/* vc - deliberately plain. One accent, one mono stack, no chrome that doesn't
   carry information. Light palette is the base; dark overrides only tokens. */
:root {
  --bg: #fbfbfa;
  --panel: #ffffff;
  --border: #e2e1dd;
  --border-strong: #cfcec8;
  --fg: #1a1a18;
  --muted: #6b6b64;
  --faint: #94948c;
  --accent: #1d6feb;
  --accent-soft: #e8f0fe;
  --easy: #1a7f52;
  --medium: #9a6200;
  --hard: #b3261e;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, monospace;
  --sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  --radius: 6px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #121213; --panel: #191a1b; --border: #2a2b2d; --border-strong: #3a3b3e;
    --fg: #e8e8e4; --muted: #9a9a93; --faint: #6d6d68;
    --accent: #5b9dff; --accent-soft: #16243c;
    --easy: #4ec38a; --medium: #e0a53c; --hard: #f0736a;
  }
}
:root[data-theme="dark"] {
  --bg: #121213; --panel: #191a1b; --border: #2a2b2d; --border-strong: #3a3b3e;
  --fg: #e8e8e4; --muted: #9a9a93; --faint: #6d6d68;
  --accent: #5b9dff; --accent-soft: #16243c;
  --easy: #4ec38a; --medium: #e0a53c; --hard: #f0736a;
}

* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); font-family: var(--sans); font-size: 14px; line-height: 1.5; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code, kbd, .mono { font-family: var(--mono); }
kbd {
  font-size: 11px; padding: 1px 5px; border: 1px solid var(--border-strong);
  border-bottom-width: 2px; border-radius: 4px; background: var(--panel); color: var(--muted);
}
.wrap { max-width: 1180px; margin: 0 auto; padding: 0 20px; }

/* ---------------------------------------------------------------- header */
header.top { border-bottom: 1px solid var(--border); background: var(--panel); }
.top-inner { display: flex; align-items: baseline; gap: 14px; padding: 14px 20px; max-width: 1180px; margin: 0 auto; }
.brand { font-family: var(--mono); font-weight: 600; font-size: 16px; color: var(--fg); letter-spacing: -0.3px; }
.brand span { color: var(--accent); }
.tagline { color: var(--muted); font-size: 13px; }
.top-spacer { flex: 1; }
.top-link { color: var(--muted); font-size: 13px; }
.top-link:hover { color: var(--fg); }

/* ----------------------------------------------------------------- hero */
.hero { padding: 34px 0 22px; border-bottom: 1px solid var(--border); }
.hero h1 { margin: 0 0 6px; font-size: 26px; letter-spacing: -0.5px; }
.hero p { margin: 0 0 16px; color: var(--muted); max-width: 62ch; }
.hero-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.btn {
  font: inherit; padding: 7px 14px; border-radius: var(--radius); cursor: pointer;
  border: 1px solid var(--border-strong); background: var(--panel); color: var(--fg);
}
.btn:hover { border-color: var(--accent); color: var(--accent); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { opacity: 0.9; color: #fff; }
.btn.small { padding: 4px 9px; font-size: 12px; }

/* --------------------------------------------------------------- filters */
.filters { padding: 16px 0; display: grid; gap: 10px; }
.filter-row { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.filter-label { font-size: 12px; color: var(--faint); text-transform: uppercase; letter-spacing: 0.5px; min-width: 62px; }
input[type="text"], input[type="number"], select {
  font: inherit; padding: 6px 9px; border: 1px solid var(--border-strong);
  border-radius: var(--radius); background: var(--panel); color: var(--fg);
}
input:focus, select:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
#search { flex: 1; min-width: 220px; font-family: var(--mono); }
input[type="number"] { width: 88px; }
.chip {
  font: inherit; font-size: 12px; padding: 4px 10px; border-radius: 999px; cursor: pointer;
  border: 1px solid var(--border-strong); background: transparent; color: var(--muted);
}
.chip:hover { color: var(--fg); border-color: var(--fg); }
.chip.on { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.chip .count { opacity: 0.6; margin-left: 4px; font-size: 11px; }
.tagbox { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }
.tag-active {
  font-size: 12px; font-family: var(--mono); padding: 3px 8px; border-radius: 4px;
  background: var(--accent-soft); color: var(--accent); cursor: pointer; border: 1px solid var(--accent);
}

/* ----------------------------------------------------------------- table */
.meta-line { display: flex; align-items: center; gap: 12px; color: var(--muted); font-size: 12px; padding: 4px 0 8px; }
.meta-line .spacer { flex: 1; }
table { width: 100%; border-collapse: collapse; font-size: 13px; }
thead th {
  text-align: left; font-weight: 600; font-size: 11px; text-transform: uppercase;
  letter-spacing: 0.5px; color: var(--faint); padding: 8px 10px;
  border-bottom: 1px solid var(--border-strong); white-space: nowrap; user-select: none;
}
thead th.sortable { cursor: pointer; }
thead th.sortable:hover { color: var(--fg); }
thead th .arrow { color: var(--accent); }
tbody tr { border-bottom: 1px solid var(--border); }
tbody tr:hover { background: var(--panel); }
tbody tr.cursor { background: var(--accent-soft); box-shadow: inset 2px 0 0 var(--accent); }
tbody td { padding: 7px 10px; vertical-align: top; }
td.id { font-family: var(--mono); color: var(--muted); white-space: nowrap; }
td.title a { color: var(--fg); font-weight: 500; }
td.title a:hover { color: var(--accent); }
td.num { font-family: var(--mono); text-align: right; color: var(--muted); white-space: nowrap; }
td.tags { color: var(--faint); font-size: 12px; }
td.tags button {
  font: inherit; font-size: 11px; border: 0; background: none; color: var(--faint);
  cursor: pointer; padding: 0 4px 0 0; font-family: var(--mono);
}
td.tags button:hover { color: var(--accent); }
.diff { font-family: var(--mono); font-size: 12px; font-weight: 600; }
.diff.Easy { color: var(--easy); } .diff.Medium { color: var(--medium); } .diff.Hard { color: var(--hard); }
.src { font-family: var(--mono); font-size: 11px; color: var(--faint); text-transform: uppercase; }
.pager { display: flex; gap: 8px; align-items: center; justify-content: center; padding: 18px 0 40px; color: var(--muted); font-size: 13px; }
.empty { padding: 50px 0; text-align: center; color: var(--muted); }

/* --------------------------------------------------------- problem view */
.problem { display: grid; grid-template-columns: minmax(0, 1fr) 380px; gap: 24px; padding: 20px 0 60px; align-items: start; }
@media (max-width: 940px) { .problem { grid-template-columns: minmax(0, 1fr); } }
.back { font-size: 13px; color: var(--muted); display: inline-block; padding: 14px 0 0; }
.problem h1 { margin: 6px 0 8px; font-size: 22px; letter-spacing: -0.3px; }
.pmeta { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; color: var(--muted); font-size: 12px; margin-bottom: 14px; }
.statement {
  white-space: pre-wrap; font-family: var(--mono); font-size: 13px; line-height: 1.65;
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px; overflow-x: auto; max-height: 62vh; overflow-y: auto;
}
.card { background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px; margin-bottom: 16px; }
.card h2 { margin: 0 0 10px; font-size: 12px; text-transform: uppercase; letter-spacing: 0.6px; color: var(--faint); font-weight: 600; }
.cmd {
  display: flex; align-items: center; gap: 8px; font-family: var(--mono); font-size: 12.5px;
  background: var(--bg); border: 1px solid var(--border); border-radius: 4px; padding: 7px 9px;
}
.cmd span { flex: 1; overflow-x: auto; white-space: nowrap; }

/* ------------------------------------------------------------------- bob */
.bob-log { display: flex; flex-direction: column; gap: 10px; max-height: 46vh; overflow-y: auto; margin-bottom: 10px; }
.msg { font-size: 13px; line-height: 1.55; }
.msg .who { font-family: var(--mono); font-size: 11px; color: var(--faint); text-transform: uppercase; letter-spacing: 0.5px; }
.msg.bob .who { color: var(--accent); }
.msg .body { white-space: pre-wrap; word-break: break-word; }
.msg .body pre {
  background: var(--bg); border: 1px solid var(--border); border-radius: 4px;
  padding: 9px; overflow-x: auto; font-size: 12px; margin: 6px 0; white-space: pre;
}
.msg .body code { background: var(--bg); padding: 1px 4px; border-radius: 3px; font-size: 12px; }
.bob-input { display: flex; gap: 6px; }
.bob-input input { flex: 1; }
.bob-hints { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 10px; }
.notice { font-size: 12px; color: var(--medium); background: var(--panel); border: 1px dashed var(--border-strong); border-radius: 4px; padding: 8px; }
.verdict { font-family: var(--mono); font-weight: 600; font-size: 12px; }
.verdict.ok { color: var(--easy); } .verdict.bad { color: var(--hard); } .verdict.meh { color: var(--medium); }
.sub { border-top: 1px solid var(--border); padding: 8px 0; font-size: 12.5px; }
.sub:first-of-type { border-top: 0; }
.sub .when { color: var(--faint); font-size: 11px; font-family: var(--mono); }
.foot { border-top: 1px solid var(--border); color: var(--faint); font-size: 12px; padding: 16px 0 30px; }

/* ------------------------------------------------------------ install line */
.hero-install { display: flex; align-items: center; gap: 12px; margin-top: 18px; flex-wrap: wrap; }
.hero-install-label { font-size: 12px; color: var(--faint); text-transform: uppercase; letter-spacing: 0.5px; }
.hero-install .cmd { min-width: min(460px, 100%); }
.cmd-note { font-style: normal; font-size: 11px; color: var(--faint); white-space: nowrap; }

/* ------------------------------------------------------------- doc pages */
.doc-wrap { max-width: 74ch; padding: 10px 0 70px; }
.doc-wrap h1 { font-size: 26px; letter-spacing: -0.5px; margin: 8px 0 6px; }
.doc-wrap .lede { color: var(--muted); font-size: 15px; margin: 0 0 18px; }
.doc-wrap .fineprint { color: var(--faint); font-size: 12.5px; margin: 8px 0 0; }
.doc { border-top: 1px solid var(--border); margin-top: 26px; padding-top: 18px; }
.doc h2 { font-size: 13px; text-transform: uppercase; letter-spacing: 0.6px; color: var(--faint); margin: 0 0 10px; }
.doc p { margin: 0 0 12px; }
.doc .cmd { margin-bottom: 8px; }
pre.sample {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px; overflow-x: auto; font-family: var(--mono); font-size: 12.5px;
  line-height: 1.6; margin: 4px 0 0;
}
.keytable td { padding: 6px 10px 6px 0; vertical-align: top; }
.keytable td:first-child { white-space: nowrap; }
.keytable th { padding-bottom: 6px; }