px; }
.question legend { font-weight: 600; padding: 0 6px; }
.question p { margin: 0 0 10px; }
.choices { display: flex; gap: 12px; }
.choice { flex: 1; margin: 0; }
.choice input { position: absolute; opacity: 0; }
.choice span { display: block; text-align: center; padding: 10px; border: 1px solid var(--border);
  border-radius: 8px; cursor: pointer; color: var(--text); font-weight: 600; }
.choice input:checked + span { border-color: var(--accent); background: #12261a; color: var(--accent); }
.choice input:focus-visible + span { outline: 2px solid var(--accent2); }
.answers { padding-left: 18px; }

.page-head { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 12px; margin-bottom: 12px; }
.page-head h1 { margin: 0; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; }
.tabs a { padding: 6px 12px; border-radius: 6px; color: var(--muted); border: 1px solid transparent; }
.tabs a.active { color: var(--text); background: var(--panel2); border-color: var(--border); }
.admin-tabs { margin-bottom: 18px; }

.tier-pill { display: inline-block; padding: 4px 12px; border-radius: 999px; font-weight: 600; font-size: .9rem;
  background: var(--panel2); border: 1px solid var(--border); }
.tier-pill.small { padding: 1px 9px; font-size: .78rem; }
.tier-fresh { color: var(--easy); border-color: #2e6b3f; }
.tier-copilot { color: var(--accent2); border-color: #2b4d75; }
.tier-barehands { color: var(--medium); border-color: #6b5520; }
.tier-cyborg { color: var(--purple); border-color: #5b4280; }

.badge { display: inline-block; padding: 0 7px; border-radius: 4px; font-size: .75rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: .04em; background: var(--panel2); color: var(--muted); margin-right: 4px; }
.badge-easy { color: var(--easy); }
.badge-medium { color: var(--medium); }
.badge-hard { color: var(--hard); }

.category { margin-top: 26px; }
.category h2 { border-bottom: 1px solid var(--border); padding-bottom: 6px; }
.welcome { position: relative; background: var(--panel); border: 1px solid var(--border);
  border-left: 4px solid var(--accent); border-radius: var(--radius); padding: 16px 44px 16px 20px; margin: 0 0 20px; }
.welcome h2 { margin: 0 0 8px; }
.welcome p { margin: 8px 0; color: var(--text); }
.welcome .welcome-sign { color: var(--muted); font-style: italic; margin-bottom: 0; }
.welcome .flagfmt { margin: 10px 0; }
/* Keep the flag format on its own line as a single unit (override the global
   code { word-break: break-all }) so it never wraps mid-token. */
.welcome .flagfmt code { white-space: nowrap; word-break: normal; font-size: 1.05rem; }
.welcome .tier-pill { font-size: .85rem; vertical-align: baseline; }
.welcome-x { position: absolute; top: 10px; right: 12px; background: none; border: none; color: var(--muted);
  font-size: 1.4rem; line-height: 1; cursor: pointer; padding: 2px 6px; }
.welcome-x:hover { color: var(--text); }

.chall-grid { display: grid; gap: 10px; }
.chall { background: var(--panel); border: 1px solid var(--border); border-left: 4px solid var(--border); border-radius: 8px; }
.chall.diff-easy { border-left-color: var(--easy); }
.chall.diff-medium { border-left-color: var(--medium); }
.chall.diff-hard { border-left-color: var(--hard); }
.chall.solved { opacity: .75; }
/* Suggested-for-you highlight: a purple glow + accent, independent of the
   difficulty colour on the left edge. */
.chall.suggested { border-color: var(--purple); box-shadow: 0 0 0 1px var(--purple), 0 0 14px -4px var(--purple); background: linear-gradient(90deg, rgba(210,168,255,.07), transparent 60%); }
.chall.suggested.solved { box-shadow: none; }
.badge-suggested { color: #12121a; background: var(--purple); border-radius: 999px; padding: 1px 9px; }
.suggested-legend { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.chall summary { display: flex; justify-content: space-between; gap: 12px; padding: 12px 16px; cursor: pointer; list-style: none; }
.chall summary::-webkit-details-marker { display: none; }
.chall-title { font-weight: 600; }
.chall.solved .chall-title { color: var(--accent); }
.points { font-weight: 700; margin-left: 6px; }
.chall-body { padding: 0 16px 14px; border-top: 1px solid var(--border); }
.desc { white-space: pre-wrap; margin: 12px 0; }
.files { padding-left: 18px; }
.flag-form { display: flex; gap: 10px; }
.flag-form input { margin: 0; font-family: ui-monospace, Menlo, monospace; }
.solved-note { color: var(--accent); font-weight: 600; }

.table { width: 100%; border-collapse: collapse; }
.table th, .table td { padding: 8px 10px; border-bottom: 1px solid var(--border); text-align: left; vertical-align: top; }
.table th { color: var(--muted); font-weight: 600; font-size: .85rem; }
.table .num { text-align: right; }
.table tr.me td { background: #12261a; }
.actions { white-space: nowrap; }
.actions form + form::before { content: " · "; color: var(--muted); }
.rejected { text-align: center; border-color: #7a2d33; }
.rejected .big { font-size: 1.25rem; }
.badge-override { color: var(--accent2); }
.audience { border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin: 0 0 14px; }
.audience legend { color: var(--muted); font-size: .9rem; padding: 0 4px; }
.audience label.check { margin-bottom: 6px; }
.checks.indent { margin: 0 0 0 26px; }